INTERNATIONAL 
INSTITUTE OF 
TROPICAL 
AGRICUL TURE 
ANNUAL REPORT 
1989190 
. -
.~ 
-~ . ::::--.:::: 
- , 
IITA 
Annual Report 
1989/90 
Contents _________ _ 
Director General's Report 
Director General's 1989/90 Report 
Looking at the Bottom Li ne: Assessing liT A's Impact 
Research Highlights 
4 
II 
IITA/CIAT Research in Biological Control Wins the 1990 King Baudouin Award 17 
Inland Valley Farming Systems 20 
Decentralization to the Savanna 22 
Profiles from liT A's First Generation of Doctoral Fel lows 24 
IITA Today 
About IITA 
Resource and Crop Management 
Root, Tuber and Plantain Improvement 
Cassava in Africa 
Polyp lo idy - a cassava breeder's bo nanza? 
Props fo r progress: a better cassava sti ck 
Plantain 's reprieve from a black plague 
Grain Legume Improvement 
Maize Research 
Rice Research 
Biological Control 
Practice makes perfect: a new mealybug threat is contained 
International Cooperation 
Doubl e im pact in Cameroon 
Annex: graduate research fe llows and scholars 1989 
Information and Scientific Support Services 
Information Services 
Genet!c Resources 
Vi ro logy 
Biometrics 
Analytical Services 
Famn Management 
Annexes 
Financial Statements 1989 
The CGIAR 
Principal Staff 
Consultants 
Publications by liT A Staff 1989 
liT A Pu blications 1989 
28 
31 
41 
42 
43 
4S 
47 
51 
59 
66 
69 
72 
7S 
80 
83 
87 
87 
88 
89 
90 
9 1 
9 1 
94 
99 
100 
103 
104 
108 
Director General's Report 
3 
Director General's 
1989/90 Report 
4 
,
n my fifth and final report as Director General, I am pleased 
to announce that the liT A Board of T nustees recently 
elected a strong new leadership team for the Inst~ute. Dr. 
Nicholas Mumba, Pemranent Secretary, the Ministry of Agricul-
ture of Zambia, was elected the new Board Chairperson to 
succeed Mr. Luis Crouch. Dr. Lukas Brader, a distinguished 
science manager and currently Director of the FAO Plant 
Production and Protection Division, was elected the new 
Director General, effective December 1990. 
In this last report I will attempt to assess the current state of 
the Institute and ~ capacity to deal w~ the interrelated 
problems of malnutrition, poverty and sustainable agriculture in 
Africa. 
Twenty-three years ago, long before sustainability became a 
buming issue, the founders ofilT A had a vision of a new institute 
in tropical Africa explicitly dedicated to this specific issue. They 
charged liT A to develop sustainable agricultural systems that 
could replace the region's trad~ional bush-fallow, or slash-and-
bum, cultivation: while increasing the productivity of the key 
food crops in these systems. liT As mandate refiects both the 
essential difference and the critical link between the goals of 
feeding hungry people today and developing sustainable sys-
tems that will serve future generations. 
Our founders recognized that the major advances in agricul-
tural technology forthe temperate zones were not well suited 
to the resource-poor farmers of tropical Africa. To serve these 
people, liT A scientists had to recognize the divers~y of their 
farming conditions and to understand the crop production 
systems that they had developed over centuries or even 
millenia. 
liT A has received increasing recogn~ion forthe qual~ of its 
scientific achievement during the past five years. Scientific 
research is a long-term process, and I have been fortunate to be 
Director General during a period when research started well 
before my tenure is producing benefits for African famrers. One 
of the hallmarks of successful international agricultural research 
is the King Baudouin Award presented every two years by the 
Consultative Group on Intemational Agricultural Research 
(CGIAR). Within this year liT A will have received two ofthe last 
three King Baudouin Awards - the 1986 Award for the 
development of maize varieties resistant to the streak virus and 
the 1990 Award. WM Centro Intemacional de Agricultura 
Tropical (CIA T), forthe dramatically successful research on the 
biological control of the cassava mealybug. 
When I joined liT A five years ago, it seemed clear that the 
Institute could not continue this record of creativity unless it 
sharpened program focus, set priorities and developed a stra-
tegic framework for its research on sustainable agriculture. An 
extensive. participatory Strategic Planning Study was conducted 
during 1986-1987 that confimred liT A's commitment to sus-
tainable agriculture. while recommending maj0r::,Program changes 
toward that goal: (I) sharpened program focus, (2) integration 
of research into a systems approach, and (3) enhanced collabo-
ration with partners in national agricultural research systems. 
Sharpened Program Focus 
The four strategic elements of liT A's new program focus are: 
• The lowland humid and subhumid tropics of Africa 
• The smallholder or family famrer 
• Farming systems 
Major agroecological zones 
First, we narrowed our geographic concentration to the 
lowland humid and subhumid tropics of West and Central 
Africa, a vast area including more than 20 countries and over 40 
percent of the population of sub-Saharan Africa. W~h the 
temrination of liT A field projects in Asia, Latin America and the 
Caribbean -while our collaboration with regional and national 
research agencies on relevant research in those regions contin-
ues - our work is now clearly targeted on a region of acute 
need. This decision reduced diffusion of research effort without 
compromising IlTA's status as an intemational center. 
IITA's second element of program focus was on the small-
holder or family famrer. This policy represented a departure 
from the earlier assumption that the products of liT A research 
were scale neutral. While some of the technology generated at 
A Nigerian fa rmer harvests improved cassava tubers. 
liT A is of equal value to large and small fanms, we recognized that 
research must be designed specifically to enhance the produc-
tivity of the fanming systems used by A frican smallholders, Later 
I give examples of how this decision is affecting our research 
objectives. 
Most African fanmers are small -scale fanmers, using manual 
methods to grow complex mixtures of crops in traditional 
farming systems. Men and women, they are efficient in the use 
of available resources and responsive to incentives. These 
farmers are poor not because their holdings are small but 
because their farming systems frequently have low and declining 
productivity. With the right kind of support, they will adopt 
appropriate new technologies, produce the surpluses needed 
to feed Africa's growing population, and provide the foundation 
for broad-based economic growth. 
The thind element of focus involved a fundamental strategic 
decision to integrate liT A 's research on the basis of farming 
systems. Farming systems research is not new at liT A, but the 
liT A Strategic Plan defines a fresh approach. The philosophy 
behind this stems from the need to address the diffi cult issue of 
the design of appropriate technology. 
Farmers generally adopt technological change in a stepwise 
manner - one component at a time. Change in any component 
of the cropping system has, however, much wider implications 
than its immediate target For instance, introduction of a pest-
Gambia 
Guinea-
Bissau 
Mauritania 
" 
.,.:.----
resistant. high-yielding variety may accelerate soil fertility decline 
and increase inter-crop competition; or changes in planting 
dates may affect the availability of labor for other tasks such as 
weeding. The farmer is. of course, concerned with managing his 
whole cropping system and judges the Jalue of new technology 
by its contributions to the productivity df the system as a whole. 
The liT A scientist must therefore address the issue of 
technology development at the system level. This can only be 
done by tnuly interdisciplinary research - the inculcation of a 
systemat ic, interactive approach to research issues rightthrough 
from planning to implementation. For many researchers, trained 
in the classical reductionist disciplines of science, this involves a 
new way of approaching their wonk A commentator once 
likened liT A's organization to a series of independent columns 
that had evolved over 15 years without connecting links. We are 
now working to forge those links. The organizational changes to 
achieve this are described later in this report 
The fourth and last element of focus was on the major 
agroecological zones of the region, outlined on the map below. 
In the preparation of the Strategic Plan, it was clear that the 
major researchable issues varied significantly by agroecological 
zone - problems of specific pests and diseases and o f adapta-
t ion to the cropping systems of the region. Intemational re-
search was required because the environments cut across many 
countries, some of which are too small and poor to mount 
effective research on their range of priority problems. 
Niger 
--
Chad 
Sudan 
-,-
Equatorial ",u"ne,._, 
Uganda 
Agroecological Zones Of West And Central Africa 
o 
L>. 
Humid Forest 
Forest-Savanna Transition 
Moist Savanna 
Dry Savanna 
Sahel 
UTA Headquarters 
UTA Research StatIons 
Angola 
" 
5 
6 
Accordingly, the decision was made to decentralize research 
to small stations in the key zones of West and Central Africa. In 
addition to liT A's headquarters station at Ibadan, in the transi-
tion zone between the forest and savanna, a research station 
was established in 1990 in the dry savanna of Nigeria for work 
on cowpeas in sorghum- and millet-based fanming systems. 
Another station is nearing completion in the humid forest zone 
of Cameroon, primarily for research on cassava and resource 
management involving agroforestry and fallow management 
systems. A third station is planned for the moist savanna for 
maize-based systems. In research on rice-based farming sys-
tems, we also recognize the distinct inland valley ecosystem 
which occurs in all ecological zones. 
Decentralization of liT A's research was a logical stage in the 
evolution of the Institute. In the first stage of liT A's history, it was 
apparent that commodity research could make the greatest 
contribution to sustainability by developing genmplasm resistant 
to major diseases for use by national systems. With access to 
genetically diverse genmplasm and sophisticated research sup-
port, the commodity scientists could do this work most effec-
tively at liT A headquarters. 
Moreover, they were notably successful in breeding resist-
ance to major pathogens - cassava bacterial blight and African 
mosaic disease, diseases of maize such as lowland rust and blight 
and the streak virus, rice blast and numerous cowpea pests and 
diseases. These successes were adopted over a large range of 
ecosystems in Africa. They provide stability of yield to these 
commodities, enabling present research to focus more on adap-
tation to diverse cropping systems in the major environments. 
Integration of Research into a Systems Approach 
The second theme of the strategic planning process was 
integration. liT A's organizational structure for research was 
revised to fonm three main thrusts, all of them integrated 
through their focus on the major agroecological zones of West 
and Central Africa. These thrusts are: 
• Resource management research - the study of the natural 
resource base in order to refine existing resource management 
technologies and devise new ones for the small-scale farmer. 
• Commodity improvement research - breeding ofimproved 
crop varieties to stabilize and increase smallholder productivity. 
• Crop management research - synthesis of products of re-
source management research and plant breeding into sustain-
able, productive cropping systems for the smallholder. 
Discussion is under way conceming the establishment of a 
fourth thrust. pest management research, that would draw 
upon liT A's resources in pest management. including the 
Biological Control Program, to fonm a new integrated pest 
management program. 
The long-standing challenge at liT A to inculcate a fanming 
systems orientation throughout the Institute has been noted. 
After considering various organizational alternatives to pro-
Resource 
Management 
Research Unit -
Systems-Based 
Working Groups 
t 
Commodity 
Improvement 
Research Programs 
Farming Systems Research 
t 
Small-Scale Farmer 
Diagram I. Integration of liT A Research Programs 
mote multidisciplinary collaboration, we adopted the simple 
innovation of inter-program, systems-based workng groups, 
each responsible for fanming systems research in one of the 
three major agroecological zones of the region: the humid 
forest, the moist savanna, and the inland valleys. Each mu~idis­
ciplinary group has a full-time economist and agronomist. as well 
as part-time member scientists from the commodity improve-
ment programs. This was a crucial new mechanism because. as 
shown in Diagram I, it integrated the work of liT A's commodity 
improvement and resource management scientists at the farm-
ing systems level. 
The workng groups are providing a validation function 
involving on-fanm testing of technologies generated by experi-
ment station research. an adaptive research function involving 
the adjustment of existing technology to a particular set of 
environmental condrtions. and a feedback function to scientists 
developing resource management technologies or breeding 
improved varieties. Through this process, liT A scientists are 
brought together in a common effort to understand major 
fanming systems and to produce new varieties and technologies 
for their improvement 
A start has been made in instrtutionalizing the environment 
in which scientists will change their behavior and accept new and 
unconventional objectves in their work. If successful , this 
reorientation will amount to a shift in the research paradigm at 
liT A. When discussed by the CGIAR in May, the donors agreed 
that the adoption of this research strategy must be recognized 
as risky because its productivity is still uncertain, but they urged 
liT A to persevere in this new directon because of the disap-
pointing impact which the conventional commodity-improve-
ment research paradigm has had in Africa. 
In planning th is integration, liT A had to detenmine the 
appropriate balance between research on resource manage-
ment and on breeding, recognizing that they both produce 
component technologies integrated through the fanming sys-
tems working groups. There is no conceptually correct or 
optimal balance beween them. Research on resource manage-
ment cannot be conducted in isolation from the crops to be 
grown with these resources, and vice versa. 
Moreover, there are significant differences between research 
on resource management and research on commodity im-
provement differences in research complexity, time horizon, 
extension potential, and relative importance among different 
agroecologlcal zones. Research breakthroughs that have the 
most immediate impact generally result from improved com-
modity varieties, but commodity research alone will not solve 
the sustainability problem. RecogniZing the need for balance in 
the research program, a decision was made in the strategic 
planning process to double the relative level of staffing for 
resource management research over five years, as shown in 
Table I . To prOVide a critical mass of scientists for commodity 
improvement research - while assuring that new technologies 
are appropriate for farming systems - a concurrent decision 
was made to reduce the scope of commodity improvement 
research from nine to SIX commodities. Research on sweet 
potatoes, rice and cocoyams is being phased out. 
Table I. Distribution of Core Scientists Among IITA Research 
Programs 
Tfpe of Research Actual 
1989 
Resource Managemert 16% 
Commodity Improvement 55% 
Crop Management H% 
------- --------
100% 
Enhanced Collaboration with National 
Agricultural Research Systems 
Actual :Jlan 
1990 1993 
2-1''£ 3L% 
4816 47!b 
2Wh 21% 
100% 100% 
The third theme Of the Strategic Plan was cooperation with 
national agricultural research systems. In 1987, the liT A Board 
ofT rustees upgraded the status of the Intemational Coopera-
tion Program by establishing the new position of Deputy 
Director General for Intemational Cooperation. This was fol-
lowed by extensive consuh:ations with tre leaders of Africa'l 
national systems to develop a strategic Jlan for inte'Tlatioral 
cooperation. with the objective of building partnerships with 
national systems to assist trem to strengthen their capability to 
use and generate technology to satisfy their own needs. 
Because liT A technology is of little use in countries which lack 
the capacity for effective collaboration, we have been encour-
aged by donors and by African govem ments to accept the 
responsibility to assist in building suel capac it,', to the extent 
that we have a comparative advantage and that such activity 
does not weaken our vitality as a research institute. Over a 
transition period of five to ten years, we are operating more 
downstream toward adaptive research thar"l would be custom-
arl for an Intemational center. We distinguish the requirements 
of national systems at different stages of their institutional 
development according to a conceptual framework that em-
phasizes the dynamic relationship required for IITA to meet 
their strategic needs. 
liT A's Strategic Plan proVided for new and revitalized mecha-
nisms for prorloting partnerships with national systems. I refer 
here to four of these mechanisms: networking, research liaison 
scientists, resident scientist teams and training. 
First. collaborative research 'letworks connect liT A with 
natior.al and regional agricultural institutions In Africa and 
beyond. to address specifiC Issues of common interest. Net-
works provide smaller countries, many of which are unable to 
mount comprehensive research and development programs, 
with forums for participation In agricultural progress. IITA acts 
as a catalyst in promoting and managing appropriate networks 
forthe tropical and subtropical regions of Africa. Because i1 is a 
major source of scientific research in the region, liT A often 
assumes the coordinating role during a network's early stages. 
IITA is presently coordinating four collaborative research 
networl<s: the Eastem and South em Afnca Root Crops Re-
search Network (ESARRN), the Cowpea and Maize Research 
Networks of the Semi-Arid Food Grains Research and Devel-
opment (SAFGRAD) ProJect. and the Alley Farming Network 
for Tropical Africa (AFNETA). In addition, IITA has actively 
encouraged the rationalization of research networks in the 
region, oarticularly across the franco phone and anglophone 
zones. 
The second mechanism is research I'aison scie1tists. We 
place high priority on deepening our understanding of the highly 
diverse national systems of West and Central Afnca. Research 
liaison scientists have been appointed, each to serle a group of 
countries by stL.dying their requirements and linking them to 
liT A ane other sources of technology and assistance. In the 
conduct of their research, liT A scientists continue their direct 
association with national scientists. The liaison scientists are 
responsible for coordinating such activities in each country and 
managing special cooperative projects within them. The goa! is 
to ensure that liT A partnerships with national systems are 
responsive to their own strategic needs and genuine cOllcems. 
The third mechanisrr is in-country resident scien':.ist teams. 
Overthe last decade, liT A has Invested over 300 scientist-years 
working within national programs of the region. thus giving us 
unique experience with these institutions and a comparative 
advantage n such collaborative activities. The objectives of 
resident scientists are to conduct adaptive research, thus 
feeding back information to IITA and other intemational cen-
ters, and to strengthen the capability of nationa programs to 
sustain such research without extemal assistance. This emphasis 
on building capaCity for adaptive research complements JSNAR"s 
role in Improving the management of research systems. Recent 
stucies confirm that national research leaders have very strong 
demand for this form of assistance. 
7 
8 
The fourth mechanism is training. Since 1971, liT A has 
trained almost 6,000 Africans. Although most of them have 
been technicians in group courses, more than 400 have been 
students conducting research for postgraduate degrees. We 
wock with liT A alumni who are rapidly moving into key positions 
of responsibility In Afncan national systems. In the long nun, 
training may be IITA's most enduring contribution to the 
solution of AfOca's food problems, and It IS being accorded 
higher priority than In the past. liT A has made significant changes 
by devoting more of its "core" or permanent resources to 
training, by increasingly decentralizing group training to national 
Institutes, by shifting emphasIs from group tralningto supporting 
graduate research, especially of Afncans at the M.5c. and the 
PhD. levels, and by increasing the proportion of women 
participants in training at all levels. 
Model for Sustainable Development 
With a mandate for research on sustainable agrccultural 
systemsforthe lowland tropics of Afnca, we feel a responsibility 
to attempt to conceptualize the role of research in realizing this 
objective, A simple model identifying the technology require-
ments at different stages of development has been a useful 
heuristic device for stimulating scientific discussion at liT A about 
how research can contribute to the efforts of smallholders to 
move from subsistence agriculture onto a path leading toward 
more productve and sustainable agriculture. In the following 
pages I describe thiS preliminary model as ~ applies ,n the humid 
forest agroecology of south-eastem Nigeria, the most densely 
populated region in sub-Saharan Africa. 
The indigenous farming systems which have evolved in the 
forest zone have remained productive because of cropping 
strategies which maintain and restore the soil's. productivity and 
reduce pest and weed problems ~ complex cropping pattems 
and sequences, mixtures of tree crops and annuals, home 
gardens and, most importantly, by the regrowth of natural 
vegetation dunng fallow penods of 5 to 20 years. Growing 
popuiation dens'lties and increased intens'lty of land use have 
caused fallows to be shortened to as few as 2 or 3 years, 
resulting in sharply declining soil productivity and increased 
pressure from weeds and pests. The regression line in Diagram 
2 shows the InVerse relationship between population density 
and the years of fallow in south-eastem Nigeria. 
Behind the statistics is the reality that traditional famning 
systems are being destabilized, forcing fanners to cultivate 
marginal lands or to destroy the forest reserves in a vicious circle 
of human and environmental impoverishment The secondary 
forest, previously sustained by long fallows, is beingtransfomned 
into bush that is less able to regenerate soil and provide 
traditional secondary benefits. Famners in densely populated 
villages must for the first time purchase fuelwood, others are 
intensifying their intercropping, adult males Without land are 
becoming increasingly common, and communal land ownership 
is giVing way to a commercialized system of individual rights to 
land tenure. A Nigerian geographer has concluded that "the 
shortage of food IS leading to a restructunng of the SOCIal 
organization on a new economic basis that is replacing tradi-
tional kinship relationships." South-eastem Nigeria may be a 
microcosm of the conditions that will prevail in more extensive 
rural areas of Africa in the future. 
T umlng to the conceptual model of sustainable agncultural 
development, Diagram 3 portrays three phases ofdevelopment 
of the farming system, from traditional to intermediate to 
market-oriented. Like many models, this IS a highly stylized 
simplification that raises as many questions as it answers, This is 
particularly true of the vertical axis showing that the output of 
the system proVides benefits in the form of increased short-run 
production, and/or greater sustainability. 
IITA's goal is to develop agncu~ural systems that are both 
productive and sustainable, By representing these benefits as 
a'tematives in the diagram. we acknowledge that there may 
ineVitably be trade-offs between short-nun productivity on the 
one hand and the conservation demands of sustainability on the 
other. In the high-populatlon-density region of south-eastem 
Nigeria. we can assume that the productive benefrts can be 
measured in terms of increased yield per area of desirable crops. 
The measure of sustalnabil~y is more complex, but the simplest 
approach is to equate it with stability of Yield. Increased predic-
tability of output from year to year represents a lowenng of risk 
for the farmer. It also creates a situation in which resource con-
servation, although not guaranteed, at least becomes possible. 
Sustainable development involves stabilization of both the 
environmental and the socioeconomic factors which influence 
famning systems. These operate at a variety of scales ~ ranging 
from the SOil fertility stresses Within a famner's field to the food 
and input pricing policies Imposed extemally. IITA scientists are 
working to develop operational strategies forthe measurement 
and management of sustainability. The issue is complex but 
depends in the first instance on a rigorous definition of the 
concepts ~ an aspect wh',ch we feel to be lacking from much 
Diagram 2, Relationship Between Population Density and 
Length of Fallow (Years) in Vii/ages of South-Eastern Nigeria 
7 
6 
5 
o 
o 
o 
o I 
o ~L_~-'--~--"--"---'---'---L.--L----'_'----JI ' 
o 200 400 60C 800 1000 1200 
Population Density (per sq km) 
of the burgeoning literature on the tOp'C. 
The horizontal axis of Diagram 3 shows examples of tech-
nologies that become relevant as the farmer moves from a 
traditional to a market-oriented system. Given the urgent need 
for marketable surpluses to feed urban populations, liT A's 
objective must be to advance fanmers toward sustainable food 
production systems that are increasingly commercialized and 
can make optimal use of higher levels of purchased inputs. 
Many national and intemational researchers in Africa have 
been working to produce Phase III technology characterized by 
high-input sole-crop packages that produce high yields on 
experiment stations. But the dramatic success of this "green-
nevolution" strategy in Asia has not been duplicated inthe forest 
zone of Africa because most fanTlers are in Phase I, the inputs 
ane not available and, most importantly, the packages do not fit 
in fanmers' complex, bush-fallow cropping systems. 
The bush-fallow rotation system characteristic of the forest 
zone has traditionally been a sustainable system compatible with 
the land-abundant situation. There is mounting concem in 
Africa, however, that sustainability IS threatened by rising popu-
laTIon densities. Ironically, part of the stress comes from use of 
improved crop varieties that increase nutrient removal without 
compensating soil amendments. 
liT A has been very successful in developing technologies that 
penn it more intensive cultivation by stabilizing output through 
Productivity andlor Sustainability 
of Farming System 
Phose II! 
Use of External Inputs 
reduced risks. Such stability arises from crop varieties resistant 
to pests and tolerant of adverse environmental factors; biologi-
cal approaches that aVOid the need for chemicals and work with 
nature to solve farlT'lers' problems; and technologies that 
protect output from postharvest loss. 
Assuming that the fanmers cou Id afford it the simple addition 
of fertilizer to the system might be thought sufficient to sustain 
production, thus penmittingthe smallholder to Jump over Phase 
II and enter Phase III. While that would be a short-tenm 
possibility to increase production, numerous examples from the 
humid tropics have shown that it is not a long-term solution. 
Diagram 4 illustrates this point with experimental data gathered 
over seven years of annual cropping without fallow at Ibadan, in 
the forest-savanna transition zone. The addition of fertilizer 
raises maize yields initially, but that is not sustainable. The soil IS 
rapidly degraded as organic matter is mineralized and nutnents 
are leached to depths beyond the reach of crops. The soil 
becomes increasingly acid, it loses structure, becomes com-
pacted, and in the worst case is itself eroded. 
Thus ~ is apparent that there can be no easy progress from 
Phase I to Phase III, even were the fanmer able to purchase and 
use extemal inputs. The key to the transition from what is 
essentially subsistence farming to market-oriented famling, 
using purchased inputs, lies in an understanding of the traditional 
system of shifting cultivation. and the restorative role of the 
natural fallow which sustained low levels of production in these 
fragile environments for centuries. 
I 
Diagram 3. JlTA Research 
Jnputs at Different Phases of 
SmaJlholder Development 
Phase II / Increased Internal Inputs 
Phose i / Decreased Risk 
--- ------
Phose I Phase f/ P/"1ase III 
Traditional Intermediate Market-Oriented 
UTA Pest Agroforestry Fertiiizer-Responsive 
Research Resistance Varieties 
Inputs 
Biological Varieties for Agncultural 
Control Irtercropplng Chemicals 
Postharvest Crop Mechanization 
Technologies Management 
9 
IQ 
J - , 
, 
, 
, 
I: 
o 
, 
, 
, 
, 
, 
With Fertilizer 
--
INithout Fertdlze~ 
Years of Continuous Cultiv<I(ion 
Diagram 4. Relationship Between Length of c"ntinuous 
Cultivation and Maize Yields at IITA, Ibadan 
The biological processes by which the vegetative fallow 
sustains production of food crops are now better understood. 
They include 
• Vegetative cover to minimize soil surface erosion 
• Recycling of nutrients from lower soil layers to the crop 
rooting zone 
• Increased input of nitrogen by fixation by leguminous trees 
or herbaceous species in the fa; low or cropping system 
• Organic matter accumulation at the sod surface and the 
consequent improverrent of biological activity. water infiltra-
tion, and moisture and nutrient retention 
liT A research in Phase II seeks technologies which integrate 
these intema biological processes into improved intercropping 
systems that enhance stability and increase producti'v'ity. 
Diagram 5 shows experimental results of maize production 
in alley farming systems at liT A. Alley farming has al' of the 
elements just described; it minimizes the trade-off betweer 
production and sustainabiiity inherent in traditional bush fallow. 
becaJse it merges the fallow and cropping cycles in time but 
separates them in space. Although alley farming has not yet beer 
adapted to the acid soils of the humid forest zone, it serves here 
as a model to demonstrate how it might be possible to increase 
cropping intensity and sustainabdity. 
The lower curve of Diagram 5 shows that resource-poor 
farmers can sustair, intermediate levels of procuction in an 
improved management system such as alley farming using 
intemal in Juts. But these systems face bioioglcallimlts that can 
be overcome only with modern extemalinputs.This is shown 
by the upper curve of ere diagram. The addition offertll,zerto 
the alley crop~ing system increased production without the 
destabilizing effects seen in the monocrops of Diagram 4, 
Alley cropping is only one so/utlon to the problems of the 
-_._------
J ~ 
-... --- .... 
With Fertilizer 
.. ------------
V\/ithout Fertil,zer 
o ______ ~ _______ ~ _________ L ___ ~ ____ _ 
Years of Continuous Cultivation 
Diagram 5. Sustainability of Maize Produaion in Alley Farming 
Systems at IITA, Ibadan 
resource-poor farmer, and may indeed only be applicable to a 
limited range of environments. Nonetheless the princip-Ies it 
embraces, as outlined in the previous paragraphs, are of general 
utility. IITA is developing a suite of altemative multi~species 
systems involving trees ard/or herbaceous legumes. 
In Phase III of the model, we recognize that extemal inputs 
are essential if farmers are to increase their output to the level 
shown in the upper curve. Farmers able to beneH from such 
technologies will be~hose who are increasingly ableto commer-
cialize their operations by selling surplus output and purchasing 
inputs. Theywill benefit from research. some of which is already 
"on the shelf," on the development of crop varieties that are 
more responsive to fertilizer and good management. and to 
simple and appropriate mechanization. 
Technology, of course, is only one of the inputs into agncul-
tural development, and the partial nature of thiS model must be 
emphasized. It is meant to show how technology inputs and the 
properties of the system change as the farmer moves from the 
dosed, intemally controlled traditional system to an open and 
more extema"y directed, markel-oriented system. The stages 
should not be considered mutually exclusive nor the trajectory 
linear. Stage III is most subject to destabilization because of its 
dependence on market forces, thus requiring continuing itera-
tion in land use management to optimize the efficiency of 
extemal inputs. 
Research for Sustainable Agriculture in the 
Forest Zone 
IITA has been successful in breeding resistance to major 
pathogens of food crops of the humid forest zone. Improve-
ments for Phase I that can be integrated relatively easily into 
existing farming systems are illustrated by liT A's research on 
cassava and plantains as I describe in the following paragraphs. 
IITA scientis:s realized major research breakthroughs on these 
Looking at the Bottom Line 
Assessing IITA's Impact 
Economists have clearly demonstrated 
that public investment in agricu~ural re-
search in Asia and Latin America has 
produced great benefrt:s, evidence that is 
important in sustaining the financial sup-
port required for successful research. 
With the exception of liT A's success in 
biological control of the cassava mealybug. 
however, there is limited quantitative 
evidence that research is producing simi-
lar dividends in Africa. 
We are frequently asked, "What is the 
impact of liT A's research?"- a question 
that is inevitably followed by " How do 
you know?" Understandably, people want 
to know whether IITA's improved agri-
cultural technology is increasing food 
production and improving the well-being 
particularly of the poor. 
The answers to these questions are 
complicated by the fact that liT A contrib-
utes intermediate products whose ben-
efits depend on the actions of others for 
their impact We conceive of liT A as a 
link in a chain (see diagram below) 
stretching from basic research laborato-
ries in the developed world, through the 
CGIARcentersto national research insti-
tutes, then extension agencies, and finally 
to our u~imatetarget. the African fanmer. 
No matter how well conceived, liT A 
technologies generally require adapta-
tion by national scientists to specific agro-
ecological environments. Impact can be 
restricted by weak linkages among na-
tional researchers, extension agencies and 
farmers which are beyond our control. 
liT A's program of activities also results 
in two indirect benefrts whose impact is 
even more difficult to measure. 
I. We helpto strengthen national agricul-
tural research agencies through our pro-
grams of training, networkng and resi-
dent scientist teams. We need to devise 
methodologies for measuring the impact 
from such activities on national institu-
tional development, which is critical to 
raising food production. 
2. We contribute to the advancement of 
basic scientific principles and methods. 
Some examples are the first classical biol-
ogical control program on a continental 
scale, the refinement of breeding tech-
niques which permit utilization of genetic 
diversity, and the conceptual approach to 
resource management research for sus-
tainable agriculture in the humid tropics. 
The bottom line is, of course, impact 
in fanmers' fields. Lack of reliable statistics 
on agricultural production in most Afri-
can countries, however, prevents us from 
conducting cost/benefit studies which can 
quantify the dimensions of the impact 
from research - such as have, in Asia and 
Latin America, shown impressive returns. 
In the absence of statistics, we have 
had to content ourselves wrth anecdotal 
reports from liT A scientists, testimony 
from collaborators in national programs 
and scattered surveys. However positive 
Chain of Collaboration to Produce Improved Agricukural Technology for Africa 
Advanced 
Laboratories 
Intemational 
Agricultural 
Research 
Centers 
National 
Agricultural 
Research 
Institutes 
National 
ExtenSion 
Services 
African 
Farmers 
such reports have been, we need firmer 
evidence to satisfy donor concems and to 
guide us in planning our research agenda. 
Accondingly, we are devoting resources 
to new studies that will provide data on 
the impact of improved technologies in 
fanmers' fields. 
Take the case of cassava, the poor 
man's crop of tuberous roots which 
farmers can leave in the ground until 
needed. liT A has been conducting re-
search on cassava for two decades with-
out reliable data on crop production or 
distribution. According to the director of 
the Federal Office of Statistics in Nigeria, 
statistics on cassava are the worst of any 
major crop - there exist "as many ver-
sions of production series as there are 
organizations interested in agriculture in 
this country". In 1987 IITA launched the 
Collaborative Study on Cassava in Africa 
(COSCA: see description on page 37 of 
this volume) in order to collect basic data 
on cassava in Nigeria and five other coun-
tries. More narrowly defined studies are 
under way about other liT A commodi-
ties. 
Knowledge of the field perfonmance of 
improved technologies will become in-
creasinglyimportantas liT A shifts emphasis 
from commodity research, with its po-
tential for green-revolution type ofbreak-
throughs, to research on the more com-
plex and long-tenm issues of sustainable 
agricultural systems. 
/I 
12 
two staple crops during 1989-1990. 
Cassava. Cassava-based cropping systems are the dominant 
farming systems in the forest zone. liT A will expand its cassava 
breeding in 1991 to its new humid forest station in Cameroon 
in order to adapt cassava to the acid soils. to improve labor 
productivrty of these systems, and to meet diverse local needs. 
liT A is able to decentralize the cassava improvement pro-
gram because the major pest constraints~viruses, bacteria and 
mealybug - have been overcome by past work at the Ibadan 
and Cotonou facilities. Despite the notoriously poor statistics 
on cassava, improved stable varieties are known to be spreading 
throughout Nigeria - improved cassava planting material was 
available in about 90 percent of the Nigerian villages surveyed 
in 1990 by IITA's Collaborative Study of Cassava in Africa 
(COSCA). 
Breeding objectives for cassava in some countries must take 
account of the importance of cassava leaves in human diets. And 
everywhere there is economically significant variation in the 
length of time in which tubers are left in the ground before 
harvest. The range extends from less than 12 to more than 18 
months, with important implications for breeders because 
quality declines as the fiber content of tubers increases with age. 
Improved cassava with bushy bronches helps to reduce weed 
growth, 
Among the breeding concems which relate to production, it 
is necessary to take account of variations in plant architecture 
appropriate for cassava in different cropping systems. liT A's 
priority is to develop varieties for smallholders who are inter-
cropping cassava in mixed systems. They prefer cassava with an 
erect growth habit and few branches because it minimizes 
competition for light with interplanted crops such as maize. 
Commercial farmers growing cassava forthe market. on the 
other hand, prefer profusely branching, bushy cassava because 
it smothers weeds when grown as a sole crop. just as it would 
smother any crop in an interplanted mixture. This attribute, 
valued because it decreases labor requirements. is expressed 
most obviously in liT A varieties which hold their leaves well 
because they are resistant to diseases which cause premature 
leaf fall. 
These diverse production requirements call for diverse 
breeding strategies. In addition. diverse utilization requirements 
call for cooperation between IITA's cassava breeders and 
postharvest technologists. For example, there is variation w~hin 
the African cassava belt in the cyanide content of cassava tubers. 
In many regions the so-called sweet cassava is preferTed 
because it is low in cyanide. and can be easily processed for 
consumption; in other regions the preference is for products 
that are prepar"ed by fermentation and heating which drive 
cyanide out of the grated or ground tubers of bitter cassava. 
Biological control research is appropriate for Phase I farmers 
and there can be no better example than the biological control 
of cassava mealybug in Africa referred to earlier. The story is well 
known - the collaboration wrth CiAT, the Intemational Insti-
tute for Biological Control (IIBC) and with many other organi-
zations; the exploration in Central and South America; the 
discovery of the tiny Epidinocarsis lopezi wasp and its introduc-
tion into Africa after quarantine by IIBC in England: and release 
of the wasp overthe African cassava belt where it has decreased 
mealybug populations below the level of economic damage. 
Without inputs of any kind from the African farmer, the appli-
cation of high-quality biological control science has resulted in 
savings of food crops valued in billions of U.S. dollars. (See story 
" liT NCIA T Research in Biological Control ... " in Research 
Highlights section.) 
African cassava growers will benefit from important research 
breakthroughs by liT A scientists this year - the establishment 
of a predaceous mite. Neoseiulus idaeus. that is a natural enemy 
of the destructive cassava green spider mite; and the discovery 
of apomixis and polyploidy among products of crosses between 
cassava and its wild relatives that expands the breeding potential 
of Africa's most important crop. 
Plantains. As a result of the Strategic Planning Study, liT A has 
expanded research on plantains. an important component of 
farming systems in the humid forest zone. According to FAO 
statistics. bananas and plantains are the second most economi-
cally important crop category in Africa, surpassed only by 
cassava. Plantains are an ideal crop for small-scale fanners in the 
humid forest zone because they fit easily into their fanming 
systems and produce high yields throughout the year. 
liT A has worked on the major constraints to plantain 
production for many years, with emphasis on the agronomy of 
the so-called "yield decline syndrome", the low multiplication 
rate, and on nematodes which are serious pests of the crop. 
The decision to expand this effort was based upon the urgent 
need to deal With threatened devastation by black S'gatoka 
disease. 
Black Sigatoka disease is the overriding constraint in plantain 
production worldwide. Its fungal spores, dispersed by wind and 
water, are beyond the control of plant quarantine measures. It 
causes plantain leaves to wither, resulting in losses so high that 
the crop may become uneconomical to grow. The disease, 
accidentally introduced into Central Africa recen~y, spread 
rapidly to the north, reaching Nigeria in 1986. It can be 
controlled by fungicides, but at a high cost beyond the means 
of African fanmers. 
liT A's strategy for research on black Sigatoka has two major 
thrusts. First, East African cooking bananas have been screened 
for reaction to the disease, and some have been found which 
are resistant Those likely to be acceptable to consumers are 
being multiplied and distributed in Nlgena. Although West 
Africans are unfamiliar with cooking bananas and much prefer 
plantains, these resistant clones are potential altematives if 
plantains decline in West Africa, and they are being tested in the 
region in collaboration with the Intemational Network for the 
Improvement of Bananas and Plantains (INIBAP). 
Second, liT A established the first plantain breeding program 
In Africa w~h the chief objective of breeding plantains resistant 
to black Sigatoka. Recallingthe disastrous impact of the rosette 
disease on groundnut production in northem Nigeria, officials 
from the Federal Ministry of Agriculture supported IITA's plans 
to launch an urgent research campaign to control black 
Sigatoka at our station at Onne, eastem Nigeria. Ittook liT A 10 
years to develop resistance to streak virus in maize, which is a 
much simpler crop for breeding purposes. There was tremen-
dous pressure on liT A agricultural scientists to save plantains 
for the millions of smallholders who depend on them forthew 
subsistence and livelihood. 
I am very pleased to be able to report that liT A had an 
Important breakthrough in this work in 1989, much earlierthan 
could have been expected IITA's plantain breeder has suc-
ceeded in making artificial crosses betvJeen Sigatoka-suscepti-
ble plantains and resistant diploid bananas, and he has obtained 
viable seed. From about 100 seedlings raised from the hybrid 
seeds, three plants appear to be resistant to black Sigatoka and 
have the characteristics of plantains. If Sigatoka-neSistant plan-
tains can be extended widely to smallholders in the humid 
forest zone, this will be another example of the impact possible 
from biological approaches that remove risks and sustain 
production. 
The research described above on cassava and plantains is 
increasing the short-run productivity of smallholder systems in 
the forest zone, but it does not enhance their sustainability. At 
the present time, under conditions of shortening fallow in the 
humid forest zone, there is no viable proven technology forthe 
fanmer that will sustain fertility under annual cropping. Cu~iva­
tion can not be intensified from the addition of fertilizer alone 
because its application rapidly leads to greater acidification and 
toxiCity of the 5Oil- It would not be economically feasible to 
apply the amount of lime and other soil add~ives necessary to 
sustain fertility of these soils. 
Resource-Management Research. New technologies are re-
quired (I) that draw upon fanmers' knowledge and are conSist-
ent w~h fanmers' systems, (2) that build upon knowledge of the 
resource base and the biological processes that enable vegeta-
tive fallow to sustain food production, and (3) that involve new 
intercropping systems that enhance stabil~y and productivity. 
liT A is increasing research on the deterrrinants of sustainabil-
ity and degradation of the resource base. Much of the conven-
tional WISdom about what is happeningto bush-fallow systems 
rests on limited scientific evidence. Since the pioneering studies 
by Nye and Greenland In the late 1950s, for example, little 
research has been conducted in this region to quantify the 
factors responsible for the rapid decline in soil productivity 
following land cleanng. USing a stable bush-fallow system as the 
standard. field experiments are needed to produce empirical 
data onthe relation of fertility decline to farmers' strategies, such 
as fallow management, crop mixtures, fertilizer use and weeding. 
The utility of empincal data resulting from field research is 
limited, however, by the high variabil~y of the m,cro-envwon-
ments in the region and the many years that are required to test 
the sustainability of technologies. Shortcuts are necessary in 
approaching the extrapolation and testing of research results. 
IITA is tackling this by a two-pronged attack The first strategy 
is to develop a detailed database of the environmental and 
socioeconomic characteristics of our mandate area. This infor-
mation can be summarized in the form of maps - for instance, 
'of climatic zones, distribution of soil constraints, population 
densities or IT'arket access indicators. More importantly. the 
data will be organized in ageographic information system which 
can be accessed by researchers of any discipline to determine 
the biophysical and socioeconomic potentials and constraints of 
their own technological interventions. 
The second thrust is to investigate the underlying determi-
nants of sustainability in the fanming systems understudy at I ITA. 
This involves interdisciplinary research on all natural resources 
- climate, the storage and transportation of water, soil fertility, 
pests, weeds and diseases, the physiology of plant growth -
13 
14 
liT A staff study firsthand 
with farmers the problems 
of alley farming with 
soybeans between rows of 
leguminous shrubs. 
and of the interactions between them. It also embraces studying 
the interaction between these biophysical determinants and 
socioeconomic regulators of the system such as the patterns of 
labor availability and capacity for utilization of inputs. The output 
of this research will be ecological-economic models which, 
when linked with the geographic information system databases, 
should give us sensitive insights into the "portability" of our 
technological innovations. 
Agroforestry will be an essential component of improved 
systems to achieve sustainable food production in this zone. The 
traditional bush-fallow system is itself a form of agroforestry 
which under population pressure must be modified to make it 
sustainable. The basic elements of agroforestry must be studied 
in order to develop a range of improved land-use options. 
Among the possible agroforestry interventions, research on 
alley farming is the most advanced at liT A While on-station 
research in the transition zone at Ibadan has produced proto-
type technologies for widespread on-farm testing, there are still 
unanswered problems associated w ith the acid soils of the 
forest zone that require on-station research. For example, 
germ plasm collecti"n and evaluation are necessary to identify 
trees or shrubs With the required attributes of "alley species" 
and which thrive on acid soils. We are often asked whether, after 
so many years of research, farmers are using alley farming and, 
if not, why they are not In trying to find answers, liT A and the 
Intemational Livestock Center for Africa (ILCA) have planted 
over 100 alley farming plots in individual farmers' fields. Studies 
are underway on the economic value of the hedgerow species. 
or "carrier cash crops" to make hedgero~ establishment more 
attractive. and on hedgerow management techniques for weed 
control. Scientists are now examining results through the filters 
of the farmers' objectives, economic profitability and adoption 
potential. In all cases we are exploring how to minimize the 
conflict between farmers' short-term needs for production and 
the longer-term benefits of sustainability. 
Agroforestry is sometimes said to combine the art of 
traditional farming with the knowledge of modem science. But 
some consider the science base to be limited, with an unhealthy 
imbalance between vast development projects and low levels of 
research. Over the last decade liT A scientists have attempted 
to correct this deficiency. and we now have several years of 
experience of process-level studies on alley-cropping systems at 
the Ibadan station. These investigations have deepened our 
understanding of the mechanisms whereby hedgerow trees 
influence the fertility of soil. including the responses of the most 
commonly used trees to management practices and competi-
tive interactions with associated crops. 
liT A's new station in Cameroon is intended to be a center of 
excellence for agroforestry research in the humid forest zone. 
Research wil l be an interactive process there, involving charac-
terization of the environment. studies of the processes of tree-
crop interaction, and design of new systems. Progress may 
require modifications in the land tenure system, so that farmers 
have secure ownership and an incentive to invest In trees. Such 
systems might be quite novel and complex, or refinements of 
present systems. We might envision a system for the twenty-
first century with three components: the compound garden 
around the household: an improved fallow with a multi-canopy 
of commercially useful trees and intercropping of such high-
value, labor-intensive food crops as vegetables: and a third field 
of cash-crop perennials, possibly oil palm or rubber. Such 
research requires creative thinking to define new scenarios for 
sustainable development 
liT A is relying increasingly on resource and crop management 
research concepts such as agroforestry that will facilitate the 
farmer's transition from traditional farming systems to the 
intensified higher-input, partially commercialized systems re-
quired for Africa to feed itsel f again. The research models and 
issues vary significantly by agroecological zone. My discussion 
has concemed the humid forest zone, the most difficult environ-
ment within IITA's mandate for developing productive and 
sustainable systerrs to support expanding populations. The 
environment within our area of primary focus with the greatest 
potential for produCing marketable surpl uses in the short run IS 
the mOist savanna of West and Central Africa. liT A is also 
intensifying its research forthis zone, where remarkable changes 
in cropping systems are occuning and where scientific break-
throughs will have their greatest imC'ediate Impact. 
Conclusions 
Control of the quality of research and management of the 
intemational research centers belonging to the CGIAR is 
implemented by a quinquennial process of extemal program 
and management reviews. The review panels consist of expe-
rienced and tough-minded scientists and science managers, 
who in the course of their lengthy and in-depth reviews become 
thoroughly familiar wrth the work of the particular center. 
liT A's qUinquennial review was conducted early in 1990 by 
panels led by two distinguished SCience managers: Dr. Jim 
McWilliam chaired the Extemal Program ReView and Sir Ralph 
Riley chaired the Extemal Management Review. They reviewed 
and evaluated progress over the past five years. 
The years 1986-1987 saw enonmous change at IITA The 
strategic planning exercise led to new priorities and strategies 
for an integrated program of research and intemational coop-
eration. Management changes Included major staff retrench-
ment caused by the 1985 financial CriSIS, a restructured personnel 
system, and a new financial Information and controls system. 
The year 1988 was a year of consolidation. The top man-
agement team was rebuilt, and the new prograrr strategies In 
liT A's first Medlum-T eC'r Plan became operational. 
The year 1989 was an exciting year in which we streng-
thened the scientific team and launched the new initiatives in the 
Medium-Term Plan. In mylastsemi-annualletterto staff ,n 1989, 
I expressed the view that "much remains to be done, but liT A 
is in excellent condition to move forward boldly on its challeng-
ing mission to make it the world's prem iere scientific institution 
for the agriculture of the humid tropics of Africa." 
The extemal review panels were penetrating and compre-
hensive in their assessment of liT A. They made numerous 
important and useful recommendations on most of which the 
Board of Trustees has already taken action. 
What was most encouraging was the panels' strong general 
endorsement of the Institute. They congratulated liT A for rts 
''vision of the future and explicit strategies to achieve its 
objectives in the complex setting of current and future African 
environments." They concluded that successful management 
changes provide a "powerful base for research" -the stage has 
been set for "new levels of productivity and impact." 
Agricultural research to produce improved technology will 
grow in importance in Africa during the last decade of the 
twentieth century and beyond. Population pressure on re-
sources will remain severe In Africa where there is still little 
evidence of a demographic transition from high to lower levels 
of fertility. The malnutrition ard poverty that must be projected 
into the next century will inevitably exacerbate environmental 
degradation and enhance the urgency of developing sustainable 
agricultural systems. 
Fortunately, many African political leaders now recognize 
that accelerating food production is both an immense task and 
an essential prerequisite for national economic development. 
Macroeconomic policy reforms and strengthening ofinfrastruc-
ture are occurTing in numerous countries. Improved agricultural 
technology will increasingly be identified as the constraint in 
getting agriculture moving In Africa. This constitutes a stark 
challenge and an opportunity for I ITA and all the CGIARcenters 
active in Africa. 
Laurence D. Safel 
Director General 
IS 
Research Highlights 
16 
IITA/CIAT Research In 
Biological Control Wins the 
1990 King Baudouin Award 
I ITA and Centro Intemacional de Agncultura Tropical (CIA T) were selected to receive the 1990 King Baudouln Award for Intemational Agricultural Research, fortheir research on the 
biological control of the cassava mealybug in tropical Africa. 
Dating from the I 970s, the 10lnt research effort backed a 
biological pest-control program at liT A which has effectively 
eliminated the threat of massive crop losses from the mealybug 
for Africa's cassava farmers. 
Sponsored by the Belgian Govemment. the King Baudouin 
Intemational Agricultural Research Award is made biennially by 
the Consultative Group on Intematlonal Agricultural Research 
(CGIAR) for outstanding research achievements. In 1986, liT A 
received the same award for its achievement in developing 
improved maize varieties resistant to maize streak virus. 
The cassava mealybug research and control program has 
covered all the interactions of the pest in the different agroeco-
logiCal zones of Afnca which IT inhabits: crop, pest, natural 
enemies, hyperparasitoids, altemative hosts, economic factors 
and other aspects. The program was designed to address 
development needs for human and material resources in 
institutionalizing the biological control approach in tropical 
Africa. This holistic approach has made It a large project-the 
largest claSSical biological control effort In the world. 
From its inception the program has entailed extensive 
collaboration arrong 25 universities, research institutes, intema-
tional and intergovemmental agencies in Africa. Europe, North 
ard South Arrerica. The funding of the project has Involved 
many donor agencies that formed a sponsoring group with a 
consultative review procedure. The size and scale of the 
campaign led to the relocation of the liT A Biological Control 
Program to rewfacdites In Cotonou, Republic of Benin, the only 
program research center of ITS kind in the CGIAR system. 
Classical approach 
The classica: approach ofbiolog'cal control, whereby the natural 
enemy of an introduced pest IS likewise introduced in order to 
control the pest pOiJulation in the new environment, proved to 
be well suited to meet the problem in sub-Saharan Africa. 
Comrr·unications and extension services in the region are weak 
and fanners are generally poor, A solution involving no invest-
ment, maintenance or other action by fanners was called for. 
Since the introduced enemy populations reproduce ard dis-
perse themselves, no distribution system beyond the research 
project was necessary. 
The goal of biological control, in thiS case, was to create a 
stable equllibnum between the mealybug and its natural en-
emies, through introductions of those enemies selected for 
their effectiveness and specificity. The basic strategy was to 
search for the predators and parasitoids of the cassava mealy-
bug in the native habitats of the pest in South America The aim 
was to establISh a complex of enemy species that would provide 
lasting and economic control of the mealybug across the diverse 
environments of the cassava belt. 
Predators or parasitoids were sent to the International 
Inst~ute of Biological Control (IIBC) in London for rigorous 
screening to ascertain their specificity for the mealybug and to 
assess any pOSSIble problem that could arise if they were 
introduced into Africa. After such certification, and with the 
approval ofthe Nigerian Plant Quarantine Service and the Inter-
Africa Phytosanitary Council, the enemy species were sent from 
England to liT A In Ibadan, Nigeria. 
At liT A, scientists developed systems for mass reproduction 
of the enemy species. They devised newtechniques and facilities 
to rear natural enemies in large numbers. Extensive laboratory 
and field experiments were condJcted to determine the 
suitability as predator and parasitoid of each introduced species. 
Successful predators and parasitoids were released from the 
ground, or aerially utilizing an aircraft specially designed and 
equipped for the purpose. Finally, releases were followed by 
monitonng surveys to determine whether or not released 
natural enemies had established successfully and to document 
the effectiveness of their control of the cassava mealybug, 
Toe world has become a global village. No matter how stnct 
plant quarantine regulations are, and no matter how efficient the 
enforcement agencies, unwanted introductions of pests cannot 
be completely stopped. ThIS biological control research project 
offers one potentially important mechanism for" combating 
future accidental introductions into sJb-Saharan Africa 
The Mealybug Problem 
The cassava mealybug was accidentaily introduced Into Central 
Africa at an indeterminate time and descnbed as Phenococcus 
manihotl (Homoptera: Pseudococcidae). In 1973 It was re-
ported to be causing serious damage to cassava in Zaire by two 
IITA scientists and In the Congo by the Institut de Recherche 
Agronomique T ropicale etde Cultures Vivrieres. By 1976, there 
were widespread mealybug outbreaks in the Bas-Zaire, Bandundu 
and Shaba regions of Zaire. The pest spread across the cassava-
growing areas of Afnca at about 300 kilometers per year. 
17 
18 
Currently it occurs in 32 countries in Africa's cassava belt, as 
identified on the above map. While It was found to have come 
from a restricted area in South America, the mealybug proved 
to be very versatile when it invaded Africa by spreading to 
cassava in all agroecological zones. 
In 1977, liT A held a workshop on the cassava mealybug in 
Zaire which broughttogetheragronomists and breeders working 
on cassava, mealybug specialists and biological control scientists 
from Africa, Europe, North America and Latin America. They 
concluded that both biological control of and resistance breed-
ing against the cassava mealybug were feasible, and urged liT A 
to begin a research program. liT A initiated a progranr in 1980 
to breed cassava varieties resistant to the pest This effort has 
recorded some successes and it is still continuing. 
A modest project In biological control corrmenced at I ITA 
in 1979 . Today, after a decade of support from donor agencies 
of developed countries (Austria, Belgium, Canada, Denmark, 
Germany, Italy. Netherlands, Norway, Sweden, Switzerland and 
the European Economic Community), African Development 
Bank, Food and Agricclture Organization ofthe United Nations 
(FAO) and Intematlonal Fund for Agncultural Development 
(IFAD), that initial effort has grown into what is probably the 
world's largest biological control program, ana it has begun to 
target other major pests as the original aim has been fulfilled. 
During this period, ClAT was already acquiring expertise in 
the biological control of the cassava mealybug In 1975, mealybugs 
were fOL .. nd attacking cassava on the ClAT farm at Palmira, 
Colombia. They were identified as P. gossypi/. Studies of the 
biology. ecology and natural enemies of the species began in 
1976. Aware of CIA T's mealybug research, liT A requested 
ClAT to search for P. manihotl, the pest species in Africa. The 
request subsequently expanded into collaboration between 
IITA and ClAT In the search for the natural enemies of P. 
monihoti in South America. 
The liT NCiA T search for enemies ofP. man/hotl fol' owed on 
the efforts ofll BC wh ch had initiated exploration for P. monihoti 
and its enemies in 1977 in the Caribbean, Venezuela, the 
Guyanas, and northeastem Brazil. After various explorations in 
several countries of tropical America, P. monihoti was finally 
dIScovered ir South Amenca late In 1980 by a CIAT entomolo-
gist. On a miSSion to Paraguay, he found mealybugs attacking 
cassava in Cacupe Research Cer'lter. Ir 1981, an IIBe scientist 
visited CIAT where a joint exploration to Paraguay for natural 
enemies of P . .rnonlhoti was planned. The joint mission collected 
a number of speCies, including the parasitoid wasp EpidlnocofSls 
(=Apononagyrus) lopezi (Hymenoptera), that has subsequently 
proved exceptionally effective i'l Africa. Further explorations 
from MexIco to Colombia, Brazil and Paraguay by an I ITA team 
brought back other species of natural enemies, which were sent 
to IIBC for quarantine and later shipped to liT A. 
So far 10 species have bee'l brought to Africa: most have 
been released at least in some localities. Three parasitoids 
(Epldinocorsis lopeZ!, E. d,versicalT'is and Allotrapa sp.) and four 
predators (Hyperospis jucundo, H. notato, Diomus sp. and 
Sympherobius moculipennis) have been recovered after the 
releases. Some could be establIShed only in restncted areas With 
particular climate or plant-growth characteristics. E. lopez;, H 
nototo and Diomus sp. are widely established. These natural 
enemies are considered to constitute the effective complex 
which keeps in check populations of P. monihotl in Its original 
South American habrtats. 
Scientific accomplishments 
The scientific accomplishments of liT NCiAT research and the 
control program Include the accumulation of scientific knowl-
edge about the cassava plant and the taxonomy, biology and 
ecology of the cassava mealybug and its exotic and local natural 
enemies. Field ecology and plant pest interactions have been 
studied and sampling methods have been developed to provide 
a basis for economic and biological impact assessment 
A computer simulation model of the cassava crop system has 
been developed The model Includes the effects of tempera-
ture, solar radiation, nitrogen and water on plant gro'Nth. A 
simulation model of the cassava mealybug has also been 
establIShed and linked with the crop model. Yet another model 
conceming the highly successful parasitoid E. lopezi has been 
developed and superimposed on the mealybug model. The 
evolutionary ecology related to the host-finding behaVior of E 
lopezi has been studied to explain under what circumstances 
and why it is an efficient parasitoid. 
Establishment and dispersal of the released natural enemies 
have been extenSively studied. The map on page 19 Illustrates 
release sites. establishment and spread of E. ,Iopezi in Africa. E 
lopez; was first experimentally released at IITA in November 
1981, at the beginning of the dry season, and one year later in 
nearby Abeokuta. At the end of 1984, three years afterthe first 
release, E. lopez'; was found in 70 percent of all fields on more 
than 200,000 square kllorreters in south-westem Nigeria, to the 
northern limit of regular mealybug distribution. ThiS dispersal 
rate is among the fastest recorded for microhymenoptera. 
Mass-rearing. Hydroponic culture techniques for cassava pro-
duction have been developed as a necessary first step in the 
mass rearing of cassava mealybug. Efficient and reliable mass 
rearing technologies for the cassava mealybug and its natural 
enemies have been achieved and costed. These technologies 
incluae the mechanized insect productio'l system and the so-
called "cassava tree", a vertical structure that holds in its 
perforated central cylinder a number of cassava cuttings, 
Aerial Release, liT A had to develop an aerial release and 
automatic packaging system for natural enemies, Since the 
African cassava belt covers an area one and a half times the size 
of the United S:ates of America. The system has been tested in 
Cote d'lvoire, Ghana, Nigeria, and Zambia. Successful establish-
" 
- - --
- --
o Cassava Mealybug Distribution 
o £ lopez; Distribution 
o E. lopez; Established 
o £ lopez; Released But Not Yet Recovered 
I Hypemsp;s norQ(a 
2 Hyperaspis roynevali 
3 Dlomus sp. 
"Cassava Belt" Boundaries 
. ,', ..... 
'. 
ments of E. lopez; and Diomus sp. in the release sites have 
demonstrated the potential of this method for large-scale and 
remote-area releases. This airplane, for example, permitted 
natural enemies to be air-released successfully over remote 
cassava fields in Zambia less than 24 hours after they had been 
packaged at liT A in Ibadan, Nigeria. 
N ew indigenous capacity. A major effort to train biological 
control experts at different levels (extension. M.5c. and Ph.D.) 
has been an important component of the biological control 
program. As of December' 1989. 408 trainees, mostly staff 
members of national plant protection services, had received 
short-training at liT A. Degree-related training is carried out at 
liT A and at the Intemational Centre of Insect Physiology and 
Ecology (IClPE). in collaboration with universities in Africa, 
Europe. and the United States. To date. 24 M.5c. and I 2 PhD. 
fellowships have been awarded for research supervised by 
scien~sts of liT As Biological Control Program. 
Following governmental requests, 14 African countries have 
received financial and technical assistance channeled by donors 
through liT A for the initiation of their own biological contro l 
programs, while seven other countries have received technical 
assistance alone. In seven countries, liT A was instrumental in 
identifying bilateral funding for the future consolidation of 
national biological control programs which conduct pre-release 
surveys and post-release monitoring surveys. These surveys are 
usually undertaken initially with the assistance of liT A. As these 
scientists gain experience. their national programs will be able 
to help develop indigenous capacity to undertake integrated 
.... 
. 
:. , .... . ' 
t '._. 
pest management programs. 
Impact 
.' 
By 1990, one of the mealybug's natural enemies, Epidinocorsis 
lopezi, had been established in 25 sub-Saharan African countries 
over areas of about 2.7 million square kilometers. effectively in 
all zones occupied by the mealybug and the cassava host plant. 
Detailed monitoring of releases in Ghana. Malawi. Nigeria 
and Zambia have shown that mealybug populations are being 
brought under control. Mealybug populations now fiuctuate 
below damaging levels in many countries as a result of the 
control exerted by the introduced natural enemies. Losses due 
to the mealybug can be expected to continue to decrease as the 
natural enemies spread further. 
The expected common phenomenon in biological control is 
that the beneficial insect will cover a more limited range of 
ecological conditions than its host. This assump~on was defied, 
however. with the success of the parasitic wasp E. fopezi. 
A benefit-cost analysis of the project has been camed out by 
an economist at the University of Califomia, Berkeley (R. B. 
Norgaard, American Journal or Agricultural Economics, vol. 70, pp. 
366-71 . May 1988). The analysis was based on a reasonable, 
least-favorable case over a 25-year period that incorporated the 
features which the experts felt might threaten the success of the 
pro/ect. The result was a benefit -cost ratio of 149: lover 25 
years, which ranks the program among the most successful 
agricultural research projects ever evaluated. 
19 
Inland Valley 
Farming Systems 
20 
,
n the upper reaches of major and minor watersheds 
throughout Central and West Africa. small inland valleys 
collect surface and subsurface moisture from adjacent. 
heavily famred uplands. Individually. these shallow. narrow 
declivities-as long as 25 kilometers. but as little as 10 meters 
across where they begin, Widening to several hundred meters 
In their lower reaches- are agriculturally insignificant Taken 
together. however. totaling tens of millions of hectares of 
relatively fertile and well-watered soils in West Africa alone. 
inland valleys represent a major potential for producing the 
additional food-especially rice-that tropical Africa needs. 
Full responsibility for West African rice improvement in the 
CGIAR system will be transferred from liT A to the West Africa 
Rice Development Association (WARDA) by the end of 1990. 
To focus specifically on the deal-opportunity for increased crop 
production in the inland valleys throughout tropical Africa. liT A. 
With WARDA's participation. has set up the Inland Valley 
Systems Research Group, which Includes specialists in resource 
and crop management, In economiCS, and in crop improvement. 
The group's mandate: to Identify and develop improved crop-
ping systems that Will pemrlt sustainable. Increased food pro-
duction by small-scale famrers In those complex and difficu~. but 
richly promising. environments. 
Despite their agncultural po-
tential. Inland valleys traditIOnally 
have been neglected. by agricul-
tural researchers and policy mak-
ers as well as by farmers, in favor of 
the more readily exploitable up-
lands and vast lowlaod areas of 
nver floodplains and mangroves. 
In recent years, however. as 
populations have grown relent-
lessly. upland famrers have been 
forced to dig deep Into their agri-
cultural capital- their sOII's fertll-
~y-to produce more food. The 
fertility of vast areas of upland has 
been substantially decreased in the 
attempt to increase food produc-
tion faster than population by 
decreasing the soil-restoring fallow 
penods between crops. The strat-
egy has defeated ~ own purpose. 
contnbutlng Instead to a recent 
decline In per capita food produc-
tion in West and Central Africa. Increased. sustainable cultiva-
tion of inland valleys. which generally have better soils and more 
available water than adjacent uplands, promises to relieve the 
pressure on overexploited upland soils while adding significantly 
to Central and West African food production. 
The availability of water makes inland valleys especially well 
suited for producing rice: in Southeast ASIa. similar wetlands. 
carefully farmed. have sustained continuous rice production for 
centunes. Agncultural scientists estimate that nce yields under 
Inland valley conditions could reach 2.3 tons per hectare, as 
opposed to potential upland yields of I .s tons. The demand for 
rice in West Africa has increased during recent decades at an 
annual rate of more than 5 percent; while production has 
increased at an annual rate of only 3 percent. To keep up with 
demand. as domestic production has dropped from 80 percent 
of consumption early in the 1960s to about half of consumption 
20 years later. rice imports by West African countries have 
increased at an annual rate greater than 10 percent. adding to 
the region's already substantial foreign trade deficit. 
Despite their agricultural advantages. and despite the clear 
need for greatly increased Afncan food production. the produc-
tivity of inland valleys remains 
largely potential. Only 10 to 25 
percent of inland valleys are culti-
vated at all. according to recent 
estimates: and on some of those in 
Nigeria. liT A researchers have 
monitored rice yields of only 1.2 
tons per hectare-about half the 
potential yield. In many of the 
cultivated valleys. moreover. the 
researchers have found erosion, 
decreased soil fertility. and other 
signs that current cropping prac-
tices in these environments can-
not be sustained. 
The challenge for IITA's inter-
dISciplinary Inland Valley Systems 
Research Group is to Identify or 
design farming systems that are at 
once appropriate to inland valley 
Ecologically sustainable agriculture 
in inland valleys depends on 
successful water control. 
ecologies and consonant with the preferences and practices of 
farmers. It is not a simple assignment: while inland valleys occur 
in all the ecological zones of West and Central Africa, they are 
very diverse, both physically and ,n the way they are fanmed, 
from zone to zone and even within zones. The only traits 
common to virtually all inland valleys in West Africa are soils that 
are hydromonphic. or waterlogged, at least some of the time, 
and condrtions that are hospitable to the vectors of debilitating 
orfatal diseases of humans and animals, including schistosomiasis; 
onchocerciasis, or river blindness; dracunculiasis, or guinea 
worm; and malaria. Water management and the control of 
disease vectors are therefore basic, and often at least partially 
linked, elements in any plan to exploit the agncultural potential 
of inland valleys. 
In most other ways, inland valleys are not alike. Some inland 
valleys slope gently, almost imperceptibly, one foot in a hundred; 
others are five times steeper. The fomration of the underlying 
rockdetermines whether a valley declines smoothly or in steps; 
and whether a valley's profile, or cross-section. is narrow-
bottomed with steep, convex slopes, or wide-bottomed, With 
gentle, concave slopes. Watershed areas vary, according to a 
valley's size and shape, from 100 hectares to 2,000. 
Both among and within Inland valleys throughout West 
Africa, soils vary in stnucture and depth, generally resembling the 
soils of the surrounding uplands from which they denve. 
Sedentary Salls fomr the upper slopes, while soils washed from 
the upper slopes make up the parent material of salls farther 
down. Differences In valley shape. water regime, and parent 
rock produce valley-bottom soil textures that range from sand 
to clay, and inherent fertility levels that range from moderate to 
very low. 
The hydrologic characteristics of an inland valley are deter-
mined by amount of rainfall. depth and texture of soil, area of 
watershed, and shape of valley. Some valleys hold standing 
water all year round; others are never flooded, A valley with 
plenty of water for agriculture may lie next to a drought-prone 
valley similar in every respect excepting the area of its water-
shed. 0,', the same valley may support flooded rice one year but 
not the next because rainfall inthe region IS variable. Within any 
valley, the mOisture level increases continuously from the upper 
slopes to the bottom, In most valleys the water table will rise 
above the surface of the valley floor during part of the year. 
Social and economic factors-including systems of land 
tenure, water-control and soil-management pract,ces, and na-
tional and regional agricultural and economic poliCies-operate 
with ecological conditions to shape the agricultural uses of 
inland valleys. In some regions, Inland-valley fields do not belong 
to the individual farmers who cultivate them, but to absentee 
landlords. orto an entire village collectively. A farmer's soil and 
water management practices, as well as his or her reaciness to 
change or irT1prove them, may depend to a large extent on the 
form of land ownership. And a farmer's estimate of the potential 
pnofit from a new high-yielding nce variety~and therefore his 
or her decision to adopt or reject it-is conditioned by the 
availability. sometimes at almost any price, of fertilizer and other 
inputs in the local market. 
All these factors impinge on the famrer, who is the ultimate 
arMerof'mproved practices. Thetypical inland·valley cultivator 
is a small-scale fanner who also cuttivates three to six times as 
much upland area. He or she is likely to be producing enough 
food forthe family, plus at best a modest sunplus forthe regional 
or national market.lnland·valley fanmlng both complements and 
competes wrth upland activrties. A cash crop of rice In the valley, 
for example, maycorrpete forlaborand all other inputs with the 
family's subsistence crop in the upland fields. 
The competition becomes more complicated when, as IS 
often the case, rice in the valley field rotates with dl)l-season 
crops, such as cassava and sweet potato; vegetables such as okra 
and tomato; and cowpea. Farmers grow these crops either 
singly or in mixtures, with each crop requiring different manage-
ment. although synergies exist in some cases. Farmers who 
follow rice with cassava, for example, plant their cassava in large 
mounds, which are fiattened before the next nce is planted. liT A 
researchers hypothesize that thiS soil preparation helps to 
control weeds during the rice season. 
Much earlier research and development on rice in Africa, 
beginninginthe 1930s on lowland envirormentsand much later 
extended to Inland valleys, has been beguiled by :re possibility 
of replicating the ancient ASian system of intensive, sus:ai'led 
paddY-rice cropping in apparently similar Afr'can settirgs. The 
failure of this effort to recognize the critical physical. ecological, 
and socioeconomic differences between Asian and Afncan 
inland-valley farming systems, and the consequent ineffective-
ness of Asian systems in raising food production in West Africa, 
has been instructive. 
The first challenge for liT A researchers is :0 understand 
inland valley farming systems in the interacting social, economic, 
and agricultural contexts in which small-scale farmers actually 
operate in West and Central Africa. With thIS understanding, 
researchers will be able to Identify the factors that IIIT'lt use of 
inland valleys for food production. ThIS process will penmitthe 
development and assessment of improved components and 
cropping systems that promise to wort in the real worle. 
Within thiS larger context, the second challerge for IITA's 
researchers's to quantify a1d analyze, and finally to understand, 
actual inland-valley agricultural a'ld ecological systems in alltheir 
ingenious compiexity. The Inland Valley Systems Research 
Group will enlist researchers from the relevant liT A programs 
in a long-term collaooration to develop aCCL.rate economic and 
ecological models of thIS diversity. Wth these models, and 
drawing on the actual experience of inland valley farmers, the 
researchers will design practical technologies for reaching real-
istic. sustainable production goals. 
21 
Decentralization 
to the Savanna 
l iT A announced In July 1989 it was moving part of Its cowpea program-seeds, scientists and lab facilities- from Ibadan, In the humid lowlands. to Kano. nearly 900 kilometers away 
in the dry savanna of nor1hem Nigena. Barely one year later, In 
time for field expenments to be planted aftel'the first rains of 
the season, the new Kana research station has become a reality. 
The transfer IS the first In a process of decentralization that will 
see parts of UTA's crop improvement programs moving from 
Ibadan headquarters to research stations In the different 
agroecologlCal zones of tropICal West and Central Afnca. More 
than changes in climate and scenery. decentralization involves 
Significant changes in liT As l'eseal'Ch philosophy and oblectlves. 
22 
"Decentralization of research is a logica l stage in the evolution 
of liT A." the Instltute's StrategIC Plan: 1989,2000 obselved In 
1988. The planners Cited the sCientific achievements of the first 
two decades of research at Ibadan, especially In developing 
broadly adapted varieties of impor1ant crops with resistence to 
major pathogens and pests. These successes, the plan con-
cluded, "now permit a Significant decentralization of research 
from lbadan headquarters to the zones w here the commodities 
studied are Important food crops." 
Decentralization IS a calculated strategy for promoting SCI-
entific research that will have practical impact~that will lead to 
real Improvements In national research systems and, ultimately, 
in farmers' fields. The strategy is based on an axiom bom of 
expenence: science that is grounded in the real worid of the 
farmer- his soils and climate. his traditional. locally adapted 
technology and cropping practlces~wlli be more responsive to 
the farmer's needs. more likely therefore to Yield improvements 
that the farmer wil l adopt and that will ultimately Increase hiS 
productivity. than will science based In far-off Ibadan. 
In the case of cowpea. for which liT A has global responSibility 
In the Intemational agricultural research system, two decades of 
sCience at Ibadan have produced a paradox. On the one hand. 
liT A researchers have developed cowpeas that. even without 
fertilizer, can double the yields of traditional vaneties: that com-
bine multiple resistance to important diseases including vin.Jses 
and other pests: and that have the medium or short gr-owing 
duration, seed color and erect plant stature favored by some 
farmers. But these Improved varieties stili require chemical 
insectic ides, espeCially the erect types with unlfolm growing 
duration (that is, determinate) which are planted as a sole crop. 
All of those Improvements were geared for two POSSibilities: 
an IntenSive cropping system of cowpea grown Immediately 
follOWing maize In the humld-forestlmolst-savanna transition 
zone around Ibadan, and a pure crop In northern savannas In 
rotation with millet and sorghum. The major goals were the 
identification and incorporation of disease and Insect resistance 
Moving to the dry 
savanna, where 
cawpeas are 
traditionally 
intercropped with 
a cereal, IITA's 
cowpea research 
should be better 
able to respond to 
farmers' needs. 
illto short-season, erect, determinate cowpeas for grain pro-
duction in monocrops with two to three insecticide sprays. The 
main beneficiaries were cOMmercial growers, who can afford 
chemical insecticides to support the improved varieties in large-
scale monocultures, 
IITA IS shlflingthe emphasis to improve cowpea productiVity 
ir traoitional cropping s">,stems, which involve cowpea-cereal 
mix:ures and are widely practiced in the Sahel and dry savannas 
of West Africa, Forthis, Kana isthe ideal site: inthe dry savanna 
zone of Nigena, the heart of the world's prime cowpea-
producing environment Here, small-scale Nigerian farmers 
grow cowpea on several million hectares to provide essential 
food and fodder, and a surplus of grain for sale. Beyond Its 
irlportance as food and fodder, cowpea is a legume which fixes 
atmospheric nitrogen in the soil through the medium of 
symbiotic bacteria on its roots. It can produce the equivalent of 
)0 to 70 kilograms of nitrogen per hectare per year, rraklng i: 
an important contributor in sustainable agriculture for the 
savanna. 
Resource-poor fanners around Kano contend with a very 
differellt much more hostile agricultural ervironment than that 
of the transition zone. Most cowpeas here grow prostrate, not 
erec:: are sensitive to photoperiod or daylength and therefore 
are late-flowering; and, being indeterminate, their growing 
duration is not fixed, but depends on exposure to sU'"llight and 
rainfall. The farrr.ers grow them because they are well adapted 
to intercropping---·in this environment the precominant fanning 
system is some kind of cereal-legume intercrop. 
In the moist savanna, cowpea is commonly grown with 
sorghum, millet and groundnut. In drier savanna, cowpea-millet 
is tt"",e Major intercrop. In both cases crops are sown in relays, 
:he millet usually first, :re legumes last, Three or four crops are 
usually n the ground at the same time for at least part of the 
growing season. 
For these complex trad:tional croppirg systems, the erect, 
e2.rly, detenn nate cowpeas developed at Ibadan are less 
suitable. Savanna farmers r"leed cowpeas that spread out close 
to the grour"ld and flower late in the season, so they do not 
compete with the earlier cereals for sunlight or soil moisture. 
Becausethey eS;Jec ally value the cowpea's stems and leaves for 
cattle feed, farmers favor ildeterrninate types, which continue 
to procuce vegetation after they rave filled their grain, as long 
as the soil has sufficient rroisture 
-hese cereal~cowpea nte'"Crops a'"e typ cally grown on 5011 
of very low fertility ana poor structure. The organic-matter 
conte'lt is virtually zero. The fields of tr"1e rew station's research 
farm at Minjibir, 45 kilometers from Kano, take on a desiccated 
look during the dry season, The nitrogen added to the soil by 
covvpea is suffic ent to support the cowpea's growth and to 
contribute some nitrogen for the intercropped cereals In the 
following seaso'!. 
After the grain harvest all leaves and stems of both cereals 
and legumes, which might improve the soil, are instead removed 
from the fields for use as livestock feed or as buildirg materals 
Commercial fertilizers are as unaffordable as chemical insecti-
Cides and herbicides. Aside from the manure produced by his 
few animals, the resource-poor farTY1er has nothing to restore 
his soil. Because of the infertile soil-as well as pests such as 
thrips, which prevent fruit set, and low residual soil moisture late 
in the growing season-the farmers' locally selected, prostrate 
cowpeas generally produce very little grain. Average grain yields 
of traditional varieties in Nigeria are estimated at about 100 to 
300 kdograms per hectare, about 60 percent of the Latin 
American average and less than 40 percent of the U.s. average. 
For IITA's cowpea scientists, the move to Kana is part of an 
attempt to understand by looking at what the fanmer actually 
does, then asking what can be done within the farmer's 
constraints to maximize the productivity of both cowpea and 
the cropping sy's:em as a whole. 
The emphasis is now on de"leloping prostrate, indeterminate 
plant types adapted to intereropping. Cowpeas will be bred for 
both fodder and grain, for resistance to the insects and diseases 
of the savanna: and for increased yields without insecticides or 
other purchased inputs. And a: Kano, pathologists and breeders 
will cany the battle against striga ana alectra to the parasitic 
weeds' hOfT'e ground 
The Kano station is s:rategically located to encourage col-
laboration between IITA researchers and their counterparts In 
both r,ational and interlational research systems. The new liT A 
station is housed wthin the Kano branch of the Institute for 
AgncJltural Research (JAR), which has Its headquarters at 
Ah'lladL. Bello Un:versity in Zaria. IITA's scientific staff at Kano, 
initially including a cowpea breeder and two plant physiologists, 
will work closely with agronomists, socieeconomists, patholo-
gists and entorrologlsts from IAR. 
The International Crops Research Institute forthe Semi-Arid 
T roples (ICRISAT), which has global responsibility ir the CGIAR 
system for sorghurr and millet, also has a Kane facility witr IAR. 
Because cowpea is only part of the miliet-sorghum-cowJea 
system, the success of the effort depencs on close cooperation 
with all involvec. While improvements in cowpea might be 
possible Just by ncorporating disease and pest resistance, the 
goa is to improve productivity of the wlole system: cereals and 
legume 
liT A is also establishing a station in the humid forest zone of 
Ca'l1eroon south of Yaounde, primaril">, for research on re-
sou:'"Ce management and cassava. For ITS other princioal crops, 
IITA \·-vill establish two additional research stations n appropri-
ate agroecological zores of tropical Africa: a moist savanna 
station, forwork or, maize; and a cowpea station, in collaboration 
with the Southern African Deve'opment Coordination Con-
ference (SADCC), for the southem Afnean region. 
23 
Profiles from liT A's 
First Generation 
of Doctoral Fellows 
P rofessor Olaolu Babalola, a soil physicist, is head of the Department of Agronomy at the University of Ibadan in Nigeria, Nematologist Barbara Hemeng is a senior lecturer 
at the University of Science and Technology in Kumasi, Ghana. 
24 
Dr. Mohamed T ejan Dahniya is an agronomist and the director 
of the Inst~ute of Agricultural Research of the Ministry of 
Agriculture, Natural Resources and Forestry, at Njala in Sienra 
Leone. 
The common bond between these three African agricultural 
leaders is the cnucial role that liT A training has played in 
detennining the direction and success of their careers. 
liT A's founders recognized early on that agricultural progress 
in tropical Africa depends on greatly increased numbers of 
African research scientists and other agricultural professionals. 
as much as it depends on improved crop varieties and farming 
systems. Among the national agricultural research services and 
other African national inst~utions w~h which liT A collaborates, 
and which bear the ultimate responsibil~ for selecting, adapting 
and transferring improved technologies, virtually all are severely 
hampered by the lack of trained agricultural professionals. 
Training in Africa for African agriculturalists at all levels, from 
extension agents and lab technicians to policy-makers and 
officials in national programs, therefore, has been a central tenet 
of IITA's mandate from the very beginning. 
In almost 25 years, liT A scientists and professional staff have 
trained more than 6,000 African agriculturalists. Of these, most 
have participated in a variety of group training courses and 
programs, both at Ibadan and in collaborating African countries. 
More than 400 trainees have come to Ibadan for research and 
field experience leading to their MSc. and PhD. degrees. 
For Margaret Hemeng, a fel-lowship at liT A for a PhD. in 
nematology from November 
1985 to March 1988 was the 
opportun~ of a lifetime. Bom 
in Kumasi, Ghana, Hemeng fin-
ished secondary school in Ghana. 
then continued her studies in 
England, eaming a BSc degree 
with honors in zoology and 
botany, followed by an MSc. in 
plant pathology. With these 
credentials she returned to 
Ghana in 1971 as a research officer at the govemment's Crops 
Research Institute. 
"While I was doing my master's project in plant pathology, I 
had already become interested in nematology," she recalls, "but 
CRI needed a plant pathologist" Her first professional opportu-
n~ to pursue her abiding interest in nematodes - the phylum 
of roundworms or threadworms. abundant in water and soils 
and in many plants and animals, including man - came in 1976, 
soon after she had become a lecturer atthe Univers~ofScience 
and Technology in Kumasi. UST received notice of a series of 
research planning conferences. part of a long-term international 
nematode project sponsored by USAID, to be held at liT A. 
Hemeng was invited to report to the first conference on 
everything that was known at UST about the root-knot nema-
tode in Ghana. 
Subsequent conferences at liT A during 1978 and 1981 
further whetted her appet~e for nematology, but back home 
she was fnustrated by her lack of advanced education or any way 
to get~. "I didn't even know enough taxonomy to identify which 
nematodes were attacking which crops," she says. "We don't 
have a research library here in the whole country." A~hough she 
was already past 40, and married w~h two young children as well 
as involved in teaching full-time, she resolved that if she couldn't 
become a nematologist in Ghana, she would go somewhere 
else. 
"I went to the library and got a directory of universities," she 
says. "I wrote all the univers~ies in the world" without finding 
what she needed. Finally she wrote to F. E. Caveness, a 
renowned nematologist at liT A, whom she had known from "so 
many years" of participation in nematode conferences at Ibadan. 
Cavenessoffered Barbara Hemenga deal: hewould sponsor her 
for advanced training at liT A and serve as the academic advisor 
for her graduate degree studies: Hemeng would work on 
"Deforestation and cropping effects on soil and root nematodes", 
part of an liT AlUnited Nations University study on deforesta-
tion. 
It was an offer Hemeng could not refuse, even though it 
meant being away from her home and family for months at a 
time. Hemeng set up a lab and living quarters in Benin City, in 
south-westem Nigeria. With two colleagues, she spent most of 
her t ime for more tihan two years "in tihe bush", collecting data 
in a forest preserve and making biannual reports to Ibadan. 
In March 1988 Hemeng retumed to Ghana, her home and 
family, and her teaching position at UST in Kumasi. She brought 
with her 28 months' worth o f data and the conviction that she 
had the raw material for a significant contribution in nematology. 
"Dr. Caveness knew," she says, "that no one else in the world 
had done tihis work" 
Two years later Hemeng is still analyzing and wriiting up her 
data. The analysis has to be done whenever she can bon"ow time 
on a computer at tihe govemment's Crops Research Institute. 
The lack of an adequate research library at UST, or anywhere 
in Ghana, delays the literature search that will be the foundation 
of her thesis. Having persisted so long and come this far, how-
ever, Barbara Hemeng is not about to give up; she fully expects 
before long to submit her completed d issertation to UST. 
In comparison with the obstacles she faces in Kumasi, 
Hemeng's experience at liT A was like the best of all possible 
worlds. "For research, liT A has the equipment, and the people 
to advise you. They've got a very good research library where 
you can do your literature review; you can get whatever 
references you need within two days. 
"There are so many scientists there-all the sciences are 
interrelated. Everyone is very busy but also very friendly: they are 
willing to give you any information you want on any aspect of 
your research. The scientists come from different countries, 
with different characters: it's almost like you've been through the 
whole world. The contacts and interaction I had there didn't 
stop when I finished my work I'm still communicating with them: 
that's been tihe most important aspect of my liT A training." 
Her long-standing liT A connection is a matter of consider-
able pride and practical value. A Hemeng lecture on agroforestry 
to students at the UST School of Agriculture quickly tums into 
an inspirational description of the opportunities for research and 
training at liT A. Even Hemeng's undergraduates get an early 
dose of liT A training: she has sent some of her best UST students 
to Ibadan with modest research projects under the guidance of 
liT A scientists. Hemeng hopes that this brief experience at 
Ibadan. which counts toward the bachelor of science degree in 
agricultur'e, will give her students an insatiable taste for topfl ight 
scientific research and the ambition to become Ghana's future 
researchers. 
M ohamed Dahniya had al-ready left Sienra Leone to 
get an M.5c. degree in agronomy 
at the University of Illinois, when 
the opportunity to pursue his 
doctoral research at IITA 
brought him back to Africa. Bom 
in Freetown, Oahniya was one 
of 10 children. Their father, a 
civil servant. sent six (three 
brothers and three sisters) to 
university. 
One of the first students at Njala University College, a branch 
of the University ofSienra Leone founded in 1964 with USAID 
funds, Dahniya got his B.5c. in agriculture in 1968. A USAID 
fellowship took him to the Univers~y of Ill inois, where he 
received an M.5c. in agronomy in 1971 , 
"My research in the U.s. was in maize," says Dahniya. His 
thesis title: "Incorporated maize organic material effects on 
subsequent crops", "I became interested in root and tuber 
crops-cassava and sweet potato. The best place to study them 
was in Africa." From liT A publications that had found their way 
to Illinois, Oahniya heard of the new intemational institute in 
Ibadan, Nigeria, which had a research program in roots and 
tubers getting under way. 
Dahniya came back to Sierra Leone as an assistant lecturer 
in the agronomy department at Njala, with time out in 1972 to 
get a postgraduate diploma in agricultural meteorology in Israel. 
After attending annual root-crops meetings at IITA in 1975 and 
1976, he registered in October 1976 as a doctoral student in the 
agronomy department at tihe University oflbadan and signed on 
at liT A to do his tihesis research on "Defoliation and grafting 
studies of cassava and sweet potatoes." 
The subject has special relevance for Dahniya and for West 
Africa. " In Sienra Leone we eat quite a lot of leaves from both 
cassava and sweet potato," he explains. "I wanted to know the 
result of continual leaf removal on tuber production." 
With his PhD. degree, awarded in 1980, Dahniya became a 
senior lecturer, then an associate professor, in the agronomy 
department of Njala University College. He has served as head 
of the departments of agronomy and crop sciences. Most 
recently, in 1988, he became director of the Institute of 
Agricultural Research in Sienra Leone's Ministry of Agriculture, 
Natural Resources and Forestry. 
As his career in Sierra Leone has progressed, Oahniya has 
maintained close t ies with liT A. He comes back to Ibadan at 
least once a year, for liT A's annual root crops collaborators' 
meeting, which draws cassava and sweet potato researchers 
from many African countries. He sends a steady stream of 
students and researchers from Sierra Leone to Ibadan. "The 
25 
26 
undergraduates go to do projects." he says. Of three under-
graduates from Njala at Ibadan in 1990. two are worl<ing in the 
root and tuber program and a third in sustainable agriculture. 
"Staff members get a good bit of research expenence at liT A. 
not just In their own area of specialization but in quite a few 
related areas," Oahniya says. "Sometimes 1 ask for a particular 
training course. This year I sent the training officer from tAR for 
two months." He has also pr-oposed sending a graduate to 
Ibadan to leam the method for evaluating the cyanide content 
of cassava. 
The cooperatron worl<s both ways: at Njala. liT A supports 
two in-country courses that train extension supervisors in 
cassava and sweet-potato agronomy and in nutrition. liT A also 
cooperates with IAR in a root and tuber improvement program 
to develop cultivars that are adapted to Sierra Leone's environ-
ments. resistant to major diseases and pests. high-yielding, 
nutntlou5 and attractive to consumers. IAR also adapts and 
distnbutes other improved liT A varieties in SielTa Leone. In 
1990. IAR got half a ton of streak-resistant maize from liT A for 
multiplication and distribution to Sierra Leone fanTIers fighting 
a streak outbreak. 
F or Olaolu Babalola. a lec-turer at the University of 
Ibadan early in the 1970s. the 
opportunity to do research in 
sorl physics at liT A made all the 
difference between achieving his 
ambitions in Afnca or going 
abroad for the second time as a 
student Babalola's mother' is il-
literate. His father. a famner and 
carpenter and an infiuential per-
son In his vl11age. near Ife town, 
can read and write. Their seven 
sons and one oaughter. Babalola says. were all educated. 
Babalola's Initiation into agnculture was fortUitous: he was 
one of four students from his high school selected for a job as 
an assistant technical officer with the Nigerian Department of 
Forestry. A Commonwealth scholarshrp in forestry was hIS 
ticket to Vancouver, British Columbia, for a bachelor's degree. 
A United Nations fellowship then took him to Oregon State 
University in the U.s.A for a master's degree In soil physrcs, 
Required to retum to Nigeria and the Department of 
Forestry as a condition of his fellowship. Babalola faced five years 
in a reforestation program in the remote northem part of the 
country. "It was too quiet in the north," he says. '''There were 
no suitable partners fOr" me to marry." Feeling the urge to settle 
down and start a family. he "bolted away" aher one year- and 
took up a career as a lecturer at the University of Ibadan. 
"I realized that to remain in the profession I had to have a 
Ph.D. ... he recalls. "The problem was that there was no PhD. 
program in soil physics In Nigeria- or anywhere In West Africa." 
His only choice, it seemed. was to desert Africa again to study 
in England or the United States. Instead. through the interven-
tion of Rattan Lal. a soil physicist at liT A. Babalola was able to 
do his research at I1TA while continuing to lecture at the 
University of Ibadan. where he was also registered as a doctoral 
student under the supervision of an agronomist. In fact. his real 
supervision came from liT A 
"I found liT A a far better place to worl< than a university," he 
says. "At liT A I was part of an ongoing program. and Lal was as 
interested in what I was doing as I ~as. At Oregon orVancouver, 
a student selects a topic and works alone at his or her own pace. 
At liT A. I was given a certain time to achieve a real research goal. 
We shared infonTIation: I discussed my work with fanTIing 
systems people and collaborated with an agroclimatologist on 
my research design." 
Once he had finished his PhD. and had joined his university 
faculty full-time. Babalola found that his increasing academic 
work prevented him from continuing research at I1T A But in hiS 
role as teacher and advisor he has been able to steer new 
generations of promising students- undergraduates as we11 as 
graduates- toward liT A. carefully matching his university's aca-
demic goals to the practical research objectives of liT As 
programs. 
"liT A has a research set-up that the university lacks." Babalola 
says. "1 can tell an IlT A scientist that we are working on 
something and we have student who rs interested in a particular 
line of research. I can ask the scientist: does this fit in with your 
program'" 
Like Barbara Hemeng in Ghana and Mohamed Dahniya in Sierra 
Leone. Olaolu Babalola in Nigeria is part of what has become 
a tradition in training in African agricultural research. The 
product of that tradition is a growing African networl< of leading 
specialists, trained in their tropical homeland to address its 
unique and urgent agricultural needs. 
IITA Today 
27 
About IITA _______ _ 
IITA Trustees and 
Senior Staff. April 
1990. 
28 
,
n 1967 liT A was established as an Intematlonal 
I'esearch institute with headquarters on a 1,000-
hectare farm at Ibadan, Nigeria and with links with 
national programs in many countries of sub-Saharan 
Afnca. It became the first African link In a worldwide 
network of Intematlonal agncultural research centers 
known as the Consultative Group on Intematlonal 
Agricultural Research (CGIAR) . The Federal Republic 
of Nlgena provided 1,000 hectares of land for the 
Instltute's headquarters and experimental farm at 
Ibadan, while the Ford and Rockefeller foundations 
provided the Initial planning and financial support. 
Objectives. liT A has four objectives: 
I . To develop systems for the management and con-
servation of natural resources for sustainable agri-
culture In the humid and subhumld tropical zones. 
There IS global concem that Afnca's growing 
population IS plaCing Increasing pressure on baSIC 
natural resources and threatening the viability of 
traditional farming systems. 
2. To Improve the periormance of selected food 
crops that can be Integrated Into Improved and 
sustainable production systems. 
ThiS IS the shared goal of many of the InstltLrtes In 
the CGIAR system. liT A conducts vanetal Im-
provement research on six crops: cassava, yam, 
plantain, maize, cowpea and soybean. 
3. To strengthen national agncultural research 
capabilities in order to accelerate the generation and 
utilization of improved technologies, by means of 
training, information and other outr-each activities. 
The objective here r5 to enable liT As partners In 
national research systems increasingly to meet 
their own technology requirements. 
4. To improve food quality and food storage, 
processing and marketing, in order to encourage 
more effiCient use of available food supplies. 
For a number of liT A commodities, parilcularly 
roots and tubers. the lack of efficient technology for 
storage, processing and conversion to commercral 
products IS a senous barrrer to their Increased use 
as both food and feed. 
Biological Control With a geographical mandate covering tropical 
regions worldwide, liT A focuses on the lowland tropics 
of West and Central Afnca. liT A conducts research 
and training activities at its headquarters and at 
substations in West and Central Africa, and in 
conjunction with regional and national programs in 
many parts of Africa As a means to enhance the 
practical relevance of its crop improvement research 
to fanming conditions, liT A has begun to decentralize 
its research from its headquarters to locations in the 
various agroecological zones where its mandated 
crops are grown. (See "Decentralization to the 
Savanna" In the Research Highlights section of this 
volume.) 
(emphasizing environmentally sound integrated 
pest management) 
IITA progral1's comprise: 
International Cooperation and Training 
(emphasIzing the strengthening of national 
agricultural research systems) 
Information Services 
Librany 
Publications 
Public Affairs 
Research Support Units 
Genetic Resources 
Virology 
Biometrics 
Resource and Crop Management 
(emphaSIZing fanming systems with major IITA 
crops and soil resources) 
Analytical SelVices 
FanTl Management 
Root, Tuber and Plantain Improvement 
(focusing on cassava. yam and pl'antain) 
Grain Legume Improvement 
(focusing on cowpea and soybean) 
Maize Research 
Rice Research 
The main conduits for sharing the results of I ITA 
research with national programs are training, 
germplasm exchange and publications/information 
exchange. 
(actIVIties being transferred to WARDA dJnng 
1990) 
Training. Thetrainlngprogram isone ofllTA's pnncipal 
means of achieving "transfer of technology" In 
agriculture from intematlonalto national levels. Training 
can help in buildingAfncan capabilities for agncultural 
research and food production by increasing the corps 
of competent :esearch workers for the humid and 
subhumid troPiCS. To da-+.:.e, over 6,000 trainees have 
Board of Trustees 
Lu is B. Crouch Choi.'person 
Busrnessman 
Scnto Domlr'go, DOminican Repubilc 
Lawrence A. Wilson* Choirperson 
Dean. Facuity o{ Agnculture 
UnIVersity or West ,'nd'es. Sr. Augustine 
Tnn.'doG. ReputJ/ic o{Trmldad Clnd Tobago 
Sheriff A. Adetunji* 
D'rector. Agncu,lturol SCiences Deportment 
Federal Ministry or SCience o,Id Tec~nology 
Log:Js, Nlgero 
E. O. Ayo 
Dlrccwr Gernercl, Federal IV 1,'1istry 8{ Agrculture and 
Natura! ResoJrces. AbujQ, Ntge(l~ 
Ayo Banjo 
Vice Chonce,'ior. 'Jnrl'erslty oflbodo'l. lbador. Nlgeno 
Randolph Barker 
Proresso'. Deportment o{ AgrlcJlrura,' Econ::;rrxs 
Comell UrllVersltv. irhGco, New Ycrk, U.'5.A 
Mayra Buvinic 
Drrector.intematronci Ce~t€r (or Research on \-Vomer; 
Woshi.igton DC. USl'. 
Robert K. Cunningham 
Agrlcuit'.)fCjl Research Consultant 
Harper.de,i, i-lert{ordsfwe. England 
Freeman L. McEwen 
Dean :Jnto'lo Agricu.lwral College Unrl'ersl)' o{G'.1€I~h 
GL'elph. O'ltGno, CO:1odo 
Nicholas E. Mumba 
Permanent Secretor,;. 1..1lnlsrry c{ AgncJlture 
LU5Clko, Zombie 
Keiko Nakamura 
DlreclOr, Departm€n~ or Soc'ol and Natural 
Enil,'O'lmentd ,Q,eseor:::h. N1ltsubishr KosellnstJrute o{ 
L,{e SClc~ces, Tckyo. Japan 
Arn0r Nj0S 
Director General, Center for Soil and ErI'I,ronmentG! 
ReseorCh. Aos-"JI'h. t\Jof'Nay 
"icrm ended during yeor 1959/90 
Gerardo Perlasca 
AgrcUituml Consulron~. Como. hal}' 
Laurence D. Stifel 
DlrectwGenerol, .rITA. Ibodan, Nlger,a 
Sakary Toure 
REctor. I\'otlono,' U'1IVC.'Slty of Cote j'llIclrc 
AbKJJor., Cote d'lvOJre 
Theo M. Wormer 
Professor o{iroplwl Botany (Rtd.) 
Unillersny Of Amsterdam, Nether/ends 
Special Advisers 
Luigi Monti 
Cytoge.'lcric;st, Ur:l'/ersJty ::J( Naples, Italy 
General Olusegun Obsanjo (Rtd.) 
~crmer >-lead orStote. Federol.Q,epJbf,c op\1igeno 
29 
30 
participated in the range of training activities, including 
group courses, doctoral or master's degree programs 
and short-term study proJects. 
Germplasm. The genetic resources unit is involved in 
collection, documentation, storage and distribution of 
germpJasm of IITA-mandated and other important 
food and agroforestry crops. Over 40,000 accessions 
of genmplasm are stored at IITA, including the world 
cowpea collection of 15,000 accessions from more 
thall 100 countries and I 1,500 accessions of rice, 
chiefiy from Africa. Seed samples and information on 
them or the characteristics of the species are made 
freely available on request. Duringthe first 12 years of 
Its eXistence (1978-1989), IITAdistributed over 4 I ,000 
samples to non-liT A users in over 80 countries, 
Information. Information services together With the 
research programs provide infomlation in many forT'rs 
to scientists in usercountries. Publications are distribu-
ted on a regular basis with a mailing database of over 
8,000 addresses. Results of collaborative and other 
research are disseminated through netvvorknewsletters 
and monographs. IITA's library facilities include a col-
lection of over 35,000 books and periodicals, a COC'-
puterized bibliographic and database sel\lice. microfilm 
and CD-ROM facilities and a scientific literature service 
for selective dissemination. Interpretation and transla-
tion services support meetings and training activities, 
Through these means I ITA maintains vital links with 
national agricultural research programs. By testing 
IITA's Innovations, adapting them to local conditions, 
and carry'lng them to farmers. national programs can 
translate research into increased food production. 
The Institute, liT A employs about 180 sCientists and 
professional staff merrbers from over 40 countnes 
and about 1.300 support staff mostly from Nigeria. 
Half the staff are located at headquarters, where 300 
hectares of the I,OOO-hectare campus have been 
developed for expenmental fields. An 80-hectare 
research station lies in the humid coastal zore at 
Onne, in southem Nigeria. A 30-hectare station was 
opened in 1990 in the dry savanna zone at Kano, 
northem Nigeria, in collaboration with Ahmadu Bello 
University's Institute of Agricultural Research. A station 
at coastal Cotonou, Republic of Benin, houses the 
Biological Control Program. A I ,OOO-hectare, hlgh-
rainfall. humid forest station is being established at 
Mbalmayo in Cameroon in collaboration with Institut 
de la Recherche Agronomique (IRA).A mOist savanna 
station IS being p!annedforCote d'ivoire in collaboration 
with Institut des Savannes (IDESSA). Eight major 
collaborative projects were under way in westem, 
central and southem African countries at the beginning 
of 1990, while other prOjects were being conducted 
on a more limited scale throughout tropical Africa. 
liT A is a nonprofit, intemational agricultural research 
and training Institute supported pnmanly by the Consul-
tative Group on Intematlonal Agricultural Research 
(CGIAR). Founded in 1971, CGIAR IS an association 
of about 50 countries, international and regional or-
ganizations and private foundations. The purpose of 
the research effort isto improve the quantity and qual-
ity of food production in developing countries. The 
World Bank, the Food and Agriculture Organization 
of the United Nations (FAO) and the United Nations 
Development Programme (UNDP) are co-sponsor> 
of this effort. (See note on page 99 of annexes.) 
Resource and Crop _____ _ 
Management 
The twin challenge for ag.riCultural research in tropical Africa is to enable farmers to produce enough food for a growing population, while 
sustaining the natural resource base so that future 
food production will not be curtailed. liT A's Resource 
and Crop Management Program concems itself with 
both Sides of the food production equation-crop 
productivity and resource sustainability-in its research 
to improve smallholder farming systems in the three 
main agroecological zones:the forest (humid tropics), 
moist savanna (subhumld tropics) and Inland valleys 
(wetlands, or lowland areas which are fiooded dunng 
the ra Iny season). 
Traditionally, farmers in the African tropics have 
solved the sustainability problem by permitting 
famnland, which loses Its productivity rapidly under 
cultivation, to revert to natural vegetation and regain 
fertility during fallow periods lasting from 5 to 20 or 
more years, The farmers would tum to earlier fallOWS 
ready to be exploited again or to virgin areas, in a 
pattern of shifting cultivation that would avoid 
pemnanently degradingthe nesource base wh de keeping 
food production at as high alevel as possible. Agncultune 
was thus "sustainable" in the long term over a broad 
cropping area. 
However, the rapid growth of population and 
demand for cropland ill recent decades has upset this 
balance. Population In sub-Saharan Africa has more 
than doubled Since 1960, and Will double again before 
Resource Managemert Research 
Crop Ecology 
SOil Chemstry 
Soi PhYSICS 
----1 Agro'lomy 
the next quarter century. In order to meet rising 
demand forfood and other agricu:tural commodities, 
the land under cultivation has had to increase 
substantially, often at the expense of restorative 
fallows. Many new areas have been opened for 
cultivation using techniques which can lead to serious 
degradation of the productive capacity. As a result, 
the sustalnabillty of the system is being thneatened. 
There is an urgent need for new or improved 
techniques or systems of land development and 
management that wiU enable production to be 
increased, prevent degradation and yet be compatible 
with pnevaillng famning systems so that famners will 
readily adopt them. 
liT A's Resource and Crop Management Program is 
thus organized (see diagram below) to conduct 
research which addresses these issues In two major 
activities, In partnership with scientists in African 
national research systems: 
• Resource management research to study the natural 
resource baseald develop existing ornewtechnologies 
for smaUholder farming systems. 
• Crop managerrent research to synthesize the 
products of resource manage merit research and crop 
improvement research (conducted by crop-focused 
programs at liT A) into sustainable and more product"e 
cropping systems, which are compatible with the 
resources and objectives of the smallholder. This 
synthesis IS in essence the goal of the concerted efforts 
of all liT A programs. 
Agroecologlcal Zone Cror::Plng Systems Research 
Agronomy Agronomy 
Soi Fertility Agricultural Econcmics A,griculLlral Economics Agricultural Economics 
Soil Microbiology Hydrology 
Agrocl matology 
Agn'cultural Economics 
\/I./eed Science 
31 
Labor required to 
clear land for 
cropping is 
becoming horder to 
mobilize in mony 
areas. 
32 
Agroecological background 
Within the general framework of the main climatld 
vegetational zones of forest moist savanna and Inland 
valleys. the two most important vanables are soli type 
(chiefly acid and nonacid) and population density 
(high, medium and low). 
Soils. A simple categorization of tl"Opical African soils 
would Include foUl- general gl"Oupings: 
Highly weathered aCid soils. 
Highly weathered nonacid soils. 
NonaCid sOils from basIc and volcaniC matenals. 
Nonacid hydromorphlc and alluvial soils. 
They have varying management requirements and 
different tolerances for intensified or continual use. 
The humid forest zone of West and Central Afnca, 
which Includes over 55 pel-cent of the land area of the 
countnes of liT A 's primary focus, has mostly highly 
weathered soils that are strongly leached and acidic. 
They degl-ade I-apidly when cleal-ed of natural 
vegetation. The central problem for agt'iculture here 
is to maintain soi l ferti lity. 
The moist savanna (subhumld) zone also has highly 
weathered soils. which are generally less leached and 
acidic. They are, however, susceptible to compaction 
and erosion. In some areas, onglnally nonacid soils 
have aCidified, often as the result of use of acid-forming 
fertilizers. In the highlands of westem Cameroon and 
East Afnca.less-weathered soils denved from volcanic 
ash and ferTomagneslum rocks are productIve. 
Thmughout both humid and subhumid areas of 
West and Central Afnca, hydmmorphlc and alluvial 
soris are aSSOCIated WIth swamps, lakes and nvers In 
the distinctive agroecologlcal zone of Inland valleys. 
Population pressure. Serious degradatIon of the 
resource base appears to be occumng under- different 
tradit ional falming systems In many places where 
populatIon densit ies are eIther hIgh or low. 
In densely populated al-eas, fallow penods have 
often become significant ly shorter, resultIng In 
accelerated leachIng of nutnents. rapId OXIdation of 
organIc matter, Increased weed populatIons, erosIon 
and decreased mOIsture retentIon. The falmers' 
options for copIng With these problems may be 
ovelwhelmed by the ,-ap,d,ty and extent of the changes, 
and, in extreme cases, IrreversIble degradatIon of the 
land and soil may result. 
Paradoxically, there are other rural areas In whIch 
too few rather than too many people make it difficult 
to maintaIn productivity. SubstantIal labor IS requIred 
to clear land, to keep weeds under control, and in 
sloping areas, to construct ridges orterracesto prevent 
soil erosIon. In many cases, the migration of la(ge 
numbers of young males to urban areas, together wIth 
Increased primary educatIon forchrldren. has removed 
a Significant porilon of the agnculturallabor force. As 
a result it is increasingly dIfficult to mobilIze suffiCient 
labor to clear trees from land that has been under 
fallow for long periods, to carry out essential tasks such 
as weeding and plantIng at the optImal tImes. and to 
maintain ndges or other sori conservatron measures. 
Thus, productiVity may decline as lack oflaborcompels 
the repeat ed use of the same land, elImInation of 
restorative fallows. and the neglect of tasks needed to 
maintain the resource base. 
Potentials and limitat ions . Each of the maIn 
agroecological zones has di fferent crop production 
potentials and constraints. In the humid forest, 
production potential IS greatest for root crops. tree 
crops and plantaIns, and In general multIstory croppIng 
systems are most appropnate. The aCIdic soils in these 
regions contain few nutnents. ToxIc elements that can 
Inhibit crop growth are found In much of the subSOIl. 
Many of the rmportant nutnents of the system are 
present more In the bIomass than In the sori, and thus 
manIpulatIon of the bIomass IS Important In preserving 
productivity and making the best use of the pl"Oductive 
potentIal. 
In the mOist savanna zone, the productive potentIal 
for cereal and gram legume crops IS greater than In the 
forest, and sod constraInts al'e generally not as senous. 
However. poor soil structure and other phySIcal SOIl 
problems remaIn Imporiant. There is also significant 
nsk of erosIon In many areas. Some of the maIn SOil 
types in the savanna and transition zones may be 
subject to acidification when intensively cultivated 
Enaticand unpredictable rainfall, and resulting perods 
of drought stress, are significant problems for crop 
production, and integrated soil and watermanagement 
is o:ten needed to achieve 'Increased yields. 
The vv'etiands include coastal plains, inland basins of 
many of the river systems, river floodplains, and inland 
valleys and swamps. They form an estimated IOta 20 
percent of the humid ane subhumld lowlands of West 
and Central Africa, the region of primary focus for 
UTA In many instances, their production potential has 
not been developed. The inland valleys are often 
espec ally sUitable for smallholder development and 
for production of rice and associated crops. In general, 
sustainability of production is much less a problem In 
these wetland areas than in most upland regions. 
However, soil toxicity and the threat of pests for both 
crops and people can be serious obstacles to 
development. as can the socioeconom'c factors that 
reduce the availability of resources needed in 
developing inland valleys. 
Resource Management Research 
Research to guide management and conservation of 
the natural resource base involves the search for 
sustainable crop production systems. This task is 
fundamental in African agncultural development and 
is enormoJsly complex, 
Resource management research entails three 
conceptual stages of actiVity. 
• Measurement and analysis of the corrponents of 
the resource base (physical, cremlcal, :::>iological. 
socioeconorric). 
• AnalYSIS of the determinants of stability/degradation 
of the resource base through study of the dynamic 
interactions among t'lose components (for example. 
transport and storage of water and soil nut-ients). 
• Design of resource management systells through 
use of principies idefltified in the analysis of stability 
and degradaton (that is, modification of existing 
practices or design of new ones which can stabil ze or 
increase era:) output while avoidirig degradation of 
the resource base. 
liT A research activities In resource management 
are conceived under five headings, and are developed 
and linked with modelling. as IIlus~rated in the diagram 
in the righthand column: 
I. Resource characterization: description and rrapping 
of the biophysical and socioeconomic characteristics 
of the I IT A mandate area. 
• Intensive studies: surv'eys of fallow management 
systeMs (crops, fallow vegetation, soil characteristics, 
field size and hOL-sehold characteristics of fallow-
based famns). 
• ExtenSive studies: climatic-elevational rr,ap of 
mardate area (climatic data from available stations in 
West and Central Africa; elevation map; construction 
of climatic sutiace). 
2. Process stJdies of the resource management 
components contributing to sustalnab~lity, often in 
collaboration with advanced laboratories and 
institutions in developed countries. 
• Biological regulation of nutrient cycling in alley 
farming as compared with monocrop systems (rates 
of input and decomposition of crop residues and 
hedgerow prunings; rate of nitrogen fixation; among 
others). 
• Interplant cOfTlpetltion under different types and 
intensities of management (weed seedbank changes 
through clearing and croJping sequence; weed grovvth 
and response to management; among others). 
• Crop growth modelling In collaboration With the 
commodity improvement programs. 
3, Design of technologies for managing natural 
resources ard overcoming constraints in production 
and sustalnability, 
• Cropping systems incorporating trees 
(improvements in the physical and chemical 
characteristics of soil; increased stability of yield; multiple 
outputs). 
• Cropping systems incorporating herbaceous 
legumes (improved weed management control of 
e'-osior; increased soil fertility). 
4, Comparative studies of who'e cropping syste'l1s to 
~~ i" 
" ' I \ \ 
! ~esource ) ( On-Farrr \ I Cil2.racterization ~ • Testing and I 
\~ ;::; 
I 'r--{ \ 
( rvo::::eliing I ~ 
\ .----- \ I <--........(~ . \ 
c: ~ Comparc.tl'le 
Process ~tudies) I System Studies) 
~~ /~ /~ 
( T eC'1nology I DeSign J 
\~ 
33 
A cover crop of 
egusi melon helps 
in controlling weeds 
in this intercropped 
(teld of maize and 
yam. 
34 
investigate interactions among resource management 
components. 
• Comparison of traditional. tree-based and 
herbaceous legume-based fallow management systems 
(interaction between weed management and soil 
fertility; competition between fallow species and crops: 
labor requirements). 
Comparison of whole cropping systems. 
5. Testing, validation and adaptation of resource 
management technologies. 
• On-farm experiments in collaboration with the 
crop management research groups and national 
agricultural research agencies (e.g. with alley cropping 
technologies). 
• Use of modelling to determine environmental 
adaptability of technologies (e.g. alley cr-opping. tillage 
practices) in relation with long-term sustainability. 
Resource Management Achievements 
From the results of about two decades on African soils 
and the ecological and social setting in which African 
farmers cultivate their crops. liT A has leamed that the 
essential pnnciple for preventing or retarding soil 
degradation is to: 
• Maintain a cover of organic matter on the topsoil. 
This mulch mimics and replaces the effects of the 
forest ecosystem in protecting and regenerating the 
productive capacrty of the soil. The mulch protects 
the soil from structural damage from rain and excessive 
temperatures, supplies organic matter to replace that 
lost in microbiological processes, encourages beneficial 
activity by earthworms and other soil fauna and 
reduces nutrient leaching and acidification. 
Otherimpol1ant plinciples arising fmm the research 
include: 
• Limit use of heavy equipment. in order to avoid soil 
compaction, and select or design equipment to use 
which will exert a low pressure on the soil. 
• Loosen compacted soils where they occur and 
restore their structure. 
• Propagate mixed cropping with shallow- and deep-
rooting species, for efficient use of soil nutrients. as 
opposed to continuous monocropping. 
• Use feltilizer judiciously in order to balance soil 
nutrients and replace losses, but avoid overuse with 
concomitant problems of soil acidification and 
toxification. 
The major research pmducts are considered to be 
prototype technologies which are intended to be 
developed or finIShed through adaptation by national 
agricultural research systems in Africa. which will in 
turn extend them to farmers. They include: 
• A lley farming. A means of sustaining soil fertility 
and an alternative to fallows. alley farming is an 
agroforestry system in which multipurpose trees 
(usually legumes) are planted in rows whrle food crops 
are planted in the "alleys" between the trees. Soil 
nutrition IS improved through nitrogen fixation by the 
tree species and application of tree prunings for their 
organic matter. 
• Mulches and cover crop systems. Fast-growing 
leguminous cover cmps are planted to provide a 
constant so il cover before, during and after-the cropping 
phase. in orderto retard soil degradation and. In many 
cases, to suppress weeds. 
• Land clearing and development, When land must 
be cleared by machine. soil disturbance and subsequent 
emsion can be kept to a minimum with such implements 
as the shear blade. which cuts the vegetation at ground 
level. Minimum or zero tillage with the use of cover 
crops. mulches and herbrcides IS requwed when land 
IS cleared in thiS way. 
• Ti llage method. Studies at liT A and elsewhere 
have shown the advantages of minimum or no-tillage 
farming. 
• Ferti lizer and soi l additives. Appropriate feltllizer 
regimes have been developed which should enhance 
crop growth and not cause soil aCIdification ortoxlcrty 
pmblems. 
• Improved fa llows. Some research has been done 
to improve fallow management practices that would 
be more effiCient In restoring soli fertility than are 
unmanaged bush fallows. 
Conducted mainly at its humid forest station at 
Onne in south-eastem Nigeria, I ITA's research on acid 
soils has followed two different but complementary 
approaches to soils management. 
The first entails soil amendments, in this case by the 
use of lime and related materials, to combat acidity 
and aluminum toxicity in the soil. Experiments over a 
numberofyears have shown that even low applications 
oflime result in reduced acidity and toxicity. permitting 
significant yield improvements in crops such as maize. 
Additions of lime to expenmental fields Increased the 
effectiveness of magnesium fertilizer applications in 
1989 experiments. 
Lime and other related fertilizers are not, however, 
always available within the forest zone of West and 
Central Afnca. Although large quantities of nitrogen 
fertilizer are produced in Nigeria, it cannot readily be 
found even within Nigeria, because of its high price 
and transport difficulties. liT A is embarking on a study 
with the International Fertilizer Development Center 
(IFDC) in Togo to examine availability and potertial of 
the raw rratenals In the region. Another problem, in 
the case of lime, is that many soil nutrients can be lost 
through leaching because they are released as a result 
of changes in soil acidity. 
Boththese problems are addressed in liT A's second 
approach to acid soil management. by enrichment of 
the soil with organic matter through use of fallow 
spec.es, including trees. The 1988/89 IITA annual 
report describes IITA's success with alley farming, a 
particular application of this approach in the transition 
and savanna zone environments. Similar experiments 
have been conducted with trees, shrubs and 
herbaceous fallows at Onne, in the humid forests of 
coastal south-eastern Nigeria. 
Herbaceous legumes such as Pueraria seem to 
perfolm equally well in alley falms in both zones, 
whereas the most widely used tree species, Leucaena 
/eucocepholo, does not perform well in the humid 
forest at Onne. As a result of recent research on 
herbaceous alternatives to Leucoeno, liT A has 
identified a number of successful species. Among the 
most prorT'ising are Acia bonerii and a shrub, F,lemingia 
congesto. These species help to increase yields of 
interplanted rralze and cassava in acid soils by improving 
the solis chemically and phYSically, Improving the 
microenvironment and reducing weed infestation. 
Another shrub, T ephrosia candida, shows great 
promise as a fallow species for the reclamation of 
degraded lard. TephcoSlQ is being tested on 'and where 
yields have declined over several years. 
ACJO baten';, indigenous to West Africa, is valued as 
a fuel wood and as a "liVing stake'· for support of yarr 
vines. In parts of south-eastern Nigeria, it forms a 
component of a managed fallow system which has 
evolved out of the mixed-species bush fallow system 
more common in the area. In some instances, farmers 
oflmo State manage the tree in rows analogous to the 
hedgerows used in alley falming. 
In collaboration with Nigerian scientists and the 
International Council for Research and Agro-Forestry 
(ICRAF), IITA is preparing a sUNey to identify other 
indigenous trees for multipurpose use in agroforestry. 
The interactive effects of our two approaches to 
soil management will be studied during the next four 
years. Much of this comparison between conventional 
soil amendment (utilizing lime and fertilizers) and soil 
organic matter "manipulation" (utilizing trees and 
herbaceous fallow species) will be conducted at the 
new liT A humid forest station at Mbalmayo, 40 
kilometers south of Yaounde in Cameroon. A soil 
chemist and soil physicist have already begun to 
prepare for surveys of local farming systems and the 
natural resource base ofthe forest environment. 
Weed control is another important focus of 
resource management research. A weed is a plant out 
of place. Plant species which playa useful role dUring 
fallow periods by helpingto enrich the soil may, dunng 
cultivation pen ods, compete with crops and become 
serious pests. Since the small farmer usually has to 
control weeds by hand, weed control is often the 
biggest demand on his or her labor. 
Weed control practiceswhich reduce labor demand 
are high among liT A research priorities, The wo main 
altematives are the use of herbicides and cultural 
practices for biological control, both of which are 
being researched by liT A SCientists. Cultural practices 
offer the better long-term solution because the cost 
ofr.erbicides limits their potential use bysmall farmers. 
Speargrass, imperato Cy'/indrico, is one formidable 
weed which can be controlled by both chemical and 
biological means. Found In inteflselycultivated areas in 
the forest zone as well as throughout the African 
savanna, speargrass is able to take over cultivated 
areas and force fal1T'ers to abandon their fields, 
Subsequently it can maintain itself as the sole plant 
species in such areas almost indefinitely, In a survey in 
Oyo State, Nigeria, such abandoned fields were found 
in 31 out of 39 villages. Imperato is able to succeed 
because it has a rhizome or underground stem which 
stores large amounts of carbohydrate. This food fuels 
the spread of the grass and helps it to sUNive and 
35 
36 
regenerate when the bioMass above groJnd is 
destroyed, such as During dry-season fires. A common 
feature of 1m per oW-infested areas is a regular fire cycle 
which assists in the maintenance of the speargrass. 
DUring 1989 IITA tests showed successful control 
of ,Imperato chemica·ly, with a number of herbicides 
and biologically, with hedgerow trees or herbaceous 
legumes. Most promising for control are the 
herbaceious species: the shad·ng effect of Puerana 
reduced the Imperato rhizome biomass by 80 percent 
within a year, The herbaceous species are relative'y 
resistant to fire, can easily be established in speargrass 
areas where the fire cycle is frequent, and require less 
labor :0 maintain than do tree species. IITA will 
therefore concentrate research on this promising 
means of Imperato control with the prospect of 
rehabilitating large areas of currently uncultivatable 
land. 
Crop Management Research 
Research to guide management of different cropping 
systems concems tself with adaptation of rew or 
improved farming practices which are intended to 
increase productivity in those systems. 
Research ofthis kind requires ttle cooperation and 
i'lteraction of scientists in many disciplines, who work 
together from the stages of initially defining the 
objectives and problems, to developing new tech-
nologies, testing them under field conditions, com-
bining Individual technologies Into viable systems, and 
validating their suitability under varying conditions, 
liT A contact and cooperation with scientists and 
extension workers from national programs as well as 
with farmers are an essential part of this effort. In 
addition, liT A needs to study and understand the 
agroecological setting, the farming systems and 
constraints in production, all of which vary across the 
areas of research concem. liT A also needs to know 
what changes are occurring overtime. This is critical 
in setting research priorities, selecting suitable research 
sites, and targeti'lg technological innovations to the 
ap;Jropriate places and falT"lers. 
Crop management research entails three linked 
activities: 
• Diagnosis: characterization of mandated cropping 
systems areas, deSCription and analysis or const--aints 
aid impact of new technology. 
• Validation and adaptation: or-fa'Ttl screening, 
testing and evaluation of technologies generated during 
experirTent-station research. Adjustment or 
adaptation of existing technology to a particular se: of 
environmental conditions, either agroecological or 
sCCloeconomic. through on-farm research. 
• Feedback: relevant information from farm-level 
characterization, diagnosis and adaptive research 
reported back to scie'ltists who are developing 
resource management tecrnologies or breeding 
improved varieties at liT A's research stations. 
Different scientists representing varied disciplines 
have been teamed to develop and Implemert the 
research agenda for specific types offarming systerT's, 
associated witr ;:.artkular crops and agroecological 
zones. At first known as crop-based systems working 
groups, these groups have been renamed for their 
agroecological zone, They wili focus on the main crop 
system in each zone as follows: 
• HL-mid Forest Systems Research Grm"p (cassava-
based crop systems). 
• Savanna Systems Research Group (maize-based 
crop systems). 
• Inland Valley Systems Research Group (rice-based 
crop systems). 
liT A research activities !n crop management are 
organized in a farming systems perspective according 
to three agroecological zones, with three correspond-
ing multidisciplinary grouDs of scientists. 
Humid Forest Systems Research Group 
• Characterization of cassava systens in Africa. 
• Adoption and impact of IITA cassava In West 
Africa. 
• On-stat'on study o· resource use and productivity 
in cassava-based imercropping and rotation systems, 
• Collaborative adaptive trials With national institutions 
in Nigeria. Ghana, Cameroon, Zaire and Sierra Leone 
(e.g. effect of lime and improved cassava varieties on 
cassava and groundnut irtercropping systems in Bas-
Zaire and use of improved varieties and altemative 
spacing on rice and cassava intercropp ng systems in 
Sierra Leone and Lioeria). 
Savanna Systems Research Group 
• Charccterization of maize-based farming systems 
in the savanna of Nigeria and Cote d'ivoire. 
• Diagnostic study of the impact on striga infestati01 
of intensi~{ir,g maize-based cropping in the northem 
savanna of Nigeria. 
• Developmentof cultural control methods forstriga, 
Inland Valley Systems Research Group 
• Characterization and classification of inland valleys 
in West and Central Africa, 
• Quantification of yield losses from weeds, 
• Development and testing of methodology for 
selectir'g upland crop varieties for the inland valleys. 
Crop Management Achievements 
Available technologies that have been identified over 
the past five years include: 
• Cassava varieties with durable disease resistance 
and well adapted to the cassava/maize system. 
• Soybeans adapted for growing In the second season 
and in association with cassava. 
• Maize varieties with durable disease resistance and 
appropriate for green maize, but not where maize 
requires storage for an extended period of time. 
Feedback on farm-level problems from the systems 
research groups is helping to set the right emphasis in 
the research agenda of resource management resear-
chers and breeders. 
Examples include problems in establishing 
leguminous trees in alley cropping systems; the relative 
contribution of trees and herbaceous legumes in 
improved fallow management systems. besides 
continuous cultivation systems: weed control problems 
in no-tillage, cassava-based systems in which herbicides 
are not used. 
During 1989. the Humid Forest Systems Research 
Group launched the "rst major activity of the 
Collaborative Study of Cassava in Africa (COSCA). 
Led by liT Aand funded by the Rockefeller' Foundation, 
the study involves scientists from the C6te d·lvoire. 
Ghana. Nigeria. Tanzania. Uganda and Zaire in a 
survey of cassava production in their countries. Scientists 
from Centro Intemacional de Agricultura Tropical 
(ClAT), the U.K. Natur,,1 Resources Institute and the 
Intemational Child Health Unit of Upsala, Sweden are 
also collaborating in the survey. 
COSCA's broad objective is to improve the 
relevance and impact of cassava research by the 
Intemational agricultural research centers and national 
agricultural research systems in Africa. The study 
entails collection of data on cassava cropping systems 
In Afnca. type and extent of use of various processing 
techniques, marketing systems. present and future 
demand in rural and urban areas, and relationships 
between consumption and consumer nutrition. The 
participating countries produce about 70 percent of 
the cassava of sub-Saharan Africa. 
COSCA gathered gener·a!. mostly qualitative 
Information from group interviews in selected villages. 
Information specific to households. farms or processing 
units will be collected from individual households. 
Preliminary analysis of village-level data reveals, contrary 
to general expectat ion, that virtually all small famners 
in the hrgh-density population areas of the humid 
forest zone harvest their cassava 12 months or less 
after planting. In low-density population areas. about 
95 percent of the farmers harvest their cassava at 12 
months or less. In comparison with past practice, 
farmers thus appear to be using varieties which require 
shorter growing periods and to be harvesting their 
crop sooner. without keeping it stored in the ground. 
Furthermore, where access to the market is good, up 
to 44 percentef farmers harvest their cassava after less 
than I 2 months. 
As market access improves. the fallow period 
seems to be declining substantially, from about 6 to 3 
years, while farmers are increasing their weedings 
from 2 to 3 times. All the villages surveyed in Cote 
d'ivoire and Ghana, and 97 percent of those surveyed 
in Zaire, are not using any improved cassava varieties. 
In Nigeria. by contrast, wher'e liT A varieties have been 
widely disseminated, about 90 perTent of the villages 
surveyed are using improved varieties. 
The survey also reveals that small-scale cassava 
growers actively experiment with new var.ieties, 
abandoning old varieties when they prove unsuitable 
and adopting new ones. When bitter varieties are 
abandoned. it is usually because of their' susceptibility 
to weed competition, their late maturity or their low 
yields. With sweet varieties. it is their low yield, their 
late maturity or their poor storage qualities. 
During 1989 the Savanna Systems Research Group, 
together' with the Institute of Agricultural Research at 
Zaria, N igeria. completed their characterization of the 
agroecological and socioeconomic factors in maize 
cropping systems in the northern Guinea savanna. or 
moist savanna, of Nigeria. The recent dramatic 
expansion of maize in the area was the stimulus forthis 
Cassava 
intercropped with 
the soybeans being 
harvested ensures 
food security for 
this family when 
other food crops 
are not avaifable, 
37 
Expansion of 
maize (arming has 
brought an 
increase in ox-
driven plowing 
in the moist 
savanna. 
38 
focus. In the mid- 1970s maizewasa minor crop grown 
mainly in backyards. At that time it was significant as 
a cash crop in only one of the villages in the survey, and 
a major food crop in only one-third of them. Cunrently. 
maize is one of the three most important food crops 
and one of the three biggest cash crops in nearly nine 
out of ten of the sampled villages. Almost all of this 
new maize is reported to derive from improved liT A 
varieties. 
The savanna group also discovered that agricultural 
production in the area had intensified. Fallow periods 
have been eliminated in 6 out of 10 villages and 
declined in another quarter of them. Fertilizer is 
commonly used in all villages. Ox-driven plows are 
frequently used in land preparation and. in about half 
of the villages. ox plowing has often been adopted in 
conjunction with the elimination of fallows and the 
increase in maize cultivation. Concurrently. in response 
to the increased profitability of farming, farmers have 
also expanded the size of their farms and diversified 
their crops. In addition to maize. rice has become a 
cash crop, while production of such cash crops as 
pepper. cowpea and sugarcane has grown. 
Population increases in general. increases rn 
population density in particular and access to markets 
appear to have been the chief causes forthe changes. 
The savanna group will concentrate on the economic 
sustainability of the system: that is. what will be the 
impact on maize production of the expected removal 
of the government's subsidy on fertilizer, and the 
impact of devaluation of the Nigerian currency on 
incentives for such cash crops as cotton and groundnut, 
which compete with maize. liT A scientists will also 
look at the long-term sustainability of soil productivity: 
in particular. the effects of replacing traditional soil 
maintenance practices with increased use of inorganic 
fertilizers. and their implications for research on soil 
ferti lity maintenance. 
In an analogous survey in the forest zone of Nigeria. 
farmers identified their preferred characteristics of 
maize. Their top priority is increased yield. combined 
with bigger cob size. Eating quality appears to be 
important mostly for green maize. Improvement in 
storage quality does not have as high a priority as yield. 
Early maturity of the crop is not an important 
characteristic. It is unlikely that farmers in the forest 
zone. where land is freely available. would want to 
adopt high-yielding varieties which require fertilizers 
and other inputs to a high degree. Other ways of 
increasing yields would seem to be the altematives for 
liT A research: durable resistance characteristics to 
drought and pests. 
During 1989 the Inland Valleys Systems Research 
Group made an exhaustive review of agronomic and 
socioeconomic research on inland valleys in Africa. 
The group formulated several hypotheses about land 
use for future research. For example, the lower the 
rainfall in agiven area, the more likely that inland valleys 
are used for agricultural production. Also. changes in 
land use in inland valleys are principally determined by 
increases in population pressure and improvement in 
transport infrastructure. Some of the hypotheses 
relate to the quantification of constraints in different 
forms of land use, with respect to sustainability. 
productivity and farmer welfare. For example, 
ecologically sustainable agricu~ural production in inland 
valleys depends primarily on water control. Also, in 
some categories of inland valleys. the productivity of 
labor is greater in upland fields than in inland valleys. 
Research Strategies for Resource and 
Crop Management 
Building on the principles and accomplishments of 
past work. the liT A Resource and Crop Management 
Program will continue to focus on prevention of soil 
degradation while intensifying use of land and other 
resources to increase production. Systems which 
have shown promise for the forest/savanna transition 
zone will be further developed and new technologies 
suitable forthe acid soils of the forest zone will receive 
increased attention. The results of past resource 
management research will be more closely integrated 
wit h the results of commodity improvement programs 
through the zone-based systems research groups. 
The program's research priorities are described in 
the inset panel "Research Directions" on the opposite 
page. 
Research Directions 
Resource Management Research 
• Description, measurement, classification 
and mapping work on the biological, phy-
sical. chemical and socioeconomic 
characteristics of the liT A mandate area 
will be expanded with adoption of a 
geographical information system (GIS) and 
a large capacity for sat ellite image analysis. 
Climate-elevat ion maps will be constructed 
into which wi ll be incorporated the results 
of intensive studies such as surveys of 
fallow management systems. 
• Quantification of fundamental relation-
ships among factors contributing to the 
sustainability of food production systems 
will be expanded. Such process studies 
(e.g. biological regulation of nutrient cycling, 
physical factors affecting soil fertility, factors 
regulating interplant competition) will 
continue on non-acidic and high-phosphate 
acidic soils. The new humid forest station at 
Mbalmayo, Cameroon, will provide scope 
for expansion of interdisciplinary research 
on low-phosphate acid soi ls. 
• Indices will be developed for measuring 
the sustainability of small farmer cropping 
systems. 
• Technology design activities will be inten-
sified. The prototype alley cropping system 
will be further adapted for small-scale farm-
ers by adding economic tree crops oriJsing 
hedgerow trees which have direct benefrts. 
• Forthe humid forest zone, development 
of multipurpose agroforestry systems which 
combine improved soil and weed 
management will continue. 
• Efforts to develop economically viable 
and sustainable fal low managementsytems 
incorporating herbaceous legumes will be 
intensified. 
• Long-term comparative studies will assess 
capacity for sustainable crop production in 
traditional and improved resource 
management systems. 
• On-farm t esting and validation of liT A 
technologies will expand, emphasizing 
adaptability of alley cropping in different 
socioeconomic conditions, in collaboration 
with the Alley Farming Network forT ropical 
Africa (AFNET A). 
• Development of systems simulation 
models will emphasize intercropping, 
nutrient cycling in alley farming systems and 
economics/ecology of inland valleys, and 
will provide a comprehensive description 
of agricultural production systems. 
Humid Forest Systems Research Group 
• The Collaborative Study of Cassava in 
Africa (COSCA) will characterize African 
cassava production systems including types 
of varieties. processing. marketing and 
consumption, initially in 16 agroecological 
zones of 6 countries. 
• Strategic on-station studies of resource 
use and productivity in cassava-based 
intercropping systems will be conducted. 
• Studies of the adoption and impact of 
liT A cassava varieties in West and Central 
Africa w ill be expanded. 
• On-farm collaborativ~ studies will be 
expanded with national institutes, on the 
modifications of alley cropping systems to 
improve sustainability ofintercropping with 
cassava. 
Savanna Systems Research Gro up 
• Maize-basedfarming systems in the moist 
savanna ofWest Africa will be characterized 
and classified. Constraints affecting their 
sustainabilitywill be identified and quantified. 
• The influence of intensification of maize 
farming on striga infestation will be studied. 
• Cultural methods for control of striga as 
well as improvement of soil fertility will be 
developed and tested on farm with national 
institutes, 
Inland Valley Systems Research Group 
• Inland valleys in West and Central Africa 
w ill be clasSified and characterized, involving 
estimation of the percentage and location 
of those valleys which are used for 
agricultural production, identification of 
factors which discourage utilization ofinland 
valleys for agricultural . production, and 
classification of the valleys into different 
categories, 
• Constraints in land use in inland valleys 
will be identified and quantified in respect 
of sustainability, productivity and farmer 
wellbeing. The quantification will include 
yield losses owing to weeds, a major 
constraint in increasing rice production, 
• Models will be developed of biological, 
physical. chemical and socioeconomic 
processes in the principal categories of 
inland valleys. Together with national 
institutes, the models will be validated and 
tested wrth a view to applying the results in 
other categories of valleys and countries of 
West and Central Africa. 
• Improvements in land use and 
management practices for different 
categories ofinland valleys will be designed 
and tested. 
• Selection methods of upland crop varieties 
for inland valleys w ill be developed together 
with the commodity improvement 
programs. 
In summary. the Resource and Crop Management 
Program integrates the results of resource management 
and commodity improvement research within crop 
management research. through the work of the zone-
based systems research groups for the humid forest. 
moist savanna and inland valleys. Those groups ensure 
linkages and feedback between resource management 
and commodity scientists who work with economists 
in the study and improvement of smallholder 
production systems. The groups' linkages also extend 
to scientists in national agricultural research systems, 
through whom liT A responds to the needs of rts 
ultimate clients, the farmers. 
International Collaboration 
The program collaborates extensively with developed-
country institutions. intemational agricultural research 
centers and national agricultural research systems. 
39 
IITA agrociimat-
a/agist S. S. Jagtap 
shows how 
computer-iJss;sted 
models contribute 
in resistance 
breeding. 
40 
Developed-country institutions. Long-term collab-
orative research with the University of Hawaii at 
Manoa focuses on making the most effective use of 
alley farming systems. The objectives include research 
and training to ensure effective nitrogen fixation in 
legume-based alley cropping systems, to realize 
maximum benefrts from mycorrhizae for enhancing 
tree-legume effectiveness in these systems, and to 
develop computer-based information systems as a 
resource for national research/extension activities on 
alley cropping systems. The target is the acid, infertile 
and highly weathered sOils of tropical Africa. 
Cooperative long-term research with Michigan 
State University seeks to quantify root competition for 
nutrients and water between associated crops In alley 
cropping systems. The long-term goal is to quantify 
the underground processes of both hedgerow and 
alley crops grown in alley cropping systems, so that 
alley cropping may be adapted to more acid soils and 
to the subhumid tropics. 
A collaborative project with the Institute for Soil 
Fertility in the Netherlands seeks to quantify the role 
of soil organisms in soil management for food 
production in the humid tropics. A long-term project 
with the Katholic University of Leuven, Belgium, will 
study the dynamics of soil organic matter and its 
relationship with food crop Yields and soil productIVIty. 
Collaboration with other international organizations. 
liT A co-sponsors the Alley Farming Network for 
Tropical Agnculture (AFNET A) with ICRAF and the 
Intemational Livestock Center for Africa (ILCA), which 
involves scientists of most African countries. Its 
general objectives are to promote and support alley 
farming research, including on-farm testing, use and 
extension of the concept across diverse environments. 
Collaboration with ICRAF in a joint project wrth 
Oregon State University Involves the stationing of an 
ICRAF scientist at liT A to evaluate mUltipurpose tree 
species for agroforestry systems in the humid lowland 
zone of West Afnca. 
Collaborative research activities are planned with 
IFDC in soil fertility management for sustainable 
agriculturaJ production in the humid forest and inland 
valley ecosystems, An IFDC scientist Will be stationed 
at the liT A station in Mbalmayo, Camemon. 
liT A participates in the West Africa Falming Systems 
Research Network which sponsors the farming systems 
research course at the University of Os hang, Cameroon. 
liT A IS collaborating With the West Africa Rice 
Development Association (WARDA) in rice-based 
farming systems research in: 
• Characterization and classification ofland resources 
for cropping in general and on rice cropping In inland 
valleys in particular. 
• Resource and crop management research on nce-
based cropping systems in Inland valley bottoms and 
uplands in West Africa. 
Cooperation with national programs. The Resource 
and Crop Management Program's networking actlVl-
ties with national research programs are based primanly 
with AFNET A. a group on cassava-based systems re-
search which has existed since 1985, and a group on 
maize-based systems research (COMBS) launched in 
November 1989. Each group holds an annual work-
shop where ongoing collaborative projects are re-
viewed and plans made for new ones. The collaboration 
mainly concems on-farm adaptive research, fOCUSing 
on soil fertility management and weed control. 
Root, Tuber and Plantain ___ _ 
Improvement 
C ass. ava, yam and plantain. widely grown by srrall farmers, are the staple foods of hundreds of millions of people in the humid and subhumid 
regions of tropical Africa. Of the three crops -
cassava, a tuberous root - is by far the rrost important, 
providing more than half the food energy consumed 
by more than 200 million people. Plantain is eaten as 
a staple food by about 60 million people. 
The liT A Root, Tuber and Plantain Improvement 
Program is organized (see diagram below) to conduct 
research mainly on cassava, yams and p1antains which 
addresses problems of crop improvement including 
breeding for pest resistance and quality factors, and 
postharvest processing. ft works with national programs 
to adapt technological advances to their specific 
needs. 
Cassava 
liT A cassava sCientists have developed high-Yielding 
pest-resistant cassava varieties with good eating qual ity 
characteristics that are being adapted to the humid 
forest. forest-savanna transition, moist savanna and 
mid-altitude agroecological zones. They have set up 
30test sites in those different zones in Nigeria with the 
help of national colleagues. By 1990, liT Avarieties had 
been released to national programs in nine countries 
forfurthertesting and releasetofarrners: In Cameroon, 
Gabon, liberia, Nigeria, Rwanda, Seychelles, Sienra 
Leone, Tanzania and Zaire. 
SCientists from those countries have confirrned 
that the new varieties are resistant to the two most 
destructive disease pests: cassava mosaic virus disease 
and cassava bacterial blight. The Catholic University 
1---
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f' 8ce,edi'~ ---------, Cassava ---- --:---l fa~_=~- I 
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, 
cc-- ___ L _____ _ 
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ofLeuven in Belgium has also conducted tests of liT A 
cassava clones, or plant material which is one stage 
short of being produced as a variety. Involving the use 
of bacterial strains from many countries allover the 
world, those tests have confirmed stable resistance of 
IITA clones to cassava bactenal blight 
While the major disease problems have been 
overcome through breeding for host -plant resistance, 
the spread of the cassava mealybug (Phenococcus 
monihoti) and the cassava green spider mite 
(Mononychellus tono}oo) throughout Afnca's cassava 
be~ has posed a major challenge in recent years 
Signif~cant success has been achieved in biological 
control of the mealybug in many cassava-growing 
areas of Africa and a similar approach is being 
investigated for the mite. (See Biological Control 
Program article.) But the ultimate goal is integrated 
pest management involving host-plant resistance. 
The mechanisms for insect resistanceltolerance 
that are observed in such IITA cassava clones as TMS 
91934 are being investigated. The presence of 
trichomes, or minute hairs, on the young cassava 
shoot seems,to discourage attack by the cassava green 
spider mite. The trichomes appear to phYSically inhibit 
feeding by the pest. Several high-Yielding varieties with 
such pubescence or hairy development have been 
identified. Hybnds between cassava and its Wild 
relatives, in particular lv1onihot tristls and M, onomolo, 
are attracting interest as improved clones with the 
resistance character of pubescence, 
Although cassava as a crop is adapted to many 
different environments, the evidence suggests that 
-----,--
--~-.-. 
Postharvest Research r Spec~al Units 
, ---1 -_-~~~i~~ri~i_ 
i Bioc"lemi-;ry 
Food Technology Tissue Culture 
41 
Cassava in Africa 
Cassava is the single largest source of 
calories produced throughout tropical 
Africa. West and Central Africa each 
account for about one-third of cassava 
lower than that of maize) and because it 
requires almost no further processing. The 
low protein content of gari is augmented 
by the soups and meat with which it is 
production in Africa: Zaire and Nigeria are usually eaten. 
the continent's leading producers (see 
figure) . About three-fourths of the cassava 
in West Africa is grown in the forest and 
moist savanna zones. Data on production 
of root crops in Africa ane especially suspect. 
but production of cassava has undoubtedly 
increased in West and Central Africa. 
a~hough perhaps not as fast as population. 
Almost no export/import trade in cassava 
products is necorded. but some trade does 
take place across land borders. 
Cassava is more productive under poor 
soil conditions than are most other crops. 
and forthis reason it often is planted last in 
the cropping sequence. just before t he 
land neverts to fallow. Production of cassava 
roots requires relatively little labor 
compared with that of rice or yams: 
moreover, the timing of these labor inputs 
is very flexible since the root can be left in 
the ground for periods of several months 
or even a few years in some cases before 
harvesting. The abi lity of cassava to 
withstand drought once the plant is 
established has also encouraged its use as 
a famine reserve crop in drier parts of 
Africa. Tolerance of poor soils and low and 
flexible labor requirements help explain 
why cassava production has historically 
increased in areas where the best land and 
most of the available labor ane devoted to 
cash crops (for exa"'ple. cocoa) or labor-
intensive food crops (yams). As population 
pressure leadsto increased use of marginal 
lands, the area planted to cassava is likely 
to expand. 
I I I I I I I I I I 
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Qce 
d'Ivoire 
-
CentnI 0 - African Republic I-
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Equatorial G i nea ._ 
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= I Congo I l-r-
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Angola 0 D 
Zambia Zimbabwe 
o "' IOO.OOO Mctrk Ton$ 
l . l~ 1 
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r- Uganda -
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0 -rEJ--6~~ R.wanda SOr{lalia 
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I iT 
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Tanzania -
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Maiawi 
The labor required for processing the 
roots into gari, one of the most widely 
consumed cassava products in West Africa, 
is very high and equals the total labor input 
for production of the roots themselves. 
This processing is usually done at the 
household or village level. almost exclusively 
by women and chi ldnen. The end product 
is suited for low-income urban consumers 
because of its low cost per calorie (slightly 
I I I I I I I I I I I I I I 
42 
individual cassava varieties often have a narrow 
ecological adaptation. Multilocational trials conducted 
over a wide range of agroecological conditions in 
Nigeria have shown differential responses of cassava 
clones (genotypes) to the various edaphic, climat ic 
and biotic factors encountered in those environments. 
Such interactions between genotype and environment 
(GxE) often complicate the selection of desirable 
genotypes and thus hinder progress in varietal 
development. In order to avoid this hinderance, the 
selection process is being conducted from early 
generat ions directly in the specific target environments. 
Reproductive biology. New discoveries at liT A about 
the reproductive biology of cassava may offer a key to 
rapid dissemination of improved varieties and, 
eventually, to the agronomy of cassava through true 
seeds. Some cassava varieties can develop viable 
seeds even when the normal fertil ization process is 
prevented, in a form of vegetative reproduction called 
apomixis. liT A breeders have observed that first-
generation hybrids between an improved clone and 
w ild Manihot relatives (known as interspecific hybrids) 
all resembled the cassava parent. 
In order to investigate t his unexpected outcome, 
the female flowers of a number of clones were 
covered with cloth bags before the opening of the 
perianth and kept bagged for some five days, by which 
time the stigmas had ceased to be receptive. Despite 
the bags, w hich had effectively prevented t he 
opportunity for fertilization with pollen from African 
honeybees or any other extemal source, many flowers 
set fru its with viable seeds which produced normal 
plants. 
liT A aims to breed high-yielding cassava varieties 
which consistently produce true seeds by this process 
(obligate apomixis) such that their progenies are 
identical with the mother plant. Such true seeds could 
serve as a cheaper and more convenient means of 
disseminating and propagating improved cassava 
varieties. 
Another exciting and promising finding among the 
interspecific hybrids produced at liT A has been cassava 
polyploids- plants with a multiple of the normal 
numberof chromosomes. (See inset story on "Cassava 
Polyploidy" .) It is still early to substantiate the advantages 
of polyploidy in cassava, but it is clear that polyploids 
grow vigorously, quickly establish a ground cover 
wh ich helps control weeds, and yields as well as the 
best improved varieties. Apomixis and polyploidy 
offer plant breeders new opportunit ies for developing 
improved varieties. 
Polyploidy-
A Cassava Breeder's Bonanza? 
During the pasttwo decades of patient plant breeding, 
liT A scientists have developed improved cassava 
varieties that are winning growing acceptance by 
farmers in Africa's vast cassava belt. Recently, while 
crossing cultivated cassava species with w ild members 
of the same genus, Manihot, the Institute's breeders 
have discovered spontaneous cassava polyploids-
plants w ith multiples of the normal chromosome 
number (2n = 36)-among some of the resulting 
interspecific hybrids. The natural polyploids, which are 
characterized by enormous vigor and variation in form 
and structure, offer hope for further increases in yields, 
broader adaptation and new breeding possibilities, for 
the most important food crop of tropical Africa. 
Cassava, a starchy root provides more than one-
third of the total food energy in the region's diet, more 
than twice as much as either maize or yam. For more 
than 200 million people in sub-Saharan Africa-40 
percent of the population, including many of the 
poorest-cassava is the staff ofl ife. Farmers appreciate 
cassava because ittolerates drought pests and diseases 
and poor soils; requires relatively little labor; and can 
be left in the ground, ready for use when needed, for 
a year or more after maturity. 
For reliable harvests, farmers propagate cassava 
vegetatively: by planting sections oflast season's stems, 
they can assure themselves of virtually identical clones 
of the parent plants. But cassava breeders, who 
produce new, improved cassava types by combining 
characteristics from genetically disparate parents, must 
take a slower, less certain route: they rely on cassava's 
readiness to reproduce sexually and to set true seed. 
For example, by sexual crossings of cultivated cassava 
with a single related species, Manihot glaziovii, a tree 
form introduced into Nigeria from South America a 
half-century ago as a source of rubber, breeders have 
transferred such valuable traits as low cyanide content 
and resistance to mosaic virus and bacterial blight into 
African cassava varieties. 
Seeking further improvements, liT A scientists during 
the I 980s crossed several varieties of cultivated cassava 
with both M. glaziovii and M. epruinosa, a more recent 
acquisition from Brazil. Among the hundreds of 
progeny from their crosses, the scientists identified a 
few anomalous plants with unusually broad, thick 
leaves and large, widely spaced stomata, the respiratory 
openings in the leaf surface that permit the exchange 
of carbon dioxide and water in photosynthesis. Closer 
43 
examination of single cells and pollen spores confinmed 
that the anomalous plants were polyploids: either 
tetraploids, having twice the nonmal diploid number, 
2n, of chromosomes in each somatic cell; or triploids, 
with 3n chromosomes. 
Natural polyplo ids originate most commonly as 
accidents during sexual reproduction, when one or 
both parents contribute gametes w~h the unreduced 
(2n) number of chromosomes. The liT A tetraploids 
were attributed to matings between cultivated cassava 
and related wild parents-both diploids, with the nor-
mal (2n) chromosome number- that had both pro-
duced unreduced (2n) gametes. Thetriploids, by this 
reckoning, resulted from mat ings between n gametes 
from one parent and 2n gametes from the other. 
Natural polyploids can also arise asexually, from a 
failure of mitosis. resulting in a replication of the 
chromosomes in a somatic cell without the subsequent. 
Sexual Polyp/oldlzation in Cassava 
The reproductive cells in the ~ower 
buds. known as pollen mother cells 
(PMC) in the mole bud and egg 
mother cells (£MC) in the female 
bud. undergo the process of meiosis 
by which the chromosomes are 
separated during the formation of sex 
cells and their numbers are reduced 
from the diploid condition (36 
chromosomes) to the haploid (18 
chromosomes). If the reduction 
process foils. the resulting sex cells 
retain the original diploid number of 
chromosomes (36). 
Following pollination, fertilization 
marks the event in which the female 
and mole nuclei (gametes) in the sex 
cells join to form a zygote. If a nor-
mal mole gamete (having 18 
chromosomes) fertilizes a normal 
female gamete (18 chromosomes). 
.the resulting zygote is diploid (36 
chromosomes). If one gamete is a 
haploid (18 chromosomes) whereas 
the other is diploid (36 chroml>-
somes), a triploid zygote (54 chrl>-
mosomes) is produced. A tetraploid 
(72 chromosomes) results from the 
union of two diploid gametes. 
Flower Chromosome Number Meiosis Chromosome 
in Reproductive (Cell Division) Number in 
Mother Cell Gamete 
~ Egg Mother Cip Normal > Cip Cell (EMC) Pollen Mother (i§ > @ Cell (PMC) Normal 
Female Egg Mother Cip > Cip Flower Abnormol Cell (EMC) 
Pollen Mother (i§ > @ Cell (PMC) Normal \ 1\ / 
, . Egg Mother Cip > Cip Cell (EMC) Abnormal 
Male Pollen Mother (i§ > (i§ Flower Cell (PMC) Abnormal 
44 
nonmal division into daughter cells. Such asexual 
polyploids are rare: among more than 200,000 plants, 
the liT A cassava scientists have found only two asexual 
individuals, both tetraploids, arising from advent~ious 
buds on two different plants. (See accompanying 
diagram.) 
In liT A's experimental fields, polyploid progeny, 
with genes from both cassava and ~ wild relatives, 
grow up to be cassava types, able to hybridize freely 
with cukivated cassavas to produce improved varieties. 
But some polyploids, which have the vigor associated 
w~h hybrids in add~ion to their other qual~ies, may 
achieve variety status w~hout further improvement In 
uniform yield trials in a variety of N igerian environments. 
from the high-rainfall, acid-soil area to the dry savanna, 
an liT A tetraploid yielded an average of 19 tons per 
hectare, rivaling one of the country's leading improvec 
cassavas. The same tetraploid displayed resistance to 
mosaic virus and bacterial blight. and produced tubers 
of acceptable food qua l~. 
As parent material for further improvement natural 
polyploids, w~h their multiplied genetic complement, 
offer breeders greater variety of fonm and structure 
than the diploids, suggesting the possibil~ of breeding 
radically new cassava varieties adapted to diverse 
environments. 
Despite their complete complement of genes from 
their wild parents, the polyploid progeny of cultivated 
and w ild Monihot parents tum out to be all cassava 
types. Thus they require relatively few backcrosses to 
recover and stabilize desirable tra~, allowing breeders 
to accelerate the transfer of useful genes from wild 
Monihot species to cultivated cassava. 
Pollination Chromosome 
and Number and 
Fertilization PlOidy Level 
of Offspring 
>~ > C0 
Diploid 
~ > G Triploid 
~ > @ Tetrdploid 
Cassava plantlets are also being produced through 
somatic embryogenesIs. whereby embryos are 
generated from non-reproductive cells of the plant. 
SomatIC embryos have been obtained in vitro from 
young leaves of several liT A cassava clones in a liquid 
culture medium. At least 10 to 15 somatic embryolds 
have been obtained per leaf. Different procedures are 
being investigated in an effoli to generate plant lets 
from the embryos. 
Embryo rescue. Making use of exotic gene sources to 
improve cassava is an important task of liT A research 
In biotechnology. Immature embryos resulting from 
interspecific crosses have a tendency to die prematurely 
Props for Progress: 
A Better Cassava Stick 
Mrs. Misitura Raufu, whose business card reads 
CASSAVA TREE SUPPLIER. doesn't need statistics to 
tell her that small-scale famners have adopted IITA's 
improved cassava varieties. Mrs. Raufu, assisted by her 
mother and several children. has been doing business 
at her lenry-built roadside stand, just across the main 
highway from liT A's Ibadan headquarters, for four 
years. She knows what farmers want: her inventory-
bundles of cassava stems, called sticks. 40 to 50 sticks 
to a bundle. that farmers cut into shorter pieces to 
plant- is all guaranteed "IITA cassava". 
And how's business? "Look," she says, leafing 
through her invoice book and displaying a recent sale: 
600 bundles at 5 naira, for a total of3,000 naira (about 
US$375). In 1990, between the first rains in March 
and the end of June, halfway through the planting 
season, Mrs. R.aufu estimates that she sold about 3,000 
bundles. Many competitors offer the same product, 
up and down the highway and along virtually every 
back road in the region. 
The infomnal trade in liT A cassava sticks began 
spontaneously several years ago, when IITA enlisted 
some local farmers in on-farm trials of improved 
cassava varieties that had perfomned especially well on 
liT A's research plots. As the crop grew, the famners-
and their friends and neighbors-could hardly fall to 
notice the marked superiority of the liT A cassava to 
the local varieties. The resu~ing demand for planting 
sticks of liT A cassava was fal" greater than the Institute, 
which IS not set up to distribute varieties directly to 
famners, could begin to satisfy. 
Entrepreneurial Nigerians like Mrs. R.aufu have 
owing to incompatibility between the embryos and 
material tissues. liT A scientists have ah"eadyestablished 
procedures forthe culture of fairly mature embryos of 
cassava and wild Man/hot species on artifiCial growth 
media. Thesetechnrques are being adapted for rescue 
of very young embryos resulting from Important 
interspecific crosses. 
Multiplication. liT A SCientists recently developed a 
technique for rapid multiplICation of cassava vanetles 
to cut down on growing time and help speed up 
adaptive research. The technique entails treatment of 
mrnistem cuttings with a fungiCide suspension and 
sprouting in perforated polyethylene bags before 
been quick to seize the opportunity for profitable 
public service. Since she could produce clones of 
liT A's improved cassava in infinite multiples. all she had 
to do was get hold of a single stick and she was in 
business. Four years later she is able to produce most 
of the sticks she needs on her own famn. buying from 
otherfamners if she runs short Indeed, she's beginning 
to wonrythat some of her customers are stealing a leaf 
from her book, harvesting enough cassava sticks fOI" 
their own needs and a surplus for market 
45 
More yams (or the 
marketplace - one 
benefit o( 
improvements in 
production o( yam 
planting material. 
46 
transplanting. No costly and bulky sOil IS needed as 
a sprouting medium. The sprouted cuttings can be 
shipped in sealed polyethylene bags which meet 
phytosanitary regulations In inter-country exchanges. 
Utilization. Eating and nutritional qualities have been 
a focus of liT A research in recent years. liT A has 
improved clones with reduced cyanide content. a 
more mealy texture when cooked and other appealing 
charactenstics. Meahness results from marked changes 
In texture after boiling. as a result of a process which 
is being investigated. 
Cassava clones have also been Improved for 
production of flour for bread making. The goal is 
cassava varieties and processing technologies that can 
produce an acceptable bread from composite flours 
with a large proportion of cassava. Suitability of 
cassava flour in bread-making depends on certain 
properties of cassava starch. Detailed studies at the 
molecular level into differences of starch from liT A 
cassava clones are being conducted with the Food 
Science Department of the University of Manitoba. 
Canada. W~h another collaborator. the Catholic 
University of Leuven, liT A has identified new clones 
that can substitute for up to 20 percent of wheat flour 
in composite-flour breads. Rapid and effective methods 
for screening of additional clones have been perfected. 
In 1988,IITA cassava breeders developed improved 
varieties With yellow root flesh, for use In traditional 
foods. The West and Central African roasted cassava 
dish "yellow gari" and other popular dishes such as 
"fufu" can be prepared more conveniently and less 
expensively with yellow cassava. Nonmally white, gari 
turns yellow if red palm oil is added to the cassava 
during roasting. Oil from the red oil palm is rich in 
carotene, a plant pigment that changes to vitamin A 
in the body. It makes yellow gan more nutritious than 
white gan, and as much as one-third more expensive. 
The yellow-flesh cassava developed at liT A combines 
high carotene content with good cultivation 
characteristics, resistance to pests and diseases, and 
a high yield: and it makes yellow gari without palm oil. 
A surveyoftrad~ional cassava postharvest systems 
In Nigeria has revealed tremendous losses (about 
one-half of the potential product) and very high labor 
input, particularly by falming women. The results 
point to an urgent need for research into and 
development of processing facil~ies, espeCIally frying 
stoves and drying areas. Postharvest equipment was 
subsequently developed and field-tested and has 
contributed to a 12-percent reduction in production 
losses and lO-percent reduction in labor input. 
Contributing to the increase in system effiCiency are 
improvements In technology and the processing 
system, attitudinal improvement among operators 
and technical training. Some 362 units of I I types o f 
postharvest equipment have been fabricated and 
distributed in 16 countries in West and Central 
Africa Further improvements are underway, including 
standardization of designs and operating procedures. 
Yam 
The six West and Central African countries from 
Cote d'ivoireto Cameroon produceover90 percent 
ofthe world's yams, a staple food fortens of millions 
of their people. This highly labor-intensive crop is 
gradually expanding into the transition zone between 
humid forest and moist savanna, as arable land 
becomes scarcer (because of shortening fallow 
periods) in yams' original humid-forest home. The 
importance of the crop, and the promise of significant 
improvements in yield, more than justify continuing 
yam research. 
The goals of liT A's yam breeders are to produce 
plants that require less laborious staking: to improve 
the yam tuber's shape and make it easier to harvest 
and handle; to in-build genetic resistance to major 
diseases and nematodes; and to make yams look and 
taste better to consumers and keep longer before 
spoiling. The growing acceptance by urban consumers 
of smaller but unifonm tubers (I to 2 kg) should serve 
to lighten the burden of the yam fanmer in future, as 
cultivation of such tubers does not entail use of tall 
stakes and large mounds. 
Even before 1988, despite the frustrating 
complexity of yam's reproductive biology, IITA 
breeders were able to make as many as 10,000 
crosses annually to select for promising characteristics. 
In 1988, yam breeders succeeded in their quest for 
high-yielding water yam clones resistant to foliar 
necrosis, a disease that causes yam plants to lose their 
leaves prematurely. Field tests in four different 
agroecological locations produced yields of about 30 
tons per hectare, which outperiormed local cultivars 
by far. Many other promising white yam clones have 
been produced and are being evaluated for further 
adaptive research. 
During the I 980s, liT A scientists made significant 
improvements in methods for producing high-quality, 
low-cost and abundant yam planting material. relieving 
(almers of their traditional need to set aside one-
quarter of each crop to use as seed for the next. 
Minisett technology has been developed as a cheap 
and neliable method of producing seed yam, With thiS 
technology, famners can produce 40,000 to 100,000 
seed yams per hectare. Further improvements include 
the use of polyethylene mulch which eliminates staking. 
conserves soil moisture and nutrients, regulates soil 
moisture and checks weed growth. The minisett 
technique has cneated a big opportunity not only for 
farmers but for researchers. in making the job of 
germ plasm preservation easier. 
Five virus-free white yam cultivars were sent to 21 
countries, a milestone reached because of in-vitro 
microtuber formation. ThiS new technique from liT A 
has resolved obstacles of quarantine policy In the 
International distribution of germplasm. It also has 
permitted germ plasm accessions to be preserved In 
vitro in IITA's genetic resources collection. 
Plantain 
West and Central Africa produce about 60 percent of 
the world's plantains. Because of its long history of 
wide cultivation and distribution of plantain, the region 
has become a secondary center of plantain diversity. 
So far. I I 6 different cultivars have been identified. 
Plantain IS a particularly useful crop for (almers in 
the humid forest zone of West and Central Africa. As 
a backyard crop. plantain coexists easily with establ ished 
farming systems. It can provide a continuous source 
of food over the cropping year. It also counteracts 
degradation of the environment through the prolific 
leaf mulch cover it produces. 
Plantains have long been considered to be disease-
free because of their resistance to panama disease 
(Fusarium axysporum f. cubense) and yellow Sigatoka 
(Mycosphaerella musico!a), This picture changed 
dramatically about 15 years ago with the accidental 
Introduction into Africa of black Sigatoka (Mycosphaer-
Plantain 's Reprieve from a 
Black Plague 
When scientists at IITA's substation at Onne, Nigeria, 
began in 1987 to bneed plantains w~h resistance to 
black Sigatoka, they expected the effort to consume 
at least 10 years- the best part of a scientist's career. 
Even then, the outcome was far from assured. No 
source of resistance was known in plantains: only in 
some of its Musa cousins. which include common 
table bananas, starchy cooking bananas and wild types, 
In any case, cross-breeding resistance genes into 
edible plantains would be a fomnidable challenge: 
plantains aretriploids, with three sets of chromosomes 
instead of the two carried by most organisms. In 
theory, bneeding is complicated by the fact that each 
of plantain'S three sets of chromosomes derives from 
a different ancestor. In practice, however. that problem 
is moot because triploid plantains are normally seedless, 
and therefone infertile, They ane easy to eat but 
virtually impossible to breed, 
Preparing forthe worst- the virtual loss of plantain 
as a major food source for tropical Africa- the liT A 
scientists pursued a fallback strategy: adapting black-
Sigatoka-resistant starchy cooking bananas, they 
prepared to offer them to lowland farmers as plantain 
substitutes, Wamed an liT A statement early in 1989: 
"Time may be running out for plantains." 
Just nine months after this gloomy forecast, by the 
end of 1989, plantain's future was looking much 
brighter, Years before they had expected any significant 
success, the scientists at liT A's Onne station were in 
sight of their goaL Gmwing in their experimental fields 
wene a few hybrid plants that looked- and, more 
impoltantly, tasted-like plantain, and that had inherent 
resistance to black Sigatoka, 
ella fUiensls), a disease which ultimately leads to leaf 
necrosIs. It is so virulent that plants are often severely 
defoliated at halvest, thel-eby reduCing yields drastically. 
(See inset story on "Plantain's Reprieve from a Black 
Plague",) 
Plantains are exceptionally susceptible to black 
Sigatoka. No resistance or tolerance tothe disease has 
been found among all the plantain cultivars in liT As 
collection, which is maintained at the Onne High 
Rainfall Station. Since plantains are mainly grown by 
family fanmers, black Sigatoka is endangering the food 
security of resource-poor fa lmer'S. 
47 
A plantain plandet 
- an improved 
variety which ;s a 
product of in-vitro 
tissue culture. 
48 
Polfination of plantain in breeding resistance to bfack 
Sigatoka. 
The breakthrough was the result of crossing black-
Sigatoka-susceptible plantains with resistant diploid 
wild bananas. To arrange such an unlikely marriage. 
the liT A scientists needed a triploid female plantain 
that would set viable seed when fertilized by their 
diploid male wild banana with genes forblack-Sigatoka 
resistance. Among the I 16 different plantain cultivars 
maintained in IITA'sgenmplasm collection, the scientists 
at first found several- by mid-1990 they had 28-
seed-producing females of the preferred type. Some 
so-called French plantains that are reported to set 
seeds very rarely elsewhere tumed out to set 50 to 60 
seeds per stem when fertilized with viable pollen 
In starting a plantain breeding program at liT A. 
genmplasm was collected from Asia, the primary 
center of plantain diversity, and West and Central 
Afnca. Wild banana species resistant to black Sigatoka 
were collected from many parts of the world. 
In the process of breeding plantain with bananas in 
orderto obtain seeds. liT A scientists made discoveries 
which changed scientific thinking about plantains. The 
team has identified 20 French plantain cultivars and 8 
False Hom cultivars all with variable levels of fertility, 
overturning the prevalent ideas that French plantains 
had very low level of fertility (I to 2 seeds per bunch) 
and that False Homs were sterile. Up to 2 19 hybrid 
under Onne's conditions. False Hom plantains. which 
never set any seed anyv.there else. managed as many 
as 15 per stem at Onne. In 1988, crossing these 
plantains with resistant wild bananas-disparate 
members of the genus MusQ- the scientists were 
rewarded with viable hybrid seeds. 
Using embryo-culture techniques to overcome the 
seeds' reluctance to genminate, the scientists produced 
some 100 hybrid seedlings, which were transferred 
from petri dishes to the fields at Onne. Late in 1989 
they announced that four o f the resulting hybrid 
plantain plants combined the physical characteristics 
of plantains preferred by African consumers with high 
levels of resistance to black Sigatoka. The resistance 
not only delays the onset ofSigatoka symptoms; it also 
slows the progress of the disease, allowing even 
infected plants to mature and bear fruit nonmally. By 
July 1990, several hundred plantain hybrids were 
growing at Onne, awaiting evaluation for black Sigatoka 
resistance, 
The battle against black Sigatoka is not over yet. 
The scientists may need at least one more round of 
breedingto reduce their hybrids' chromosome counts 
to the triploid number. as the offspring of diploids and 
triploids, the resistant plants are tetraploids, with four 
pairs of chromosomes. Because they produce pollen, 
tetraploids are capable of crossing with other 
tetraploids, producing seeds that are hard and 
unpleasant in the eating of the fruit 
Once this consumer-acceptance problem is 
overcome, the resistant triploid hybrids will be rapidly 
mu~iplied by culturing shoot-tips in a medium that 
induces a proliferation of clones. Finally, liT A and the 
Intemational Netwonkforthe Improvement of Bananas 
and Plantains (INIBAP) will further multiply and 
distribute the clones to national programs, which will 
reproduce them for distribution to smallholders 
throughout Africa's humid-forest zone. 
seeds per bunch were obtained. 
Operational strategy. The plantain research program 
IS focused on the genetic improvement of plantain for 
black Sigatoka resistance. This should ultimately 
benefit the family fanmers of West and Central Africa 
who produce the bulk of the plantain crop for their 
own consumption In their backyards and small fields 
close to villages. 
Genetic Improvement involves the use of 
conventional breeding techniques, integrated with the 
use of in-vitro culture techniques to surmount speCific 
problems. 
Research Directions 
Cassava management will be intensified. • The sources of resistance to banana 
weevil will be identified and incorporated 
into plantain breeding populations. 
• Cassava genotypes will continue to be 
selected for major agroecological zones: 
humid forest, moist savanna, dry savanna 
and mid-altitudes. Quality characteristics 
being defined in the Collaborative Study of 
Cassava in Africa will be emphasized. 
• Crosses between cultivated cassava and 
its re lated Monihot species will be 
continued for manipulation of ploidy levels 
and for exploring possibilities to introgress 
new genetic sources from Monihot species 
to cultivated cassava. 
• Investigations into the rapid decline in 
yield of plantains under fanming conditions 
in West and Central Africa will continue. 
• Cassava genmplasm from Centro Inter-
nacional de Agricultura Tropical (CIA T) 
from selected agroecological zones in South 
America will be crossed onto liT A's improv-
ed cassava mosaic virus-resistant varieties 
and tested (or agronomic characteristics in 
conresponding African zones. The pro-
mising material thus identified will be sent 
out in seed fonm to national programs for 
evaluation and further adaptation and use. 
• The search for new sources of host-
plant resistance to the cassava green mite 
as a component of integrated pest 
• Research will continue to improve 
understanding of the physico-chemical 
bases for quality of traditional food products 
prepared from cassava. yams and plantains. 
Yam 
• Selection of genotypes for resistance to 
necrosis will be emphasized because of its 
importance for minimum staking. 
Plantain 
• Further research will enlarge under-
standing of the epidemiology and biology 
of the causal organism of black Sigatoka 
disease. 
• The search for increased flowering and 
better synchronization of flowering will be 
intensified. More locations with different 
environmental conditions will be used for 
flower induction. 
• DNA analysis will complement and 
extend on-going preliminary work on 
isozyme and storage protein electro-
phoretic analyses. 
• Breeding of durable host-plant resistance 
to black Sigatoka in plantain from different 
genetic sources will be attempted. 
The achievements described in the inset story. 
within two years of starting the plantain breeding 
program. indicate that other breeding objectives may 
also be achievable in the near future: breeding for 
banana weevil resistance. nematode resistance and 
dwarfism. and against yield decline. 
International Collaboration 
Germplasm exchange and dissemination of improved 
lines have intensified in recent years and become 
prime outreach activitie5. Dissemination of improved 
lines was at first delayed, however, by the slow process 
of multiplying planting material: and delayed further by 
national plant quarantine regulations. Both obstacles 
were at least partially overcome by the introduction of 
tissue culture and reliable indexing techniques, which 
eliminate viral and other diseases. 
Root crops. Several thousand true seed of cassava 
and over 10.000 disease-free clones in tissue culture 
fonm have been shipped to 38 African countries. 
where those varieties best adapted to local conditions 
are selected. Among the new releases derived from 
liT A genmplasm are the CARICASS series in Liberia. 
the ROCASS and NUCASS series in Sienra Leone. 
ClAM 76-7 in Gabon. Kinuani in Zaire. and N C-
Savanna and NC-Idiose in Nigeria. True seeds from 
local cassava clones outcrossed with liT A improved 
crosses have been introduced to liT A for evaluation. 
selection and hybridization with liT A clones in order 
to combine desirable t raits from local genmplasm with 
the high yields and pest resistance of the latter. 
liT A and Centro Intemacional de Agricultura 
Tropical (ClAT) have expandedtheirsharingof cassava 
genmplasm. ClAT has conducted trials with two IITA 
improved clones. Preliminary results indicate that 
one. TMS 30572. produces a stable yield under a wide 
range of ecological conditions in Colombia. Another 
clone. TMS 3000 I. was found to be resistant t o 
superelongation disease. a major South American 
disease of cassava. CIA T has introduced 149 cassava 
fami lies into liT A. and a CIA T scientist has joined the 
liT A research team. This will ensure that the genmplasm 
base for the improvement of cassava in Africa is being 
broadened. 
In Cameroon. Rwanda and Zaire. liT A has trained 
over 20 scientists, 600 technicians and extension 
agents and 2,600 farmers or representatives offarmers' 
associations in using root crop technologies. Improved 
varieties of cassava and sweet potato have been 
produced and released to fanmers by those national 
programs and by the National Root Crops Research 
Institute and National Seed Service of Nigeria. using 
liT A genmplasm. Sienra Leone. Liberia. Mozambique. 
Togo, Malawi. Kenya. Tanzania and Uganda. among 
other countries. are actively developing their national 
49 
50 
root and tuber improvement programs and attracting 
donor support for those programs in collaboration 
with liT A. liT A scientists have been assigned to 
cooperative root crop programs in Ghana, Cameroon. 
Rwanda and Zaire. 
The Eastem and Southem African Regional Root 
Crops Network (ESARRN) has coordinated among 
the countries ofthe region and IITA the planning and 
execution of regional research of common interest. 
liT A also participates in the Central and West African 
Regional Root Crops Network (CEWARRN). 
liT A partiCipates in the African Plant Biotechnology 
Network (APBNet) and the Intemational Plant 
Biotechnology Network (I PBNet) which I ink the 
countnes of Africa with advanced biotechnology 
laboratories. 
In 1989 IITA handed overthe responsibility for the 
improvement of sweet potato to a sister institute, 
Centro Intemacional de la Papa (ClP). The links with 
ClP remain close as IITA continues the process of 
aSSisting CIP in implementing ItS responsibility to 
Africa for sweet potato gemnplasm. 
IITA has research links with several advanced 
laboratories in areas which complement on-going 
research. Mutation breeding of yam and cassava. and 
somatic embryogenesis in yam, are being investigated 
In collaboration with the Intemational Atomic Energy 
Agency. Vienna. Collaborative agreements for research 
on various aspects of cyanogenesis and cassava 
detoxification and utilization are currently being planned 
with univers'lties in Austral'la, Denmark. Netherlands, 
UK and USA. Somatic embryogenesis in cassava is 
being pursued with the University of Bath, UK as well 
as research on the processing quality of plantains. 
Plantain. To strengthen plantain research, IITA has 
establIShed linkages the Intemational Networkforthe 
Improvement of Bananas and Plantains (I NIBAP). With 
the purpose of testing hybrids of both the Honduras 
Foundation (FHIA) and liT A in different agroecological 
environments in Africa and Central and South America. 
Phylogenetic studies in plantain are being given a 
boost with analysis of restriction fragment length 
polymorph ISms (RFLP). in collaboration with the U.S. 
Department of Agriculture in Georgia. USA The 
research aims to evaluate genetic diversity in plantain 
and improve understanding of the organization of the 
plantain genome. Studies of postharvest processing 
qualrty and starch. quality of plantains are being 
conducted With the Overseas Development Natural 
Resources I nstrtute, UK 
Grain Legume Improvement __ _ 
P rotein-rich grain legumes-mainly cowpea and, In recent years, soybean-are especially important In many parts of Africa where diets are otherwise 
scanty in protein sources. These plants. capable of 
producing their own nitrogen requirements from the 
nitrogen in the air, are also a basic component of any 
sustainable crop system in the savannas of Africa. 
The Grain Legume Improvement Program is 
organized (see diagram below) to conduct research 
mainly on cowpea and soybean which addresses 
problems of crop improvement and utilization in the 
target areas of farmer use. 
Cowpea 
Cowpea in Africa is traditionally considered to be a 
food legume ofthe poorest farmer's diet and is mostly 
cultivated as a subsistence crop. In the mixed fanning 
systems of the Sahelian regions, cowpea is the 
predominant legume and a major source of human 
food and fodder for cattle. It IS a secondary crop 
mainly in semi-arid zones, in association with millet, 
sorghum, maize, cassava and cotton, It is drought-
tolerant and can be grown in poor soils, Cowpea is 
able to fix nitrogen in the soil efficiently at around 30 
to 70 kilograms per hectare per year. 
Unlike many other legumes, cowpea may be 
consumed at different stages In its development as 
leaves green or dned. green pods, green peas and 
grain, of which the last IS the most popular. Dried 
cowpea IS highly nutritious: 24-percent protein, 20-
I 
percent oil and the rest carbohydrates with IT'inerals 
and other nutrients. Dried cowpea seeds take 
comparatively less time to cook then IT'any other food 
legumes, an ilT'portantconslderation in most developing 
countries where cooking fuel is scarce and expensive. 
Research conducted on cowpea by national 
programs of Afncan countries and liT A has made 
cultivation of the crop more attractive to both small-
and large-scale growers. New varieties with higher 
yield potential, a range of maturities, and resistance to 
some diseases and insect pests are being grown in 
larger areas and different agroecological zones than 
before. IITA has the global responsibility among 
intemational centers to conduct research on cowpea. 
Ecologies of cowpea. In the different agroecological 
zones in which they are grown in Africa, the appearance 
and growing habits of cowpea differ according to 
diversity among genotypes, climatic conditions, 
cropping systems and production problems. 
In the Sahel, traditional farm varieties are an 
indeterminate, vi ny, spreading type with a growing 
penod of upto 120 days. They are fast-growing, cover 
the soil surface and produce large quantitiesofbiomass. 
Millet is the main cereal here; cowpea is cultivated In 
mixtures with millet. Cowpea is consumed as green 
leaves, dried leaves, green peas, dry grain and fodder. 
After haNest, the dned plants are bcndled and stored 
for use as fodder for cattle during the harsh dry-
'weather period. 
I I 
I SADCC CO\lvJeaResearch I 
Mapu:o, Mozambique 
I liT A Headquarters 
Ibadan, '\Jlgena 
I Cowpec Research Statlor 
Kano, Nigena I 
I 
I 1 I i 
Breeding Pes: Managellent Postrarvest Moist Dry Savannc 
Research Savanna 
Cowpea, Soybean Cowpec.. Soybean Soybean 
-1 Breeding H Entomology H Ertomolcgy H Blochemls:ry H Breeding y B~eeding 
-1 Agronomy Y Pattlology Y Pati',ology Food --1 Physiology I 
-1 Pathology Technology 
51 
52 
In the dry and moist savannas, cowpea IS mostly 
intercropped with millet. sorghum and maize as a 
secondary crop after the cereal crop is established. 
Cowpea IS growc mostly for dry grain and fodder. 
With the first rains, famners often plant an early-
maturing cowpea along with a cereal. Afterthe cereal 
'IS established, the main cowpea crop is planted for 
both grain and fodder. 
In the lowland humid tropics (humid forest and 
transition zones) which have a bimodal rainfall 
distribution of two seasons, cowpea is planted in the 
second (short rainfall) season, in fields previously 
established with a cereal or root crop. Cowpea in this 
region is cultivated mostlyfordry grain and isalso used 
to a limited extent as a green leafy vegetable. Early-
to-medlum-matunng (60 to 70 days) varieties are 
preferred. Short, compact and upright varieties are 
considered most suitable. 
In the forest zone, cowpeas have traditionally been 
grown on a trellis for green pods for household 
subsistence needs. The cortinuous rain and high 
humidity which prevails for 9 to 10 months of the year 
prevent farmers from growing cowpea for dry grain. 
However, in all these zones, cowpea faces severe 
yield loss from indigenous insect pests. Even after 
screening almost all of the existing gemnplasm (15,000 
accessions), the resistance to some insects is low, 
resulting in the need for new (uncon'ventiona:) 
approaches to stabilize yields under farm conditions 
without the use of chemical pesticides. 
Achievements. Havingglobal respons!bility'forcowpea 
gemnplasrT' collection, IITA has collected more than 
15,000 accessions and maintains them at its 
headquarters at Ibadan. liT A headquarters lies near 
the center of origin and genetic diversity of the crop, 
al'ld within the region that produces most of the 
world's cowpeas. Since 1986 special efforts have been 
made to collect wild Vigna germplasm which is 
expected to playa key role in breeding for Insect 
resistance and other characteristics in future. 
liT A's early 'worK in cO'Npea improverrent was 
mainly devoted to basic research in crop physiology 
and to the identification of sources of resistance to 
insects and diseases. Sources of resls<:'ance to most of 
the important diseases have been identitled and 
incorporated in b"'eeding lines. Many of the elite lines 
distributed in intemational trials since the mld-1970s 
have high leveis of combined resistance tothe princi pal 
bacte';al, fungal and virus diseases. 
Late In the 19705, the mentation of the program 
evolved to include insect resistance, wthtre emphasis 
on insects encountered in Africa, The strategy was to 
acheve yield stability through resistance to both insect 
and disease pests. Several lines with multiple resistance 
to diseases and resistance to one or more insect pests 
have been developed. Many of those varieties have 
been released by naflonal programs. 
In the Sahel, the Semi-Arid Food Grains Research 
and Development (SAFGRAD) project team based at 
BurKina Faso began research on drought tolerance 
and resistance to striga In 1980. Through their efforts, 
"Sources of resistance to those two constraints were 
identified. A cowpea breeder was based at the 
International Crop Research Institute for the Semi-
Arid Tropics (ICRISAT) Sahel ian Centre at Niamey. 
Several lines with resistance to aphid, bruchid, bacterial 
blight and Macrophomina ashy stem blight are being 
developed. Crosses have been made for combining 
striga resistance and drought tolerance. Several lines 
combining striga resistance and multiple Insect and 
disease resistance were selected in 1989 for further 
trials after screening in Niamey and northem Nigeria. 
From research conducted through the SAFGRAD 
project and from lines developed at liT A headquarters, 
several lines have been selected in the Sarelian countries 
by national programs for further tests or release to 
famners for cultivation. VITA-?, SUVITA-2 and TYx 
3236 are among the more popular lines released in 
tre Sahelian countnes. In 1989, mixed cropping on-
station trials w,thout insecticide application showed 
higher grain and fodder yields than did local vanetles. 
Lines ITS?D-549 and IT87D-1491 were selected for 
on-farm testing by national scientists. 
In the savanna, a cowpea research station was 
established In July 1990 in Kano, northern Nigeria. 
(See story "Decentralization to the Savanna" in the 
Research Highlights section.) IITA IS working closely 
with the Institute of Agnculture Research (IAR) at 
Af]madu Bello University, Zaria and ICRISAT scientists 
based at Kano. liT A scientists at the station Include a 
cowpea breeder and two physiologists (one supported 
by the Tropical Agncultural Research Center of Japan). 
Seve"al segregating lines combining aphid, striga 
and alectra resistance appear promising. Several 
cowpea lines tested through intemational trials by 
national programs inthe region have been re'eased for 
cultivation by famner;. In 1989 on-famn tnals with 
minimal :nsectiCide applications, 1Vx 3236 showed a 
moderate level of resistance to thrips and diseases 
with a consequently improved yield potential. ThiS 
vanety has perfomned well in both the Sahel and 
savanna zones. Other lines 'ikewise tested in 1989 in 
the savanna with minimal insecticide applications have 
yielded consistently higher than local varieties: IT84S-
2246-4, KVx 165- 14- 1 and IT84S-223 1-15, VITA-3. 
which is resistant to leafhoppers. was released in 
several Latin American countries where leafhoppers 
are a major cowpea pest. 
In the humid forest and transition zones, liT A has 
succeeded in developing several lines with high yield 
potential (2,000 kilograms per hectare) with multiple 
virus resistance and with multiple disease and insect 
resistance. Cowpea lines have also been developed 
with medium (70 to 75 days) and early maturity (60 
to 65 days) with a diversity in seed color and plant type 
suitable for humid tropics, for cultivation during the. 
short rainy season or the dry season in paddy rice 
fallows. These varieties are for grain production as 
sole crops using insecticides to control pests. Their 
yield. with improved management but no fertilizer, is 
more than I 00 percent greater than that of t raditional 
varieties. The improved varieties require less spraying 
with insecticides because of their short duration and 
partial resistance. The cash cost of spraying is only a 
small fraction of the value of the increased output in 
many countries. Some of the best performers in 
intemational trials have been released to national 
programs: IT82E-18 to Zaire and Mozambique, IT82D-
889 and IT83D-442 to Bolivia, 
In the mid-altitudes, an liT A cowpea br-eeder was 
based in Kenya with the International Centre for Insect 
Physiology and Ecology (IClPE) from 1985 to 1987. 
During that time several local cowpea varieties and 
liT A lines were identified with superior agronomic 
character, Among the liT A lines tested in the region, 
IT82D-889, IT82D-885, IT82D-789 appearto periomn 
better than others, A cowpea project was approved 
by the Southern African Development Coordination 
Conference (SADCq during 1989, with funding from 
the European Economic Community, Through this 
project. the needs of southem African countries will 
be served and varieties suitable for eastem Africa are 
expected to be developed, 
Among the international trials conducted in 1989 
over a range of locations. the following cowpea lines 
consistently periomned better than others: extra early 
maturity IT82E-32, IT84S-2246-4, IT84D-666; medrum 
maturity IT85F-2020, IT83S-872. IT83D-2 19; bruchid-
resistant lines IT81 0 - 1007, ITB4S-2246-4, ITB5F-2205; 
aphid-resrstant lines ITB4S-2246-4, ITB5F-B67, ITB3S-
72B-5, 
Percentage bruchid Infestation and yield losses due 
to bruchrds were studied during 19B9. Compansons 
were made among standard local variety Ife Brown. 
resistant check TVu 2027 and two bruchid-resistant 
cowpea lines, ITBI 0-994 and ITB4S-2246-4, whrch 
ar-e derived from crosses made with TVu 2027, The 
results rndicated that two months after infestation Ife 
Brown was I OO-percent rnfested, as opposed to 7.3 
to 14.7 -percent infestation in thetwo bruchid-resistant 
lines. TVu 2027 was IBA-percent infested, Similarly, 
percentage loss in weight at 60 days after infestation 
in Ife Brown was IB.6 percent. compared with the 
other three resistant lines which varied between 1.7 
and I ,B percent, 
Impact. Fifty-one countnes worldwide In different 
agroecological zones have benefited from the 
numerous cowpea lines developed through liT A. 
These cowpea varieties have been released to farmers 
for cultivation by the national programs. Several lines 
are also utilized by national programs for incorporation 
of useful traits into the local varieties. 
The thrip-resistant cowpea vanety TVx 3236 is 
popular with farmers in the north em parts of Nigeria, 
Cameroon (savanna), Senegal (Sahel) and Botswana, 
Along with TVx 3236, the variety ER-7 is frequently 
cultivated rn southern Afnca, partrcularly in Botswana, 
Several lines with multiple resistance to diseases 
have been developed, rncluding Vita-I and Vrta-3 
which have already been released. Vita-3, with 
tolerance to drought and resistance to leafhoppers. is 
popular in Latin America where leafhoppers are a 
major pest of cowpea, It IS extensively cultivated by 
The savanna area 
of Kana, Nigeria, 
where the two 
farmers shown 
here are preparing 
to plant cowpea, 
provides a good 
environment (or 
II TA to adapt 
improved varieties 
to the traditional 
mixed cropping 
systems. 
53 
54 
farmers in Brazil, JalT'aica and Guatemala. 
Cowpea strategies. The aim of cowpea research at 
IITA is to reduce the risks in cultivation forthe fanner, 
thereby IncreaSingthe fanrner's productivity and income. 
At liT A cowpea research focuses on the crop in its 
agroecoJagical context, as part of a cropping system 
with particular requirements for resistance to insect 
pests and diseases. From 1988 the main breeding 
objectives have emphasized: 
• Morphological and physiological adaptation for 
intercropping with cereals. 
• Multiple pest and disease resistance for 
incorporation into :ocally adapted varieties. 
• Irrproved drought tolerance in cawpeas, especially 
forthe millet cropping system of the semi-arid zones. 
• Resistance to post-flowering pests. 
• Pest resistance characters from wild Vigna species. 
Because conventional breeding and sources of 
genes from cowpea collections have not been 
successful against insect pests in some cases, the 
program is relying increasingly on biotechnology 
research on the wide crosses. In 1989 wild Vigna 
species were screened for resistance to major pests of 
cowpeas. Several species appear to have high level of 
resistance: V. vexil/ota, V. luteoia and others to cowpea 
aphid and bruchid: II vexillata and V. oblongi(oliQ to the 
Maruca pod borer. Some V. oblingifolio appear 
resistant to pod sucking bugs. 
International collaboration. liT A works closely with 
many national agncultural research systems in sub-
Saharan Afnca and othertropical regions of the world. 
in the aevelopment and adapta:ion of new technology 
for cowpea production. liT A collaborates with 
advanced laboratories in specific problerr areas for 
basic research and has initiated contract research for 
solving some ofthe difficult crop protection problems. 
These include resistance to post-flowering pests of 
cowpeas through interspecific hybridization; resistance 
to strigaand alectra; resistance to root knot nematode 
and cowpea aphid biotypes In the tropiCS. 
In Nigeria. I ITA ~ascontracted research on resistance 
to Striga gesnenoides and Alectro vagelll to IAR and 
resistance to root knot nematodes to the University 
oflbadan. liT A collaborates on resistance to bruchids. 
Ca/i'osobruchus moculotus and Bruchidius atrolineatus 
with the Federal University ofT echnology. Akure and 
School of Biological Sciences. Imo State Universty, 
respectively. In Niger. liT A works with Institut National 
de Recherches Agronomiques du Niger on Macro-
phomina ashy stem blight resistance; and in Zambia, 
With Msekera Regional Research Station. Chipata. on 
cowpea aphid-borne mosaic virus, among others. 
With advanced laboratories in Italy (Unlverslta 
degli Stud! dl Napoli and Istituto del Gemnoplasma. 
Bari) and the U.S.A. (Purdue University). IITA has 
recently focused on biotechnology research for 
resistance to post-flowering 'Insect pests and cowpea 
bruchid neSistance. The Italian govemment has sup-
ported this basic research. liT A has contract research 
arrangements for the biotechnology research with 
Purdue University. IITA also collaborates with the 
University of Dunham. where the mechanISm ofbnuchid 
resistance in Nu 2027 and cowpea trypSin inhibitor 
gene (Cp TI) were originally Identified. Nu 2027 was 
identified as resistant to bruchid by liT A In 1974. 
ICiPE In Kenya has worked with IITA In the 
development of diet for Maruca pod borer under a 
research contract for a period of three years, funded 
by the Genman Technical Cooperation (GTZ). IITA 
has also collaborated with ICiPE In the identification of 
a mechanism of resistance to Maruca pod borer in 
Nu 946. and research on integrated pest management 
in cowpea mixed cropping with other cereals. In the 
U.K., liT A has contract research atTangements with 
Wye College for cowpea aphid biotype resistance 
research and identification of geographical races of 
this pest in the tropics. With the University of Bristol. 
Long Ashton Research Station. IITA collaborates for 
striga research which has resulted in the identification 
of B30 I striga and alectra resistant cowpea by the 
Long Ashton group. B30 I is the only line which 
appears to be neslStant to Virtually all the straInS of 
strigaand alectra In West Afnca. IITA has collaborated 
in the past with the Plant EnVironment Laboratory. 
Department of Agriculture. University of Reading. in 
cowpea phySiology research. 
Collaborative attempts are being made to transfer 
the coat protein gene of cowpea aphid bome-mosaic 
virus to cowpeas, by innovative biotechnology 
techniques, giving a novel approach forthe control of 
several strains of the virus. This worl<: could possibly 
provide for control of other potyviruses affecting 
cowpea. (A total of eight potyviruses ane reported 
from cowpea from all overthe world.) 
In the near future collaborative studies will 
commence with the bean/cowpea collaborative 
research support project of Michigan State University 
and with the Boyce Thompson Institute. U.s.A.. to 
Identify fungal. bacterial and vinus pathogens Involved 
in control of cowpea pests. 
The results of these cumulative efforts should 
ultimately help In solVing some of the more difficult 
cowpea production problems and make the crop less _______ :::::::~~~==~;; 
risky and more profitable to fanme" in the tropics. ~ _____ 
Soybean 
From the beginning, liT A has attached great importance 
to improvement of soybeans forthe tropics. and more 
recently to research on soybean processing and its 
utilization in human diets. As a nitrogen-fixing legume 
and cash crop in substantial demand, soybean has 
great potential as an important component of 
substainable farmi ng systems in the moist savannas of 
Africa. And although the crop is not yet widely grown 
by small-scale fanme" there and has traditionally been 
little used in Africa for food, it also has very great 
potential as a source of inexpensive protein in human 
diets, of valuable cooking oil and of animal feed. 
Improved soybean varieties must resist the major 
disease and insect pests and have growth cycles which 
frt agroecological conditions and the main features of 
local farming systems. The second research aim is to 
develop appropriate technologies for convenient home 
and village utilization. If people know what foods 
soybean can be used in and how to make them, this 
nutritious legume (40-percent protein and 20-percent 
oil) can generate a strong demand in the marketplace 
so that farmers will continue to produce soybean for 
the benefit of all. 
Ecologies of soybean. The best agroecological 
environments for soybean production are similar to 
those for maize and sorghum. In all environments. 
however, soybean has faced the two paramount 
problems of poor nodulation with soil bacteria and 
poor seed longevity. These problems are described 
In the "Achievements" section below. 
The moist and mid-altitude savannas are the most 
favorable zones for soybean production in West and 
Central Africa. Because of the relatively short rainy 
season, crop management and seed storage face 
fewer problems than in the wetter zones. Improved 
vaneties need to have a maturity range from 75 to 130 
days in orderto stay within the nonmal range of rainfall 
distribution. In these agroecological systems, maize 
and sorghum are the main crops and soybean is 
planted with them in rotation or is intercropped. 
Soybean production in these zones has been expanding 
rapidly in Nigeria, Ghana, Cote d'ivoire and Zambia 
over the past five years. 
The transition zone between humid forest and 
moist savanna is also suitable for soybean production. 
Recent investigations show that soybean yields in this 
zone are higher than those of cowpea and groundnuts. 
However, the bimodal rainfall pattern with two seasons 
makes maturity range an important factor. Some 
farmers plant within one or each rainy season, while 
some plant one crop across both seasons. 
The humid forest agroecological zone IS the most 
challenging for soybean improvement. because of acid 
soils and weathering of the bean on the plant before 
harvest. Harvests from an intercropping system with 
cassava have shown encouraging results, however. 
Inland valleys can also be promising for soybean 
production, as shown in intercropping trials with rice. 
Early maturity (75 to 90 days) is a particularly important 
characteristic in this zone. 
In all zones, apart from the immediate goals for 
research already described, the long-tenm issues for 
research concern crop rotation, intercropping and 
alley fanming systems. The effects of soybean on 
maintenance of good soil physical and chemical 
properties, and its effect on yields of associated crops, 
are at the heart of that concem, together with the 
socioeconomic effects of soybean cultivation on the 
farm families. In the savanna and transition zones it is 
not yet known whether soybean has any effect on 
striga populations in associated cereal cropping systems. 
In the humid forest and inland valleys, tolerance of acid 
soils is an important character for study. 
Achievements. When liT A began to collaborate with 
Nigerian scientists in the 1970s in soybean research, 
the two most critical weaknesses in the exotic high-
yielding varieties which they were testing were: (I) 
the inability of the plant to utilize nitrogen from the air, 
and (2) the low rate of genmination of the seed after 
it had been stored between cropping seasons. Both 
were subsequently overcome by breeding and a 
"tropicalized" soybean was created. 
Cowpea and 
soybean are 
screened for 
resistance to insed 
pests and insed-
borne diseases in 
this screenhouse 
designed by liT A. 
55 
Soybean is 
beginning to fulfill 
its promise as more 
formers grow 
the crop ond 
consumers learn 
how to process 
and use it 
56 
The first problem concemed the way soybeans. like 
other legumes. use nitrogen from the air. The roots 
of legumes are normally invaded by rhizobia. harmless 
bacteria from the soil which capture atmospheric 
nitrogen and convert it into a form which is useful for 
the nutrition of their host plant. Hence. legumes need 
little or none ofthe nitrogenous fertilizer which is so 
important for cereal crops. for instance, tothe obvious 
advantage of the farmer. Compatibility between host 
plant and colonizing bacteria determines whether' the 
plant roots form nodules where the bacteria can 
reside. Nodulation with rhizobia in the roots is crucial 
for the soybean to acquire the nitrogen it needs. 
The second problem concemed the rapid loss of 
the seed's germinating ability in the warm. moist 
storage conditions so common on African farms. Very 
few seeds remained viable, or alive and able to grow. 
between harvest in one year and planting in the next. 
An liT A team consisting of a breeder. physiologist 
and mio'obiologist began to work on those problems 
during the I 970s. Genotypes with traits forovencoming 
both nodulation and seed storability were found. but 
other characteristics had to be improved before they 
could be combined in successful varieties for Africa. 
Pods and leaves were vulnerable to insect and disease 
attack. Pods tended to "shatter" before harvest. 
scattering their seeds. Under storms or strong winds. 
stems fell over or lodged. Seeds were not uniformly 
cream-colored. 
By 1983 liT A had developed several varieties with 
improved nodulation and seed longevity and other 
agronomic characters. Subsequent research concen-
trated on resistance to shattering. foliar pathogens and 
pod sucking bugs. and on a uniform cream seed color. 
By 1989 significant progress had been made it improving 
genetic backgrounds of varieties for Africa with mu~iple 
resistance characteristics. Soybean yields of up to 
2.500 kilograms are now obtainable with liT A vaneties 
which have been released in Nigeria and other West 
African countries. In 1989. 23 African countries 
requested improved seeds from liT A to test for 
adaptability to their local environments. 
Improved cultivars with a short maturity period of 
90 days. which are suitable for intercropping with 
sorghum in the dry savanna. began trials with ICRISA T 
at Kana in 1989. Several lines were identi fied with a 
high level of resistance to the diseases of frogeye leaf 
spot and bacterial pustules. both of which are spreading 
and becoming economically significant In the region. 
O ver half the potential yield of one suscept ible local 
cultivar. 5amsoy I. was lost to frogeye leaf spot in trials. 
while the improved resistant variety TGx 996·26E 
maintained its high yields under heavy disease pressure. 
Consumer aspects came under IITA's purview in 
1985. when a food technologist joined the soybean 
team. The importance of improving the protein 
content of African diets has been the guiding principle 
of this research. Soybean utilization work has focused 
on improvement of technology for household and 
small·scale uses. as well as the food products made 
with such technology. 
New methods of processing soy milk to elimrnate 
burning hazards and reduce the labor requirement 
have been successfully introduced. leading to 
commercial adoption of the technology. Soy flour' has 
been used to improve the protein content of low-
protein traditional foods without increasing the cost 
or the cooking time and without changing the 
appearance or taste of the foods. 
For example. work in 1989 with soy milk residue 
and flour has given gari (a traditional food made from 
cassava) a I O-pencent protein content as against less 
than I-percent protein in the traditional gari. Several 
recipes utilizing soy milk residue were developed. and 
work continues on developing other uses for the 
home and small-scale industry. Tofu was produced 
using local plants as a coagulating agent "Soyamusa", 
a new extnuded. inexpensive soy-plantain baby food 
has been developed. Screw presses constructed in 
Africa that can process soybean are now available and 
their performance is being evaluated. 
Research Directions 
• Emphasis is being given to problems of 
the savanna zone: the dry savanna for 
cowpea and moist savanna for soybean. 
• Understanding of the biology of striga 
and its control are major objectives of a 
new liT A cross-program project with a 
twofold approach: to reduce the striga 
population and improve host-plant 
resistance to striga in maize and cowpea. 
priority. Technologies for incorporating 
resistance to insect pests and diseases into 
local cultivarswill continue to receive special 
emphasis. 
Cercosporo sojina. the causal organism of 
Ce",ospora leaf spot on soybean, and of 
sources of resistance will continue and the 
mode of inheritance of resistance will be 
determined. 
Cowpea 
• Development oflocally adapted cowpea 
genotypes will continue, for mixed cropping 
systems in the savanna with millet and 
sorghum, with emphasis on stab le 
resistance to insect pests and diseases. 
• Collaboration with the Semi-Arid Food 
Grains Research and Development 
(SAFGRAD) cowpea network will 
strengthen understanding of small-scale 
farmers' systems and will resu lt in 
approaches relevantto theirneeds. Strong 
support will also be given to the Southern 
African Development Coordination 
Conference (SADCq cowpea project 
• Development of improved small-scale 
and home-use technologies for 
incorporating soybean into traditional foods 
proceeds with the Institute for Agriculture 
and Training (IAR& T) at Ibadan, Nigeria. 
Simple low-cost processes are also being 
developed for soybean products that 
simulate meat. fish and African cheese. 
Soybean 
• Improvement of cowpea grain types 
and a range of maturities will continue, 
which meetthe diverse needs of producers 
and consumers of cowpeas in the tropics 
of Africa. 
• Strengthening of national programs and 
regional networks for cowpea in West and 
Central Africa continues to have a high 
• Development of varieties that are 
suitable for farmers in tropical Africa will 
seek to combine the following traits: stable 
and high yield, promiscuous nodulation, 
resistance to the majordiseases and insects, 
good seed storability, and resistance to 
lodging and shattering, with a range in 
maturities from 80 to 130 days. 
• Collaboration with the Institute for Agri-
cultural Research (IAR; Zaria, Nigeria) and 
the International Crop Research Institute 
for the Semi-Arid Tropics (ICRISA T) will 
emphasize sorghum/soybean intercropping 
and crop rotation systems. 
• Studies of the production, utilization 
and marketing systems used by soybean 
farmers in Nigeria will give direction for 
setting goals and objectives for liT A soybean 
research. • Identification of the different strains of 
Research strategy. A multidisciplinary team at liT A 
works toget her with scientists in national programs to 
develop improved varieties and production and utili-
zation technologies. The interaction with each institute 
or university is unique and diverse. according to need. 
In its genetic improvement work. the team 
concentrates on incorporating resistance to pod 
shattering, lodging and pod-sucking bugs into elite 
varieties which can nodulate freely and whose seeds 
retain their viability in farm stores. 
Improved cu ~ivars have been sent to liT A from 
strong breeding programs In C6te d'ivoire. Z imbabwe. 
Brazil and Thailand. Some national programs are 
evaluating liT A breeding lines for trait s that are 
important to them and for which they have a 
comparative advantage in conducting the research. 
Some programs request a large sample ( 100 kilograms) 
of one or two variet ies for on-farm testing. Often they 
wish to promote soybean production and utilization 
but do not have an active cultivar testing program. 
Some request seed of all liT A breeding lines. while 
others would like to receive 10 to 15 varieties for a 
replicated yield t rial. 
liT A maintains a soybean breeding capabi lity. 
including a germ plasm collection. W hen soybean 
becomes widely grown and consumed by African 
farmers. or if significant production problems appear. 
th is capability is ready to be used in conjunction with 
nat ional program efforts. 
Processing and utilization have gained priority as 
research topics at liT A in the conviction that consumers 
will increase demand for soybeans once they know 
what foods to prepare with soybean and are able to 
process them. Early in the 1980s liT A held workshops 
with N igerian and American scientists and producers 
on tropical soybean production and uti lization. The 
participants establ ished that the need to disseminate 
new home-level and small-scale processing techniques 
was urgent. In subsequent years a project was 
launched together w ith the Institute for Agricultural 
Research andT rain ing (IAR& T), N igeria, and a soybean 
utilizat ion specialist was provided to liT A from Japan. 
Other soy-based foods on the liT A research agenda 
are weaning foods; meat. fish and dairy substitutes; bis-
cuitsand breads made from composite flours including 
soy flour; and various uses for soy milk The soybean 
5 7 
58 
research team is also developing methods and equIp-
ment to improve processing of soy oil, flour and milk. 
International collaboration. In breeding, collaborative 
projects are concentrated in Nigeria, taking advantage 
of the favorable range of soybean-growing 
environments and ready consumer acceptance. With 
the National Cereals Research Institute, liT A is 
evaluating effects of acid sods on its breeding lines, and 
seed storability in the savanna. Resistance to insect 
and d'isease pests is being investigated by University of 
Ibadan students, while socioeconomic studies of 
soybean production have been undertaken at the 
University of Agriculture, Makurdi. 
In other countries, the Institut des Savannes 
(lDESSA) in Cote d'ivoire IS evaluating breeding lines 
underh igh-input production, utilizing cultivars received 
from Brazil. Long Ashton Research Station of the U.K. 
and IAR, Nigeria have collaborated in studYing striga 
on cowpea forthe pastseven years. and have succeeded 
in identifying B30 I as a cowpea cultlvarhighly resistant 
to striga strains in West Africa, 
Similarly, much of liT A's soybean utilization research 
is conducted in Nigena. IAR& T IS developlngtrad~ional 
foods with a soybean component in a collaborative 
project With liT A. funded by the International 
Development Research Centre (IDRC). Baby foods 
are being developed w~h the National Horticultural 
Research Institute (NIHORT) and University College 
Hosp~al at Ibadan, and the Federallnsbtute for Industrial 
Research, Oshodl (FIIRO). A Japanese postharvest 
technologist has been prOVided by the Japan 
Intemational Cooperation Agency OICA) to adapt soy 
food products to the requirements of Africa. Two 
companies, in Ghana and Nigeria, have teamed up 
with IITA to design and build screw presses for 
soybean oil extraction. Two other Nigerian companies 
are evaluating those screw presses. 
Soybean has become an attractive crop in tropical 
African countries. The main obstacles to successful 
cultivation have been overcome with patient research 
by liT A and coli abo rating partners over the past 20 
years. Soybean IS relatively high-yielding and easy to 
grow in comparison with other legumes. Consumers 
are beginning to find uses for soy products at home as 
a food and at a commercial level as vegetable oil, 
livestock feed, baby food and other food products. 
Maize Research 
I ITA conducts a full-scale improvement program for maize because of its importance as a source offood and feed, because of its high labor productivity, and 
because of its potential for rapid impact. Recent years 
have seen a significant expansion of maize production 
in West and Central Africa. Maize is expected to 
become increasingly important as population growth 
and urbanization intensifY demand for easily transported 
and storable food grains, and as demand for livestock 
products increases. 
IITA's research strategy for maize focuses primarily 
on the lowland moist savanna and humid forest zones 
of West and Central Africa. liT A collaborates with 
CIMMYT in a germplasm development program for 
those zones, which includes work on both open-
pollinated and hybrid varieties and efforts to maintain 
stable resistance to streak virus, downy mildew and 
lowland IlJst and blight. A maize research station is 
being established in the West African moist savanna 
forthe development of gemnplasm with emphasis on 
resistance to the parasitic weed striga. At Ibadan 
headquarters, methods to screen germplasm for 
resistance to pests and pathogens and tolerance of 
other stresses is being refined. (See diagram below.) 
In addition. maize scientists are actively involved in the 
savanna systems research group. Collaboration with 
and support to West and Central African national 
maize improvement programs continues, as does 
active participation in regional maize research networks. 
Dunng 1989, IITA maize sCientISts studied key 
aspects of the diseases downy mildew and maize 
streak vi nus, including host-plant/pathogen interactions, 
survival mechanisms and sUl\leys on incidence and 
distribution in Nigeria. Research on the parasitic weed 
I En:omo o&'/ 
striga was aimed at improvement of resistanceltoler-
ance levels in both open-pollinated and hybrid maize 
varieties. Significant improvement in resistance to the 
stem borer Eldano sacchorino was demonstrated in 
selected lines. Nitrogen-use effiCiency of key liT A 
varieties was studied, and work began on characterizing 
some of the physical and chemical properties of maize 
grain in relation to consumer preferences. 
Ecologies of maize 
The moist savanna, where maize has spread since the 
I 970s, has the greatest potential for maize production 
of all agroecological zones In West and Central Afnca. 
Maize has increasingly replaced sorghum in this region. 
Improved maize varieties have spread in several states 
of Nigeria's moist savanna through active promotion 
by Agricultural Development Prolects. which have 
used IITA varieties to make improved seed, including 
hybnds, available to famners, together with fertilizer. 
Without applications offertilizer or organic manures, 
however, low soil fertility lim:ts continuous maize 
cultivation. The parasitic plant striga also looms as the 
foremost pest threat to stable yields in the savanna. 
This zone holds IITA's highest priority for development 
in the region, with the emphasis on yield improvement 
by fanners who can use improved varieties, good hus-
bandry and a few purchased inputs. 
The humid forest, INhere maize was first introduced 
In Afnca, is characterized by high rainfall and humidity 
at elevations below 800 meters above sea level. It 
includes the coastal rainforests of West Afnca and the 
equatorial rainforest of Central Africa. The complex 
ecosystem ofthis zone presents the maizefannerwith 
a series of challenges: disease and insect attacks. low 
light intensity during the growing season, acid soils and 
59 
Maize has 
expanded rapidly in 
the moist savanna 
of Nigeria, as 
farmers have 
adopted improved 
IITA varieties. 
60 
high humidity that makes grain drying and storage 
difficult Rapid urbanization in this zone has nevertheless 
stimulated the demand (or "green" or fresh maize 
("com-on-t he-cob") as well as for dried grain. 
The mid-altitude zone- from 800 to 1.500 meters 
above sea level- in some parts of West and Cent ral 
Africa is ideally suited to maize. With good 
management. farmers can achieve and sustain even 
higher yields in this zone than in others, because of its 
rich volcanic soils and intense solar radiation yet cool 
nighttime temperatures. 
Achievements 
Most African farmers who grow maize cultivate their 
land with minimal resources which, combined with 
various stresses. produce yields of less than one-
quarter of their potential. liT A's maize research 
program has sought to breed maize varieties for these 
famners which are (a) resistantto the main disease and 
insect pests affecting the crop and (b) better adapted 
than their present cultivars to the growing conditions 
and which thus will produce higher- yields. The pro-
gram's end product of improved gemnplasm must be 
useful for national researchers, who adapt it into varie-
ties suitable for local conditions in each agroecological 
zone, ultimately for the farmers themselves. Within 
this frame the program has achieved notable successes, 
some of which are described in the following pages. 
Diseases. Of all pests. diseases pose the most critical 
threat to tropical maize development. Since the I 970s 
liT A has focused research with national programs on 
five major diseases: maize streak virus. downy mildew. 
stem/ear rot fungi, rusts and blights. The focus of the 
maize program's early breeding efforts was on 
combining the potential for high yield with significant 
resistance to lowland rust and blight. the two most 
important maize diseases at that time. Building on 
gemnplasm identified by Nigerian research and 
CIMMYT. IITA breeders developed two open-
pollinated varieties. Because of their resistance to 
those foliar diseases, the two varieties were quickly 
and widely adopted throughout Nigeria. As a result 
lowland rust and blight are no longer an immediate 
danger to improved maize crops. 
As the doubly resistant varieties were winning ac-
ceptance throughout Nigeria and in several other 
African countries, in the mid- 1970s the maize scientists 
added maize streak virus to their agenda, then downy 
mildew, and striga a few years later. In 1977, the 
program also began to tailor varieties for the mid-
altitude zone. 
liT A maize scientists have received accolades for 
10 years of effort in conquering maize streak virus. one 
of the main pests of maize in Africa. They devised 
novel screening techniques and a breeding strategy 
which identified a highly stable type of resistance. 
innovations which led to success and eamed liT A the 
King Baudouin Award for Intemational Agricultural 
Research in 1986. liT A organized an accelerated 
breeding campaign with CIMMYT and African national 
scientists to incorporate the resistance genes into 
improved varieties. By early in the I 980s. high-yielding. 
streak-resistant varieties- both open-pollinated and 
hybrid-with different maturing rates and grain types. 
were ready for farmers in all the maize-producing 
zones of Africa. 
Maize pathologists are gathering fundamental 
knowledge on downy mildew. a devastating fungal 
disease. Limited to a few areas at present. downy 
mildew appears to have a potential to spread together 
with expanding maize cultivation which must be 
assessed. Besides undertaking studies on the causal 
organism and the disease cycle. the pathologists have 
begun to investigate the interactions between host 
plant and pathogen. liT A pathologists are also worl<ing 
with Nigerian scientists to improve screening 
techniques for identifying resistant germplasm. 
They have succeeded in artificially infesting large test 
plots where different maize lines are screened for 
resistance. They have begun to develop moderately 
striga-resistant varieties for tropical Africa using genes 
from temperate-zone maize. In 1988 liT A scientists 
began studies with colleagues from University College. 
London on the physiological basis for resistance. 
Insect pests. The main insect pests of maize in Africa 
are: stem borers. which attack the growing maize plant 
itself: leafhoppers. which are vectors of viruses that 
attack the plant; and the various enemies of stored 
maize. chiefiy the grain weevils. To combat these pest 
problems. maize entomologists work at understanding 
their biology. their population dynamics and their 
complex interactions with the plant In quest of maize 
plants with built-in pest resistance. the researchers 
devise methods for multiplying and raising large 
populations of the pests. for infesting maize plots 
under controlled conditions. and for keeping accurate 
scores on how well the test plants survive. 
Stem borer resistance poses an unusually difficult 
challenge to maize breeders. In 1989. after improving 
the screening method against Eldana. one of several 
important stem borer pests, liT A scientists screened 
numerous maize lines for resistance and could demon-
Scientists from liT Aand the Institute for Agricultural strate significant improvement in resistance levels. 
Research and Training (IAR& 1) at Ibadan. jointly 
conducted a survey on the incidence and distribution 
of downy mildew disease in 1989. They investigated 
survival mechanisms of this fungal disease and potential 
sources of inoculum. as a step in building an 
understanding of its epidemiology and its potential to 
spread into new maize areas or to develop more 
virulent strains. liT A scientists. with colleagues from 
the University of Califomia at Davis. plan to apply the 
biotechnology technique of restriction fragment length 
polymorphism (RFLP) analysis. a new tool for examining 
such genetic variability. 
Striga. The parasitic plant striga, or "witchweed". is 
becoming a serious pest as maize production expands 
from the humid forest into savanna areas. the home of 
striga. The striga genus co-evolved with the native 
African crops of sorghum. millet and cowpea. which 
may have thus developed some tolerance of the pest. 
Maize has little natural resistance since it was introduced 
into Africa less than 500 years ago and was grown 
mainly in the forest zone, where striga does not occur. 
Up to 90 percent of a maize crop can be lost to striga 
In severely infested fields. 
Over the past decade liT A scientists have screened 
thousands of maize varieties or lines forstriga resistance. 
and have identified some moderately resistant types. 
Maize, as a crop 
new to the savanna 
which is the home 
of strigo, has little 
natural resistance 
to the pest and 
must be bred for 
durable resistance. 
61 
Maize is increasing 
in popularity as a 
food for urban 
populations. a trend 
which influences 
farmer acceptance 
of different varieties 
and. hence, 
breeding research 
objectives. 
62 
On-farm trials with Benlnois scientists have 
confirmed that resistance to weevils needs to be 
improved for the humid forest zone. The scientists' 
strategy defines three lines of defense: a better husk 
cover and physical and chemical characteristics of the 
kemels. The Natural Resources Institute. U.K. will help 
liT A to test for resistance and to elucidate the possible 
chemical and physical factors associated with resistance. 
liT A entomologists conducted a survey on the 
insect vectors of maize streak virus. C/codulino 
leafhoppers. in different Nigerian agroecological zones. 
They studied the grass hosts of the vi nus and the 
capaCity of the vinus to be transmitted from these 
grasses to maize. They need such information in order 
to understand how the vrrus survives the dry season. 
when there IS little or no maize. and where reinfection 
comes from. at the beginning of each new rainy 
season. These studies should also be able to show 
whether new strains of the virus are appealing in wild 
grasses which could Jeopardize currently resistant 
maize varieties. So far none has been found. 
Entomologists also began to study the feeding 
behaVior of the leafhopper, In order to improve 
understanding of host -plant/vector/virus interrelations. 
Fertilizer. Maize farmers in Afnca are aware of the 
benefrts of fertilizer and use it when they can find and 
afford it. The recent spread of maize in the savanna 
• 
was facilitated by availability of subsidized chemical 
fertilizers. especially nitrogen. However. fertitizerprices 
are increasing and distribution systems often favor 
large-scale farmers. Furthermore. maize root systems 
tend to develop poorly in tropical SOils. so that their 
recovery of nitrogen from fertilizer is often inefficient. 
sometimes as low as 20 percent of total nitrogen 
applied. 
liT A scientists have begun to look at the possibilities 
for breeding African maize for improved efficiency in 
nitrogen uptake and use. They have evaluated the 
yield performance of certain improved maize varieties 
under varying conditions of soil nitrogen fertility. It is 
clear. however. that high yields from any maize variety 
cannot be sustained without some form of nitrogen 
enrichment of the soil. Economical ways to improve 
soil fertility and soil nutrient retention are being 
researched by t he /ITA Resource and Crop 
Management Program. These methods need to be 
combined with maize vanetles that are designed to 
Increase the efficiency of nitrogen use. 
In 1989. SCientists measured dry matter production 
and nitrogen uptake and distribution in the plant. In 
several maize varieties, in orderto identify mechanisms 
associated with efficient nitrogen use. Grain Yield of 
different varieties declined as the nitrogen level 
decreased: however, vanetles which yielded well with 
high nitrogen levels also tended to be the better 
Yielders under low nitrogen. Different results had. 
however. been found earlier among varieties tested in 
liT A's outreach program in mid-altitude Zail'e and in 
savanna trials in Burkina Faso. 
Eating quality. Little worl< on quality characteristics for 
human consumption has been done In developed 
countries because maize is used there mainly as an 
animal feed. However. looking toward the future 
when maize Will be a major food source for the urban 
population in Africa. urban preferences will infiuence 
quality characteristics in the maize supply. Already. 
consumer taste and texture charactenstics greatly 
Influence differential marl<et pnces for maize. liT A 
scientists in the Republic of Benin have found that 
fanmers like the high yields and disease resistance of 
liT A varieties. but are used to different grain textures. 
Hence. the research IS important forfanmeracceptabllity 
of the new improved varieties. 
liT A scientists began to characterize some phYSical 
and chemical properties of maize grain and to study 
their relationship with consumer preferences. The 
ratio of sugar to starch. and the hardness of the kemel. 
are important eating characteristics of green maize. In 
the dry grain of mature maize. soft floury kemels are 
preferred in many areas while hard kemels are preferred 
in others, depending on the type of dish being prepared. 
Research on genetic control of this characteristic, and 
its relationship with protein content of maize, has 
commenced. 
Breeding. The "pay-off' from the work descnbed 
above is the development of new, improved varieties. 
liT A breeders must always be engaged in pioneenng 
work against new challenges, such as striga, as well as 
conduct regular programs of"maintenance" breeding 
to keep up the levels of resistance to such disease 
pests as streak virus, downy mildew, rusts, blights and 
stem/ear rots. 
Breeders can develop tvvo types of maize: open-
pollinated varieties, which farmers like because they 
can propagate the seed on-farm from yearto year; and 
hybrid varieties, whose advantage is a higher yield but 
for which seed must be bought anew each year. liT A's 
maize program works on both types, because both 
are important in the development of small-scale maize 
farming. They also form complelT'entary components 
in maize breeding strategies: hybrid varieties can be 
developed outof open-pollinated "base populations." 
From open-pollinated populations come the "inbred" 
lines with specific genetic traits which are used in 
developing new hybrids as well as in "fixing" desirable 
genes into unchanging forms, as a genetic resource. 
Inbred lines can in tum be combined to fann new 
open-pollinated varieties. 
The use and commercialization of hybrid maize can 
be a milestone in maize development in any country. 
because it contributes to the profitability of the local 
seed industry. which is so Important for sustaining a 
source of high-quality hybrid and open-pollinated 
seed for famners. By 1984. hybnds produced at liT A 
had helped to establish two successful Nigerian seed 
companies. 
liT A maize breeders in 1989 reviewed work on 
inbred lines and hybrids and corrected deficiencies in 
certain traits. They tested 3,000 experimental hybrids 
in order to diversify the gemnplasm base. 
Research strategy 
Research strategy must respond to changing needs 
and possibilities, tadoringits research priorities according 
to pest and environmental problems and to consumer 
needs in each agroecological zone. For example, the 
advantages of easy cultivation and high productivity 
could lead to overproduction and depressed prices 
for maize for human consumption. Hence, future 
strategies should entail altemative use of maize as 
livestock feed or industnal applications. (See table on 
maize breeding objectives on this page.) 
In the moist savanna, breeding for resistance to 
striga ranks as the highest priority. Basic research is 
needed on host-parasite relations, resistance 
mechanisms and resistance screening methods. And 
looking ahead, the potential for downy mildew to 
spread with expanding maize production calls for 
preemptive research measures to contain such a 
threat 
liT A is establishing a research station for maize 
research in the moist savanna zone. Other IITA 
research programs with an interest in the zone will 
also use the facilities. An adjunct CIMMYT breederwill 
work there to adapt susceptible gemnplasm to resist 
African pests. 
Breeding objectives for maize in West and Central Africa 
Agroecological 
Zone 
Humid 
forest 
Moist 
savanna 
Mid-altitudes 
Cropping System 
Maize/cassava 
:'1aize monocrop, 
Maize/sorghum. 
Maize/cowpea 
Maize intercrop, 
Maize/legume 
Breeding objectives 
Biotic 
Downy mildew, stem borers, 
ear and stalk rots, streak virus, 
storage weevils, curvularia, rust 
and bl'ght 
Stnga, hybrid vigor, streak virus, 
downy mildew, stem borers, 
",st and bl'ght 
Blight rust, streak virus, 
hybrid vigor, ear and 
stalk rots, stem borers 
Abiotic 
Nitrogen use efficiency, 
intercropping 
characteristics 
Nitrogen use efficiency, 
drought 
Acid soil tolerance 
63 
Maize plants in the 
foreground show 
symptoms a( downy 
mildew, which has a 
high priority in 
humid (arest 
research at IITA in 
the hands a( Dr. O. 
M. O/anya and 
others. 
64 
For the humid forest, liT A scientists wi ll continue 
their research at the Ibadan campus headquarters. 
The first priorities are resistance to insect pests (stem 
borers and storage weevils), downy mildew. and ear 
and stalk rots. The possibilities of improving green 
maize will be further examined. Also, maintenance 
breeding against streak virus and lowland rust and 
blight must continue. 
The highest research priorities forthe mid-altitudes 
are development of higher-yielding varieties with re-
sistance to mid-aMude rust and blight and streak virus. 
liT A scientists aim at developing "durable" resistance 
that won't break down after a few years. Durable 
resistance is often based on the interaction of many 
genes in complex forms which pests have difficulty in 
overcoming, even with their own natural mechanisms 
for adapting to new situations. A durable resistance to 
a pest can give stability to the fanner's maize yield, 
which is crucial for the small farmer whose resources 
leave little margin for risk-taking in selecting a crop to 
plant. 
With the deeper understanding gained fr-om those 
efforts comes the ability to breed improved maize 
germplasm and to help scientists In national maize 
programs in improving vanetles to meet their own 
particular needs. liT A scientists develop and test 
improved germplasm and distribute it to researchers 
in African national systems and to others for adaptation 
to local cultivation needs. They also tap the resources 
of advanced laboratories for primary research 
technologies needed in the adaptive process. 
The effort also enlists scientists from other IITA 
programs. Colleagues in the Intemational Cooperation 
Program, for example, work with national research 
systems in training scientific manpower. Scientists in 
the Virology Unit investigate maize viruses. Maize 
scientists contribute improved germ plasm and their 
disciplinary research to the Savanna Systems Research 
Group in liT A's Resource and Crop Management 
Program. In tum. the gr-oup feeds back the results of 
its trials under actual farming conditions. This 
information guides the maize scientists In returning full 
circle to defining their future research objectives. 
liT A and ClMMYT are addr-esSing the major genm-
plasm issues of Africa as a whole. liT A concentrates on 
West and Central African pr-oblems while ClMMYT 
takes the lead in East and Southern Africa. They ex-
change and test germ plasm and information between 
the two regions to ensure that all Afncan countnes 
have access to the best available matenals. 
International collaboration 
liT A's most active partnerships with national research 
systems have been with Cameroon, Nigeria and Zaire. 
liT A also participates wrth 26 national marze programs 
through the Semi-Arid Food Grams Research and 
Development (SAFGRAD) maize network, and posts 
a coordinator with SAFGRAD project headquarters 
in Burkina Faso. Within the international research 
system, liT A's maize research program shares research 
findings and genetic materials with ClMMYT in Mexico 
and other institutions. 
The devastating Sahel ian drought early in the 1980s 
galvanized the 26 national programs bordering the 
West Afncan Sahel desert and dry savanna areas. with 
donor agencies and technical support rnstitutions, to 
link their research systems in the struggle to keep 
agricutture alive in those areas. Countnes take on 
research responsibilities according to their capacity, in 
such areas as resistance to drought. streak virus, striga 
and stem borers. and improved grarn quality and 
storability. For these dry savanna areas where maize is 
intercropped with cowpea, liT A has contributed maize 
and cowpea germ plasm, training and technical advice 
and support. Many member countries have seen their 
capacity to utilize and generate new germplasm grow 
as a result of SAFGRAD activities. 
In Cameroon. the National Cereals Research and 
Extension (NCRE) project houses an liT A maize 
Research Directions 
• Priority is being given to problems of the 
moist savanna zone, the most favorable 
lowland environment for maize. A station 
for maize research in the moist savanna 
zone is being established. 
• Understanding of the biology of striga 
and its control are major objectives of a 
new liT A project with a twofold approach: 
to reduce the striga population and improve 
host plant resistance. 
• Strengthening of national programs and 
regional maize networks in West and 
Central Africa continues to have a high 
priority. Transfer of technologies for 
screening for resistance to maize streak 
virus will continue to receive special 
emphasis. 
understanding of small-scale farmers' 
systems. 
• Development of locally adapted 
popUlations, inbred lines and hybrids will 
continue emphasizing: stable resistance to 
foliar and ear diseases and to maize streak 
virus; resistance to stem borers and storage 
insect pests; grain types and a range of 
maturities to meet the needs in the lowland 
and mid-altitude tropics. 
• Close collaboration of the maize 
program with liT A's Savanna Systems 
Research Group is strengthening liT A's 
breeder who develops new varieties with local scientists 
for the western mid-altitude plains, a major maize-
producing and -consuming part of the country. NCRE 
has developed high-yielding open-pollinated varieties 
for the area resistant to highland blight and rust. 
Hybrid maize is also expected to make an impact 
there, since NCRE has produced inbred lines with 
excellent combining ability. 
Since liT A varieties resistant to maize streak virus 
have not yet been w idely introduced in Zaire, the 
disease continues to damage the maize crop there. An 
liT A breeder and entomologist in a bilateral aid 
program have helped scientists in the national maize 
program to select and test streak-resistant varieties on 
farms. Those varieties have begun to enter the national 
seed multiplication process. liT A and Zairean scientists 
have also constructed a leafhopper rearing facility. 
needed in continuing the selection of future resistant 
varieties for Zaire. 
Substantial facilities at liT A headquarters are an 
asset to national program scientists who use them on 
visits or research attachments to enhance their own 
work. The process nows two ways: visiting scientists 
and collaborators in tum add insights from their own 
experience to ongoing liT A work. providing an extra 
dimension to research accomplishments at liT A. 
During 1989/90. a Ghanaian breeder took the 
opportunity. as a visiting scientist at liT A. to utilize liT A 
materials and facilities to strengthen maize work in 
Ghana. Dr. Baffour Badu-Apraku. who received his 
doctorate from Cornell in 1986. has since that year 
headed Ghana's maize program based at the Crops 
Research Institute, Kumasi. He is happy that his year-
long stay at liT A has produced substantial results. 
W ithin two experimental generations. Ghanaian 
maize varieties have been improved with resistance 
genes to maize streak virus. Also, inbred lines from 
liT A and Ghana have been matched to produce 
better Ghanaian hybrids. 
On his retum to Kumasi, Dr. Badu-Apraku will 
work in transfenring the maize streak resistance 
technology to t he Ghanaian program, with the use of 
leafhopper-rearing faci lities that liT A is helping to set 
up. He is also keen to combine eating qual ity 
characteristics of local "dent" varieties (soft-textured 
kemels which are prefenred in Ghanaian-style cooking) 
with high-yielding improved varieties. 
The value of the mutual support among liT A and 
its collaborators is renected in a letter received from 
the recently retired head of Nigeria's maize research 
program, Dr. C. E. Ago: 
I took over leadership of maize at the Notional 
Cereals Research Institute in I 981 . The eight years 
which followed were the most dramatic for any crop in 
Nigeria. Notional production rose from about I million 
tonnes to about 4.0 million tonnes. Notional overage 
production rose from about 500 kglha to about 2.0 
t/ha. The hybrid maize program was executed to on 
admirable point Seed companies were functioning. A 
notional seed low was in place. A notional varietal 
release mechanism was in place. The notionally 
coordinated research program designed along the lines 
of the notional maize breeders meeting was 
functioning. In all these, we cooperated closely with 
others in order to make these happen. I like to feel I 
mode a small contribution. And I urge you to keep up 
the good work.. Please express my personal thanks to 
the program at IITA for all its help when I was in 
maize. I wish you success in your future endeavours. 
Yours Sincerely, 
C E. Ago 
65 
Rice Research ________ _ 
66 
A frica produces only half as much rice as it consumes, a shortfall which must be made up with imports. Yet the potential for expansion and intensification 
of rice cultivation is great With an estimated 203 
m',llion hectares of land suitable for rice, African 
farmers cultivate only some 4.9 million hectares. or 3 
percent of the total. 
Demand, primarily from urban consumers, is 
Increas',ng faster for rice than for other staple crops: 
Africans consume about 5 percent more rice each 
year than during the previous year. With improved 
rice varieties, improved cultivation methods and greater 
exploitation of available land, Afnca should be able to 
make upth',s ricedefic"t and more, ard provide ""orthe 
expected grovvth in consumpt on needs. 
To hamess tee ~otentlal of Ahcan nce, liT A began 
In 1970 to develop technologies for efficient and 
sustainable production in different growing 
environments. With the strengthening of the research 
prog"am of the West Africa Rice Development 
ASsoCla:lon (WARDA), IITA has since 1987 beeo 
gradually transferring rice "esearch activity to Its s ster 
institute, wite the goal of completing the handover by 
the end of I 990. liT A deoded to ohase out of nce 
imJrovement as a way to rationalize resources in the 
Consultative Group on Intemational Agricultural Re-
search (CGIAR) system and to penmlt a sharperfocus 
on ilS other mandate crops. 
WARDA scientists are beingthoroughlyfamil.arized 
with the IITA nce ge'TT1plasm collection, production 
technologies and benefits of researC1 experience 
gained over the past 20 years. liT A sCientists have 
continued germplasm collection, breeding trials and 
cropping system research dJring the current interim 
period so that momentum is not lost during the 
transition. SCientls:s from both Institutes have jointly' 
visited each other'str als and worked outacooperative 
long-term plan, contributing to a smooth trcnsitior. 
Strategies. R.ice breeding work since 1987 has been 
ta,lorec tothe needs ofthetransferofllT A's gerTIplasm 
ard research results to WARDA. Ea'iier strategy had 
been based on breecing of pest- and disease-res'lstant 
varieties that 'llouid respcnd to mprDvements in crop 
management with higher grain yields than possib,e 
with tradtional varieties. T ne target ecosystem for rice 
had been the Inland valleys of West and Central Afnca. 
Since the Intemational RICe Research InstITute (IRRI) 
works on global nee problems, liT A had sought to 
com~lement those efforts by focusing on resistances 
to constraints that are more important in, or In some 
cases wholly restricted to, Africa. liT A rice scientists 
participated in the interdisciplinary Rice-based Systems 
Working Group (rena01ed the Inland Valley Systems 
Working Group In 1989: see Resource and Crop 
Management Program article). 
liT A has continued to collaborate with scientists In 
national programs n West and Central Africa in 
strergthening and broadening research into different 
environments. These linkages, budt up over the past 
tV'lO decades, are an invaluable part of the corpus of 
work being given to WARDA, and must be sustained 
during this interim period. Examples of past 
collaboration are given in later paragraphs. 
Central to liT A strategy In working with national 
programs has been the facilitation of timely and 
purposeful exchanges of germplasm. The rice program 
has supported the Intemational Network for Genetic 
Evaluation of Rice (INGER-Africa), an IRRI project 
which distributes advanced germ plasm for testing In 
Africa. 
The program has also responded to special requests 
for germplasm at different "unfinishec" stages i'l the 
breeding process. Some examples are: crosses to 
combir,e particular traits: early-stage experimental 
materials, such as segregating populatio'ls; a'ld larger 
volumes of seed for pre-release multilocationa, testing 
and seed multiplication, These activities provide national 
program breeders with access to the worlds best rice 
germplasm, in the forms most useful for treir needs. 
Achievements. The IITA Rice Research Program will 
close at the end of 1990, as all rice improvement work 
IS transferred to WARDA So It IS tmely that some of 
the achievements of 20 years of rice research at IITA 
be summarized in these pages. 
Vv'rth i:s first experiments in breeding upland rice 
dUring the mid-I 970s, liT A found that ASian varieties 
adapted poorl'ito the aCid, nutrien:-poor African soils, 
and they succumbed to diseases. So the rice program 
assembled and began building on a base of traditional 
African land race gerrnplasm, as well as excellent lines 
from the Institut de Recherches Agronomiques Tropical 
(IRA T) and some valuable BraZilian materials which 
had evolved in or been selected forslmilarecosystems. 
IITA breeders selected for a shorter. hlgher~tillering 
plant type in order to improve the yield potential. and 
for longer grains of higher market value. while at the 
same time preserving the excellent stress and disease 
resistance of the source matenal. liT A scaled down its 
upland work after the strategic review recommended. 
In 1987, that it concentrate ItS resources on the inland 
valleys. 
Perhaps the greatest impact of the upland nce 
work has been the spread of the vaneties ITA 150 and 
ITA 257 across the forest and mOist savanna belts of 
Nlgena. Through aggresSive seed production programs 
by the Federal Govemment and State Agricultural 
Development ProJects. seed has reached the farmers 
and the varieties have met with an enthUSiastic 
reception. ITA 257 has taken on such cololful local 
names as "Canada", "three-month r ice" and 
"Waniklran" (meaning "antelope" In the Tiv language. 
for its rapid maturation and brown husk color 
resembling antelope skm ). ITA 257 IS also well accepted 
In Sieml Leone. one of West Afnca's most nce-
dependent countries. The short~duration growth cycle 
of ITA 150 and ITA 257 results In quick retums on 
Investment for farmers and improved total Income, 
because the two varieties are ready for harvest when 
pnces are at their annual peak In July/August. well 
before the lowland nce crop reaches the marketplace. 
Thelrexcellent eating quality also eams price premiums. 
UTA's prevIous prionty environment for nce. the 
Inland valleys- which stretch from the humid forest 
northward to the savanna-present many challenges. 
not all of which can be solved With better breeding. 
Inland valleys are ubiqUitous In West and Central 
Afnca. and are under-utilized at present With good 
water supply yet suffiCient drainage. these valleys are 
Ideally surted to nce. Yetthey are also charactenzed by 
lack of water control. rough tillage. uneven stand 
establishment and heavy weed Infestations. For thiS 
environment. liT A selected for a plant type that would 
help the plant to compete With weeds and tolerate 
phySical stresses. Such vanetles have good seedling 
and vegetative vigor. moderate to high tillenng and 
moderately long. erect leaves. and medium to tall 
height yet they have stiff. erect stems that reSist 
buckling or blOWing over. Breeding efforts aimed to 
combine resistances to three major constraints 
blast fungus. yellow mottle VlnuS and Iron toxlclty-
With high Yield and good plant type. 
liT A's breeding program for the inland valleys 
began early in the 1980s. and was proposed for 
priority by liT A's strategic review in 1987. Excellent 
vanetles are just now reaching the final testing stages 
In national research programs. They are pOised to 
make a significant Impact In this agroecologlcal zone 
over the next decade. and also will enable WARDA 
to begin its work In the area With superb el ite matenals. 
Despite Its high productivity. the limited extent of 
Imgated rice cultivation In the region led liT A's strategic 
review of 1987 to recommend reduction In that area 
of research. Finall y. tolerance of nce yellow mottle 
ViruS and gall midge has been Incorporated Into 
varieties of the "green revolution" high~yieldlng type. 
long proven to be appropriate fOI- this form of 
cultivation. 
Work on Imgated paddy varieties began before ItS 
upland work early In the I 970s. and has achieved an 
exceptional record of success. The best of them have 
world~class yield potential. For example. in 1983. ITA 
21 2 was among the top few varieties in global yield 
trials conducted at 30 locations all over the wolid by 
INGER In addition to the,,- high Yield. farmers prefel-
them for their better blast resistance and slender grain 
shape. which bnngs higher pnces. Five of the Imgated 
vanetles have been released by the Government of 
Nlgena and are Widely grown In irrigation proJects. 
They are also rapidly spreading Into other West and 
Central Afncan countnes. ITA 222 and ITA 306 are 
spreading In Cameroon. ITA 306 IS commercially 
grown In Ghana. ITA 212 IS Important In the RepubliC 
of Benin. Also notable In Imgated paddy nce breeding 
was the 1977 I-elease of "suakoko 8" In Llbena. the 
first Afncan Improved vanety to show resistance to 
IrOn t oxIcity. An liT A collaborative pl"OJect With the 
Central Agllcultural Research Institute (CARl) of Lib en a 
developed It. Several vanetles With Iron toxicity resIs-
tance but better plant type than suakoko 8 have Since 
emerged. most notably ITA 247. ITA 249 and ITA 328. 
The rice in this 
Nigerian market 
place is evidence 
that a beginning 
has been made in 
tiffing the region's 
rice deficit 
67 
68 
from collaborative research wltr CARl, WARDA and 
Nigeria's National Cereal Research Institute (NCRI). 
To exploit the research results to the fullest, liT A 
has collaborated with INGER-Africa since 1985, 
supplying logistical needs for the program. INGER-
Africa hel ps to systerr,atize the flow of advanced 
germplasm, as well as to foster awareness and 
communication among the small and scattered national 
rice breeding projects of sub-Saharan Africa, 
1989190 Highlights 
Breeding. In upland rice breeding, final-stage 
multilocational yield testing of the Most advanced 
material ensures that the best lines ilave been ide,'ltified 
and adequate amounts of seed secured for efficient 
transfer to WARDA Data gathered fromlntematlonal 
trials overthe past three years confirms the outstanding 
performance of five I,nes in particular ITA 301, ITA 
305, ITA 3 IS, ITA 3 17 and ITA 321. These varieties 
are now being considered for release in many countries. 
Final-stage testing of advanced germplasm for the 
Inland valleys has also identified several highl)i promising 
lines. Five new lines were given ITA numbers in 1989/ 
90, namell, ITA 340, ITA 342, ITA 344, ITA 346 and 
ITA 348. The designation of an ITA number indicates 
"elite" status based on outstanding performance over 
years and in many testing locations. In addition, about 
150 advanced lines were distributed to national 
programs forthelrown testing, through INGER-Africa 
and also by specia' request of collaborating scientists. 
Lines were also submitted for worldwide testing 
through the global INGER network. This year 
represents the first Widespread distribution of IITAs 
rainfed lowland material, which is indicative of the 
CUrTent maturation of this relatively new breeding 
proJect. The payoff is Just beginning, and WARDA Will 
benefit in utilizing these new materials. 
Breeding for the irrigated paddy zone focused 01 
rice yellow mottle virus resistance. a growing threat 
Progenies of eight new crosses combining resistance 
to rice ,'ellow mottle virus with good plant type were 
Identified as promising during the 1989/90 crop year. 
Resistance comes from the donor parents ITA 235 
and CT 19. About 80 advanced lines were submitted 
to INGER-Africa for regional testing under virus pres-
sure. Five particularly promising lir·es will be considered 
for ITA status after another season's testing. These 
lines will help WARDA in starting work on the virus. 
African gall midge. A severe outbreak of African gall 
midge, a tiny. mosquito-like insect, deS"':royed thousands 
of hectares of rice in N 'genaduring 1988, driving many 
farmers out of the rice-growing business altogether. 
The pest continued to spread In 1989, devastating 
even larger areas. During 1989/90 IITA condccted 
studies on the pests life cycle, its biological control and 
identification of resistant lines for WARDA's future 
breeding use, in collaboration with scientists from 
NCRI, several Nigerian universities and local agricultural 
developmentprojectstaffin affected areas. The project 
has cor:firmed that several wasp-like species are 
extremely effective in parasitizing the gall midge and 
look promising as blocontrol agents. Through training 
of local extension agents, farners have leamed how 
best to avoid the pest, as well asto help liT A and NCRI 
staff to collect detailed survey data and to run multllo-
catlonal trialS. This project helped maintain contacts 
with the Nigerian Drogram so that WARDA will have 
a strong ongoing linkage to take over from 199 I . 
INGER-Africa. T en types of nurseneswere composed 
and diStnbutedln 1989/90, tailored to upland, rainfed 
lowland. inigated. and IT'angrove swamp nee ecologies, 
as well as special sets for blast and yellow mottle vi·"Us 
diseases. In 1989, INGER-Afncaorganized amonitonng 
tour to East Africa. which visited Madagascar and 
Kenya, fo'iowed bya workshop InNairobl.ln I 990the 
tourvisiled the mid-altitude. cold-affected environment 
of Rwanda and planned to visit Buri<'na FasQ, Cote 
d'ivoire and Mali. I RRI and WARDA have made plans 
for the transfer of INGER-Afnca to WARDA. 
USAID/IRA collaboration. IITA has contributed the 
work of a breeder and agronomist to a bilateral pro-
ject, National Cereals Research and ExtenSion (NCRE), 
between the US. Agency for Intematlonal Develop-
ment (USAID) and the Instltut de Recherche 
Agronomlque (IRA) of Cameroon. Their goal IS to 
breed high-yielding varieties and more cost-efficient 
crop management technologies for the cOL..ntry's 
irrigated rice development projects, and in the process 
to train Cameroonian researchers to high scientific 
standards. Cold tolerance is a major objective In the 
mid-altitude projects in the southwest, whiie blast and 
bacterial leaf blight are the primary cone ems in the 
north em lowland areas. Several superior varieties 
have been identified and are being disseminated to 
fallT'ers. The costs ard benefits of green manures-as 
intemal sources of nitrogenous fertilizer-and different 
crop rotations have been assessed. Some improved 
mac'lines such as automatic transplanters were tested 
and found promising. liT A's involve01ent Inthe NCRE 
project will finish at the end of 1990. 
Biological Control 
The Biological Control Program originated at liT A in 1979 as an urgent experiment to combat the cassava mealybug and the cassava green mite: two 
recent and decidedly unwelcome immigrants from 
South America. Uncontrolled, the two pests were 
spreading rapidly in Africa's cassava belt- an area 
largerthan the United States of America- threatening 
yield losses as high as 80 percent to the sub-Saharan 
region's most important crop, the staple food of some 
200 mill ion people. 
The conventional, chemical response--frequent 
dousings with potent insecticides-would have been 
ecologically brutal, socially unacceptable, economically 
expensive and practically impossible. 
A biological altemative, enlisting nature's own agents 
and mechanisms to keep pest populations in tolerable 
balance, appealed as an effective solution. liT A's 
scientists already knew that, on their home ground in 
South America, mealybug and mite populations are 
naturally controlled by biological antagonists, including 
parasitic wasps and ladybugs. 
Arduous field research in South America, all the 
more difficult because the mealybug is present at low 
levels in the coevolved ecosystem of that region, had 
identified that pest's primary natural antagonist: 
Epidinocorsis /opezi, a parasitic wasp. The successful 
I I 
establ ishment of this wasp in Africa promised prompt, 
self-perpetuating and self-regulating mealybug control. 
The biological strategy was also attractive because 
of its logistical efficiency. To succeed, E./opezi required 
no effort from networks of extension agents, nor from 
individual farmers. liT A 's biological controllers needed 
many thousands of laboratory-bred wasps, to broadcast 
from airplanes or release on the ground with 
govemmental cooperation in the affected countries. 
For a natural enemy-of the cassava green mite, liT A 
and cooperating governments appear to have 
established the exotic phytoseiid Neoseiu/us idoeus 
from Brazil, in the Republ ic of Benin in West Africa and 
in Kenya in East Africa. 
Program achievements 
Biological control of the cassava mealybug worked 
from the start: the introduced wasps, multiplied at 
liT A and released in cassava-growing regions, readily 
established themselves in the African environment 
and promptly set about reducing mealybug depredation 
by half or better, in many areas to virtually subeconomic 
levels. (See story on 1990 King Baudouin Award in the 
Research Highlights section.) 
The early success of the campaign established biol-
ogical control as a key element in liT A's research. The 
I I Research I I Technology Development I I Support to National Biological Control Programs 
I I 
--i Exploration I H Sampling I I Implementation I I Training 
--{ Taxonomy J H Mass Rearing I 
---j Quarantine I Mass Releases I H Pest Problem I --i Technical Evaluation 
--1 Biology I Academic 
--1 Ecology I H Ecological and I Biological Studies 
--i Systems Analysis I H Rearing I 
Experimental Releases I 
and Monitoring --i Release I 
Y Follow-up Monrtonng 
I 
I 
I 
j 
69 
IITA had to invent 
this "cassava tree" 
to produce cassava 
leaves as part of its 
mass-rearing 
system for 
mealybugs and 
their natural 
enemies. 
70 
application of biocontrol strategy to other crop/pest 
pl-oblems I-ests on a full understanding of the ecology 
and life cycle of the pest and its antagonists. The bio-
control project became a full liT A program in August 
1988 and moved to new quarters in the liT A station 
at Cotonou, Republic of Benin in November 1988. 
To the original pair of enemy targets, the program 
is now, through such ecosystem analysis, exploring 
opportunities to add the complex of cowpea pests. 
the banana and plantain weevil. the larger grain borer 
(a storage pest of maize), the mango mealybug (see 
Inset story "Practice Makes Petiect") and polyphagous 
grasshoppers, which are a pest of a number of crops 
in the savannas. The potential for control of the 
parasitic weeds striga and Imperato is being explored. 
In all cases. biological control will be used as one 
among other components- hast-plant resistance, 
cultural practices- to develop an environmentally 
sound, integrated pest management approach. 
New research facilities on a 50-hectare site at the 
liT A Benin station Include laboratories and offices for 
scientists. their students and technicians, and visiting 
sCIentists: a library. an insect/mrte museum and a 
communication center. and six air-conditioned ''tefion 
greenhouses". an insectary and mechanized units for 
mass rearing of insects, Meeting and training facilities 
adjoin the new complex, which have been planned for 
shared use with kindred organizations for research on 
pests of crops outside liT A's mandate (including 
plantation crops. cash crops). Africa now has an 
environmentally safe facility to conduct biological 
control research for all of its major pests. 
A unique technology of the liT A insect -rearing 
system is the artificial cassava tree, an armature on 
which up to 180 cassava plants grow in a nutrient 
water solution. The device was developed by the 
program's scientists to simulate ideal natural conditions 
for the mass rearing of the mealybug and mite pests 
and their antagonists. Its inventors refined the system 
in 1988 by eliminating all mechanical and electrical 
components. substituting a drip-irrigation system that 
increases plant growth while it reduces the need for 
labor and the chance forerTor. This rearing technology 
can be adapted to different environmental conditions, 
including c/imatized greenhouses or plastic shelters. 
T he program had distributed several such "cassava 
trees" to 14 national programs by 1990, enabling 
cassava-growing countries to begin arming themselves 
for biological control of the mealybug, the cassava 
green mite and other pests. 
Since its initial success, the program has maintained 
its biological offensive against the cassava mealybug. 
By 1989. natural enemies of the cassava mealybug had 
been released in about 150 sites in 19 countries of 
westem. central, eastem and southem Africa. The 
principal one of them, the wasp E. lopezl, has made 
itself at home over more than 2.7 million square 
kilometers in 24 countries of the continent's cassava 
belt. The distribution of this parasitoid greatly exceeds 
that of any other ever introduced into Africa for 
biological control purposes. liT A sCientists have 
identified other natural enemies of the mealybug In 
South America, and have successfully introduced 
some of them into the African environment One of 
the program's most important contributions to reseanch 
strategy is that it has made evaluation of campaign 
effectiveness into a feature Dfits regular activity. Some 
ecological pockets remain, where control has not 
been satisfactory, which are being studied and subjected 
to alternative solutions. In other areas, scientists are 
becoming familiar with the pnnciples of biological 
control. They differ from chemical control in that the 
aim is to reduce (not eliminate) pest numbers to an L-
equilibrium such that economiC damage IS kept minimal. 
The results from the work of the biocontrol team 
for cassava green spider mite (Mononychellus tanoJoo) 
are promising. ThiS exotic pest was first seen attacking 
cassava In East Africa early in the I 970s, from where 
It quickly spread to 27 cassava-belt countries where it 
has been causing losses of up to 80 percent of yield. 
Since 1984 the team has made expenmental releases 
of nine predator species and various strains In ten 
countnes of the Afncan cassava belt. covering different 
agroecologlcal zones. Since early In 1989, populations 
of two phytoselld species imported from Brazil have 
been released and recovered throughout the wet 
season for some, but not all. release srtes. This pattern 
has persisted In Benin since April 1989. Subsequent 
wet and dry season recovenes have also been made 
of the phytoselids from Brazil released during the wet 
season in 1989 In Kenya. 
Training. The program has also trained blocontrol 
profeSSionals at three levels of competence. At the 
most baSIC level, laboratory and field technicians are 
taught the baSiC methods of biological control, 
entomology and general crop protection. Thelrtralnlng 
emphaSizes techniques for surveYing pest damage, 
and for sampling pest populations before and after 
release of their natural enemies. Promising candidates 
for master's degrees In biological control or pest 
management. recrurted from the technical training 
courses or directly, are sent to selected universities In 
Afnca or overseas. And doctoral candidates, Including 
top-ranking students from the master's program and 
other well-qualified applicants, cap their unlversrty 
studies With thesIs research In Afnca. 
By 1988, more than 250 biological control specialists 
from 35 Afncan countries had received liT A training. 
During 1989, a total of 128 trainees took courses at 
liT A and also in Zaire, Tanzania and Mozambique: 16 
fellows pursued MSc. or PhD. programs. 
Benefit:cost ratio. liT A's experience testifies that 
biological control strategies, well conceived, well 
planned and well executed, can work agaInSt major 
pests of Important crops in Africa's diverse 
environments-and can repay their costs many times 
over. Assuming the rapid spread of both the cassava 
mealybug and E. lopezi throughout the entire cassava 
belt. an Independent review team recently estimated 
the annual gain in cassava yield from control of the 
mealybug at 10.2 million tons. 
"Reasoning that the benefits Will continue for years, 
decades and even centuries, as seems likely," the 
reviewers concluded, "the benefit:cost ratio of the 
liT A prolect will become very large' '- and IS estimated 
at 149: lover 25 years for the mealybug project. 
Operational strategies 
The objectives of biological control research are being 
expanded to Include the pests of other crops In liT A's 
mandate. and weeds, as biological control science 
becomes a component of Integrated pest management 
T roinees at a 
recent biological 
control course at 
Cotonou examine 
host-plant cassava 
leaves as port of 
their curriculum in 
control methods. 
71 
72 
in the liT A research agenda. Biocontrol worl< will be 
integrated with the search for host-plant resistance in 
commodity improvement work. w ith w eed control 
strategy and with worl< on other fronts of pest 
management as contributions to reduction of the risks 
for family famns. 
The IITA Medium-T emn Plan ( 1989- 1993) envisages 
a gradual decrease of research and control activity 
with mealybugs as the present campaign reaches ~s 
successful conclusion, probably by the end of 1991. 
Research and practical action to control green spider 
mite are expected to continue throughout th is five-
year period, but the nature of IITA's involvement will 
gradually change. The implementat ion of biocontrol 
campaigns w ill be t ransfenned to national biological 
control programs and liT A will concentrate on research 
and research training. 
The Biological Control Program scales ~s research 
Practice Makes Perfect: 
activities and operations according to the character 
and dimensions of the problem in its geographical 
area. The selection of pests and the problems to be 
tackled depends on their economic importance. 
liT A 's biocontrol scientists t ake a phytosanitary 
approach to pest control problems- their assumption 
is that a vigorous plant in a healthy environment is less 
susceptible to damage by the pest. They proceed from 
this point o f departure to develop a full understanding 
of the plant w~hin its ecosystem. The objective is to 
produce a holistic solution to the pest problem and 
apply control measures that accord with the greater 
environmental and economic objectives of the 
concemed govemment. 
Against each pest, the program organizes a group 
of appropriate specialists for a three-pronged attack 
that includes research, training and support of national 
biocontrol programs. Researchers study the plant's 
A New Mealybug Threat Is Contained 
A new mealybug was accidentally introduced into 
West Africa during 1981 - 1982, It quickly spread 
through Ghana, Togo and- since I 986--the Republic 
of Benin. It has recently invaded also Cote d'ivoire, 
Nigeria, Gabon, Congo and Zaire, Reported from 45 
species of crop plants, omamentals and wild plants, ~ 
main target is the mango tree, Where populations of 
th is mealybug have been high, the heavy accumulation 
of honeydew and the resulting black cover of sooty 
mold has stopped further plant growth, flowering and 
fru~ing, and has often led famners to fell their trees. 
After an initial misidentification, the species was 
newly described as Rastrococcus invadens W illiams 
(Homoptera, Pseudococcidae) wM a south-east Asian 
origin. Intensive search by the CAB Intemational 
Inst~ute of Biological Control (IIBC) in India led to the 
discovery of a promising parasite wasp, Gyronusoideo 
tebygi Noyes (Hymenoptera, Encyrtidae). 
Studies on the bioecology of R invadens in Africa 
began wM a Food and Agriculture Organization 
(FAO)-financed project atthe Plant Protection Services 
in Cacaveli, Togo and at the Plant Protection Services 
in Porto Novo, Benin. Both services are supported by 
the Gesellschaft fOr T echnische Zusammenarbeit 
(GTZ). At an FAO-sponsored worl<shop in Lome in 
October 1987, the groundworl< laid earlier by liT A's 
Biological Control Program against the cassava 
mealybug was recognized as a model for action against 
R invadens, A regional project forthe biological control 
of this new pest was set up and, w~h the agreement 
of the Inter-Africa Phytosan~ry Council of the 
Organization of African Un~, the introduction of 
natural enemies was recommended by the worl<shop 
participants. Close collaboration between liT A's 
biocontrol program and IIBC in training. the introduction 
of natural enemies and research was also 
recommended. In all the countries concemed, the 
expertise to canry out research and operational aspects 
in the fight against R invadens was already in place in 
national biological control programs, which had been 
set up and trained during the cassava mealybug 
project 
Releases of G. tebygi reared at the Cacaveli 
insectary started at the end of 1987 in Togo. The 
parasitoid proved to establish on R invodens wherever 
~ was released. By the end of 1988 ~ had penetrated 
into the border area of Benin's Mono Province, and 
pest populations soon collapsed in Togo. 
At liT A. a special project on biological control of 
mango mealybug, separately funded by the Swiss 
govemment had been added in the biocontrol program 
late in 1987. It has extended ~ activ~ies into several 
countries, as described here. 
Research Directions 
• Expansion of the current cassava 
simulation model to include different 
ecological zones, effects of soi l and plant 
nutrition, different cassava varieties (local 
and liT A improved) in different cropping 
systems (monocrop and intercropping), 
the mealybug and ~s natural enemies, and 
hyperparasitoids. The model wil l 
consolidate all our knowledge on the 
cassava mealybug system in Africa. 
• Evaluation of the impact of two Brazi lian 
strains of phytoseiids which are showing 
some success in the field against the cassava 
green m~e. Establishment in the field can 
be declared if these exotic populations 
survive the next dry season (November 
1990 - February 1991). 
• Development of a demographic 
simulation model of the insect pest of 
cowpea, the bean fiower thrip 
(Megalurothrips sjosted~) which will be 
incorporated into the cowpea model as a 
means of assessing plant-pest interactions. 
Other studies of the effects of the pest on 
the plant and on the pest's egg-laying 
behavior will be undertaken. 
• Analysis of the mango mealybug's 
population dynamics, the results of 
biological contnol experiments on mango 
trees and the impact of the released 
• In Nigeria, the quarantine authorities were informed 
of the presence of R. invadens in the south-east of the 
country and were assisted in a survey to detenmine the 
spread of the mealybug. Throughout 1989, numerous 
shipments of G. tebygi were sent to the National 
Hortcultural Research In~ute for release in all infested 
areas covering the southem half of the country. 
paras~oid on the mealybug and on the 
mango market. 
• Development of growth models for 
maize and two stemborer pests, together 
w~ a series of pest -plant field ecological 
studies and pest population studies. 
• Development of a biocontrol campaign 
for the larger grain borer Prostephonus 
truncotus. an important pest of maize. 
• Development of a survey of the banana 
and plantain weevil and its interactions 
w~h ~ host species. 
• Collaboration with IIBC in the 
assessment of altematives to chemical 
contnol forlocust and grasshopper in Africa. 
Parasitic 
Gyranusoidea 
tebygi loy their 
eggs in mongo 
mealybug lorvoe on 
a mongo leaf. 
• In Ghana, the Quarantine and Plant Protection 
Services of Pokoase were supplied w~h G. tebygi and 
assisted in releases over all infested zones. The exotic 
paras~oid quickly established ~elf and spread. A 
marked reduction in mealybug population dens~ies 
followed. 
reduced mealybug populations in the south, so that 
mangos could be harvested abundantly again after 
several years of almost total crop fai lure. 
• In Gabon and Zaire, G. tebygi was released during 
1989 in collaboration w~h the national biological 
contnol programs. 
• In Benin, G. tebygi was reared from January 1988 in 
newly constructed biocontrol facilities. In May 1988 
the paras~oid was released forthe first time at Calavi. 
In November-December 1988, the Plant Protection 
Services at Porto Novo made more releases covering 
all infested areas of the country with wasps, which 
came partly from the liT A biocontrol program and 
partly from a newly established insectary at Porto 
Novo. G. tebygi has become established throughout 
Benin even in remote fields. During 1989 ~ drastically 
In summary, preliminary results show excellent 
control. Mango mealybug populat ions have been 
reduced to negligible levels and mango production has 
been restored following two years (1987- 1988) of 
crop failure. Nevertheless, the mango mealybug is still 
spreading and releases are continuing in affected 
areas. 
As in the biological control of the cassava mealybug, 
the mango mealybug project is characterized by highly 
coordinated intemational collaboration in a clear-cut 
and simple approach, leading to ecologically and 
economically sound pest contnol. 
73 
Locusts hove been 
targeted for IITA 
research into 
biological 
alternatives to 
chemical pest 
control. 
74 
phySiology and growth patterns. the better to 
understand the plant's vulnerability to the pest. They 
study the biology and ecology of the pest. in both field 
and laboratory. and of the pest's natural enemies. both 
exotic and indigenous. Developing appropriate 
sampling methods and computer simulation models. 
the researchers investigate the agricultural and 
ecological contexts in which plant and pest coexist. 
and assess the economic costs attributable to the 
pests and the net benefits to be derived from biological 
control. or from other fonms of integrated pest 
management 
Models of the crop-pest problematique have been 
developed for cassava and cowpea. Models for maize 
and for the intercropping system of cassava + maize 
+ cowpea are being developed. These models open 
the way to a scientific understanding of the systems 
involved. which leads to development of pest 
management/control strategies and, eventually, to 
assessment of the effectiveness of the control effort. 
International collaboration 
The control strategies forcassava mealybug and cassa-
va green spider m~e are examples of how the liT A 
biocontrol program trains future leaders and technicians 
of national crop protection programs. Training goes 
hand in hand with a two-phased approach to control 
programs: preliminary research activities and program 
operations. The liT A program works with national 
staff toward the eventual transfer of all operations to 
a national or regional program responsibility. 
A "pioneer" staffis trained to take on differenttasks 
as described in preceding paragraphs. The first task in 
the research phase is a survey of ecological conditions 
in the infested target areas for pest control. The 
densities of pest populations and conditions which 
promote or inhibit the survival of pests and natural 
enemies are investigated. Exotic predators are selected 
and are released in the field in an experimental effort 
to assess the likelihood of success for a large-scale 
program. Aftera tnal period of varying length. according 
to ecological conditions. the liT A-assisted national 
team follows up the releases with another survey, to 
determine whether the introduced predator species 
has established ~elf and how much of a dent ~ has 
made in the pest population. 
The operations phase of the pioneering campaign 
begins with trial rearing of natural enemies, after the 
national govemment has confirmed its commitment 
to a biocontrol program with budget and manpower 
allocations. A small-scale rearing operation serves to 
fam il iarize the new staff with the production process 
and the problems they are likely to face in sustaining 
a full-sized produdion effort. 
The liT A biocontrol program provides the mother 
stock of natural enemies and new cultures periodically 
as required in order to maintain fitness of the 
populations being reared. For emergency releases 
requested by countries. and for compaigns against 
cassava green mite for which natural enemy rearing is 
problematical. the liT A program is ready to provide 
regular assistance. The liT A program has thus assisted 
national programs across the African cassava belt. The 
next countries slated to receive assistance in starting 
up rearing activities are Burundi, Gabon, Ghana, 
Tanzania and Zaire. 
International Cooperation ___ _ 
T he special role of international cooperation at liT A IS to strengthen the capac~ies of African national research systems to select. adapt and generate 
Improved technologies for their own agricultural 
development. The best cultivars or technologies from 
liT A cannot be delivered to famners' fields without the 
participation of the national programs at every stage. 
from the early definition of problems to the fine-tuning 
of solutions for local use. 
Cooperation strategies . .. 
The principal means by whICh liT A strengthens 
agricultural research in the 22 countries ofits mandated 
area are training. information dissemination, germplasm 
exchange and other collaborative project activities 
which convey liT A technologies. 
Four mechanisms have been designed forthe strate-
gies In the IITA Medium-Temn Plan (1989-1993) to 
enhance usefulness of collaborative research and train-
ing activities and enable IITA to respond with greater 
sensitivity to perceived needs. They are: 
• Networking. Collaborative networks link liT A with 
national and regional research institutions in Africa and 
elsewhere. to address common problems and issues. 
• Research liaison scientists. The Medium-Term Plan 
provides for three research liaison scientists. One is 
working with the anglophone countries of West Africa. 
while another will work with all Central African 
countnes. A third (t o join liT A during 1990) will work 
with the francophone West African countries. 
• Resident scientist teams in specific countries col-
laborate with national colleagues in adapting liT A tech-
nologies to meet crop research problems and needs. 
• Training. The training program within International 
cooperation provides training opportunit ies to national 
SCientists In the form of graduate research fellowships, 
short-term courses and short-term attachments to 
acquire specific skills In IITA research programs. Short-
term fellowships are arranged for visiting scientists 
from national programs to do collaborative research 
fOI-periods of up to 12 months. whereby they acquil-e 
new Insights and skills at IITA which can be applied in 
solVing specific problems III their home countries. 
Training achievements are described In the last part of 
this article. 
The international cooperation program manages 
special projects which involve the national programs 
with IITA as the executing agency. During 1989. liT A 
operated 18 such pmjects in various sub-Saharan 
countries with 46 scientists, whose technical support 
was designed to strengthen national capacities to 
conduct adaptive research. Examples of on-going 
collaborative projects are described in the next section 
on achievements. Salient funding features are given in 
table I on the next page. 
. . . and achievements 
N etworks. Through network activity. IITA has 
encouraged complementarity among research 
programs of various countries and their interaction 
Dr. D. K Kossou, 
a visiting 
collaborating 
scientist at IITA, 
is engaged in 
entomological 
research with the 
maize program. 
75 
Table I. Bilateral and multilateral special projects, 1989 
Project Donor(s) Total life budget 1989 budget 
staff US$ million US$ million 
Institution-Bu i Id i ng 
NCRE II/Cameroon USAID 19 14.31 3.35 
(terminates December 1990) 
RAV/Zaire USAID II 8.12 1.96 
(terminates September 1990) 
Resident Scientist T earns 
Ghana Grains Development CIDA I 12 0.13 
Ghana Smal holder IFAD 0.8 0.Q7 
Cameroon Root Crops France 2 0.7 0.Q7 
(terminates June 1990) 
Congo Kindamba IFAD 0.4 0.07 
SADCC Cowpea Project EEC 3 1.78 
(to begin In 1990) 
Networks 
5AFGRAD USAID 2 4.08 1.00 
E5ARRN USAID 1.94 0.42 
IDRC 0.76 0.06 
AFNETA ClDAlIDRC 2 3.17 0.73 
USAID 1.00 
DANIDA 0.07 0.57 
IFAD 1.20 
Other Research Projects 
On-farml Adaptive Research EEC 2.79 
(to begin In 1990) 
Improved Agricuttural Research Systems FF 0.15 0.11 
Soybean Uti ization IDRC 0.16 0.05 
Legume Viruses IDRC 0.46 
(to begin in 1990) 
Ut lization of Cassava Flour AGCD 0.64 0.24 
Dynamics of Soil Organi{ Matter AGCD 0.16 0.16 
Training Projects 
Human Resources Development UNDP 0.78 0.34 
Training a'Women Agricultural Professionals FF 0.28 0.17 
(EastJSouthem Africa; to begin in 1990) 
Training of Women Agricultural Profess'lonals FF 0.42 
(West/Central Africa; to begin In 1990) 
Totals 42 45.30 9.51 
76 
with other intemational agricultural research centers. 
Through networks, liT A backstops research efforts 
with improved germ plasm and technical information. 
liT A has helped networks in identifying funding sources 
and providing technical support until the member 
institutions can sustain the effort on their own. Such 
networking projects include the second phase of 
SAFGRAD, ESARRN and AFN ET A. These networks 
have elected steering committees which guide their 
coordinators in implementing activities. 
AFNET A came into being during 1989 and held an 
inaugural conference and a training course in August 
on alley farming research technologies. The first two 
issues of its newsletter, The Arnetan, were published in 
that year. AFNET A has received collaborative research 
proposals from 28 institutions in 17 count ries, which 
were funded and launched from early in 1990. 
ESARRN activities during 1989 included germ plasm 
exchange. workshops and scientific exchange visits 
among member institutions. In Malawi. introduced 
liT A cassava lines were hybridized with the best local 
selections, producing some 146,000 seeds through 
open pollination. Prolific local parents produced four-
fifths of all seeds. Two seedling nurseries were 
established for cassava and one for sweet potato. and 
improved IITA cassava lines were imported in tissue 
culture form and multiplied for distribution in various 
projects. Three graduate students completed their 
MSc. degrees with ESARRN support. Altogether 24 
technicians were trained in-country and at liT A. 
The SAFGRAD maize network supported several 
of its member countries in testing of improved 
germplasm and crop management techniques. It 
sponsored various technical training and exchange 
visits. including a five-month course for technicians 
from three countries in trial management. varietal 
maintenance and related areas. 
The SAFGRAD cowpea network received feedback 
on 42 of its 53 regional trials. National programs will 
repeat the trials during 1990 and promising lines will 
be taken to the next stages of multilocation trials and 
on-farm testing. before release to farmers. National 
sCientists benefited from formal group training. 
exchange visits and interaction with liT A scientists in 
research planning. Some new cultivars have gained 
wide acceptance in West African countries after being 
developed in the networ!<. including SUVITA-2 which 
was developed in Burkina Faso and is being widely 
cultivated in Seno province. Mali. 
Research liaison scientists. The scheme was 
introduced during 1988 as an initiative intended to link 
Acronyms ci ted in the text 
AFNETA Alley Farming Network for Tropical Africa 
AGCD Belgian Agency for Cooperation and Development 
ClAT Centro Intemacional de Agricultura T ropicaJ 
ClDA Canadian Intematlonal Development Agency 
ClP Centro Intemacional de la Papa 
ClMMYT Centro IntemaClonal de Mejoramiento de Maiz y Trigo 
CT A Technical Centre for Agricultural and Rural Cooperation. Netherlands 
DANIDA Danish Intemational Development Agency 
EEC European Economic CommunIty 
ESARRN East and Southem Africa Roots and T ubef"j Research Network 
FF Ford Foundation 
GCF 
GTZ 
IBSRAM 
ICRAF 
ICRlSAT 
IDRC 
IFAD 
Gatsby Charitable Foundation 
German Agency for TechnICal Cooperation 
Intemational Board for Soil Research and Management 
Intematlonal CouncIl for Research In Agro-Forestry 
Intemational Crops Research Institute for the SemI-And TropIcs 
IntematJOnal Development Research Centre. Canada 
Intemational Fund for Agricultural Development 
Intemational Livestock Center for Africa 
Intemational Network for Improvement of Bananas and Plantams 
National Cereals Research and Extension Project. Cameroon 
Applied Agricultural Research and Outreach Project. Zaire 
Southem Afncan Development Coordination Conference 
ILCA 
INIBAP 
NCRE 
RAV 
SADCC 
SAFGRAD 
UH 
Semi-Arid Food Grains Research and Development Project. Burktna Faso 
Univef"jity of Hohenheim. Federal Republic of Germany 
UNDP 
USAID 
United Nations Development Programme 
U.s. Agency for International Development 
identified needs in research and training in national 
institutions with the relevant liT A programs. The 22 
national agricultural research systems in liT A's particular 
area of concem, West and Central Africa. are diverse 
in terms of research infrastructure. technical expertise 
and manpower, material resources, capacity to set 
and pursue research priorities that are in line with 
national development goals. and capacity to transfer 
research results to the farm through effective extension 
linkages. It is essential that liT A understand all these 
aspects of national systems. To that end the research 
"Farmers' Day" at 
liT A brings together 
scientists and 
trainees fram the 
international 
cooperation 
program with 
Nigerian farmers. 
to gain a practical 
perspective on 
research concerns. 
77 
78 
liaison sCientist role has been conceived and 
information-gathering begun in a five-year action plan. 
liT A research liaison scientists made introductory 
visits during 1989 and early In 1990 to research 
institutions in four franco phone countries of Central 
Africa (Cameroon, Congo, Gabon, Zaire) and four 
anglo phone countries ofWestAfrica (Gambia, Ghana, 
Liberia, Siena Leone) to discuss new initiatives in 
collaborative research In the I ITA Medium-Tenm Plan. 
In Gabon, IITA scientists participated In a Joint 
assessment of collaborative maize and cassava trials. 
Plans were made for training course and study tours 
to liT A by two Gabonese researchers. 
In Gambia, liT A scientists joined consultations of 
the govemment's task forces on rice, cropping systems 
and resource management; and contributed to 
preparations for Gambia's medium-term research 
plan. Seeds of elite liT A rice and cowpea varieties as 
well as fanm tools (rolling InJector planter, nce weeder) 
were made available for evaluation and adaptation. 
A visit with IITA research and training programs 
was atTanged for a Ghanaian researcher from the 
University of Science and Technology, Kumasl, for 
exchange of ideas and familiarization with current 
research on processing/eating qualities of improved 
cassava clones, soybean seed longevity and 
promiscuous nodulation, and evaluation ofleguminous 
tree speCies, e.g. leucaena, for alley cropping. 
An liT A scientist visited Liberia in connection with 
the setting up of a plant and soils laboratory at the 
Central Agricultural Research Institute, Suakoko. For 
Sienra Leone, IITA delivered half a ton of streak-
resistant maize seed at the request of the Inst~ute of 
Agricultural Research, Njala, and improved rice seed 
for on-farm assessment and multiplication. 
Resident scientist teams. T earns of two orthree liT A 
scientists work in specific country projects on adaptive 
research problems: principally, in the Cameroon 
National Root Crops Improvement Program, the 
Ghana Grains Development ProJect, Ghana 
Smallholder Rehabilitation and Development Program, 
Nigerian Soybean Utilization Program, SADCC 
Cowpea Research Project and, before it was 
completed, the Rwanda fanming systems research 
project, The teams work with national institutions on 
food crop production problems for wh ich liT A has 
developed technologies that require adaptive research 
to suit local conditions. First fielded in the region in 
1984, these teams are preferably based In national 
programs at an early stage of development. 
liT A's project with the Cameroonian National 
Root Crops Improvement Program, to disseminate 
new cultivars to farmers, completed its final activity in 
1989 with the release of three sweet potato varieties 
and three cassava clones. A 1989 evaluation concluded 
thatthe program had succeeded In wldelydisser1"inating 
new sweet potato varieties in lowland and mid-
altitude zones of Cameroon. Researchers and 
technicians received in-service training, and 360 
extension agents attended training courses, 
In the grain legume component of Ghana Grains 
Development Prolect, IITA genmplasm was screened 
for selection of early-maturing, high-Yielding, disease-
resistant cowpea varieties which combine erect or 
semi-erect plant type, acceptable seed colour and 
cooking quality su~able forthe maize-cowpea rotation 
system in Ghana. liT A and local germplasm was 
screened forthe development of high-yielding, bnuchid-
resistant varieties. Exotic soybean varieties were 
screened for the selection of high-Yielding, early-to-
medium-matur'lng varieties which combine 
promiscuous nodulation, seed longevity, and shattering 
and disease resistance. Extension staff received in-
country training. 
In the Ghana Smallholder Rehabil itation and 
Development Program, highlights of 1989 included 
selection of five clones of cassava from IITA for trials 
in farmers' fields by the Crop Services/Extension 
Department The clones selected were TMS 91934, 
TMS 30572, TMS 4(2)1425, TMS 50395 and TMS 
3000 I. Eighty-five clones of "poundable" cassava 
were selected from seedlings for further evaluation, 
The Soronko variety of cowpea wasfoundto intercrop 
well With the TMS 9 1934 cassava variety. Three lines 
of sweet potato-two from liT A and one local 
variety-were selected for high yields and cooking 
qual~y. They have been multiplied for distribution to 
fanmers in the 1990 planting season. 
The Soybean Utilization Project aims to develop 
and introduce improved soybean utilization technology 
for use in households and in small-scale processing 
enterprises in rural Nigeria, During 1989, a monitoring 
survey measured the impact of soybean production 
and utilization In Oyo State, revealing that the project's 
training sessions had reached an aggregate audience 
exceeding I 1,000 people. Extruded soybean products 
were introduced for home use ill selected areas and 
development of small-scale processing technology 
continued. 
Preparations began in 1989 forthe SADCC Cowpea 
Research Project, which will developcowpeagenotypes 
w~h surtable resistance and eating quality characteristics. 
Institution-building. The prime examples are the 
NCRE project in Cameroon (see inset story) and the 
RAV project of Zaire. Such projects bring liT A scien-
tists to work with national colleagues in strengthening 
specific aspects of their research programs. 
The year 1989 marked 16 years of continuous 
association of liT A with Zaire, and the end of RA V's 
first phase. Initially the govemment had invited liT A to 
seek solutions to cassava pest problems and CI MMYT 
to undertake maize improvement. which let to the 
creation of two national programs for those crops, 
with USAID support. The cassava program's successes 
in tum led to creation of RAVin 1985 to oversee the 
cassava and maize programs and a' third body for 
legumes. All three RA V programs have chalked up 
notable successes in development of new crop varieties, 
resource and crop management. human resources 
and links between research and extension services. 
During 1989 RAV continued on-fanm testing of 
promising disease-resistant and high-yielding cassava 
clones, and transfenred streak vinus and downy mildew 
resistance to two maize varieties. Two new varieties 
each of cowpea, soybean and maize were released. 
Research continued on methods for improving soil 
fertility and agronomic practices which contribute to 
increased yield potential. 
Training achievements 
To conduct agricu~ural research and development, all 
national systems need capable and committed 
professional staffs. When liT A began operating in 
1967, the lack of scientists and professionals in African 
agriculture-especially Africans- was enormous and 
growing. Training in research for African agricultural 
professionals at all levels, therefore, was part of the 
Institute's original mandate; and training remains an 
essential aspect of liT A's miSSion today. No proposal 
to develop or transfer technology from liT A fails to 
consider the training requirements of the participating 
countnes. In international cooperation's varied 
partnerships with national systems. training is the 
constant theme. 
To realize the potentials in their own programs or 
to contribute effectively to regional projects, nearly all 
national agncultural research institutions in tropical 
Afnca need to improve professional skills on a regular 
basis through training In various fonms. The liT A 
training program seeks to strengthen their capacities 
in both research and training. Since 1971 liT A has 
organized training courses for more than 6,000 
participants, most of whom have come from Afncan 
countries. 
liT A's Strategic Plan ( 1989-2000) set the following 
guidelines for development of its training program: 
• Shifting emphasis at liT A from group to individual 
training. 
• Decentralizing group training to national programs. 
• Increasing the proportion of core liT A resources 
for training. 
• Strengthening training materials. 
• Increasing women's participation in training. 
Individual training seeks to improve research abilities 
through doctoral. master's and non-degree levels of 
training tailored to specific needs in national programs. 
To promote the increase of graduate researchers in 
Africa, in 1988 liT A initiated the Graduate Research 
Fellowship Program, that eventually will support 30 
graduate students in conducting their research with 
liT A scientists. Between April 1988 and December 
1989, IITA accepted 15 graduate trainees out of 244 
applications for the fellowship program, thus achieving 
the Medium-Tenm Plan target 
In 1989 liT A scientists supervised 48 PhD .. 30 
M.5c., and 29 non-degree trainees. (See annex to this 
article for a summary table.) As part of liT A's special 
relationship with the University of Ibadan, 12 of the 
PhD. and M.5c. trainees benefited from liT A research 
faci lities while being registered with the University. 
Group training. The aim in group training courses is, 
foremost, to expand research knowledge and skills. 
The RA V project 
focuses research 
attention on 
cassava leaves. 
an important 
vegetable in some 
parts of Zaire. 
79 
80 
Double Impact In Cameroon 
For country and continent- a cooperative project in 
agricultural research in Cameroon, funded by the 
U.s.A. and drawing on liT A knowhow, has had a 
double impact, helping Cameroon to benefrt from its 
own research and to become a producer of 
technologies which can benefrtother African countries. 
The National Cereals Research and Extension 
(NCRE) Project was conceived t o build up 
Cameroonian capability in cereals research and in 
translating the results into practical technologies for 
the farmer. The project was based at the Institut de la 
Recherche Agronomique (IRA) at Yaounde, with 
financial support from the United States Agency for 
Intemational Development (USAID). liT A fielded up 
to 19 scientists at a time during the first two project 
phases ( 1981- 1990). 
The liT A resident scientist team worked on the 
four staple crops of maize, rice, sorghum and millet 
with national staff at stations in Cameroon's six different 
agroclimatic zones. The team's brief was to help their 
Cameroonian colleagues to develop research 
programs, as well as to carry the research through on-
farm trials and produce results useful to small -scale or 
subsistence farmers. 
Parallel with the research agenda was a program to 
transmit research results to extension agencies for 
onward transmission to farmers, and to communicate 
farmers' problems to researchers as feedback to 
enhance the usefulness offuture work. This operation 
was handled through a testing and liaison unit (TLU). 
The first phase of the project (1981-1985) saw 
development of disease- and pest-resistant maize 
varieties and crop management techniques, with on-
farm trials conducted by the TLU. Rice, sorghum and 
millet varieties were also selected and improved, the 
latter two with help from the Intemational Crops 
Research Institute forthe Semi-Arid Tropics (ICRISA 1). 
New high-yielding sorghum varieties were released to 
farmers. Apart from fielding the trials, the TLU trained 
extension workers and tested new farming techniques 
and technologies. Cameroonian researchers also began 
to network with their peers in other African institutes 
and intemational centers. 
A second phase was launched in 1986 to continue 
the development of the IRA research programs for 
crops in all six agroclimatic zones, and to establish 
TLUs in all zones. The same goal was reaffirmed: the 
transmission of research results to the farm and 
feedback to researchers on their usefulness. The liT A 
team. in working with counterpart Cameroonian 
scientists, was to transfer knowledge and knowhow to 
them through training programs and working together. 
A lready by 1989, seven varieties of lowland maize 
and four of highland maize were being or about to be 
released, as were four rice varieties and five sorghum 
varieties. New agronomic techniques had been 
introduced with significant impact use of minimum or 
no t illage in the North Province had begun to reduce 
erosion offragile alfisols. Use of an insecticide as a seed 
treatment for maize and sorghum had improved 
seedling establishment and led to higher yields than 
with earlier seed treatments. TLUs had successfully 
worked back up the research pipeline to improve on-
station experimentation by sensitizing researchers to 
farmers' problems. The TLUs had characterized the 
complex production systems in each zone, identifying 
constraints and opportunities for improvements. 
By the end of 199 I , ~ is expected that three Came-
roonian researchers will have completed their doctor-
ates and eight their master's degrees in relevant discip-
lines, while additional doctoral and master's degree 
candidates w ill be completing their studies. By 1989, 
one sorghum breeder and one agricultural economist 
had already retumed to the project with M.Sc. degrees. 
The project donor, USAID, has ranked Cameroon 
in the foremost group of African countries that can 
research and produce agricultural technologies for 
other African countries. IRA has become one of the 
strongest of its kind in the region. Cameroon has 
developed its research manpower and facilities to a 
stage of maturity that can demonstrate successful 
impact from liT A 's work with a national research 
institution. 
Because of these favorable factors for agricultural 
research, liT A has selected Cameroon for the location 
ofthe new humid forest station and has begun to set 
up research faci lities for cassava and resource 
management at Mbalmayo, near Yaounde. 
liT A has also decided to continue to provide 
support to IRA for a thind project phase, from 1991 
through 1994. The liT A team will continue to focus on 
cereals research, TLtJs and human resources 
development, together with two new components: 
sustainable production systems and economic policy 
research. During this final phase, Cameroonian 
counterpart staff will gradually replace liT A scientists. 
The second and closely related aim is to impart skills 
and foster attitudes that prepare the researcher-
trainees to become, in tum. trainers who will pass their 
knowledge and skills on to others: research colleagues. 
extension specialists, farmers and other agricultural 
professionals. 
During 1989. 304 technicians and scientists 
participated in I S group training courses at liT A. which 
collectively amounted to 61 weeks of training. Some 
I 10 persons participated in regional or in-country 
courses in Benin, Buri<ina FasQ, Guinea Bissau, Kenya 
and Mozambique. Another 128 participated in 
individual training programs. (See table 2 fora summary 
of courses and trainees.) Two courses contributed to 
the development of new liT A-supported research 
netwonks: on alley fanming and soil and plant analySiS. 
With regard to the participation of women during 
1989. S6 women took Pa!t in IITA courses (18 
percent of all participants). while 9 women participated 
in regional or in-country courses (8 percent). Some 16 
women made up 20 percent of graduate trainees at 
liT Nlbadan and elsewhere during 1989. 
Group training received new stimulus during 1989 
for future development. A new group training 
coordinator arrived. and key plans began to be 
implemented: decentralization of group training 
actiVities to national programs. and a shift in emphasis 
from group to individual training. 
Training materials. Decentralization and sharing of 
training responsibilities with national programs depend 
on well-trained researchers and easily accessible 
sCientific and technical information. Training materials 
offer a means to make Information available. 
Training matenals apply in a broad range of actiVity 
throughout the training process: assessing needs, 
specifYing objectives. developing curricula and 
programs. Instruction, evaluation and follow-up 
procedures. The contents should be easily adaptable 
forthe purposes of national programs. and the fonmats 
should encourage reproduction and use. 
In 1989. a reference manual on cassava in tropical 
Afnca was prepared With UNICEF support and used 
Initially In two training courses. The liT A food crops 
utilization and nutlition training manual was recast for 
use In the fourth training course on the subject. 
A new training matenals speCialist amved during 
1989 and put the production of training matenals on 
a new footing. concentrating on training cumcula, 
research guides, production gUides, slide collections. 
posters and charts, and evaluation Instruments. 
Women in training. Agricultural researchers generally 
underestimate the contribution of women. who 
produce by far the greater share of Africa's home-
grown food supply. They are often unaware of the 
impact of new technologies on farm women's lives. 
liT A is committed to improving the condition of 
African women falmers through promoting research 
results which reinforce or supplement their 
contribut ion. In IITA's research programs, 
multidisciplinary wonking groups that coordinate 
cropping systems research are responsible for making 
sure that new technologies fit the needs of women 
farmers. And whenever training opportunities are 
announced. the liT A training program encourages 
nomination of women participants. 
In 1989 liT A developed and obtained funds for a 
proJecttotrain African women for leadership roles: 10 
agricultural professionals from West Africa will receive 
grants to study for M.5c. or PhD. degrees. 
Besides the efforts to include women participants 
in training. liT A is aware that simply increasing numbers 
is not enough. Gender perspective and gender 
sensitivity must become part of training cumcula. IITA 
is studying ways to program Its training actlVl"tles and 
materials which will promote its objectives for women 
In agricultural research. 
Collaboration with international centers. For several 
years. IITA has wonked with ClAT and CIP In a jOint 
training project on human resource development for 
generation and transfer of root and tuber crop 
technologies. funded by UNDP.IIT A also collaborates 
IITA research 
fellow Mary 
Mgonja from 
Tanzania expects 
to complete the 
requirements for 
her Ph.D. at the 
Univeristy of 
Ibadan in 1990. 
IITA's 
multidisciplinary 
research groups 
must ensure that 
new technologies (It 
the needs of 
women farmers. 
81 
82 
with ICRAF, ILCA. IBSRAM, INIBAP, ICRISAT, CTA, 
University of Arkansas and other institutions in course 
plann;ng, development of training materials, course 
presentation and follow-up, including evaluation. 
Future directions in training. liT A's training program 
aims to help national programs and research networks 
eventually to do for themselves all the field-level 
training that is needed to support their own research 
efforts. Decentralization is a strategy which promotes 
this aim ofilT A's long-term planning. National programs 
and IITA together offer training that is increasingly 
organized, conducted and sustained by those programs. 
IITA's approach to the "training of trainers" in 
national programs is evolving and varied according to 
Table 2. IITA group training courses in 1989 
IITA Ibadan 
Editing and publication 
Village and institution-level cassava survey 
(Collaborative Study on Cassava in Africa) 
Advanced soil and plant analysis 
Root crops research and technology transfer 
Sustaina:Jle food production systems 
Fooc crops utilization and nutrition 
Alley farming 
Plantain research and technology transfer 
On-farm experimentation 
Cowpea and soybean research and technology transfer 
Maize research and technology transfer 
Total liT A Ibadan 
IITA Cotonou 
Biolog cal control 
Biological control 
T otaJ liT A Cotonou 
Regional/in-country 
the needs and opportunities in those programs. Training 
of researchers to train others IS a central part of liT A's 
decentralization strategy. Forfull-time training officers 
in national programs, IITA arranges two-to-three-
month attachments to enable thenn to work alongside 
liT A training staff to acqutre on-the-Job expenence 
Wherever possible, liT A offers training In national 
training institutions and invites national scientists to 
join in training as coordinators, teachers and advisers. 
liT A in the first Instance collaborates in training with 
those countries that have well-defined plans and goals 
for research and training. especially those countries 
With which IITA already has collaborative ties. 
Involvement in training activities reinforces collaborative 
ties between liT A and the recipient country. 
Weeks 
2 
2 
4 
10 
3 
5 
2 
3 
2 
8 
10 
51 
5 
5 
10 
Trainees 
total women 
24 
20 
17 
24 
33 
32 
34 
13 
21 
19 
16 
253 
19 
12 
51 
4 
3 
4 
6 
3 
22 
2 
2 
3 
51 
2 
3 
5 
Countries 
5 
7 
14 
18 
18 
10 
18 
8 
9 
10 
10 
12 
15 
Cassava production, processing and utilization (Guinea Bissau) 2 22 5 
o Maize and cowpea production (Burkina Faso) 2 
Vegetative seed production (Kenya) 2 
Root and tuber crop production. processing and utilization (Mozambique) 2 
Rapid mUltiplication of root crops (Ben,n) 
Total regional/in-country 9 
Grand total 70 
23 
17 
19 
29 
110 
414 
2 
9 
65 
9 
2 
Annex to International Cooperation: Graduate Research Fellows and Scholars 1989 
Research Fellows (Doctoral Degree Studies) 
Program Country University Sponsor Thesis
' 
Biological Control Program 
Ms A. Akpokodje Nigeria University of Ibadan IITA 
Mr. S. Bruce-Oliver Gambia University of California, Berkeley IITA 
Mr. A. Chalabesa Zambia Wye College, London I ITA 
Mr. A. R. CUJOe Ghana Wye College, London I ITA 
Mr, G. Goergen Germany. Fed. Rep. University of Giessen I ITA 
Mr. H. Rogg Germany, Fed. Rep. University of Giessen G1Z 
Grain Legume Improvement Program 
Mr. S. A. Adebit.n Nigeria University of Ibadan IITA 
Mr. H Adu-Dapaah Ghana University of Ibadan USAID/IiTA Studies on phenotype stability 
and male sterility in cowpea. 
Ms N. F. U. Agwaranze Nigena University of Ibadan IITA' 
Mr. B. Asafo-Adje; Ghana University of Minnesota CIDA Genetics of soybean breeding. 
Mr. I. D. Atokple Ghana Ahmadu Bello University IITA' 
Mr. S. Blade Canada McGill University ClDA Evaluation of improved cowpea 
lines under intercropping 
systems in various agroclimatic 
zones in Nigeria. 
Ms K. K Mogotsi Botswana University of Botswana FF 
Ms A Noameshie Togo University of Ibadan IITA 
Mr. S. Ogh,akhe Nigeria University of Lagos SelflllTA Host plant resistance studies on 
the legume pod borer. Maruca 
testulalis Geyer (Lepi doptera: 
Pyralld.e). 
Mr. T. Omobuwajo Nigeria Obafemi Awolowo University IITA 
Ms C P. Paul Sri Lanka University of Ibadan Italy 
Mr. M. Tour€! Mali Universite Laval Ste. Foy. Canada IITN 
Maize Research Program 
Mr. Y. A Akintunde Nigeria University of Ibadan IITA' 
Mr. M. Asanzi Zaire Ohio State University USAID 
Mr. 0.1- Osanyintola Nigeria University of Ibadan IITA 
Resource and Crop Management Program 
Mr. P. T. Akonde Republic of Benin Universitat Hohenheim UH 
Mr. A. I. Babalola Nigeria University of Ibadan Self 
Mr. M. Baten Bangladesh University of Ibadan FF/Self/llTA 
Ms R. Emst Germany. Fed. Rep. Universitat Hohenheim UH Malze.cassava cropping systems. 
Mr. 1. L. Gaiser Germany. Fed. Rep. Universitat Hohenheim UH 
Mr. B. D. Kadiata Zaire Institut Facultaire des Sciences IITA' 
Agronom'que 
I Applies to graduQte students who completed their research ot liT A dunng I 989. No entry in this colurrn If theSIS not yet completed. 
2 Funded by the !,ITA Graduate Research Fellowship Program. 83 
Research Fellows (Doctoral Degree Studies) - continued 
Program Country University 
Resource and Crop Management Program - continued 
Ms S. Liya United Kingdorl' University of Ibadan 
Mr. H. J. Lutzeyer 
Mr. A. G. Maul 
Mr .... E. Nloku 
Mr. M. A. Olagoke 
Mr. O. Onafeb 
Mr. G. O. Oyediran 
Mr. B, A. Ruhigvva 
Mr. D. E. Sia\\! 
Mr. M. A. K. Smith 
Mr. G. Tia" 
Mr. B. Ugwu 
Ms A. Weber 
Rice Research Program 
Mr. M. S. Mansaray 
Ms M. Mgonja 
Germa,,",y. Fed. Rep, 
Germar,y, Fed. Rep. 
N'geria 
Nigeria 
Nigeria 
Nigeria 
Zaire 
Ghana 
Nigeria 
Crina 
Nigeria 
Germany, Fed. Rep. 
Siena Leone 
Tanzania 
Root. Tuber and Plantain Impro"lement Program 
Mr. Agueguia Cameroon 
Mr. M. H. Makame Tanzania 
Ms R. Ndlbaza Tanzania 
Mr. T. E. Nj:x'( Cameroon 
Ms O. Salau Nlgena 
Mr. N. Vi. Wanyera Uganda 
84 
Universitat Hohenheim 
Universitat Hohenhelm 
University of Nigeria 
University of N geria 
University Of Ibadan 
Obafemi Awolowo university 
Institut Facultaire des Sciences 
Agronomiqu€s 
University of Ibadan 
University of Ibadan 
Agrcultural University, 
Wagenirgen 
University of Nigeria 
Unlversrtat Hohenheim 
N. a·a University College 
Univers·ty of Ibadan 
University of Ibadan 
University of Ibadan 
University of Ibadan 
University of Ibadan 
University of Ibadan 
University of Ibadan 
Sponsor 
Self 
UH 
UH 
Self 
AGCD 
IITA' 
Self 
IITNAGCD 
SelflllTA 
Self 
IITN 
Netherlands 
Self 
UH 
I ITA' 
FF 
UNDPIGCF 
UNDP 
UNDP 
UNDP 
Sef 
UNDP 
Thesis
' 
Weed management. 
Socioeconomic surveys in 
SOMe villages in the Republic of 
Benin. 
Derrand elasticities for food in 
the minor food-prodJong areas 
of southem Nigeria. 
Relative efficiency of resource 
allocation in yam and rice pro-
ductior in south-east Nigena. 
Wetlard soils of dfferent 
agroecosystems: 
characterizat on and 
productivity evaluations. 
Alley cropping tria using 
Leucoena leucocephala and 
Acioa borteni mixtures. 
EFlciency of resource use in 
food crop production in 
south-eastem Nigeria. 
Research Scholars (Master's Degree Studies) 
Program Country 
Biological Control Program 
Mr. A. J-M. Anga Cote d'ivoire 
Mr. A.M. Animashaun Nigeria 
Mr. H. Bralmah Ghana 
Mr. K. Kanan Cote d'iveire 
Mr. P. Ndaylragije Burundi 
Mr. G. Oduor Kenya 
Mr. F. Senkondo Tanzania 
Mr. A. J. Sumani Zambia 
Mr. K. Tata Hangy Zaire 
Mr. L. T raore Guinea 
Grain Legume Improvement Program 
Mr. J Afun Ghana 
Mr. L. A Okosun Nigeria 
Ms N. Ssemakula Uganda 
Resource and Crop Management Program 
Ms U. A Anoka 
Mr. M. O. Atayese 
Mr. O. O. Awotoye 
Ms J. Baie 
Mr. A. Dikko 
Mr. L. R. A. Hermans 
Mr. P. Idis: 
Mr. P. Karinge 
Nigeria 
Nigeria 
Nigeria 
Belgium 
Nigeria 
Belgium 
Nigeria 
Kenya 
University 
University of Wales 
Voiye College, London 
University of Reading 
Simon Fraser University 
University of Ottawa 
Imperial College 
Wye College. London 
University College. Cardiff 
University College, Cardiff 
Unlvers te de Mor,treal 
Wye College, London 
Univ'ersity of Ibadan 
University of I badan 
University of Nigeria 
University of I ::.adan 
University of I bacan 
Unlversite Laval 
Agricultural University, Norway 
Katholleke Universlteit. Leuven 
Ahmadu Bello University 
Universit)' of Nairobi 
Sponsor 
IITA 
IITA 
IITA 
IITA. 
I ITA 
I ITA 
I ITA. 
IITA 
IITA 
IITA 
CIDA. 
Self 
FF 
Self 
Self 
Sel' 
AGCD 
IITA' 
AGCD 
IITA. 
FF 
Thesis
' 
Biolog)/ of mealybugs and 
natural enemies, 
A comparative study of 
"calendar" and "guided" 
insecticide applications for 
contra' of cowpea pests. 
Screening of cowpea lines for 
drought tolerance, 
Effect of early season on 
Imperato cy,lir:dnco 
Nitrogen mineralization 
potential of sOils (alfisols and 
ultisols) collected under fallows 
of different ages and 
relationship with size of 
popUlations of nitrifyi'lg micro-
organisms. 
Dynamics in maize plot treated 
with fertilizer N and leaves of 
different woody species. 
Effect of alley cropping 
Colliondra wlothyrsus and 
nitrogen rates on m.aize and 
ccwpeas, 
I Apolres to graduate students w~o ccmpleted their researc:h at UTA dUring 1989. No entry in this column If thesIs not yet compJeted. 
2 Funded by the nTA Graduate Research FellOWShip Progro:n. 85 
Research Scholars (Master's Degree Studies) - continued 
Program Country University 
Resource and Crop Management Program - continued 
Mr. T. Leyman Belgium Rijksuniversiteit Gent 
Rice Research Program 
Mr. R Rodrigus Belgium 
Root. Tuber and Plantain Improvement Program 
Mr. C. E Felix Nigeria 
Mr. C. M. Githunguri 
Mr. M. Ntimp,rangeza 
Ms A. Peters 
Mr. G. S. N. Phin 
Mr. R. N. Sauti 
Mr. M. Walangu'.ulu 
86 
Kenya 
Burundi 
Belgium 
Malawi 
Malawi 
Zaire 
Universite Llbre de Bruxelles 
University of Ibadan 
University of Ibadan 
University of Nairobi 
Katholieke Universiteit, Leuven 
University of Ibadan 
University of Ibadan 
Instltut Facu:ta:re des Sciences 
Agronomiques 
Sponsor 
AGeD 
AGCD 
UNDP 
IDRe 
Thesis
' 
Effect of cassava-based 
cropping systems on soil 
physical and chemical 
properties of an alfisol in 
western Nigeria. 
Cassava varietal response to 
drought stress, 
IDRClESARRN -
AGeD 
IDRe 
USAIDI 
ESARRN 
UNDP 
Screening plantain afld banana 
germplasm for resistance to 
black Sigatoka disease using 
different techniques. 
Mechanism of resistance of 
cassava to cassava green mite. 
Information and 
Scientific Support 
Services 
Information Services 
T he Information Services Program embarked on a campaign to promote public awareness in Nigeria of I IT A's goals and accomplishments. At a meeting 
of the main Nigerian print and electronic media 
houses with liT A in November 1989. the Media 
Forum for Agriculture was established. The Forum 
was inaugurated In April 1990and held a workshop on 
ftCommunication for sustainable agriculture" at which 
participated the representatives of the major 
newspapers. magazines, radio and television agencies, 
research institutes. farmers' organizations. the Central 
Bank of Nigeria, the Nigerian Agricultural and 
Cooperatives Bank and FAO of the United Nations. 
The Director General, Dr. Laurence D. Stifel, gave 
a public lecture on the work of IITA at the Nigerian 
Inst~ute of Intemational Affall"s In March 1989 and a 
presentation at the National Workshop on the 
Economic Recovery Program, which was organized by 
the Office of the PreSident of the Federal Republic of 
Nigeria in February 1990. Both events were reported 
extensively in national newspapers, which published 
the texts of his presentations in part or whole. 
Many joumalists visited IITA and reported on the 
research here. Selections of IITA's press coverage 
dUring 1989 have been produced in two volumes 
ent~led IITA in the News. 
Ubrary Services. The library offered training in the use 
of the online public access catalogue to 205 people, 
who included scientists from UTA and national 
agricultural research institutions. Training was also 
provided for staff of other libraries in Nigeria and the 
librarian ofthe Central Agricultural Research Institute 
(CARl) of Liberia. 
Assistance to national research institutions 
continued inthe form ofliterature searches, interlibrary 
loans, preparation and supply of bibliographies, 
donations of duplicate or redundant publications and 
proviSion of general information. 
As a part of its selective dissemination of information , 
the library introduced a weekly CUrTent-awareness 
series to circulate among scientific staff the tables of 
contents of professional joumals received at the 
library. About 150,000 page copies were circulated 
during 1989. For users outside the Institute, SCientific 
Information was provided in response to 3 12 requests 
by mail from 42 countries, which included 19 in Africa. 
A guide to the library and its services was published in 
English and French ed~ions. 
In-house database management was improved 
with implementation of the thesaurus module of 
BASIS. About 12,300 records were added to the 
library's database during 1989. Database error 
correction and retrospective data input of selected 
joumal articles were increased. Eleven additional 
databases on compact disk (CD-ROM) were acquired. 
Publications, The total editorial output for jobs 
completed during 1989 exceeded 5,000 pnnted pages. 
A management review brought innovations to liT A 
publications. The content and style of IITA Annual 
Report 1988/89 show modifications intended to 
enhance communication to the non-scientific as well 
as SCientific readership. Research Briefs published its 
last issue during 1989. A new semiannual penodical 
for scientists which presents current information on 
research results was launched In 1990, ent~led IITA 
Research. 
liT A hosted the Fourth Conference and General 
Assembly of the African Association of Science Editors 
from 5 to 9 March 1990. Participants came from all 
regions of Afnca as well as other parts of the world. 
The conference pnovided IITA editlorial staff with an 
opportun~y to interact with African professional 
colleagues andto contribute towards strengthening of 
scientific editing capabilities in Africa. 
Interpretation and Translation. Interpretation 
services were provided to 13 training courses and 
several meetings. Many thousands of pages of scientific 
and information documents were translated. 
87 
88 
Scientific Support Services 
Genetic Resources 
Since the establ.shme'lt of ts crop improvement 
programs in 1970, liT A has devoted considerable 
resources to assembling and evaluating gennplasm of 
cowpea (Vigna unguiculata), African rice species (OtyZQ 
sotl:VO, O. globerrimo) , yams (Discoreo spp.), cassava 
(Monlhot escuiento), maize (Zeo mays), bananas and 
plantains (Muso spp.), soybean (Glycine max), sweet 
potato (Ipomoea botoros) and bambara groundnut 
(Vigna subterroneo). IITA established its genetic 
resources unitir. 1 975to collect, characterize, evaluate 
and preserve germ plasm species of its mandated 
crops. 
T'legermplasrT' collection, which illcludestheworld 
colleGians of cowpea and African land races of rice, 
supports breeding and related research activities by 
I!TA, national programs in trap cal Africa and 
organizations with kindred objectives elsewhere. liT A's 
plant geneticists seek to promote the usefulness of this 
germplasm and to enlarge knowledge about its 
taxonorry, genetics, 'nterspecific relationships and its 
potential contribution as a genetic resource for breed ing 
programs. 
Achievements. liT A plant explore" had, by early In 
1990, conducted 58 exploration and collection missions 
in 31 African countries, The unit maintains a collection 
of 15,000 accessions of cowpea, 1,400 of wild 'ligna, 
12,000 of nce, 2,000 of bambara groundnut, I ,400 of 
soybean, 1,800 of yams, 1.200 of maize and SOMe 
hundreds of samples each of other species. The liT A 
seed storage unit comprises two storerooms for an 
"active collection", with a combined capacity of 409 
cubiC meters that are kept at 5°C± I 0 and 30-3S%RH; 
and a "base collection" seed sto"e of 132 cubic rf1eters 
conditioned at -20°e. In addition, 2,000 lines of 
cassava and wild Monihot, 1,000 clones of sweet 
potatoes and 300 clones of plantain and bananas are 
maintained by !ITA's root. tuc>er and plantain 
improvement program. 
Current germplasm research includes: 
• Gerrrplasm characterization and evaluation of 
cowpea, rice, yam and their related species, 
• Surveys of Vigna afld Oryza distribution in Africa. 
• Interspecific hybridization betwee1 cowpea and 
wild VI:gna, in orderto study the genetic affinity between 
species and to identify potential bridg. ng species 
which can help effect crosses in breedingforresistance 
against flowe';ng pests. 
• Agrobotanical variability of Vigna species within the 
(otiong group closely related to cowpea 
• Genet c inheritance studies of particular traits. 
• Seed longevity in cowpea and bambara groundnut 
• Genetic diversity and differentiation of the African 
rice and land races of ASian rice collected in Africa. 
• Seed viability andtuberqualityofthe yam germplasm 
collection. 
Operational Strategies. Exploration and collection 
activities seek to fill gaps in the col!ections of African 
Oryza, Vigna and Dioscorea. Germplasm samples will 
be acquired from other parts olthe world. Germplasm 
of other mandated crops will be collected within the 
region, particularly of cassava and maize. 
A sound system of germplasm storage and periodic 
regeneration, combined with duplicate/triplicate 
storage in allied collections elsewhere for security 
against 105s, has been developed. Duplicate germplasm 
accessions will be eliminated by morphological 
comparison and chemical techniques. A core collection 
of each species will be selected for full evalJation. 
The unit conti1ues to service demands for seed 
materials which average around 200 requests per 
year, 
Characterization and evaluation are systematically 
conducted for cowpea, wild Vigna, rice and yam, Many 
accessions are grown out in experimental fields each 
year for these activities. The urit has already 
characterIZed and evaluated more than half of the 
exist'ng collection of bambara groundnut. The 
collection of soybean has been characterized for six 
agronomic char-acters. A computerfl'e is kept on each 
accession with information on descriptive and 
agrobotanical characteristics, and on resistance to 
selected diseases, pests and physiological stresses. 
Improvements are planned foryamtubertreatment 
and storage facilities, in orderto increase shelf life and 
reduce tuber loss. 
Training courses are conducted for national scientists 
or technicians in gerrrplasm exploration, collection 
and conser.;ation, seed technology anc gene bani<. 
management, a'l1ong other related areas. 
Collaborative linkages. Research projects 1ave 
commenced with the Universita degli Studi di NaJoli, 
the Istltuto del Germoplasma, Bari, and the Istituto 
Nazion2.le della N utnzione, Rome. The areas of 
common Interest are cytology of cowpea and wild 
~;gno; wide crosses between cowpea and wild Vigna: 
cell and protoplast culture of cowpea; variability of 
Vigna germplasm With respect to seed-protein 
electrophoretic band patte'Tls, nutritional values and 
artinutritional factors: and chemical studies related to 
insect pest resistance. These activities will utilize 
biotechnology techniques in exploitingtre gene pool 
of wild Vigna for cowpea improvement. 
liT A plant genetiCists often workcloselywrth IBPGR, 
other intemational organizations and genebanks in 
collecting and supplying germ plasm samples and 
disseminating germplasm information to researchers 
ail over the world. They coliabDrate With liT A crDp 
improvement scientists and virologists and with 
scientists from national programs to evaluate 
germ plasm for resistance to insect pests, diseases and 
physioiDgical stresses. The un ~ alsD helps tD strengthen 
national programs in West and Central Africa in 
exploration, collection, conservation, evaluation and 
documentation. 
Seed health and plant quarantine are shared 
concems with Virologists and others at liT A A major 
seed health problem Df legume crops is seed-bome 
virJses. In conjunction with the IITA seed health 
committee, accessiors of Vigna and Glycine which may 
bevirally contaminated are grown under screenhouse 
conditions to produce virus-free materials. The unit 
liaises with the Nigeran Plant Quarantine Service for 
both the impDrt of plant matenals and certificatiDn Df 
mater·als for export, 
A seed health unit is being set up to ensure proper 
transfer of germ plasm materials in coordination with 
the national plant quarantine authorities. 
Germplasm security. Duplicate germ plasm storage 
ensures secu~ ofholdings.IRRI and liT A are comparing 
their respective noldings and intend to make complete 
set Df duplicates Df all African collections for stDrage 
at each center. In additlDn, IITA recently sent 2,000 
accessions of nce germplasm to the national seed 
storage laboratory for duplicate storage and research 
purposes. 
AbDut Dne-thlrD of liT A's cowpea collectiDn has 
been duplicated at the US natiDnal seed storage 
laboratory. Part of that collection is tD be duplicated 
fDc the IstitutD del GermDplasma, Bari. 
Dunng 1989 CIP and IITA produced a set of 
duplicates Df all liT A's sweet pDtato germplasm fDr 
conservation and research purposes at ClP. Duplicate 
samples of bambara ground nut will be sent tD Fa!. 
Federal Republic Df Germany for stDrage. Other 
duplicate storage arrangements are made for Muso 
specimens through the IntematlDnal Network for the 
Improvement of Banaras and Plantains (INIBAP) and 
at the Katollc Universitet Leuven; and for soybean 
germplasm with the Intemational Soybean Program 
(INTSOY), US.A. and ASian Vegetable Research and 
Development Center (AVRDC). 
Virology 
The virology unit conducts research on virus diseases 
occurring in IITA's mandated crops In Africa. The unit's 
activities are closely linked with the work of breeders, 
pathDlogists and entomoiDgists In each ofllTA's crop 
improvement programs, 
ViroiDgy at liT A characteristically fDcuses on two 
different but cDmplementary fields Df interest. The 
first Includes studies onthe etiDlogy and epidemloiDgy 
of virus diseases as well as research which supports the 
development of new disease-resistant vaneties. 
Quarantine aspects of crop improvement and 
intemational transfer of improved germplaslT' also fall 
within this field. 
The second concerns virus purification, 
characterization and detection techniques. The unit 
maintains pure and characterized virus isolates that 
are used in testing breeding lines for resistance. When 
an unknown virus IS found or a known virus has 
assumed an unfamiliar fonne, the liT A Virologists try to 
Identify and purify ~, develop antISera, and deScribe 
the pathogen in terms of isolate characteristics for 
reference and comparison. 
Recent, rapid developments in molecular biology 
have opened up highly effective means for detection 
of viruses. New biotechnological procedures permit 
detection with, for example, serological techniques 
which utilize monoclonal antlbDdies (MAB) and 
complementary DNA (cDNA) fragments. Because of 
its speCific binding or hybridization properties, cDNA 
can be used in the development of extremely sensitive 
detectlDn methods. IITA VIrDIDg!sts have sDught the 
help of advanced laboratones In applying such 
techniques with selected crops. 
Agroecological Focus. Studies Df the ecology, 
epidemiology and agroecological significance of virus 
diseases are framed within the agroecological zones of 
the speCific crop-pest problem. Part of the work in 
cowpea virology, for example, will be conducted out 
of the new liT A research station at Kana, in the dry 
savanna of northem Nigeria. 
Achievements. During 1989, the unit continued to 
test the resistance of elite cowpea and rice genotypes 
from the breeding programs tD newly recognized 
viruses or virus strains. The unit also continued to test 
routinely all breeders' germplasm of cowpea and 
soybean for presence of seed-bome virus in orderto 
ensure its phytosanitary safety. 
EpidemiologICal studies as well as long-term 
eval uatlDns of the ecolDgy and geograph Ical distribution 
89 
90 
have allowed the virologists to obtain a reliable picture 
of the economic importance of virus diseases in IITA's 
mandated crops. 
Field surveys In Nigena during 1989 unexpectedly 
tumed up an instance of rice yellow mottle virus 
infection of Oryza longistaminato, near Numan, in the 
Benue Rlver valley of Gongola State. This exciting 
discovery is the first such occurrence of that virus 
reported in a perennial wild rice variety in Nigeria; 
although it has been reported in this species from 
other West African countries. In order to obtain a 
better insight into pathogenic variation in the virus, 
collections of wild rice, as well as O. sativQ gemlplasm 
tolerant of the virus, ane being tested using the 
standard IITA isolate and the newly obtained Isolate of 
the ViruS from O. /ongistominota, 
The results of such studies to date have shown that 
pathogenic properties of this new "wild reservoir" 
isolate of the virus do not differ significantly from those 
of the standard Isolate that has been used at IITA In 
resistance screening since the virus was first found in 
Nigeria in 1978. Likewise, comparison of a wide range 
of Isolates of cowpea aphid-bome mosaic virus and 
other viruses found in cowpea in Africa forpathogenic 
variation in a wide range of elite gemlplasm has shown 
that types of these viruses which occur in Nigeria are 
well covered, for resistance screening purposes, by 
the standard Isolates of the viruses at liT A. 
IITA virologists have made significant progress in 
characterizing viruses. Several newly discovered viruses 
and new strains of viruses occurring in liT A's mandated 
crops and related or associated weed species have 
been purified forthe production of antisera, which are 
being used for diagnostic purposes and virus indexing 
at liT A. Such antisera have been provided to several 
national program scientists at their request. 
Maize mottle virus was punfied forMAB production 
required for large-scale, reliable diagnosis of similar or 
identical diseases in this crop in other parts of Africa. 
Maize mottle virus is the second most important virus 
of maize in Nigeria and possibly has a continent-wide 
distribution. 
Collaborative research.IITA is acquiring experience 
and capability in MAB and cDNA techniques through 
cooperative research with scientists at the U.S. 
Department of Agricu~ure laboratory at Be~ville, 
Maryland The objective 15 to produce MBAs and 
cDNA probes for the detection of viruses affecting 
root an d tuber crops. 
A project with the Intemational Development 
Research Center, Canada, is assisting national programs 
in Africa in identifYing viruses in their rnajorfood crops. 
National program scientists will be trained in the use 
of MABs, which ane being produced by the Canadian 
Department of Agnculture at Vancouver. MABs will 
open a shortcut to crop Virologists at liT A as well as 
national programs which do not have the equipment 
and other facilities to identifY viruses with conventional 
methods. Once they have been trained in the use of 
MABs, they should be in a better pOSItion to conduct 
reliable virus identification specific to their own areas. 
Afterlocally prevalent virus strains have been identified, 
liT A and national program bneeders can adopt 
strategies to incorporate appropriate virus resistance 
in improved crop varieties. 
Biometrics 
The biometrics unit advises all IITA's scientists and 
postgraduate students on mathematical and statistical 
aspects of agricuH:ural research. The unit assists scientists 
and trainees in designing surveys and experiments, 
analyzing and interpreting data, using statistical 
infomlation in publications and presentations, and 
applying appropriate mathematical and statistical 
techniques in their work. The unit also designs and 
teaches the statistics components of most liT A training 
courses, and conducts occasional, more specialized 
courses in statistics and statistical computing. 
During 1989 students and researchers from the 
universities oflbadan, Ife and Benin and several other 
groups from Nigeria came to the unit for assistance. 
The IITA biometrician contributed to the on-fanm 
research workshop in April and the training course 
which followed from ~ in September. Subsequently he 
presented the analytical methods component of that 
course at a worl<shop in Camenoon. Together with a 
visiting specialist, the biometrician analyzed sets of 
cowpea Intemational variety trials from 1983 to date. 
These data were used with further assistance from the 
unit in a course on analysis of genotype x environment 
interactions. A visiting specialist from the Food and 
Agriculture Organization of the United Nations spent 
one month with the unit in training in experimental 
deSign. 
Analytical Services 
The analytical services laboratory assays soil. plant and 
water samples submitted by liT A researchers and 
their collaborators. The lab analyses soil and water 
samples for various physical and chemical properties. 
Plant samples are analyzed for primary and secondary 
nutrients and for micronutrients. 
The laboratory contributed dunng 1989 to the 
development of liT A research stations. Forthe humid 
forest station being established at Mbalmayo, 
Cameroon, the lab designed a new soil and plant 
analysis laboratory; selected methods and procedures 
for soil, plant and water analysis; and prepared orders 
for equipment. chemicals and supplies. The lab also 
analyzed samples for site characterization. For the 
moist savanna station at Kana in northem Nigeria, the 
laboratory performed soil analyses for site 
characterization and water analysis for irrigation, Lab 
support forthe stations at Onne and Cotonou included 
analysis of soil, plant and watersamples from research 
projects, analysis of dnnking water and supply of 
deionized water for their laboratones. 
The unit also acalyzed soli and plant samples from 
on-farm trials and from national research centers 
within and outside Nigeria. Laboratories from Liberia 
and Sierra Leone were assisted with procurement of 
spares and supplies or with assessment and advice for 
improvements. On-the-job and formal training of 
laboratory staff from developing countries continued 
as regular activities of the unit 
The decentralization of IITA research activity from 
headquarters to different agroecological zones affects 
the laboratory in various ways. Samples received froM 
each zone have distinct properties and require 
development of new analytical methods and 
procedures. Because of the distances involved from 
sample Origin to IITA problems can arise concerning 
contamination during shipment and time lapse between 
sample collection and its analysis. 
Networking. Thefirst advanced training workshop on 
soil and plant analysis for laboratory directors and 
supervisors from tropical regions was organized In 
1989 and repeated early in 1990. 
A proposal to establish a soil and plant analytical 
laboratories network for Africa (SPALNA) was 
developed during the two workshops. Formal 
inauguration ofthe network IS scheduled early In 1991. 
The goal of the network is to improve soli and plant 
analytical services to support research at national 
programs through collaboration among laboratories 
in Africa. The network will concentrate on such 
priority areas as maintenance of laboratory equipment, 
training, infrastructure, communication of new 
developments in analytical methods, quality control of 
analytical data, standardization of rrethods and 
improvements in supply of equipment and materials. 
In future, the range of analytical services at IITA will 
be extended significantly with the introduction of a 
high-pressure liquid chromatograph. To process the 
increasing number of soil, plant and water samples 
from liT A researchers and collaborators, further 
automation of the analysis and of data processing will 
be required. Development of new methods of soil and 
plant analysis will also continue. 
Farm Management 
The farm management unit is responsible for the 
management, maintenance and developmert of 
experimental famrs at IITAs headquarters and at four 
research stations in Nigeriaand Cameroon. In addition, 
the unit's mobile team supports research testing in the 
different agroecological zones of Nigeria. 
The new moist savanna research station at Minjibir 
near Kano, northem Nigeria, is being developed in 
collaboration with the Inst~ute for Agncultural Research 
of Ahmadu Bello University, ZalCa The Kano station 
covers 105 hectares of which 30 hectares are assigned 
for liT A use. Access roads, soil conservation installations 
and rudimentary irrigation facilities have already been 
proVided. During 1989 and early In 1990 a small 
building complex was erected which houses field 
laboratories, crop threshing and drying areas, a farm 
workshop, implement storage sheds and field offices. 
FenCing of the experimental fields iswell advanced and 
land development to improve soil uniformity is under 
way. 
The new high rainfall station at Mbalmayo, 
Cameroon IS being established on a I ,OOO-hectare site 
in a forest reserve, involving much basic land 
development work Boundary demarcation, road 
development and land clearing (by hand, in order to 
minimize soil disturbance) comlTlenced during 1989, 
The farm management staff assists resource~ 
management scientists in studies of soil-conserving 
tillage methods. For the purposes of these studies, 
most trials on IITA famrs are planted w~h no-till 
materials that reduce soil erosion and degradation. 
The unit also multiplies improved crop varieties 
91 
92 
developed by IITA scientists and their collaborators, 
distributing up to 100 tons of seed annually to 
govemment seed serlices, seed companies, and 
farmers, in Nigeria and other African countries. At 
Ibadan, the unit maintains a demonstration area, 
where UTA crop vaneties and farming technologies 
are shown to more than 2,000 visitors each year. 
On a collaborative basis, the unit assisted other 
interT'ational agricultural research centers during 1989. 
Kana-based staff of the Intemat·onal Crop Research 
Institute forthe Semi-Arid Tropics (ICRISAT) received 
support in planting trials on 22 hectares, Dry-season 
irrigated sorghum Isolation sites were also proVided 
for ICRISAT at the liT A headquarters farm at Ibadan. 
The unit also worked with Ibadan-based sCientists of 
the Intemational Livestock Centerfor Afnca (ILCA) to 
determine optimal methods of shrub establishment in 
pastures for alley cropping. 
West African training course. Early in 1990 the unit 
conducted the first research farm management group 
training course to be held at liT A. Seventeen research 
farm managers from five countries of West Africa 
reviewed the following topics during the three-week 
course: surveying for soil conservation, maintenance 
and calibration offield machinery, and farm workshop 
planning and management. JOint organized by IITA, 
ICRISA T and the University of Arkansas, the course 
will be repeated in 1991 and 1992 as a contribution 
toward improved experimental farm support for 
national research programs in the region. 
Annexes 
93 
Financial Statements 1989 _________ _ 
Extracts from Financial Statements for the Year Ended 31 December 1989 
The full Financial Report and the Report of the Auditors Arthur Andersen and Company are available from liT A on request 
Statement of Financial Position 
Statement of Activity 
Statement of Changes in Financial Position 
Donors 1989 
94 
95 
96 
97 
98 
IITA 
STATEMENT OF FINANCIAL POSITION 
31 DECEMBER 1989 
ASSETS 
Cash and Short-Term Deposits 
Accounts Receivable: 
Donors 
Others 
Inventones 
Other Assets 
Property, Piant and Equipment 
LIABILITIES AND FUND BALANCES 
LIABILITIES 
Accounts Payable and Other liabilities 
Accrued Salaries and Benefits 
Payments In Advance - Donors 
FUND BALANCES 
Capital 
Capital Development 
Operating 
Expressed in US $ T~ousonds 
1989 1988 
6,936 5,293 
8,058 8,490 
503 563 
3,627 4,461 
178 238 
55)68 51,677 
75,070 70)22 
8,094 6,998 
3,053 3,641 
3,465 3.1 16 
14,612 13.755 
55,768 51.677 
976 1,576 
3,714 3,714 
60,458 56,967 
75,070 70,722 
95 
IITA 
STATEMENT OF ACTIVITY 
FOR THE YEAR ENDED 31 DECEMBER 1989 
Expressed ir; US $ Thousands 
REVENUE 1989 1988 
Grants 31,218 33,577 
Other Income 619 616 
31,837 34,193 
EXPENSES 
Research Programs 18,342 17,398 
Conferences and Training 1,883 2,083 
Information Services 1,432 1,441 
General Administration 3,522 3,979 
General Operations 2,886 2,764 
Property, Plant and Equipment 3,634 4,453 
Exchange (Gains) I Losses (263) (547) 
Total Expenses 31,436 31,571 
Allocation to Capital Development Fend 401 1,349 
Allocation to Operating Fund 1,273 
31,837 34,193 
96 
IITA 
STATEMENT OF CHANGES IN FINANCIAL POSITION 
FOR T HE YEAR ENDED 31 DECEMBER 1989 
SOURCES OF FUNDS 
Excess of Revenu e over Non-Capita Expenses 
Decrease in Accounts Receivable - Donors 
Decrease in Accounts Receivable - Other 
Decrease in Inventories 
Decrease in Other Assets 
hcrease in Accounts Payable and Other Liabilit ies 
hcrease in Payme nts in Advance - Donors 
APPLI CATION O F FUNDS 
Purchase of Property. Plant and Ecuipment 
Increase il Accounts Receivable -- Donors 
Increase in Accounts Receivable - Other 
Decrease in Accrued Salaries and Benefits 
Decrease in Payment in Advance - Donors 
INCREASEI(DECREASE) IN FUNDS 
CASH, BEGINNING OF YEAR 
CASH, END OF YEAR 
Expressed i,~ US .$ Thousands 
1989 
4,035 
432 
60 
834 
59 
1,096 
349 
6,865 
4,634 
588 
5.122 
1,643 
5,293 
6.936 
1988 
7,075 
143 
24 
2,036 
9,278 
6,237 
4,234 
247 
243 
231 
11,192 
( i ,9 14) 
7,207 
5,293 
97 
DONORS 1989 
Donors 
Afncan Development Bank 
Australia 
Austria 
Belgium 
Canada 
China 
Commission ofthe European Communities in Nige-ia 
Denmark 
Finland 
Food and Agriculture Organization 
Ford Foundation 
France 
Gatsby Chantable Foundation 
Gemnany. Federal Republic of 
India 
Intemational Development Research Center 
Intemational Fund for Agricultural Development 
Italy 
Japan 
Netherlands 
Nigeria 
Norway 
Rockefeller Foundation 
Sweden 
SWitzerland 
Unted K'ngdom 
United Nations Development Program 
Un'ted Nations Un versity 
Unted States Agency for Intemational Development 
Unverslty of Hohenhetm 
World Bank 
Closed and Miscellaneous Projects 
Total 
98 
Expressed in US $ Tho!.<sar,ds 
Core Funding Special Project Funding 
225 
94 
90 
510 264 
1,637 202 
10 
9 
106 70 
237 
260 
100 74 
273 
262 
1.379 40 
24 
487 
650 
641 885 
2,280 
654 571 
24 15 
588 
503 
194 121 
933 46 
743 
147 
41 
5,435 5,550 
136 
4,690 II 
7 
21.517 9,701 
The CGIAR ___________ _ 
The Consultative Group on Intemational Agricultural 
Research (CGIAR) is an informal association of coun-
tries, international organizations and private institutions, 
formed in 1971 to provide sustained support for a 
well-defined and closely monitored program of 
international research on food commodities of vital 
importance to the developing countries of the world. 
Cosponsored by the World Bank, the Food and 
Agricu~ure Organization of the United Nations (FAa) 
and the United Nations Development Programme 
(UN DP), the CGIAR operates without a formal charter, 
relying on a consensus deriving from a sense of 
common purpose. The CGIAR started with a nucleus 
of four existing intemational agricultural research 
centers, including liT A. The number of centers has 
increased to I 3, supported by 39 donor members and 
other contributors, who provided about US$260 
million in funding during 1988. 
E_ch CGIAR-affi liated center is independent and 
autonomous, with its own structure, mandate and 
objectives, and is overseen by its own board of 
trustees. Some centers focus on one or two 
commodities for which they have global mandates, 
while others have regional or ecological mandates for 
one or more commodities. Still others perform 
specialized functions in the fields of food policy research, 
genetic resources conservation, and the strengthening 
of national agricultural research in developing countries. 
The CGIAR is serviced by an executive secretariat. 
which is provided by the World Bank and located in 
Washington. A Technical Advisory Committee (T AC), 
comprising a chairman and 13 scientists, is drawn 
equally from developed and developing countries. 
The T AC makes recommendations on research 
programs and priorities, and monrtors performance 
through annual program and budget reviews and 
periodic extemal reviews by independent scientists 
invited to serve on specially constituted panels. The 
TAC is supported by a secretariat provided by the 
three cosponsors of CGIAR and located at FAa 
headquarters in Rome. 
The CGIAR meets twice a yeac once in Washington 
during October/November and once elsewhere during 
May. The meetings hear and discuss recommendations 
about over-all strategy, budgetary needs and 
management issues. Reports from individual centers, 
as well as independent extemal evaluations, are 
presented periodically at those meetings. 
Centro Intemacianal de Agricultura Tropical 
CIMMYT 
Mexico 
IFPRJ 
USA 
ISNAR 
Netherlands 
ICRISAT 
India 
IRRI 
Philippines 
CiAT 
CIMMYT Cencro Intemacional de Mejoramiento de Maiz y Trigo 
Colombia 
ClP Peru WARDA Cote d'ivoire 
ILCA 
Ethiopia 
ILRAD Kenya 
IITA Nigeria 
ClP Centro Intema(lonal de 10 Papa 
IBPGR IntematJOnal Boord for Plant Genetic Resources 
ICARDA Intemational Center for Agricultural Research in the Dry 
Areas 
ICRISA T Intemational Crops Research Insriwte for the Semi-Arid 
Tropics 
IFPRI Intemational Food Policy Research Institute 
IITA Intemarionallnstiwte of Tropical Agriculture 
ILCA 
ILRAD 
Intemational Livestock Center for Africa 
Intemational Laboratory for Research on Animal 
Diseases 
IntematJonai Rice Research Instiwte IRRI 
ISNAR Intemational Service (or National Agricultural Research 
WARDA West Africa Rice Development Association 
99 
Principal Staff _____________ _ 
Manage ment and Support Se rvice s 
Executive Management 
L D. Stifel. Ph.D .. director general 
S. A Adetunji, PhD ., special assistant to the director general 
J. Cramer, B.A., executive assistant to the d irector general 
J. H. Davies, B.Sc., directo r, office o f the director general 
J. P. Eckebil, PhD., deputy director general. international cooperation 
K S. Fischer. Ph.D .. deputy director general, research 
F. McDonald, M.s., assistant to the deputy director general, research 
R Oyekanmi, ACA., internal auditor * 
W. P. Powell. B.5e.. deputy director general, management 
W. M. Steele, PhD., special assistant to the director general· 
Admin istrative and Auxiliary Services 
K.. A Aderogba, F.C.I.S., principal administrat ive officer· 
C. A. Enahoro, manager, Ikeja guest house 
A R. Middleton, BSe.. manager. inte mational house 
R I. Olorode. security manager 
D. J. Sewell, manager, aircraft operations 
Budget and Finance 
D. A Govemey. F.CA .. d irector. budget and fi nance 
B. A Adeola. F.CI.S .. accountant 
O. E. Adepoju, ACA .. analyst. accounting procedures 
G. A Agbarin. GD.CS .. technical analyst • 
O . A Ajayi. M.B.A. senior technical analyst • 
C A Babalola. ACA .. analyst. accounting procedures 
P. O. Balogun. ACA. finance manager 
J. Bolarinwa. M.B.A. payroll accountant 
P. O. Etuk. M.B.A. budget and planning coordinator 
E. D. Greene. M.Sc., materials manager 
G. R Mcintosh, CM.A.. procedures manager, financial information 
systems 
F. O . Ogunyemi, F.CAA. accountant· 
S. j. Udoh. A.M.N.l.M .. chief accountant 
D. Wheeler. c.p A .. project manager. financial information systems 
Computer Services 
L J. McDonald. U.S .. computer manager 
S. Adalumo. M.Sc.. computer electronics and operations officer· 
A A Akinbola. B.Sc.. computer programmer 
N. N. Eguzozie, SSc., computer programmer 
T. D. Oluyemi, MSc., computer programmer 
Human Reso urces 
J. Thackway, M.A.. director. human resources 
1. A. Akintewe. MD .. senior medical officer 
J. O. Badaki. M.B.A. employee relations manager 
O. A. Cole, MD .. medical officer 
J. B. Elegbe, MSc .. manpower development manager 
100 
Information Services 
S. M. A Lawani, PhD., d irector 
J. A. Adedigba. MA. principal librarian 
A O. Adekunle. M.5e.. editor 
O. R Adeniran. M.5e.. principal librarian 
A. R Astill, M.A. editor· 
K Atkinson. M.5c.. editor and head. publications 
S. Auerhan, Lie., interpreter/translator 
B. Auvard, BA .. interpreter/translator 
A. A Azubuike. M.Se.. principal librarian 
S. Bailey. Lic .. interpreter/translator 
O. Hounvou. D.AS .. interpreterltranslator 
E. Molinero. lie .. head. interpretation/translation 
C Moudachirou. lie.. interpreter/translator * 
E. Nwulu, M.Sc .. audio-visual specialist 
J. O. Ojurongbe. BSc., production manager 
L Ouedraogo. lie., interpreter/translator· 
j. O. Oyekan. B.Sc .. head. public affairs 
D. R M. Raj, PhD., senior science writer and editor 
E. T ordeur, lie.. translator· 
F. N. Ubogu. MSe.. principal librarian 
Physical Plant Services 
j. G. H. Craig. director 
E. O. A Akintokun. research vehicle services officer 
A Amrani. heavy equipment services o ffi cer· 
A K. Bhatnagar, B.Se., assistant director 
A C. Butler, building and site services officer 
P. G. Gualinetti, construction site engineering services officer 
J. Kane. electrical services officer· 
E. Ojinere, heavy equipment/fabrication services engineer 
A. Oyedeji. heavy equipment services officer 
S. Quader, electronic services o fficer 
• Le~ during the year (I April 1989 - ] I March 1990) 
Research and Support Services 
Biological Control Program 
H. R. Herren, PhD., director 
D. T. Akibo-Betts, PhD., entomologist and East/Southern Africa 
regional coordinator 
W . N. O. Hammond. PhD .. entomologist and West/Central Africa 
regional coordinator 
P. Neuenschwander, Ph.D., entomologist and research coordinator 
F. Schulthess, PhD., ecologist 
T. Shanower. PhD., entomologist 
A Wodageneh, Ph.D .. training officer. FAO 
j. 5. Yaninek. PhD., acarologist 
J. B. Akinwumi, M.5c.. engineer 
T. M. Haug, M.Sc., mass rearing specialist 
B. Megevand, M.5c., mite rearing specialist 
Associare experts 
C. Boavida, M.5c .. ecologist 
M. T amo. M.5c .. ecologist 
Grain Legume Improvement Program 
5. R. Singh, PhD .. director 
K F. Cardwell, PhD .. plant pathologist 
P. Q. Crawford, PhD .. crop physiologist 
K E. Dashiell, PhD .. breeder 
L E. N . jackai, PhD., entomologist 
D. M. Naik. PhD .. agronomist/breeder. Zimbabwe 
O. Nakayama, PhD .. food technologist 
B. R. Ntare. PhD., breeder and liaison scientist to ICRISAT. N iger 
B. B. Singh, PhD .. breeder 
I. Watanabe, PhD" plant physiologist 
H. O . Ogundipe, M.Sc., food technologist 
Posrdoctoral fellows 
c. N. Akem, PhD" pathologistlbreeder 
G. O . Myers, PhD" breeder 
Maize Research Program 
I. W . Buddenhagen. PhD., director· 
M. Winslow. PhD., director 
N. A Bosque-Perez. Ph.D., entomologist 
5. K Kim, PhD" breeder 
j. H. Maneck. PhD .. breeder 
T. Mesfin, Ph.D., vector entomologist 
M. Rodriguez, PhD., agronomist • 
G. K. Weber. PhD., national program coordinator 
Postdoctoral fel/ows 
A. E. Awad, PhD .. striga biologist 
j. G. Kling, PhD" breeder 
O. M. Olanya, PhD" pathologist 
Visiting scientists 
B. Badu-Apraku, PhD., breeder 
D. K. Kossou, PhD., entomologist 
Resource and Crop Management Program 
D. 5. C. Spencer, PhD" director 
I. O. Akobundu, PhD., weed scientist 
A. N. Atta-Krah, PhD .. coordinator. alley farming network 
K. Dvorak. PhD., agricultural economist 
H. C. Ezumah. PhD .. agronomist, cassava-based working group 
B. S. Ghuman, PhD., soil scientist • 
M. P. Gichuru, PhD., agronomist (soil fertility) 
G. Gillman. PhD .. soil chemist 
N. R. Hulugalle, PhD" soil physicist 
A. E. Ikpi, PhD" economist 
A-M. N. lzac. Ph.D., agricultural economist 
5. 5. jagtap, PhD" agroclimatologist 
B. T. Kang, PhD .. soil scientist/agronomist 
T. L Lawson, PhD., agrodimatologist .. 
K. Mulongoy, PhD., soil microbiologist 
H. J. W. Mutsaers, PhD .. agronomist, maize-based systems working 
group 
M. C. Palada, PhD., agronomist, rice-based systems working group· 
N. Sanginga, PhD .. assistant coordinator. alley farming network 
J. Smith. PhD .. economist. maize-based systems working group 
M. Swift. PhD .. leader. resource management research 
Collaborative Study of Cassava in Africa 
F. I. Nweke, PhD., agricultural economist, team leader 
G. R. Mull ins. PhD .. East/Southem Africa regional coordinator 
Y. C Prudencio, PhD., regional coordinator 
Postdoctoral (e/lows 
R. j. Carsky, PhD., agronomist 
S. Ehui, PhD., agricultural economist • 
G. Fairchild. PhD .. soil microbiologist 
A C. Goldman, PhD., economic geographer · 
R. A Polson, PhD., agricultural economist 
E. Tucker, PhD., weed scientist 
Visiting scientists 
P. O . Adetiloye, PhD., agronomist • 
S. Hauser. PhD .. agronomist 
R. Markham. PhD .. entomologist 
Assodate experts 
J. Foppes, (r., agricu ltural economist, Onne station 
M. C. Van der Meersch, Ir .. microbiologist 
101 
Rice Research Program 
M, Winslow, PhD .. program leader and breeder 
K.. Alluri. PhD., coordinator, INGER-AfricallRRlliaison scientist 
T. M. Masajo, PhD., breeder 
Postdoctoral rellow 
R. c. Joshi, PhD., entomologist 
Root, Tuber and Plantain Improvement Program 
S. K Hahn, PhD .. director 
A M. Almazan. PhD .. biochemist/food technologist • 
R. Asiedu, PhD .. breeder 
Y. W . Jeon. Ph.D., postharvest technologist 
S. Y. C. Ng. M.5c .. tissue culture specialist 
D. S. O . Osiru, PhD .. crop physiologist 
J. A Otoo, PhD .. agronomistlbreeder 
M. C. M. Porto, PhD .. ClAT-IiTA physiologistlbreeder 
G. D. Sery, PhD., regional coordinator. INIBAP. Onne station 
R. L A Swennen, PhD" agronomistlbreeder. officer-in-charge, Onne 
Postdoctoral rellows 
M. Bokanga, PhD .. biochemist 
A G. O. Dixon, PhD .. breeder 
G. Eggleston, PhD .. biochemist 
Visiting scientists 
K V. Sai, PhD .. cytogeneticist 
T. Ikotun, PhD .. pathologist 
H. Kanno, PhD .. entomologist, jlCA 
I. G. Mok. PhD .. breeder, ClP • 
Associate Expen 
D. R. Vuylsteke, Ir., agronomist. INIBAP, Onne station III 
Analytical Services Laboratory 
J. L. Pleysier, PhD .. head 
Biometrics 
P. W alker. M.A. biometrician 
Farm Management 
D. C. Couper, M.5c .. fann manager 
P. D. Austin, B.5c .. fann manager, Onne station 
S. L Claassen. M.5c., assistant fann manager 
P. V. Hartley. B.5c" fann manager/engineer 
Genetic Resources Unit 
N. Q. Ng, PhD .. head and plant geneticist 
S. Padulosi, Dott.. plant explorer 
Virology Unit 
H. W . Rossel. Ir" head and virologist 
G. Thottappilly, PhD .. virologist 
102 
International Cooperation 
H. Gasser. PhD" director, training program 
E. Arubayi, M.B.A. coordinator, monitoring and evaluation· 
E. F. Deganus, B.5e., project development coordinator 
j. L Gulley. PhD .. group training coordinator 
O. M. Ogunyinka, M.5e., coordinator, monitoring and evaluation 
j. C. Sentz. PhD .. USAID liaison scientist 
j. B. Suh, PhD., research liaison scientist 
A P. Uriyo, Ph.D., project development coordinator 
R Zachmann. PhD., training materials specialist 
CIDAICIMMYT/IIT A Ghana Grains Development Project, Ghana 
A M. Hossain. PhD .. breeder 
Gusby Charitable Foundation/liT AlNational Root Crops 
Improvement Program, Cameroon 
j. B. Abaka-Whyte, PhD .. breeder and project leader 
M. O. Akoroda, PhD., agronomistlbreeder 
IFAD/IITA Ghana Smallholder Rehabilitation and Development 
Program 
O . O. Okoli. PhD .. breeder and root crops coordinator 
Semi-Arid Food Grains Research and Development (SAFGRAD) 
Project, Burkina Faso 
j. M. Fajemisin, PhD., pathologistlbreeder. project leader and maize 
network coordinator 
N. Muleba, PhD., agronomist and cowpea network coordinator 
USAIDIIDRClIlTA East and Southern African Root Crops Research 
Network (ESARRN), Malawi 
M. N. Alvarez, PhD .. breeder and network coordinator 
USAID/IiT AlNational Cereals Research and Extension (NCRE) 
Project, Cameroon 
E. A Atayi. PhD., chief of party and agricultural economist 
S. W. Almy, PhD., social economist 
D. C. Baker, PhD., agricultural economist 
V. Balasubramaniam, PhD., agronomist 
O . P. Dangi, PhD., breeder 
L Everett. PhD .. breeder 
M. P. Jones, PhD .. breeder 
M. Kamuanga. PhD., agricultural economist 
J. Kikafunda-Twine. PhD .. agronomist 
D. McHugh. M.Sc .. extension agronomist 
j. A Poku, PhD., extension agronomist 
A. C. Roy, PhD .. agronomist 
J. T. Russell , Ph.D .. extension agronbmist 
L Singh, PhD .. breeder 
T. Stilwell, PhD .. deputy chief of party and soil chemist 
H. Talleyrand. Ph.D., agronomist 
T. Woldetatios, PhD .. extension agronomist • 
• Left during the year (I April 1989 - 31 March 1990) 
USAIDIIITA Applied Agricultural Research (RAY) Project. Zaire 
F. E. Brockman. PhD., chief of party and agronomist 
M. S. Alam, PhD., entomologist 
C D. S. Bartlett, PhD., agricultural economist 
T. Berne, PhD .. agronomist 
L H. Camacho. PhD .. breeder 
B. Chiti-Babu. farm manager 
A. D. Fiorini, PhD., regional outreach specialist 
K. M. Johnson. PhD .. breeder 
D. Keita, M.5c.. outreach specialist 
G. F. Montalban, plant superintendent 
A O. Osiname, PhD .. agronomist 
M. Seye, M.A., administrative officer 
D. A Shannon, PhD., agronomist 
W. O. Vogel, PhD., agricultural economist 
liT A Benin Station 
J. N. A Quaye, M.A.. leader, management un it and offlcer-in-charge 
Technology Transfer Unit 
M. N. Versteeg, Ph.D., agronomist and leader 
Consultants _____ _ 
S. O. Adeyeye. cassava breeding research 
S. A Aman, training 
Guy Baird. research evaluation 
R. A Boxall, grain storage research 
A H. Bunting, research evaluation 
Russell Cramer, editing 
Direk Ditwiler, cassava research 
Clifford S. Gold, biological control 
L S. Halos, postharvest technology 
Haldore Hanson, writing 
Joseph A Kwarteng, training materials 
D. S. Mikkelsen, research evaluation 
Alan W . Moore, writing/editing 
Sagary Nokoe, research evaluation 
B. C. Nzotta. editing 
Chris Parker, striga biology 
Henry Romney, public relations 
P. A Shah, biological control 
Eric M. Sicely, bio logical control 
Eric T oliens, economics 
Anthony Wolff, writing 
A Youdeowei, editing 
Co llaborative Projects on Food and Technology 
F. Adesanye, food utilization 
J. O. Akingbala. food techno logy 
T ola Atinmo, food utilization 
O. C. Aworh, food technology 
J. Burdon, food utilization 
J. Delcour, food technology 
L Denton, food utilization 
Janet Kwatia, food utilization 
K G. Moore, food utilization 
P. O. Ngoddy. food technology 
G. B. Oguntimein, food utilization 
S. L Oke, food utilization 
J. E. Okeke. food technology 
O . Olatunji, food technology 
Sidi Osha, food utilization 
A S. O. Oyakhilome, food utilization 
D . Taylor, food utilization 
,:-. C. Uwaegbute, food util ization 
Carol W ill iams, food utilization 
103 
Publications by liT A Staff 1989 _______ _ 
Published Journal Articles and Monographs 
Alam, M.S. 1989. Whitefly (Hemiptera: Aleyrodidae) - a potential 
pest of rice in West Africa. /nremalional Rice Research Newsletter 14: 3. 
Alam. M.S. and J.A. Lowe 1989. Incidence of two grain suckers in 
irrigated and upland rice. International Rice Research Newsletter 14: 3. 
Balasubramanian, V. and A. Egli. 1989. Un ape~u sur les systemes de 
production au Bugesera et Gisaka-Migongo (BGM). Bull. Agric. Rwanda 
2: 86-98. 
Boussienguet. J. and P. Neuenschwander. 1989. Le complexe 
entomophage de la cochenille du manioc en Afrique. 3. Cle et 
annotee pour la determination des hymenopteres parasitoides 
associes a ce ravageur. Rev. Zool. Afr. 103: 395-403. 
Brewbaker, Land S.K. Kim. 1989. The MIR (maize inbred 
resistance) trials: performance of tropical-adapted maize inbreds. 
Research Series 062. University of Hawaii. College of Tropical 
Agriculture and Human Resources. 
Chen, Y.S., B.T. Kang and F.E. Caveness. 1989. Alley cropping 
vegetable crops with leucaena in southem Nigeria. Hort Sci. 24: 839-
840. 
Cobbina, j., AN. Atta-Krah and B.T. Kang. 1989. Leguminous 
browse supplementation effect on the agronomic value of sheep and 
goat manure. BioI. Agric. Hort 6: I 15- 12 1. 
Cobbina, j., B.T. Kang and A.N. Atta-Krah. 1989. Effect o f soil 
fertility on early growth o f leucaena and gliricidia in alley farms. 
Agro(orestry Systems 8: 157-164. 
Efro n, Y., S.K. Kim, J.M. Fajemisin, J.H. Mareck, c.y. Tang, Z.T. 
Dabrowski, H.W . Rossel. G. Thottappilly and tW. Buddenhagen. 
1989. Breeding for resistance to maize streak virus: a multidisciplinary 
team approach. Plont Breeding 103: 1-36. 
Ehui, S.K. and T.W . Hertel. 1989. Computing the socially optimal 
forest stock for the Ivory Coast In: B. Greenshields and M. Bellamy 
(eds.). Govemment intervent ion in agriculture. Aldershot. Darmouth 
Publishing Co. Ltd .. UK 337p. 
Ehui, S.K. and T.W . Hertel. 1989. Deforestation and agricultural 
productivity in the C6te d'ivoire. American journal of Agricultural 
Economics 7 1(3): 703-711 . 
Ehui. S.K .• T.W . Hertel and P.V. Preckel. 1990. Forest resource 
depletion. soil dynamics. and agricultural productivity in the tropics. 
j. Environ. Econ. 18: 136-154. 
Gichuru. M.P. and B.T. Kang. 1989. Calliandra co/orhyrsus (Meissn) in 
alley cropping system with sequentially cropped maize and cowpea in 
southwestem Nigeria. Agro(orestry Systems 9: 191-203. 
Hahn. S.K .• j.C.G. lsoba and T. lkotun. 1989. Resistance breeding in 
root and tuber crops at the Intemational Institute of Tropical 
Agriculture (IITA), Ibadan. Nigeria. Crop Protection 8: 147- 168. 
104 
Ikeorgu, j.E.G .. H.C. Ezumah and T.A.T. Wahua. 1989. Productivity 
of species in cassava/maizelokralegusi melon complex mixtures in 
Nigeria. Field Crops Reseorch 21 : 1-7. 
Ikeorgu, J.E.G .. T.A.T. Wahua and H.C. Ezumah. 1989. Effects of 
melon (Owl/us lanaws Thunb.) and okra (Abelmoschus esculemus [L] 
Moench) o n the soil moisture and leaf water status o f intercropped 
cassava maize in Nigeria. T rop. Agric (Trinidad) 66( I): 78-82. 
Jackai, LE.N. 1989. A laboratory procedure for rearing the cowpea 
coreid, C/ovigral/a tomemosicol/is StAt, using dry cowpea seeds. Bull. enL 
R .. 79: 275-281 . 
Jackai, L.EN. and S. Oghiakhe. 1989. Pod wall trichomes and 
resistance of two wild cowpea. Vigna vexil/mo. accessions to Maruca 
teswlalis (Geyer) (Lepidoptera: Pyralidae) and C/ovigral/o comentosicollis 
stAI. (Hemiptera: Coreidae). Bull. ent Res. 79: 595-605. 
Kang, BT. 1989. Nutrient management for sustained crop production 
in the humid and subhumid tropics. In: J. van der Heide (ed.). Nutrient 
management for food crop production in tropical farming systems. 
Institute of Soil Fertility (IB). Haren, Netherlands. 3-28. 
Kang, B.T. and L. Reynolds (eds.). 1989. Alley fanming in the humid 
and subhumid tropics. Proceedings. IDRC, Ottawa. 
Kang, B.T., L. Reynolds and A.N. Atta-Krah. 1989. Alley fanming. 
Advances in Agronomy 43: 3 15-359. 
Kang, B.T., A.C.B.M. van der Kruijs and D.C. Couper. 1989. Alley 
cropping for food crop production in the humid and subhumid . 
tropics. In: B.T. Kang and L. Reynolds (eds.). Alley fanming in the humId 
and subhumid tropics. IDRC, Ottawa. 16-26. 
Lohr. B., B. Santos and AM. Varela. 1989. Larval development and 
morphometry of Epidinocarsis lopezi (De santis) (Hym .. Encyrtidae). 
parasitoid of the cassava mealybug. Phenacoccus man;ho(i Mat.-Ferr. 
(Hom .. Pseudococcidae). Z. ong. Ent 107: 334-343. 
Lohr, B .• AM. Varela and B. Santos. 1989. Life-table studies of 
Epidinocarsis lopez; (De Sant is) (Hym.. Encyrtidae), a parasitoid of the 
cassava mealybug. Phenacoccus manihoti Mat.·Ferr. (Hom., 
Pseudococcidae). Z. ang. Ent 107: 425-434. 
Mareck.J .H., N.A Bosque.Perez and M.S. Alam. 1989. Screening 
and breeding for resistance to African maize borers. Annual Plant 
Resistance to Insects Newslener 15: 58-59. 
Moraes, G.J. de, J.A. McMurtry and j.S. Yaninek. 1989. Some 
phytoseiid mites (Acari: Phytoseiidae) from tropical Africa with 
descriptions of one new species. Internat j. Acarology 15: 95- 102. 
Moraes, G.J. de. H. van den Berg and J.5. Yaninek. 1989. Phytoseiid 
mites (Acari: Phytoseiidae) of Kenya. with descriptions of e ight 
species. Internat j. Acarology 15: 79-93. 
Mulongoy, K. and A BedoreL 1989. Properties of worm casts and 
surface soils under various plant covers in the humid tropics. Soil Bioi. 
Biochem. 2 1 (2): 197-203. 
Mutsaers, H.j .W . 1989. A dynamic equation for plant interaction and 
application to yield-density-t ime relations. Annals or Botany 64: 52 1-
531. 
Mutsaers. H.J.W. 1989. On-farm research: de tropenboer 
herontdekt Landbouwkundig Tijdschri~ 10 1 (617): 21 . 
Nangju , D. and B.T. Kang. 1989. Cowpea. In: D.L. Plucknett and H.B. 
Sprague (eds.). Detecting mineral deficiencies in tropical and 
temperate crops. Boulder, Westview Press. 145-153. 
Neuenschwander, P., W .N .O . Hammond, AR. Gutierrez, AR. 
Cudjoe, R. Adjakloe, j.U. Baumgartner and U. Regev. 1989. Impact 
assessment of the biological control of the cassava mealybug, 
Phenacoccus manlhoti Matile-Ferrero (Hemiptera: Pseudococcidae), by 
the introduced parasitoid Epidlnocarsis lopezi (De Santis) 
(Hymenoptera: Encyrtidae). Bull. enl Res. 79: 579-594. 
Neuenschwander. P., T. Haug. O . Ajounu, H. Davis, B. Akinwumi 
and E. Madojemu. 1989. Quality requirements in natural enemies 
used for inoculative release: practical experience from a successful 
biological control program. Joumal or Applied Entomology 108: 409-
420. 
Ntare. B.R. 1989. Evaluation of cowpea cultivars for intercropping 
with pearl mil let in the Sahel ian zone of West Africa. Field Crops 
Reseordl 20: 3 1-40. 
Sanginga, N., S.K.A Danso and G.D. Bowen. 1989. Nodulation and 
growth response of Allocasuarina and Casuarina species to 
phosphorus fertilization. Plant and Soil I 18: 125-132. 
Sanginga, N .• K. Mulongoy and A Ayanaba. 1989. Effectivity of 
indigenous rhizobia for nodulation and early nitrogen fixation with 
Leucaena /eucocepha/a grown in Nigerian soils. Soil Bioi. 8iochem. 
2 1 (2) 23 1-235. 
Sanginga. N., K. Mulongoy and A Ayanaba. 1989. Nitrogen fixation 
of field -inocu lated Leucaena leucocepha/a (Lam.) de Wit estimated by 
the '5 N and the difference methods. Plant and Soil 117: 269-274. 
Sanginga. N. and e. van Hove. 1989. Amino acid composition of 
azolla as affected by strains and popUlation density. Plam and Soil I 17: 
263-267. 
Schulthess. F., j.U. Baumgartner and H.R. Herren. 1989. Sampling 
Phenacoccus manihoU in cassava fields in Nigeria. Tropical Pest 
Management 35: 193-200. 
Smith. j .• G. Umali , M.W. Rosegrant and AM. Mandac. 1989. Risk 
and nitrogen use on rainfed rice: Bicol. Philippines. Fertilizer Research 
21 : 113-123. 
Swennen. R. and E. De Langhe. 1989. Threats to the highland banana 
in eastern Africa. Intemational Network for the Improvement of 
Bananas and Plantains (IN IBAP). Musoromo 2(1): 2-4. 
Thottappilly. G. and H.W. Rossel. 1988. Occurence of cowpea 
mottle virus and other viruses (cowpea yellow mosaic virus, southem 
bean mosaic virus) in cowpea. FAO Plane Protection Bull. 36(4): 184-
185. 
van Alphen, J.j .M., P. Neuenschwander. M.j. van Dijken, W .N.O . 
Hammond and H.R. Herren. 1989_lnsect invasions: the case of the 
cassava mealybug and its natural enemies evaluated. The Entomologist 
108: 38-55. 
van der Kruijs, A.e.B.M.,j. van der Heide and BT. Kang. 1989. 
Observations on decomposition rates of leaves of several shrub and 
tree species applied as mulch under humid tropical conditions. In: J. 
van der Heide (ed.). Nutrient management for food crop production 
in tropical farming systems. Institute of Soil Fertility (I B), Haren, 
Netherlands. 36 1-366. 
Vuylsteke. V.R. 1989. Shoot-tip culture for the propagation. 
conservation and exchange of MUSQ germ plasm. Practical Manuals for 
Handling Crop Germplasm in Vitro: 2. International Board for Plant 
Genetic Resources (IBPGR), Rome. Italy. 
Winslow, M.D .• M. Yamauchi. K. Alluri and T.M. Masajo. 1989. 
Reducing iron toxicity in rice with resistant genotype and ridge 
planting. Agronomy Joumol 81 : 458-460. 
Yaninek, j.S., AP. Gutierrez and H.R. Herren. 1989. Dynamics of 
MononycheJ/us wnajoa (Acari: T etranychidae) in Africa: experimental 
evidence of the effects of temperature and host plant on popUlation 
growth rates. Environ. Entomol. 18: 633-640. 
Yaninek, J.S., H.R. Herren and A.P. Gutierrez. 1989. Dynamics of 
MononycheJ/us wnajoQ (Acari: T etranychidae) in Africa: seasonal 
factors affecting phenology and abundance. Environ. Entomol. 18: 625-
632. 
Published Conference Papers 
Adetiloye. P.O .. AA Adekunle and H.e. Ezumah. 1989. Cassava 
intercropping with maize, cowpea and plantain at different intercrop 
populations and mixture complexities in a humid tropical 
environment. Agron. Abstr. 1989 Annual MeeUngs ( 15-20 Oct): 49. 
Adetiloye. P.O . and H.e. Ezumah. 1989. Performance and 
production of plantain and cassava j ntercropp ing systems. In: liT A. 
Cassava-based cropping systems research 11. 13-23. 
Asadu, c.L.A., H.e. Ezumah. F.O . Akammigbo and FJ. Nweke. 
1989. Relative changes in t he nutrient composition of six cultivars of 
white yam grown in three ecozones of southeastem Nigeria. In: liT A. 
Cassava-based cropping systems research II. 126-137. 
Balasubramanian. V .• lo Sekayange and j.e. Rubyago. 1989. Effect of 
pigeonpea varieties and plant arrangements on the productivity of 
pigeonpea + maize/beans association. Agron. Abscr. 1989 Annual 
Meetings (15-20 Oct): 50. 
Bosque-Perez. N.A and Z.T. Dabrowski. 1989. Mass rearing of the 
maize stem borers Sesamia calamistis and EJdana saccharina at liT A. In: 
Centro Intemacional de Mejoramiento de Maiz y Trigo (CIMMYT). 
Toward insect-resistant maize for the third world. Proceed ings. 
Mexico OJ. 
105 
Bosque-Perez, N.A., J.H. Mareck, Z .T. Dabrowski, l. Everett, S.K. 
Kim and Y. Efron. 1989. Screening and breeding maize fo r resistance 
to Sesamia calamisris and Eldana saccharina. In: ClMMYT. Toward 
insect-resistant maize fo r the third world. Proceedings. Mexico O.F. 
Efron, Y., S.K. Kim, V. Parkinson and N .A. Bosque-Perez. 1989. 
liT A's strategies to develop striga-resistant maize germplasm. In: T.O. 
Robson and H.R Broad (eds.). striga-Improved management in 
Africa. Proceedings. FAO, Rome, 14 1- 153. 
Ezumah, H.e. and N.C Hulugalle. 1989. Studies on cassava-based 
rotation systems in a tropical alfisol. Agron. Abstr. I 989 Annual 
Meetings (15-20 Oct): 53, 
Haug. T. and B. Ml!gevand. 1989. Development of technologies in 
support of contemporary biological controL In: j.5. Yaninek and H.R. 
Herren (eds.). Biological control: a sustainable solution to crop pest 
problems in Africa. 14 1- 146. 
Herren, H,R, 1989, The Biological Control Program of liT A: from 
concept to reality. In: J.S. Yaninek and H.R Herren (eds.). Biological 
control: a sustainable solution to crop pest problems in Africa. 18-30. 
Ikeorgu. j.E,G .• R.P. Unamma and H.e. Ezumah. 1989. Effect of 
fertil izer and t ime of introduction of cassava or maize on productivity 
of yam and cassava-based intercrops in a humid uttisol. In: liT A. 
Cassava~based cropping systems research II. 36-4 1. 
Jackai, LE.N. and S.R. Singh. 1989. Etude sur les techniques de 
criblage pour la resistance de la plante-h6te aux insectes nuisibles du 
niebe. In: Y. Oemarly (ed.). Les leguminenses a graines. Actes du 
Seminaire organise par la FIS. Madagascar, 22-27 Feb 1988. 
Stockholm, Fondation intemationale pour la science. 23-S0. 
Kang. B.T. and O . Onafeko. 1989. Spatial chemical soil variabi lity in 
alley cropped plots. Agron. Abstr, 1989 Annual Meetings (15-20 Oct): 
55. 
Karunwi. A. and H.e. Ezumah. 1989. Economics of ind igenous 
cassava processing techn iques in a humid forest ecology of Nigeria. In: 
liT A. Cassava-based cropping systems research II. 181 - 193. 
Klay. A. and G.J. de Moraes. 1989. Problems and issues in managing 
and rearing natural enemies. In: j. S. Yaninek and H. R Herren (eds.). 
Biological control: a sustainable solution to crop pest problems in 
Africa, I 27- 132. 
uwani. S.M. 1989. Constraints to the exchange of informat ion and 
documentation on banana and plantain in West Africa. In: P. 
Thompson and C. P. Montpellier (eds.). Information and 
documentation for banana and plantain. Proceedings. Internat ional 
Network for the Improvement of Banana and Plantain (I NI BAP) 
workshop. 2-5 Jun 1987, La Grande Motte, France. 257-265, 
Markham. R.H. and E.M. Sicely. 1989. Appropriate support fo r 
national programs: training, research, administration and fund ing. In: J. 
S. Yaninek and H.R. Herren (eds.). Biological control: a sustainable 
solution to crop pest problems in Africa. 156-16S. 
106 
Nail<, D.M. 1989. Research on grain legumes in SADCC count ries. In: 
G. Mudimu and R.H. Benton (eds.). Household and national food 
security in southem Africa Proceedings of a conference, 3 1 Oct - 3 
Nov 1988. University of Zimbabwe/Michigan State University Food 
Security Research Project Harare. 
Neuenschwander. P. and A.P. Gutierrez. 1989. Evaluating the impact 
of biological control measures in Africa. In: J.S. Yaninek and H.R 
Herren (eds.). Biological control: a sustainable solution to crop pest 
problems. 147- 155, 
Ntare. B.R .• L.K. Fussell and P.G. Serafini. 1989. Recent 
developments in millet/cowpea cropping systems fo r low rainfall areas 
of Sudano-Sahel ian zone of West Africa. In: Proceedings of a 
workshop on soil. water and crop management systems for rainfed 
agriculture in the Sudano-sahelian zone of West Africa. 11-1 S Jan 
1987. 
Oyedokun. J.B., T.A. Akinlosotu, M.O. Omidiji and H.C Ezumah. 
1989. Introduction of cassava through maize in a hu mid environment 
In: IITA. Cassava-based cropping systems research II. 24-35. 
Rossel. H.W ., G. Thottappilly. j.M.W . van Lent and H. Huttinga. 
1989. The et iology of cassava mosaic disease in Nigeria. Proceedings 
of an intemat ional conference on African cassava mosaic disease and 
its control. 4 - 8 May 1987, ORSTOM, Cote d'ivoire, 43-56. 
Seshu, D.Y" K. Alluri. F. Ceuvas-Perez. S.W. Ahn. M. Akbar, K.G. 
Pillai and M.J. Rosero. 1989. Report of activities and accomplishments 
of the International Rice Testing Program 1985-89.lntemational Rice 
Reseanch Institute (IRRI), 68p. 
Shannon, DA, K.N. Kabaluapa and M.e. Ngoyi. 1989. Alley 
cropping: a promising technology for the savanna of Zaire. Agron. 
Abstr: 1989 Annual Meetings (15-20 O ct): 59. 
Shannon. D.A. M. Kubengu and M.C Ngoyi. 1989. Evaluating maize 
variet ies in on-farm trials in south central Zaire. Agron. Abstf. 1989 
Annual Meetings ( 15-20 Oct): 59, 
Thottappilly, G. and H.W. Rossel. 1988. Virus diseases of sweet 
potato in Nigeria. Report of the UNDP/CIAT/ClP/IiTA Workshop on 
Sweet Potato Improvement in Africa. 28 Sept - 2 Oct 1987. Nairobi, 
Kenya, 53-64. 
Unamma. R,PA, A. Udealor. T ,O , Ezulike, G,e. Orkwar, LS.O . 
Ene,J.E.G.lkeorgu and H.e. Ezumah. 1989. Evaluat ion of the 
productivity of cassava-yarn-maize intercrop in the rainforest zone of 
Nigeria. In: IITA. Cassava-based cropping systems research II. 47-S6. 
Vogel. W .O. and H.J.W . Mutsaers. 1989. Economic retums of alley 
farming, In: BT. Kang and L Reynolds (eds.). Alley farming in the 
humid and subhumid tropics. Proceedings. lORe. Ottawa. 197-207. 
\ 
Waage. J.K. and F. Schulthess. 1989. Relevant research activities in 
support of sustainable pest management In: J.5. Yaninek and H.R 
Herren (eds.). Biological control: a sustainable solution to crop pest 
problems in Africa 133-140. 
Wilson. G.F. and R. Swennen. 1989. Alley cropping: potentia! for 
plantain and banana production. In: B.T. Kang and L Reyno!ds (eds.). 
Alley farming in the humid and subhumid tropics. Proceedings. !ORe. 
Ottawa. 3 1-41 . 
Wodageneh. A. 1989. Constraints confronting national biological 
control programs. In: J.S. Yaninek and H.R Herren (eds.). Bio logical 
control: a sustainable solution to crop pest problems in Africa. 166-
172. 
Yaninek. j.S. and M.J.W. Cock. 1989. Identifying pest problems in 
relation to implementing biological control in Africa. In: J.5. Yaninek 
and HR Herren (eds.). Biological control: a sustainable solut ion to 
crop pest problems in Africa. I 16- I 26. 
IITA Series 
Balasubramanian. V. 1989. Alley shrubs in a high-altitude, semi-arid 
environment IITA Research Briefs 9( I): 3. 
Hahn. N.D. (ed.). 1989. In praise of cassava. Proceedings of the 
interregional expert group meeting on the exchange of technologies 
for casssava processing equipment and food products. 13- 19 Apr 
1988. liT A. Ibadan. Copublished w~h UNICEF. 241 p. 
Hahn, S.K. and R.l. Theberge. 1989. Root and tuber crops: food 
security in Central Africa. Third Central Africa regional workshop on 
root and tuber crops: proceedings. I 16p. 
Lawani, S.M. 1989. The cowpea, biotechnology and natural pest 
control. IITA Research Briefs 9(2): I, 6. 
Mutsaers, H.J.W . 1989. Nigeria adopts improved cassava varieties 
bred at liT A. IITA Research BriefS 9( I ). 
Neuenschwander, P. 1989. Biological control of mango mealybug. 
IITA Research BriefS 9(3): 5-6. 
Nweke. F.1. 1988. Collaborative study of cassava in Africa: project 
description. COSCA Working Paper I. liT A. 
Nweke, F.I.. H.C. Ezumah and D.s.C. Spencer. 1988. Cropping 
systems and agronomic performance of improved cassava (Manihoti 
esculenta Crantz), in a humid forest ecosystem. RCMP Research 
Monograph 2. 
Singh, S.R., LE.N. Jackai. B.B. Singh, B.N. Ntare, H.W . Rossel, G. 
Thoctappilly, N.Q . Ng, M.A. Hossain, K. Cardwell. S. Padulosi and 
G. Myers. 1989. Cowpea research at IITA. GliP Research 
Monograph I. 23p. 
Scifel, l.O. 1990. liT A research for sustainable agriculture in Africa. 
28p. 
Scifel. l.O. 1990. Toward recovery in national food production. 19p. 
Stifel. l.O. 1989. Transforming Nigerian agriculture: the role of 
research. 28p. 
Swennen. R., O. Vuylsteke and S.K. Hahn. 1989. Combatting the 
black Sigatoka threat to plantains. IITA Research Briefs 9(2): 2-4. 
Vuylsteke. O. and R. Swennen. 1989. Plantain/banana tissue-culture 
laboratory established in Nigeria. IITA Research BriefS 9(2): 3. 
Weber, G.K. and A.D. Akalumbe. 1989. Macroeconomic data 
related to production, consumption and nutrition. Maize Database for 
Sub-Saharan Africa: I. 
Yaninek, J.S., G.J. de Moraes and H.R. Markham. 1989. Handbook 
on the cassava green mite Mononychellus tanajoa in Africa: a guide to 
its biology and procedures for implementing classical biological 
control. 140p. 
Yaninek, j.S. and H.R. Herren (eds .). 1989. Biological control: a 
sustainable solution to crop pest problems in Africa. Proceedings. 
224p. 
107 
IITA Publications 1989 __________ _ 
A(netcm. Newsletter of the Alley Farming Netwcrk for Tropical Africa. 
\/ci. I. nos. 1.2. (Bilingual: English and French.) 
e.iological control: a sustainable solution to crop pest problems in 
Africa, Edited by J. S. Yaninek. G. J. de Moraes and R. H. Markham. 
Proceedings. ISBN 978-131-039-1. 224p. 
Bulletm du reseau des plantes 0 tr...'bercui'es trop/coles. Vol. 4, n° 1-4. 
Bulletin du n2seou des systemes de productIOn el"1 A(nque de l'Ouest 
N° 4. 
Cameroon National Root Crops Improvement Program annual 
report 1988. 
Cassava-based cropping systems research 11: contributions from the 
second annual meeting of the collaborative group in cassava-based 
cropping systems researcr. 
Cassava in tropical Africa: a reference manual. ISBN 978-131-041-3. 
184p. 
CGIAR Task Force on Sub-Saharar Africa: strengthening maize and 
cassava research in eleven CO'Jntnes of coastal West and Central 
Africa: plan of action/request to donors. 
Collaborative Study of Cassava n Africa: project description. F. I. 
Nweke. COSCA Working Paper I 
Cowpea research at IITA. S R. Singh et 21. CLIP Research Monograph 
I. 23p 
Cropping systems and agronomic performance of Imoroved cassava 
(Momhoti esculento Cranz) in a hum d forest ecosystem. F. I. I'<weke, 
H. C. Ezumah and D. S. C. Spencer. RCMP Research Monograph 2. 
48p 
Echo de /'lito Vol. 9, rO 1,2. 
ESARRN Newsletter, Eastem and Southem Afnca Root Crops 
Research Networx 
Food crops utilization and nutrition training manual. ISBN 978-131-
040-5. 250p. 
Genetic Resources Unit af'nual report 1987, 
Grain Legumes Improvement Program annual report 1987, 
Groupe d'intervention dL. Gcrai pour l'Afrique subsaharienne: Ie 
renforcement de la recherche sur Ie ma,'s et Ie manioc dans onze pays 
cotiers de l'Afrique occidentale et centrale: plan d'action/requHe aux 
donateurs. 
Guide des acventices d'Afrique de l'Ouest. I. O. Akobundu and C. W. 
Agyakwa. ISBN 978-131-03 1-7. 522p. 
Handbook on the cassava green mite Mononychelius tonojoo in Africa: 
a guide to its biology and procecures for implementing claSSical 
biological control. Edited by J. S. Yaninek, G. j. de Moraes and R. H. 
I",arkham. ISBN 978-131-037-5. l40p. 
108 
IITA Medium-Term Plan 1989-1983. (ColTected edolon) ISBN 978-
131-042-1. 97p. 
/i'TA ReseC!(ch BriefS. Va!. 9. nos. 1-4. 
In praise of cassava. Proceedings of the Interregional expert group 
meeting on tre exchange of techrologles for cassava processing 
equ ,pmer,t and food products. April 1988. Edited by Natal e D, Hahn. 
Copublished With UNICEF. ISBN: 978-131-034-0 (IITA)! 97830600 
17 (UNICEF). 241p. 
Interra:ional Cooperation anc Training Program annual report 1987 
IRTP-Afnca reports 'rom the nurseries 1986 ard 1987 
Media Forum for Agriculture: preliminary meeting 
Meeting of the directors of Nigeriar agricultural research institutes 
witn liT A. IITA rv'eeting Reports Series 1988/5. 
Plan a moyen terme de I'loa. (COr1ge). ISBN 978-131-029-4. 101 p. 
Resource and Crop Management Program annual report 1987. 
Rice Research Program annual report 1987. 
Root and tuber crops: food security in Central Africa Third Central 
Africa regional w::>rkshop on root and tuber crops: proceedings. 
Edited by S. K. Hahn and R. L. Theberge. ISBN 978-131-054-5. 116p. 
Root crops and low-input agriculture. Third eastern and southern 
Africa regional workshop on root and tuber crops: proceedings. 
Root, Tuber and Plantain Improvement Program annual report 1987. 
Screening techniques for host plant resistance to insect pests of 
cowpea (Repnnt) L. E. N. Jackal and S. R. Singh. 23p. 
Semi-Arid Food Grains Research and Development (SAFGRAD) 
Project annual report 1987. 
Soybeans for good health: how to grow and use soybeans in Nigeria. 
22p. 
Summary report of an IRTP-Africa rice monitoring tour to Kenya and 
Madagascar and workshop in Nairobi. Kenya. 10-23 March 1989. 
Sustainable crop and livestock production for Rwanda. 
Transforming N gerian agriculture: the role of research. Laurence D. 
Stile! 28p. 
TroDico,1 Root Crops Netvvork. Newsletter, Vol. 4. nos. 1-4. 
West Af'1cor) Forming Systems Research Bulletin. No. S. 
I 
Maize 
Soybean I 
I Yom 
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IITA Annual Report 1989190 
ISSN 0331-4340 
Editing 
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Design and production 
INTERNATIONAL 
INSTITUTE OF 
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ANNUAL REPORT 
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