r 
1] 
contents 
3 Foreword 
4 Research Highlights 
20 liT A Today 
66 Annexes 
Armmln rrce]p@lTll (Q)[ lillnce 
TIml~ce~ldkQ)M ~lffill1!n~ce @[ 1rl1@~licc~ Awruccruillll1!nl1~ 
1l~~@ 
2 
Agroecological zones of humid and subhumid 
tropical Africa 
by length of growing season (in months) 
_ humid forest 
(8 - 12 months) 
~ forest-savanna transition 
L-..J (5 - 7 months) 
_
moist savanna 
(3 - '4 months) 
D dry savanna (I - 2 months) 
D outside the zones of research interest 
o liT A headquarters 
~ liT A research stations 
Niger 
Namibia 
_________________________________ Foreword 
The Board of Trustees and the staff of IITA have pleasure in presenting to you the annual report for 1990. 
Our report gives an overview of the progress we have made in research and other program activities during 
1990. highlighting significant results in each program. Impmved crop varieties well surted for the various stress 
conditions of tropical Africa have been developed. while we continue to provide national systems and farmers 
with sustainable plant protection technologies. Research on sustainable production systems In fragile tropical 
environments which involve alley farming techniques continues to produce encouraging results, as is clearly 
demonstrated in tests and adoption of alley farming under farmers' conditions. 
Research and training activities have continued to be implemented according to the objectives and proposals 
lard down in our medium-temn plan for the period 1989-1993. Funding limitations. however. forced us during Nicholas E. Mumba 
1990 to limit the number of senior staff-years in research to 55, vis-a-vis the 66 envisaged in the medium-term 
plan. Notwithstanding the prospects for continuing restriction in funding for the foreseeable future, we will 
endeavor to increase our research capacity through intemal shifts and by attracting special projects. 
The year 1990 was marked by a number of events that will have a direct bearing on IITA activities in the short 
and long temn. They include: 
• The submission of the reports of the extemal review panels to the CGIAR mid-term meeting. While a number 
of suggestions were made for further improvements in research activities and in the program structure, the 
reviews and the comments by various donors were positive and an encouragement for the way the staff of IITA 
IS canying out its responsibilities. 
o The opening of the savanna station at Kano in northem Nigena. the establishment of the humid forest station 
at Mbalmayo in south em Cameroon. and the opening of a biotechnology laboratory at our headquarters at 
Ibadan. 
o The endorsement by the CGrAR of a region-wide. agroecologically oriented ("ecoregional") approach to 
agricultural research and the reconfirmation of the need for closer cooperation with national agricultural 
research systems, as well as the admission of a number of new international centers to the system . 
• IITA was again fortunate to receive, this time jointly with ClAT. the King Baudouin award for excellence in 
agricultural research. The award recognizes our contributions to the biological control of the cassava mealybug. 
o The election of Nicholas E. Mumba in July 1990 as chaimnan of the Board ofT rustees for a two-year period. 
replacing Luis B. Crouch who had resigned for reasons of health. 
o The appointment of Lukas Brader as Director General for a five-year term from I December 1990. 
The trustees and staff of IITA feel confident in shouldering our research and training agenda in addressing the 
needs in the humid and subhumid regions of sub-Saharan Africa. Our agenda, moreover, increasingly involves 
close cooperation with our agricultural research partners in the countries concemed. We t rust that the donors 
of the CGIAR will continue to respond with confidence in us and continue their support, which helps to bring 
us closer to the goal of eliminating hunger and improving the well-being of the peoples of tropical Africa. 
-ii:R 
Nicholas E. Mumba 
Chainperson. Board of Trustees 
~ --"-'I~~ Or 
-
Lukas Brader 
Director General 
Lukas Broder 
3 

A new maize has broken the subsistence mold of agriculture in northem N igeria, enabling farmers to begin modernizing their age-old practices with 
intensified famning. 
The main elements for intensification were in place by 
the end of the 19705: nationwide road links and an 
agricultural extension system. Maize became the crop 
which activated the process during the 1980s- the 
extension services were there to promote its cultiva-
tion, and the harvests could be transported from 
northern fields to southern markets. With an improved 
maize variety in that setting, well adapted to that 
environment, famners at last had a crop technology 
which could earn them enough cash to buy the 
fertilizerand hire the field hands essential forintensified 
famning. 
With the process in motion. agricultural scientists have 
begun exploring ways to help strengthen or enhance 
it The prime concem is howto sustain intensification-
how to enable farmers to continue gaining high 
enough profits from highly productive crops to buy 
the required inputs for the next season's cycle. The 
issue, moreover, is not simple economics, but an 
understanding of the right mixtures of crops and 
rotations in order to maintain productivity over the 
long term. The sustainability of the intensified system 
involves stabilization of the increases in famners' har-
vests and their well-being, which is the goal of all 
development efforts. 
Beginnings 
In most of West and Central Africa, population 
density has increased rapidly during the past 20 years. 
The increasing pressure on the land has caused most 
fanmers to shorten their customary fallow periods. 
The result has been decline in crop yields, since no 
other measures to sustain famn productivity have 
compensated for the reduced fallows, and since the 
availability of famn labor had, at least through the mid-
19805, not increased along with the increasing regional 
population. 
Agricultural productivity has improved markedly in 
the moist savanna zone (or, Guinea savanna) of 
northem Nigeria. Recent surveys there by IITA and the 
Institute for Agricultural Research (VIR) of Ahmadu Bello 
A new maize 
modernizes 
savanna farming 
University have shown increases in use of improved 
maize, fertilizer, and improved management practices, 
such as animal traction and effective weeding, as fallow 
periods have become abbreviated. Farmers have 
asserted that they are betteroffthan before, attributing 
their well-being to greater profitability of famning. 
Several elements combined to prime the agricultural 
"take-off' in northern Nigeria. A good road network. 
linking the northern and southern parts of the country, 
was built with revenues from oil production during the 
I 970s. During the same period an extension program 
was organized as part of the World Bank-assisted 
agricultural development projects, initially in the north 
at three centers. With an extension system in place to 
introduce new technologies and supply fertilizer to 
farmers, and with roads to serve these inputs and 
delivery of the produce to markets in the populous 
south, all that remained to trigger the dynamic was the 
right crop technology. 
The traditional cash crops of the north were groundnuts 
and cotton. Neither was profitable enough to attract 
famners' interest in expanding production. But by late 
in the I 970s, IITA had developed a high-yielding maize 
Maize harvests 
bring a cash 
economy to 
savanna farmers. 
5 
6 
vanety, TZ3, by building on two composite breeding 
lines of Nigeria's Federal Department of Agncultural 
Research. In experimental trials the newvarietyyielded 
consistently one-and-a-halfto two tmes as much as 
local varieties, Also, it was resistant to the fungal 
diseases of rust, blight, and ear rot. and highly adapted 
to growing conditions in the savanna, 
The agricultural deve.opment projects In:roduced TZB 
to north err: farmers and demonstrated how to obtain 
high yields using fertilizer. When the fanmers found 
that the maize gave them a far more profitable retum 
than othe" cash crops. they began to expand produc-
tion rapidly. 
During the next decade, the spread of maize in the 
moist savanna was phenomenal. According to IAR and 
IITA research, maze had been grown in that zone as a 
backyard crop in the I 970s. By I 989, maize had 
become a major food crop in virtually all villages, and 
a major cash crop in more than two-thirds of them. 
Most of thIS maize was the high-yielding TZB-in ove" 
half olthe villages surveyed by lA, and "TA, almost no 
local maize vareties were being cultivated. Improved 
maize had overtake'l and changed the role of i:s 
predecessor. 
Sorghum, traditiona Iy tle favorite food crop, is still 
planted over a greater area than ma ze. However, 
since lZB outyields local varieties of sorghum and 
millet, the other staple cereal in the region, TZ3 Call 
reduce the land requirement fa, feeding famlers' 
families. Many fanmers have found that, by growing TZB 
for household consumptiol, they can free additional 
land for cash croos. With the surplus overfood needs 
being marketed, fatmers have increased their cash 
income which they can use to reinvest in cash crop 
production, 
The characteristics which enabled TZB to make fanming 
so com mercially viable are its high yields and attractive 
appearance. Expenments on fanmers' fields show that 
TZ3, with moderate levels of fertil zer, yields 21-1 15% 
more than local maize. Its grain quality, with a pearly 
white color and resistance to the disfiguring ear rot. 
make it compatible wrth local food prefe--ences. For 
the new maizeto have played such a role at all, IITA. and 
IAR scieltists believe, It had to be able to show a 
substantial advantage over existing options-a minor 
improvement wO'Jld have been unlikely to succeed 
on the scale that TZB has. 
Sustaining the phenomenon 
How long-lived will the poenomenon be? Can inten-
sification with TZB be replicated in savanna areas of 
other countries? 
Whether intensification can be replicated is an easier 
question to answer than "OW long-lived it will be. The 
first requirement for intensification is a set offavorable 
economic preconditions-transportation li1ks, tech-
nical advice, fertilizer-as well as a favorable growing 
environment The second requirement is the nght 
crop technology-a crop variety well-adapted to the 
environment with an all-around performance good 
enough to attract farmer commitment to providing 
the inputs. Inextricably linked With these two sets of 
recuirements is a t1ird: suitable quality of the crop, 
which detenmlnes its marketability. Demand for the 
product mJst provide a satisfactory return to the 
famler-investor. 
Replication to some extent already seeMS to have 
occurred, and Nigeria's neighbors appear to be emu-
lating her savanna success, although confirmatory data 
oave yet to be collected. TZB and de'ivative varieties 
are reported to have been expanding in the 
Cameroonian savanna, under strong demand from 
:>reweries, benefiting from an extension network and 
fertilizer SJPply line that had been set up for cotton. 
Westwards, ,n Benin, Ghana. and Cote d'ivoire, pro-
duction of 1ZB and its derivatives also appears to have 
been expanding. 
InitialliTA investigations have, however, revealed that 
there may be a problem with the technology: TZ3 may 
need to be adaDted to the lighter soils that exist in 
-noist savanna areas west ofNlgena, ifit is to perform 
as well as it did in Nigeria. And specifically In Benin, 
there may also be a need to breed for a softer, more 
flou'Y grain texture to suit consumer preferences. 
In assessing how far the phenomenon might develop 
n Nigeria orhow long it could last, there are again the 
market factors and the status of favorable precondi-
\Ions to be considered. First of all, market demand for 
maize as a food, and as a basic ingredient in brewery 
products and animal feeds, continues to absorb pro-
duction increases. The livestock and poultry industries, 
for example, prefer maize as a feedstock because it 
produces more weight gain per unit w eight of feed 
than do most other sources of carbohydrates. 
The question of sustaining intensification. moreover, 
spotlights two distinct and critical issues: economic 
sustainability, in temns of the profitability of maize 
production; and environmental sustainability, in keep-
ing up soil fertility and keeping down pests and 
diseases. 
The foremost economic problem looms with fertilizer, 
a mainstay of intensification. The N igerian government 
has hitherto subsidized fertilizer prices in order to 
encourage agricultural development. but is now com-
mitted to the removal of that subsidy for economic 
reasons. Fertilizer prices are expeded to double or 
triple when that occur<;. 
IITA scientists believe that high fertilizer prices will 
induce a reduction in maize hectarages and an increase 
in the areas planted to sorghum (for food needs) and 
the cash crops of groundnuts or cotton. 5ince those 
crops are less productive than 1ZB, the retums to 
famning will diminish. Famner<; will be able to afford 
fewer of the inputs required for intensified famning. 
Environmental sustainability becomes a problem when 
cereals dominate the cropping regime, as sorghum and 
maize do in the moist savanna. Cereal dominance 
drains the soil of nutrients, because cereals demand a 
high level of soil fertility to be productive. And cereal 
dominance leads to a build-up of specific pests-
insects, fungal diseases, nematodes, the parasitic weed 
striga, among others- because a similar pest and 
disease complex preys on all cereals. An ominous 
threat lies in the proximity of sorghum, historically 
striga's main host, with maize, also highly susceptible, 
The combination appear<; to be hastening the spread 
of the pest. (5ee striga inset on page 46.) 
Achieving sustainability 
To counter the effects of anticipated fertilizer price 
increases, IITA is examining ways to improve the effi-
ciency of the maize plant's use of nitrogen. 
Several research institutes in Benin, Cameroon, Cote 
d'ivoire, Ghana, N igeria, and Zaire have joined forces 
with IITA in a collaborative group on maize-based 
The right 
combination of 
fadors on northern 
Nigeria's moist 
savanna has 
permitted maize to 
nourish like no 
other cash crop. 
7 
Legumes which 
provide (odder can 
playa key role in 
the savanna, in 
countering the 
effects o( cereal 
dominance. 
8 
systems research (COMBS) . to explore ways to help 
promote sustainability by expanding the role of nitro-
gen-fixing legumes in the cropping system. Legumes 
restore soil ferti lity with nitrogen from their residues 
or direct deposits. 
N itrogen-fixing legumes also hold promise in helping 
to "balance" the total crop system. Since legumes 
attract different pests and diseases. they can prevent 
the build-up of cereal pests and diseases. 
UTA is examining the possibilities of forage legume 
rotations With the N igerian Animal Production Re-
search Institute (NAP'"). as livestock is a cnucial compo-
nent of savanna farming. IITA and IAR are investigating 
why traditional legumes. such as cowpea, are not more 
widely grown. and whether there are problems which 
crop scientists could tackle. They are also adapting 
soybean for cultivation in the moist savanna, and 
improVing ways to utilize it In order to stimulate new 
demand. 
Agroforestry. incorporating leguminous shnubs. has 
tested well in many combinations with maize overthe 
past decade in forest-fringe areas. and is being adapted 
to the moist savanna in ongoing trials in many coun-
tries. (See "Alleys across Africa" inset on page 26.) 
The present prospects for maize are still bright. as 
research on both striga and legumes has demon-
strated progress. Growing urban populations hold a 
promising market for maize products. Industrial de-
mand for maize is already evident in livestock feeds 
and brewery products. High-yielding maize. which has 
given farmers in northem Nigeria an opportunity to 
produce commercial-scale harvests. is a crop with the 
potential to reed further regional development. 
______ The research horizon 
for cassava as a 
cash crop 
Africa's cassava belt stretches across the conti-nent from the west coast. between Senegal and Angola. to the east coast. between Somalia and 
Mozambique-the green core of the African tropics. 
Cassava is the single most important crop for the 
famners of that vast region. and forthe more than 200 
million people. farm families and citydwellers. who 
depend on ~ for their daily energy. 
For many farmers, cassava has become more than a 
staple food. Sold fresh. or processed in a storable 
form, it is a source of income as well. Improved 
varieties of cassava have enlarged this role of the crop 
in Nigeria. and show signs of spreading in other 
countries. New information on the cash-crop role of 
cassava has come from the first large-scale study of 
cassava in Africa, undertaken by IITA in a joint effort 
w~ other Inst~utes. donors. and govemments. 
Improvements in the crop and in its cultivation are 
required for more than the greater well-being they 
may bestow on farm families. according to the land-
marl< study. Urban populations and their food needs 
are increaSing, and farmers are straining soil resources 
ever more to support their own and the market 
demand. If the environmental and economic conse-
quences are not to get out of hand. crop scientists and 
national policymakers must see to it that farmers have 
su~bletechnologies. both improved cassava varieties 
and cu~ivation practices. that will enable them to keep 
pace w~h the growing needs and to sustain the 
expanded production w~hout exhausting the soil. 
The need for a clear view of the impact of improved 
cassava varieties and of economic pressures on pro-
duction led IrrA to organize a study together with 
others. on cassava farming and food systems in Africa. 
Called the collaborative study of cassava in Africa 
(COSCA). ~ covers the production. processing. marl<et-
ing. and consumption of cassava and other important 
crops associated w~ cassava-based systems. The aim 
of COSCA is to collect information that will enable 
agricu~ural researchers to produce technologies which. 
in tum. farmers need to use to achieve national food 
production goals. 
Collaborating in the study with IITA are Centro Inter-
nacional de Agricu~ura Tropical (ClAT) . the Natural 
Resources Inst~ute of the Overseas Development 
Administration. uK, and the RockefelierFoundation. as 
well as national teams in the participating countries: 
(5te d·lvoire. Ghana. Nigeria. Zaire. Uganda. and 
Tanzania. Those countries were chosen because they 
embrace the range of important cond~ions-<:Iimate. 
population dens~. and market access-which shape 
cassava systems. and because they could provide 
scientists to help execute the study. Moreover. they 
collectively produce 70% of Africa's cassava harvest 
each year. The study sample comprises 250 repre-
sentative vi llages. 
Significance 
The significance of cassava forthe economic develop-
ment of African countnes cannot be overestimated. 
Cassava root flesh is eaten as a starchy staple dish. to 
which is added soups or sauces of other foods for 
variety. Cassava leaves are also eaten as a vegetable In 
many places. Cassava crops are a reliable food source 
for most of the year. In some places they are harvested 
continuously throughout the year. tiding farmers over 
the "hungry season" after other crops have been 
planted but are not yet mature. Famine rarely occurs 
where cassava is widely grown, because cassava can 
produce a harvest even under erratic rainfall or 
drought and in poor soils. Its high productivity per Unit 
of land and labor have rewarded scientific efforts to 
improve yields and increase production. and hold 
promise of further gains in helping to meet national 
economic goals. 
Cassava goes to 
market in a big 
way. in rapidly 
developing areas 
where farmers 
have improved 
varieties. 
9 
Market needs for 
increased 
production are 
driving farmers' 
selection of cassava 
varieties to grow. 
/0 
Some key areas for future crop improvement re-
search are already suggested In findings from the 
analysis of COSCA'S first phase of data collection. on 
producton In 1988/89. Other components of phase 
I are still being analyzed. and include a broad charac-
tenzatlon of cassava procesSing. d,stnbut,on. and con-
sumption. Phases II and III. to extend through 1992. 
focus on crop Yle\ds, farm Size, resource management. 
farmer decISion-making. postharvest procesSing. qual-
Ity factors, and socioeconomiC factors, Including health. 
Breeding ob/ectlves Will be formulated on farmer 
preferences In selecting cassava vanetles forthelr own 
cultivation whiCh have emerged from the COSCA 
findings. Farmers who live in areas With good access to 
markets, or who live In areas of high population 
densrty. look pnmanly for high Yields. early crop 
maturity, and effective resistance to diseases and 
Insect pests. These needs reflect a growing market 
onentation of farmers and economiC pressures to 
Increase productJon. Vaneties that can store long 
underground, or "sweet" vanetres that produce low 
levels of cyanide. do not appear to be cntlcal needs. 
By Implication. processing quality In cassava should be 
an Important related breeding ISsue. At present 
however, a Wide range eXists In processed forms of 
cassava, each With rts particular taste or texture which 
appeals to specific consumer groups. Perlhaps the 
Influences of urbanizatron Will eventually narrow this 
range down to a manageable number of quality 
vanatlons, when research will be able to address Issues 
In quality preferences. In the short term. therefore. 
Improvement in processing technologies will have to 
satisfy market demand for processing Improvements. 
Trends 
Farmers affirmed that cassava production had in· 
creased dunng the past 20 years. In 70% of the 250 
Villages which COSCA surveyed. They believed that the 
Increases had been stimulated by a favorable market. 
inCidence offood scarcrtyorfamlne. population growth. 
declining soil fertility. and drought. In the" eyes. then. 
the key determinants appear to have been climate. 
demographic pressure and Improved market access. 
Cassava production appears to be Increasing relatively 
more In villages In the humid trop'CS. as opposed to 
the dner clrmatrc zones of the savanna or the mid-
altitudes. Within the humid zones. production IS 
Increasing at a greater rate 1n villages where population 
denSity IS relatively high and where market access IS 
relatively good. (See figure I. oppoSIte.) Where pro-
duction IS Increasing. it is replaCing mainly other 
cu~,vated crops. as opposed to tree crops or fallow 
crops. Where cassava IS replaCing other cu~ivated 
crops. fallow periods are declining. which is leading to 
decline in SOil fertlity. 
Cassava IS Widely produced with purchased inputs. 
such as hired labor. Improved planting materials. 
fertilizers. and mechanized land preparation. Those 
observations hold more in areas of high rather than 
low population density. and in areas of good rather 
than poor market access. In Nlgena. where state 
agncultural development projects have mu~iplied and 
proVided Improved cassava varieties to farmers, the 
study reports the presence of such vanetles in nearly 
90% of 64 villages VISited. and the"cu~lvatlon by many 
farmers In nearly 60% of those villages. Improved 
vanetles out yielded local vanetles by margins ranging 
75-300% in specifiC Villages where yields were 
evaluated. In the five other survey countries apart 
from Nigeria, however, no such developments were 
observed. because Investment in research, multipli-
cation. and distribution of planting matenals had not 
been made. 
The study Cites a Significant degree of tumover In the 
] . Production trends in sampled villages, according to:
high Population density low
2% 3%
good Market access poor
2. Age of harvest in sampled villages, according to:
high Population density low
under 12 months \_)at 12 months
( j above 2 mor.ths
good Market access poor
cassava varieties which farmers grow, as they replace
existing varieties with new ones that possess desired
attributes such as disease resistance, high yields, or
early maturity. The proportion of low-cyanide or
sweet varieties being cultivated is declining, although
over 70% of all varieties grown still are sweet varieties.
High-cyanide varieties are judged by farmers to be
superior in pest resistance, yield, and underground
storage, although not in early maturity.
In areas of high population density, all farmers reported
that they harvest their cassava at or before 12 months
after planting (see figure 2), whereas 10% of the
farmers in low-density areas harvest their crop after 12
months. Similarly, nearly 45% of farmers in areas with
good market access reported that they harvest their
cassava at less than 12 months after planting, whereas
less than 10% of those in areas of poor market access
do so.
Dynamics
For the first time on such a large scale, COSCA has
substantiated the importance of cassava for farmers as
a cash crop. Farmers have begun to respond to the
market dynamics with an approach to intensified
cassava farming. Cassava, once characterized as the
"poor man's crop", is being thrust into an enlarged role
in providing a low-cost food source for growing urban
populations.
As economic pressures shorten the fallow periods
and accelerate soil degradation processes, cassava
farmers need to be able to increase their production
in a sustainable way. Research should develop the
varietal improvements indicated in the study, as well as
the resource and crop management technologies that
can ensure sustainability of an intensified farming
system.
This package can ______ _ 
double the income 
from the harvest 
Moniya farmers 
use an IITA-
improved grater in 
processing fresh 
cassava for making 
gari. 
12 
Precessing technology can determine how much cassava farmers will benefrt from their labor, Well-designed equipment in a well-organized 
system can significantly improve farm families' income 
from their cassava harvest. even double it, as IITA has 
found w~h two new projects during 1990. 
Research and development of postharvest t echnol-
ogy is a broad subject area covering all operations in 
processing, storage, and utilization of a food crop. In 
cassava processing, the first challenge is to solve the 
mechanical problems of excessive product losses and 
labor input, and of poor product quality. W~h such 
basic Improvements. the retums to cassava farmers in 
the fonm of productivity and income can also begin to 
improve. 
In Africa, cassava is processed largely by women, so 
research gains hold a speCial significance for the well-
being of fanm women and their families. 
New directions 
IITA has analyzed existing cassava processing systems, 
In orderto define the problems and the directions for 
technology development Postharvest losses as a 
whole can exceed 40% of the harvested crop, half of 
which is attributable to processing. The contributing 
factors are field cond~ions, characteristics of the crop 
vanety, and lack of efficient tools or knowledge of 
efficient methods, as well as workers' attitudes, 
Processing alone requires more time than harvesting 
and handling operations. The labor input is estimated 
at 82 person-days for a harvest of I Otons per hectare. 
More than 80% of that time requirement is contrib-
uted by women and children. 
The IITA postharvest research un~ has, since 1988, 
developed an equipment package forthe main stages 
in cassava processing. The package includes a peel ing 
knife, machines for grating, dewatering, chipping, dry-
ing, grinding, and sifting cassava, and a stove w~h fryer, 
Each of them takes the cassava one step further 
toward a particularfood preparation. All of them are 
being tested in pilot locations in Nigeria. Designs are 
modified during field tests, to adapt the equipment to 
the work setting. The un~ is developing the package 
together with end users in each commun~, which 
helps enhance the util~ of the various machines. 
Selection of the pilot test locations has been based on 
local needs or problems, which are first assessed in a 
comprehensive survey. Interviewers are locally 
recnu~ed and trained, They keep reconds of available 
equipment. system capacities, and operational 
requirements, among other data. Family infonmation 
and community profiles are recorded, including income 
sources, crops and areas planted, production potential, 
expend~ures, and activ~ies other than fanming. Such 
basic information is later used in assessing the impact 
of technology utilization, or the qual~ of life before 
and after the technology is introduced, 
Moniya, A group of 18 women at Moniya, near IfTA on 
the northem edge of Ibadan, have called themselves 
the "Stop Hunger" group and decided to set up a 
community center for processing cassava. Their aim 
was to improve the quality of the food they and their 
families consume, and to reduce the time they must 
spend in processing activ~. The equipment package 
for Moniya, where cassava had been processed by 
pooled family effort contained a grater, chipping 
machine, dewatering device, sifters, stove/fryer, and 
grinder. Subsequently other equipment. such as new 
peeling tools and a baking oven, was installed there for 
testing, 
The Moniya group began operating the center 
essentially as a food exchange scheme, taking on some 
contract processing as well. Farmer.; gave their fresh 
cassava tubersto the center in exchange for processed 
cassava. Duringthe latter part of 1990, operations had 
improved so much that the center began processing 
cassava on a commercial basis. By the end of the year, 
commercial processing had exceeded the volume of 
exchange and contract processing combined. 
After six months of operation, the center had reduced 
losses under the family processing system by 50%, 
while the labor requirement had been reduced by 
70%. These savings result from a combination of the 
anrangement ofthe facil~ies, training, att~udinal changes, 
as well as the new technology package. The new 
system has improved product qual~, and leaves the 
women with more free time to devote to other 
actiVITies. 
Aba Lawyer. This nural village in Oyo state, w~h 26 
households, is the s~e of anothercommun~ process-
ing center, which farmers set up to increase their 
income through improvements in their customary 
processing activ~ies. Farmer.; here grow a variety of 
food crops besides cassava, but depend on processing 
their cassava into "gari" meal for their cash income. 
The technology package for the village contained 
grater, chipping machine, grinder, farm cart stove! 
fryer, sifter.; and dryer. 
Six months after the new system and equipment had 
been introduced, processing labor inputs had been 
reduced by 72%. and fuel consumption by 30%. 
Processing losses had declined by 55%. The conse-
quent increase in productiv~ has tnpled production 
volumes, and family incomes have doubled. 
Product quality has also Improved, which has at-
tracted higher prices. Aba LBwyer farmer.; no longer 
need to travel to distant markets in onder to sell their 
produce-bulk buyer.; now go to the village for its 
high-quality gari, and pay the same price as the farmers 
would receive for ~ in town, effectively paying them a 
premium for qual~y. 
The quality of life has improved dramatically for the 
commun~. The village environment is clean and 
looks prosperous, income-generating activities are 
expanding, the villagers are beginning to participate 
more actively in commun~ functions. They have set 
up their own day-care facil~ for young children, who 
are starting to leam the alphabet at an early age. Few 
now need to leave Aba Lawyer in search of better 
opportunities. 
Left: At Moniya, 
frying the grated 
and dried cassava 
on an ffTA-designed 
stove saves fuel and 
time in making gari, 
Right: Built-in 
sieves separate 
large (rom small 
particles of cassava 
nour in this UTA-
designed grinder at 
Abo Lawyer. 
I j 
Making a home _______ _ 
for the soybean 
in Africa 
14 
F rom the beginning of soybean research atllTA. early in the 19705, breeders have seen soybean as an ideal crop for tropical Africa. As a legume, it 
converts nitrogen from the air into a form that it can 
use, and t hus has no need of applied fertilizer. It also 
provides a nitrogen source for the next crop, if its 
leaves and roots are plowed into the soil after the 
grains are harvested. As a food crop, it provides an 
inexpensive source of protein and fats to improve the 
quality of traditional diets. Soybean cake, a byproduct 
of oil production, also makes a high-protein animal 
feed. But the main impetus behind "TA'S soybean re-
search has been the need to add protein in African 
diets usinga vegetable legume, because animal sources 
of protein cannot easily be increased in the present 
setting. 
During the mid-I 9705, breeders overcame plant 
characteristics that had blocked earlier attempts at 
adapting American-bred varieties to the tropics. 
Soybean plants, like most legumes, use nitrogen from 
the air for nourishment in a process called nitrogen 
fixation. T he roots of legumes are invaded by bacteria 
which capture atmospheric nitrogen and convert it to 
a fomr which is useful for the nutrition of the host 
plant. Unlike other legumes indigenous to Africa, such 
as the cowpea, the roots of American-bred soybeans 
were not congenial hosts to African bacteria and did 
not form nodules where bacteria could reside. During 
the I 970sand 19805, however,lITA scientists bned high-
yielding soybeans that accepted the bacteria found in 
African soils and improved nodulation. 
Besides the problem of poor nodulation, seeds of 
American soybeans quickly lost their ability to gemri-
nate in the warm, moist environment of tropical farms. 
In storage from harvest of one year to planting the 
next, very few seeds would retain thei r ability to 
germinate and grow. IITA breeders improved the 
soybean's "storability" under African ambient condi-
tions. The two biggest obstacles to soybean produc-
tion in tropical Africa were thus largely removed. 
Othercharacteristics needed improvement- the ten-
dency of pods to shatter and disperse the beans 
before they could be harvested: the tendency of the 
stems of improved varieties to buckle under the 
weight of high pod yields: and vulnerability to a few 
tropical insect pests and diseases. 
Apart from those basic problems, researchers needed 
to tackle the particular problems of adapting soybeans 
for cultivation in different environments and different 
agroecological zones. For example, in the dry and 
moist savannas where soybeans grow best, the rainfall 
each year spans a period of some 90 to 180 days. 
Improved soy varieties for the savannas should there-
fore be able to mature within that period, leaving a 
margin for planting considerations. They should also 
be able to frt into existing crop rotation systems and 
intercropping systems which combine legumes with 
cereals such as sorghum, millet. and maize. 
Most importantly. however, scientific attention had to 
tum to new objectives conceming the processing and 
utilization of soybeans by African consumers. Farmers 
would have little incentive to grow the crop if they 
could neither use it themselves nor sell it to others. 
Utilization research 
For thousands of years, East Asian farm families have 
grown and eaten soybeans. Not until the twentieth 
century, however, was the crop adapted to other 
environments by scientists in the United States, Canada, 
China, Brazil, and Australia. Their research has enabled 
soybeans to be grown not only in temperate countries 
but also in the sUbtropical-to-subtemperate zones of 
southem Brazil, central and northem India and 
Queensland, Australia. Availability of home-level as 
well as industrial processing methods and export 
markets has fed demand for soybeans, and hence 
production of the crop, in those countries. 
Most of the available processing techniques, however. 
are not appropriate for tropical Africa. Asian homes 
make soybean foods using techniques and equipment 
not found in African households. Most of the industnal 
processing techniques developed in Europe and the 
Americas -require large capital investments. Relatively 
few researchers have investigated soybean processing 
or utilization methods from the African perspective. 
Having succeeded in adapting the crop to tropical 
conditions, HTA sought to create technologies for 
processing soybeans, enlisting the support of the 
Intemational Soybean Program (INTSOY, at the Uni-
versity of Illinois, USA) , the N igerian govemment and 
other donors. In 1985, IrTA acquired a screw press for 
oil extraction and a dry extruder for making soy fiour. 
A food technologist joined the staff. In October 1985, 
IrTA held the tropical soybean workshop. which con-
cluded that the main obstacle preventing rapid ex-
pansion of soybean production in Africa was that 
consumers lack the means of processing and using 
them at household or village level. 
The research first focused on equipment and process-
ing methods geared to household and small-scale 
business enterprises. Together with the Institurte of 
Agricultural Research and Training (IAR&T) at nearby 
Moor Plantation in Ibadan, IrTA launched a project with 
funds from the Intemational Development Research 
Centre (IDRC) of Canada and a food technologist sent 
by the Japan Intemational Cooperation Agency OICA). 
The goal is to develop new recipes which enhance the 
nutrition and taste of traditional dishes, make use of 
implements already in the typical N igerian home, burt 
do not increase the t ime or cost of preparing tradi-
tional foods. 
Among the project's successes in adding soybeans to 
basic dishes is soy fiour, or paste, in the various 
vegetable sauces which accompany a starchy staple 
(such as pounded yam or cassava). New methods of 
processing soy milk have eliminated the hand-buming 
hazards and reduced time-consuming labor, and have 
been successfully introduced. "Soy gari" (cassava meal 
with added soy flour that has a I 0% protein content 
as against less than I % protein of traditional Nigerian 
gari) has been developed and introduced. "Soyamusa", 
a new extnuded, inexpensive baby food of plantain 
and soy, has been tested with the help of the National 
Horticu~ural Research Institute (NIHORT: also in Ibadan). 
Several recipes urtilizing soy milk residue have been 
developed. The project also evaluated the perfonm-
ance of screw presses foroil extraction made in Africa. 
Nigerian impacts 
In 1984 soybean was virtually unknown, being neither 
grown nor used, in Nigeria's Oyo state where HTA'S 
15 
Students learn 
about soybean 
processing on a visit 
to the Notional 
Cereals Research 
Institute, which 
spearheads 
soybean research in 
Nigeria. 
16 
campus headquarters is located. As a resu lt of the 
IDRc-funded project. IrrA and IAR&T have introduced 
the soybean in four local govemment areas of Oyo. A 
recent survey has revealed that about one-third of all 
farmers in those areas are growing soybeans. Among 
soybean growers. the average area planted to soybean 
is nearly one-quarter of a hectare. Over half of the 
growers cook and eat soybean in their home. Those 
who eat soybean consume an average of 1.4 kilograms 
of soybean per week per family. These figures reflect 
a very rapid rate of adoption of soybeans as a crop and 
a food. 
From surveys conducted in N igeria's Benue state. 
where traditional soybean varieties have been culti-
vated by the Tiv tribe. fanmers show a strong prefer-
ence for seed of the improved varieties over the 
traditional variety. and the number offanmers planting 
improved seed is increasing. The surveys. conducted 
by a volunteer of the Canadian University Service 
Overseas (cuso), have also revealed that almost nine 
in ten villages in eastem Benue have increased their 
soybean production over the past five years. and 
more than half of them consider the crop to be a 
major cash eamer. 
IITA has also helped other African countries to produce 
improved soybean varieties. Zaire and Ghana have 
released IrrA varieties for fanmers to begin planting. 
The genetic backgrounds of soybean varieties have 
been improved. Soybean yields of up to 2.5 tons per 
hectare have become possible with improved IrrA 
varieties that have been tested in many African 
countries. More than 25 African countries are in-
volved in annual trials to test IITA soybean varieties for 
suitability for local conditions. 
For soybeans to real ize their full potential as a protein 
source in African diets, research must continue into 
new products and adaptive uses in traditional diets. 
The path for such research has been mari<.ed by the 
IITA and IAR&T collaboration. W~h development of 
new projects in other countries in future, the promise 
of soybeans seems likely to be fulfilled. 
I 

Prime rice-growing 
wetlands exist 
among Africa's 
inland valleys, but 
farmers need to 
have the right 
technologies to 
exploit their 
potential. 
18 
intensified cultivation, with fertilizer and good weed 
control. The objective is to produce rice varieties with 
ample yields which can resist or tolerate t he specific 
diseases, insect pests, and environmental stresses 
present in each area. 
Rice research in Africa within the CGIARsystem has been 
conducted by three organizations: over the past 20 
years from both IITA and the West Africa Rice Devel-
opment Association (WARDA); and for the past 30 
years from the Intemational Rice Research Inst~ute 
(IRRl). WARDA'S capabd~yhas been strengthened, so IrTA 
has since 1987 been gradually transferring its rice 
research activ~ to ~ sister institute. The goal of 
completing the handover by 1990 has been accom-
plished. IITA will continue, however, to collaborate 
with WARDA and IRRI in development of improved 
technology packages for rice-based cropping systems. 
IrrA'S experience in the region is summarized in the rest 
of this article. 
Two decades 
To hamess the regional potential, IrTA began research 
in 1970 into varieties for efficient production in the 
different growing environments of West and Central 
Africa. IrTA breeders sought to develop insect- and 
disease-resistant varieties that. together with 
improvements in farming methods, would yield more 
generous harvests than possible w~h traditional varieties 
and methods. The farming ecologies they targeted 
were the rainfed uplands, inland valleys (which are 
seasonally flooded), and the irrigated paddies. 
Uplands. In its first experiments in breeding upland 
rice dunngthe mid- I 970s,IrTA found that Asian genetic 
types adapted poorlytothe acid, nutrient-poor African 
soils and succumbed to diseases, SO UTA'S program for 
upland rice began building on a base of traditional 
African genetic material, together w~h some valuable 
materials from similar areas in Brazil and from the 
Instltut de recherches agronomiques tropicales (IRAT) 
of France. Breeders improved the yield potential and 
shortened the plant. while producing longer grains 
with a higher market value---at the same time 
preserving the excellent stress and disease resistance 
of the source material. 
Perhaps the greatest impact of the upland rice work 
has been the spread of the varieties rTA 150 and ITA 
257 across the forest and moist savanna belts of 
Nigeria. Through aggressive seed production by the 
federal govemment and state agricultural develop-
ment projects, seed has reached the farmers and the 
varieties have met with an enthusiastic reception. rrA 
257 has taken on such colorful local names as "Canada", 
"three-month rice", and "Wanikiran" (meaning "ante-
lope" in the Tiv language, for its rapid maturation and 
brown husk color resembling antelope skin). rTA 257 
has also been released in Sierra Leone. The short-
growth cycle of ITA 150 and rTA 257 gives quick retums 
on investment for farmers and improves total income, 
because the two varieties are ready for harvest when 
prices are at their annual peak in July/August, well 
before the lowland crop reaches the market. Their 
excellent eating quality also eams price premiums. 
Inland valleys. In a revision of research strategy, up-
land work was scaled down after 1987 so that 
resources could be concentrated on the rich potential 
of the inland valleys. Such val leys are scattered across 
the region, from the coastal forests northward as far 
as the dry savannas, usually watered by streams which 
rise and fall with the rainy seasons. They are relatively 
fertile and ideally suited for rice, but to date have 
remained under-utilized because of the environmental 
hurdles they pose for farmers: water control problems, 
rough soil tillage, uneven establishment of the crop 
after planting, difficult weeding in soggy soils. T radi-
tional farmers find it hard to modify their bush-fallow/ 
slash-and-bum farming regimeto these wetlands. The 
threat of water-bome diseases has also discouraged 
explo~ation, in the absence of public health measures. 
IITA began ~ breeding program for the inland valleys 
early in the 1980s. The aim was a plant type that could 
compete with weeds, tolerate physica! stresses, resist 
iron toxicity and diseases such as blast fungus and 
yellow mottle virus, and show a high yie ld. 

IITA Today 
;~.;--: ~:., 
~ •• -. • ~ :"I 
~~ 
I 
f ~ 
20 
21 IITA and the CGIAR 
24 Resource and crop management 
26 Alleys across Africa 
30 Food for thought from second-season cropping 
33 Root, tuber, and plantain improvement 
34 Cyanide in cassava - it's not there, it just happens 
36 Mites meet a hairline defeat 
40 T omonrow's role for yam ancestors 
41 Grain legume improvement 
42 Putting cowpea viruses on the map 
45 Maize research 
46 Please save the savanna from that witch 
50 Rice research 
5 I Biological control 
52 Plant protection - sustaining protector as well as plant 
55 Research support services 
59 International cooperation 
65 Information services 
liT A and the CGIAR 
I ITA was established in 1967 as an intematlonal research institute with headquartecs on a 1,000-hectare farm a: Ibadan, Nigena and with links with 
national programs in many countries of sub-Saha--an 
Africa. It became the first Afncan link i1 a worldwide 
network of Intematio1al agriCl;itural research centers 
known as the Consultative Group on Intemational 
Agricultural ReSearc.l (CCIAR). The Federal Republic of 
Nigeria provided the anc for the headquarters and 
experimental farm at Ibadan, while the Ford and 
Rockefeller foundations provided the Initial planning 
and financial support. 
II-A has four objectives: 
I. To improve agrcuttural production systems forthe 
African hcmid and subhumld tropics which can be 
s'Jstained without degradation of the enviro1ment. 
2. To improve the performance of selected food 
crops which can be integrated into im::>roved and 
sustainable production systems. 
3. To develop naCional agricultural research capabilities 
includirg 1uman resources on a basis of shared 
Board of Trustees 
responsibility with IITA, by lleans of training, informa-
tion, and other Dut--each activities. 
4. To improve food qual ty and availability, irciuding 
food storage, processing, and marXeling 
IITA conducts research and traini'lg activities at its 
headquarters and stations in West and Central Africa, 
and in conjunction with regional and national programs 
in many parts of Slob-Saharan Africa. As a means to 
enhance the pract cal relevance cfits crop improvement 
research to farming conditions, ITA has begun to 
decentralize its resea'l:h from its headquarters to 
locations in the various agroecological zones where its 
mandated crops are grown. 
IITA maintairs vital links with na~ional agricultural research 
programs, through various forms of cooperative 
research and training arrangements. By developing 
new technologies With liT A, adapting them to local 
conditions, and taking them to far:-ners, national 
programs can translate research into increased food 
product,on. 
Nicholas E. Mumba. ChorrpersorJ 
Pem;onef1t Secretary', IvlJnlstry of Ag.'1culrure 
Lusaka, Zamb,;a 
Robert K. Cunningham Gerardo Perlasca 
Luis B. Crouch, Chairpersor;* 
Buslr'essman. Santo DO'T)inp. Comif'ic;m RepubIr: 
E. O. Ayo* 
o,rector Genercl. Federal Mif'istry of Agri:r..lture 
end Nawrol Resources, Abuja. N,'gerie 
Ayo Banjo 
Vice-Chancellor, University of Ibado'1, Ito&:m. 
N,'gerio 
Randolph Barker 
Professor. Deportment of Agrcu,'turol Economics. 
Come,'1 University, ir.t;oCQ, New York. USA 
Lukas Brader 
DlrectJr Generu/, /ITA, Ibedar], Nigena 
Mayra Buvinic 
DlrectJr. IntemotiO'lol Cen~er for Rese'Jrcl-: on 
Women, Washl.'lgton, DC USA 
Agricd~urol Research CJnsultcJnt /-Iorpender;, 
Hertiordsnlre. England 
Susanna B. Hecht 
Groduate Smool of Architecture Qr1d UtTIan 
Plonnlng, Un;\/ersity 0; California. Los Angeles, USA 
Freeman L. McEwen 
Dean, Ontar;o AgriCUlture! Col,'ege University of 
Guelph, Gue,'ph Ontan'a Car:odo 
Keiko Nakamura 
D;rector. Deportment of Socia,! ond Natural 
Envlronme,ltal Research, Mltsub,sh Kasei Ir.stitute 
of L,fe SCience. Tokyo, Japan 
Arnor Nj0S 
D;rector Ge,lerol. Cer.ter :or 5011 one! Em,'ronme'ltcl 
Reseorcr.. Acs-Nlh, Norway 
O.Odegbaro 
Acting D,;rector, Depcrtmef't 'Jf Agricuttural 
5cier]ces. Federal Mirllstry of SCJence and 
Technology, Logos, Nigeria 
Agric'.Jlturd CO,1sultant Come, Iter/y 
Laurence D. Stifel* 
Dlrectcr General, IITA Ibcdan. Nigena 
Bakary T oure* 
~ector. National Ur.l'lerslty of Cote d'ivoire. Abidjon, 
Cote d Ivolre 
Theo M. Wormer 
PrJfessor rrtd.), Universi~1 0; Amste,'dcJm. 
AlT'sterda:T1, Ner.t;erlar'ds 
Special Advisers 
Luigi Monti 
CytogenetiCist Unive"Sltv of Naples. Italy 
General Olusegun Obsanjo (Rtd.) 
,r::orrner Heed of Stete, Federal f<..epcrb/1c of N,geriCJ 
"* Term ended dunng ,1990 
21 
22 
IITA programs comprise: 
Resource and crop management 
(errphasizing soil resources and farming syste'T1s 
'with cassava, maize, and rice) 
Root, tuber and plantain improvement 
(bcusirg on cassava, yarr aid plantain) 
Grain legume improvement 
(focusing on cowpea and soybean) 
Maize research 
Biological control 
(emphasizing envi'Dllme'ltally sound pant 
protect on) 
Research support 
Genetic resources 
Biotechnology 
Virology 
Biometrics 
Analytical services 
Research farms 
International cooperation and training 
(emphaSizing self~development of national 
ag1cultural research systems) 
Information services 
Public affairs 
Librarf 
Publications 
IITA is a nonprofit. internat anal agricultural research 
and training ins:itute supported primarily by the CGIAR. 
liT A employs about I 80 scientists and professional staff 
members from over 40 countries and about I ,400 
support staff, mostly from Nigena, Most of the scaff are 
located at headquarters, where 300 hectares of the 
I ,000~hectare campus have bee1 developed for 
experimental fields, An 80-hectare researcr station 
lies il the high-rainfall coastal zone at Onne, in 
southern Nigeria. A 30-hectare station was opened in 
1990 in :re dry savanna zone at Kana, northern 
Nigeria, In collaboration with Ahmadu Bello University's 
Institute for Agricu tura Research. A station at coastal 
Cotonou, Re:lublic of Ben n, hOJses the biological 
control program. A I ,000~hectare, humid forest station 
began operating il 1990 at Mbalmayo, Cameroon, in 
co laboration with Institut de la recherche ag.'Dnomicue 
(IRA). Several collaborative projects were L..nderway in 
sub-Saharan African countries during 1990. 
Founded in 1971, the CGIAFl. is an informal association 
of about 40 public and private sector donors, which 
include government agencies, international organiza-
tions, and private fou1dations. During 1990 t1ey 
proVided aboct US$ 235 million n core fending, The 
CG AR. supports 16 intemational research centers. whose 
collective goal is to improve the qJantity and quality 
of food production in developing countries. 
Cosponsored by the World Ban<. the ;cood and 
Agriculture Organization ofthe United Nat ons (FAO), 
and the United Nations Development Programme 
(UNDP), the CGIAR operates without a formal c'larter, 
relying on a consenSJS derived from a sense of 
common purpose. 
Each CGIAFl.-affiliated center is independent and 
autonomous, with its own structure. mandate, and 
objectives, and is oversee1 by its own board of 
trustees. Some centers focus on one or two 
commodities for which they have global ~andate5, 
while others 1ave --egiona or ecological mandates for 
one or more commodities. Still others peform 
sJecia ized functi01s in SL.ch fields as food po icy, 
genetic resources, agroforestry, inigation management, 
and the strengthening of national agricultural research 
in develop:ng countries. 
The CGIAR is serviced by an executive secretarat, 
Wh'C1 is proVided by the World Bank and located in 
Washington. A Technical Advisory COMmittee (T AC), 
comprising a chairman and 18 scientists, is d--awn 
equal,yfrom developed and developing countries, TAC: 
makes recommendations on research prograMS and 
priorities, and monitors perfonnance through annL..al 
program ane budget reviews and penodic external 
reviews by independent sciertists invited to serve on 
speCialy constituted panels. T'C IS supported by a 
secretariat provided by the three cosponsors of CGIAE 
and located at FAO headquarters in Rome. 
ClMMYT 
MexICo 
ClAT 
Colombia 
ClP 
Peru 
IFPRI 
USA 
INIBAP 
France 
ISNAR 
Netherlands 
WARDA 
Cote d' Ivoire 
The CGIAR meets twice a year. once in Washington in 
October or November, and once elsewhere in May. 
The meetings review program activities undertaken 
by the centers, discuss agricultural research needs, and 
adopt strategies to address the needs, as well as 
review proposals on funding and management issues. 
IITA 
Nigeria 
ICARDA 
Syna 
ICRJSAT 
India 
IRRI 
Philippines 
<l ~U~~d 
)# ILCA Ethiopia 
ILRAD 
Kenya 
ICRAF 
Kenya 
{7/ 
23 

• Tillage methods. Studies at IITA and elsewhere have 
shown the advantages of minimum orno-tillage farming. 
• Fertilizer and soil additives. Fertilizer regimes have 
been developed which can enhance crop growth and 
not cause soil acidification or toxicity problems. 
• Improved fallows . Some research has been done to 
improve fallow management practices that would be 
more efficient in restoring soil fertil ity than are 
unmanaged bush fallows. 
(2) Crop management research combines the prod-
ucts of resource management and of crop 
improvement. conducted by other IITA programs, into 
sustainable cropping systems which have greater 
productivity yet are compatible with t he smallholder's 
resources and objectives. This synthesis of crop 
management is. in essence, the product of the 
concerted efforts of all IITA programs. 
Mu~idisciplinaryteams of scientists examine the factors 
which inhibit or could promote production in the key 
cropping systems in each of the three main 
agroecological lones. Thethree research groups cover: 
• Humid forest systems (for cropping systems based 
on cassava). 
• Savanna systems (for maize-based cropping). 
• Inland valley systems (for rice-based cropping). 
Technologies which will enhance farmers' crop 
management practices in a sustainable way have been 
identified over the past six years. They include: 
• Cassava varieties wit h durable disease resistance, 
well adapted to the cassava/maize system. 
• Soybeans adapted for growing as a second~season 
crop, in association with cassava. 
• Maize varieties with durable disease resistance. 
Feedback on famn-Ievel problems from the systems 
research groups is helping to set the right emphasis in 
the research agenda of resource management 
researchers 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; weed control problems in no~tillage, cassava~ 
based syste;ms in which herbicides are not used. 
The results of the past year's research are outlined in 
these pages, together w ith their significance for IITA 
goals in general. 
Resource management research 
Maps and models. In 1990 IITA began cooperative 
working arrangements in agroclimatology, modell ing. 
and a geographic information system with national 
and intemational institutes. A database of daily rainfall 
data for nine tropical African countries was establ ished. 
Software for data analysis and quality control was 
developed which enabled IITA to share the data. 
IITA'S agroc limatologist developed a resource 
information system ( R1S ) which can generate maps 
showing specified environmental and socioeconomic 
conditions. The RIS database carries information which 
characterizes the African continent in I O~mile~square 
areal units. The information is important in <malysis, 
planning, and sample survey work 
Soil management 
Effective technologies for soil improvement are the 
result of well~cons i dered research. Since the 
technologies are designed for smallholder famners to 
use, they must involve little or no addit ional expense 
by users. Such research requires a long lead time for 
results to crystallize into clearcut applications. 
Soil erosion studies continued in Nigeria (on non· 
acidic soil types) and Cameroon (on acidic soils) under 
tillage, no t illage, and bare fallows, w ith support from 
the official Gemnan aid agency GTZ. Generally, soil loss 
has been much greater from the acidic than from the 
non~acidic soils, under al l treatments. Acidic soils are 
more easily eroded and are lower in nutrients than 
non~acidic soils. Moreover, the subsoil under acidic 
soils is not as rich in basic minerals as the subsoil under 
non~acidic types. Acidic soils are typical of the humid 
forest, while the soils ofthe forest~savanna transition 
and savanna zones are non-acidic. 
Experiments began during 1990 to characterize the 
acidic soil at IITA'S new humid forest station at 
Mbalmayo, central Cameroon, near the capital city of 
Yaounde. Soil physical properties, such as bu lk density, 
temperature, and water infiltration rate, were measured 
under different crop management practices. 
Computerized 
generation of mops 
is bosed on data 
for oreal units 10 
miles square. 
25 
26 
Changes in the main constituents and physical 
properties of soils were investigated in Nigeria. as they 
occurred following land clearing. cropping. and fallowing. 
The causes of these changes wi ll also shape new soi l 
and vegetat ion management practices which will 
improve soil fertility. 
Sustaining ferti lity. IITA research on improving acid 
soils has followed two different but complementary 
approaches. Soil amendment is one. utilizing lime. 
fertilizers. and similar materials to combat acidity and 
aluminum toxicity in the soil. Even low applicat ions of 
lime can reduce toxicity. penmitting crop yields to 
Increase. 
A second approach to soil enrichment----using prunings 
from shrubs ortrees-<:an betaken independent ly or 
together with amendments. An alt ernative t o 
amendments is required because lime or fertilizer is 
frequent ly not available to fanmers. 
Alley cropping or fanming is an agroforestry system 
which takes this second approach. sustaining soil 
fertility while reducing the need for fallow periods. 
Selected shrubs ort ree species (usually n~rogen-fixi ng 
legumes) are planted in rows with food crops in the 
"alleys" between the hedgerows. Soil nutrition is 
improved w~h n~rogen and other nutrients from 
prunings of the hedgerow trees which are left on the 
ground to decompose. Other cont ributions of alley 
cropping to the soil include moisture conservation, 
weed suppression. and erosion contro l. "Alley 
cropping" becomes "alleyfanming" when the hedgerow 
prunings are grown to feed livestock and the woody 
stems are used as fi rewood or stakes for climbing 
crops. A~ogether. the alleyfamn mimics the restorative 
processes of bush fallows concurrently with crop 
production. (See "A lleys across Africa". opposite.) 
Alley cropping has evolved from IrTA research since the 
19705, primari ly for renewal of the non-acidic soils of 
the forest-savanna transition zone, but more recent ly 
for similar soils elsewhere and forest-zone acidic soils 
as well. Currently. long-temn trials are investigating: 
• what tree species are best for particular conditions 
or locations (such as acidic or non-acidic soils, or in 
combination with various food crops or cover crops), 
Alleys across Africa 
The promise of alley fanming is being put to the test in 
a pioneering research scheme which links 2 1 countries 
across tropical Africa Coordinated by the Alley Fanming 
Networkfor Tropical Africa (AFNETA), 52 of the planned 
total of95 experiments were in the ground by the end 
of 1990. The accompanying table summarizes all the 
projects by type of research and target agroecological 
zone in each country. humid forest. forest-fringe-to-
moist-savanna (subhumid), dry savanna (semi-arid), 
and mid-aMudes (highlands. 800- 1.500 meters above 
sea level). 
AFNETA ~elf w as established in 1986 w~ technical 
guidance from IrTA. the Intemational Council for 
Research in Agro-Forestry (ICRAF) , and the Inter-
national Livestock Center for Africa (ILCA). Project 
funding is being provided by the Canadian Intemat-
ional Development Agency (OOA). the International 
Development Reseanch Centre (IORC), and the Inter-
national Fund for Agricu~ural Development (IFAD). In 
1990 AFNETA membership grew to 47 institutions in 25 
countries. AFNETA fosters research and development 
of alley famningtechnologies uti lizing members' pooled 
efforts and experience. The aim isto build a foundation 
of research for prototype alley fanming systems as a 
key means to sustain agricu~ural production in Africa 
for the foreseeable future. 
The co llaborative projects coverthe primary areas of 
research issues in a progressive sequence: 
I. Screening for selection of mUltipurpose 
shrub and tree species. 
The hedgerows must su~ a variety of purposes in the 
different zones: providing organic matter for soil 
renewal, forage for livestock. poles for climbing crops 
and other uses, and firewood. Mu~ipurpose tree 
screening trials began at 28 s~es overall agroecological 
zones in 14 countries. Each trial involves 10-15 local 
or exotic species which are assessed under continuous 
growth and alley fanming management. 
2. Alley farming management. 
Once su~le hedgerow species have been identified, 
studies of system management and productivity can 
evaluate effects of hedgerow management in t enms of 
different spacing and time factors, tree responses to 
fertilizer use, managemerrt of hedgerow prunings and 
their contributions to soil fertil ity. comparisons among 
various alley cropping systems, and integration of tree 
cropping and fallowing systems w~h alley famning. The 
management t rials commenced at 4 3 s~es over all 
zones in 17 countries. 
3. Livestock integration. 
Trials focusing on livestock benefrts are concerned 
with two aspects. The first is production of forage by 
the hedgerows and pasture crops in the "alleys". The 
second is the fodder value from forage, in terms of 
digestibility, protein content. other characteristcs. and 
the consequential gains in livestock productivity. 
Uvestock integration projects were fielded at six sites 
over three of the agroecologieal categories (all 
excepting the dry savanna) in three countries. In 
addition, some factors relating to livestock issues are 
being tested in the species screening and management 
trials-for example, the foddervalue of certain species, 
and fallows management for producing fodder. 
4. On-farm research and socioeconomic 
assessment. 
Finally, research and development must be conducted 
on-farm for fine-tuning the technologies, assessing 
efficiency and productivity underfarmers' management. 
and determining farmers' interest, acceptabi lity, and 
potential adoptibility of technologies. Some I B projects 
over the range of zones in 9 countries have started, or 
plan to start by 1992. Wrth increasing experience, 
more countries will talke up this kind of research, 
following the general thrust of network activity. 
The four types of projects are designed to provide 
comparable data sets for agroecological conditions 
across tropical Africa. Each collalborating scientist in 
the 35 participating national institutes is collecting data 
on a minimum set of variables at each site, w hich 
include site conditions, hedgerow characteristics, pest 
damage, and crop yields, among others. During the 
fourth year of operations, AFNET A will assess the results 
to date at an international conference on alley farming. 
_ ETA collaborative projects w ith national research programs, 1989- I 993 
Type of research project Agroecological zones 
Humid Subhumid Semi-arid Highlands 
Tree species selection Ghana Benin 2 Benin I Malawi 
Guinea COte d'ivoire I Burkina Faso 2 Uganda 
Uberia Ethiopia COte d'ivoire I 
Ghana Ethiopia 2 
Guinea Ghana I 
Senegal I Mali 2 
Togo 2 Senegal I 
Zaire I Togo I 
Zambia 2 
Farm management Cameroon 3 Benin I Burkina Faso 3 Kenya I 
Ghana I COte d'ivoire I COte d'ivoire Malawi I 
Guinea I Ethiopia I Ethiopia I Uganda 2 
Uberia I Guinea I Ghana I 
Nigeria 4 Malawi 2 Kenya I 
Sierra Leone I Nigeria 2 Mali 2 
Sierra Leone I Togo I 
Tanzania 3 Zambia 2 
Togo 2 
Zaire 2 
Livestock integration Cameroon 2 Benin 3 Rwanda 
On·farm and Cameroon I COte d'ivoire I Burkina Faso Kenya 
socioeconomic COte d'ivoire I Nigeria 4 COte d'lvoire Rwanda 
research Nigeria 3 Sierra Leone I 
Tanzania I 
Zaire 2 
27 
28 
• what management pract ces are most efficient for 
different objectives, and 
• how alley farming affects soil fertility and crop 
productivity. 
For exaMple, results of 1990 trials on both acidic and 
non-acidic soils suggest that some hedge'Uw t--ees 
compete with the crops for soil rutrients, because 
they have lateral roots which spread near the soil 
surface. The solution is to select hedgerow species 
with deeper rooting pattems. In other trials over a 
nine-year period, maize crops without fertilizer yielded 
as much as non-alley-cropped maize which received 
45 kilograms of nitroge'l fertilize, each year. Four 
hedgerow species were involved: Acioo, Alchomeo 
Ghricidic, and Leucaenc. All but Acioa recycled sig-
nificant amounts of the minerals copper, iron, 
-nanganese. and zinc back to the soil with prunings 
which, in the long term, should boost Yields further. 
Weeds. Often the biggest demand on farme,' labor 
is weed control, usually a rlanual task. Weed scientists 
are investigat ng cultural and chemical Means to reduce 
the labor reqL.irement in weeding. 
Cultural practices, such as planting of a fast-growing 
cover crop or hedgerow trees, as in alley farming, offer 
the more efficient solution in the long run. Cover 
crops can serve as a live mulch: a :Jrotectve layer of 
vegetation which can control weeds, reduce 
evaporation, prevent erosion, lower daytime soil 
temperatures, and enrich the soi, with organic matter. 
A leguminous cover crop of.rers the additional 
advantage of providing a source of nitrogen for ':.he 
next crop, If It IS plowed back Into the soil at the end 
of the g'Uwing season. 
The legume Pseudovigna orgenteo, less of a climber 
than other herbaceous legumes, was assessed as a 
live-mulch cover crop with ma ze. In 1990 tnals it 
controlled weeds adequately. Crot'J/a(!o velTlJcosa 
suppressed weeds in trials grown with other crops. 
Maize grown in I 990triais intne same pots subsequent 
to the Croto/aria crop, which had been plowed under, 
required less weeding a1d less nitrogen fertilizer than 
maize ir plots without previous Crow/ana cultivation. 
The economics of resource management 
A series of studies, beginning with southeasterT1 Nigeria 
in 1990, ,5 documenting the complexity of farmers' 
resource problems and their responses to them. With 
the knowledge gained from these studies, which Will 
cove .... farming systems in West and Central Africa, IITA 
scientists should be able to desgn technologies or 
interventions appropriate to the problem situation. A 
study in Cameroon wi I begin in 1991. 
The Nigerian p'lase has shown that economic 
pressures, other than changes in population dens ty, 
result in di-ninishing retums to farming, chietlythrough 
degradation of the soil. RISing demand for food crops 
from urban areas, the rising cost offarm labor, and ir.-
migrat on of new farmers are othersources of p--essure 
which stimulate SJch reactions as shortened fallows, 
increased fertilizer use, the closing of common use 
privileges of forest lands, and changes in land tenure 
and tree tenure arrangements. For example, farmers 
in areas where the population density s thinning may 
rotate the r land under long-term falows because 
fa'TT1ing activity is reduced. Alterratively they may 
overuse some farmland. permitting only short fallows, 
becaJse there is not enoL..gh labor to bring heavily 
overgrown land back under cultivation. In such a 
situation, new technologies wit'l a high labor demand 
will not be acceptable. 
Meanwhi!e, IITAresource eco10mists in I 990 evaluated 
the relative economic benefits from soil eroSion control, 
in southwestem Nigeria, using three systems: al',ey 
cropping with Leucoena (in 2-meterand 4-meterwidths 
between hedgerows), notillage, and bush fallow (With 
3-year and 9-year fallows), The study gauged the 
theoretical "profitability" of those altematives us ng a 
capital budgeting approach with a 10% interest charge, 
and taking into account the long-run and short-run 
impacts of soil erosion on agricultural productivity. 
Where popu'ation density s low and access to 
forestlalds "costless", the 9-year bush fallow syste'T1 is 
most profitable, followed by 4-meter-wide alleys, no 
tillage, 2-meter-wide alleys, and the 3-year fallows. 
Where land values are rising and fallows become an 
economic "luxury" because of lost production 
opportunities, the 4-meter alley cropping system is 
most profitable, followed by no-till, 2-meter-wlde 
alleys, and fmlly the 9-year and 3-year bush fal ows. 


Research directions 
Resource management Savanna systems 
• Description, measurement, classification, 
and mapping work on the biological, 
physical, chemical, and socioeconomic 
characteristics of the IrrA mandate area 
sustainable fallow management systems 
incorporating herbaceous legumes. 
• Assessment of agricultural sustainabil ity 
under trad~ional and improved resource 
management methods. 
• Characterization and classification of 
maize-based farming systems in the moist 
savanna 
• Quantification of fundamental rela-
tionships among factors contributing to the 
sustainability of food production systems. 
Process studies (for example, biological 
regulation of nutrient cycling, physical factors 
affecting soil fertil ity, factors regulating 
interplant competition) to continue on 
non-acidic and acidic soils, including the 
low-phosphate acid soils at the new humid 
forest station at Mbalmayo, Cameroon. 
• On-fann testing and validation of new 
technologies, emphasizing alley farming 
under different socioeconomic conditions. 
• Development of systems simulation 
models, emphasizing intercropping, nutrient 
cycling in alley farmi ng systems, and 
economics/ecology of inland valleys. 
• Investigation of the effects of intensified 
maize farming on striga infestation. 
• Development and testing of cultural 
methods for control of striga and 
improvement of soil ferti lity. 
Inland valley systems 
Humid forest systems 
• Characterization and classification of 
inland valleys in West and Central Africa 
• Development of models of envir-
onmental and socioeconomic processes 
in in land valley agroecological systems. • Development of indices for measuring 
the sustainability of small-scale cropping. 
• Development of multipurpose agro-
forestry systems which combine improved 
soil and weed management 
• Investigation of resource use and 
productivity problems in cassava-based 
intercropping systems. 
• Investigation of the adoption and impact 
of improved cassava varieties. 
• Design of technologies or interventions 
to improve land use and management 
practices. 
• Development of economically viable and 
• Collaboration w~ national i n~utes, to 
improve cassava intercropping in al ley 
farming systems. 
Maize clearly would neverbe profitable while the stem 
borer problem persisted. Hence, maize trials were 
conducted under protection of a pesticide, to measure 
the yield potential in the case that resistant varieties 
become available. To beat the unpredictable beginning 
of the rainy season, planting had to start late, so an 
early-maturing variety ensured crop maturity by late in 
October. At harvesttime, farmers realized almost as 
much-about four-fifths- from the second season's 
crop as they had from their first, mh the benefit of 
protection against stem borers. Irr A maize breeders 
are reckoning these results in their calculations of the 
possible gains from breeding for stem borer resistance 
and other goals. 
Cowpea crops were protected by three or four 
insecticide sprayings, an operation which posed no 
hurdle for the farmers. Their highest yield was about 
I ,500 kilograms of grain per hectare; their lowest, one-
tenth of that Even mh an average yield of around 700 
kilograms fanners could realize a retum on their 
investment, because of the high market prices for 
cowpea during the study years. Spraying materials 
were no problem because the research team supplied 
all the ~ems, against cash payment But the vaiue from 
this experience for the team remains to be gleaned-
whether farmers will in future take the trouble to 
purchase their own supplies from the nearby town. 
Soybean needed no sprays or fertilizers, and the yields 
were as good as w~h cowpea. But the market 
experience was not similar-in Alabata, no active 
market forthe soybeans materialized, and the farmers' 
expectations could not be realized. Hence, Alabata 
fanners professed themselves disappointed w~ the 
crop and uninterested in further cultivation. In Ayepe, 
however, soybean harvests were consumed by the 
grower and the crop may have retained a small niche. 
To the IrrA team, soybean clearly commands interest 
as a food crop for growers' consumption, w~h some 
possibility of commercialization. But until market 
channels are developed, and until grain quality and 
home processing are improved fortrad~ional types of 
use, soybean is unlikely to occupy much of a place in 
this regional setting. 
The cassava factor. In both villages, cassava usually 
accompanied maize grown during the second rainy 
season. Cassava seemed to be the insurance crop. 
while the maize if successful would provide a bonus. 
Farmers often grow cowpea mh cassava, and will 
li kely grow soybean again and combine ~ w~ cassava 
as well. Experience has taught them the value of 
insuring their investment, while their entrepreneurial 
spirit still leads them to risk a new crop for new gains. 
31 
32 
the amount harvestec each year has to feed a 
proportionately greater number of people than the 
year before. Inland valleys afford a chanceto supplement 
the harvests of the main producing areas, and to help 
satisfY the growi'lg dema1d for 'ice among African 
conscmers. (See Research Highlights article "A 
comucopia to come".) 
IITA'S research group forthe Inlaod valleys, Olade up of 
scientists from several disciplines to ensure a b'Dad 
and deep consideration of the problematique, drew 
up the following research strategy in 1990 for the 
coming five or s x years. 
• Measu--emen:ofland area occupied by inland valleys 
io West and Central Afnca, and the proport on 
already being cultivated 
• Identi~catlon of the reasons why inland valleys are 
I ttle used for cropping, the changes in land use in them 
over time, and what triggers manges in land use. 
• ClasSification of the different types of inland valleys 
in the region and selection of representative 
experimental sites, 
• Identification and assessment of problems With 
different forms of land use in the valleys, in terms of the 
sustainabllrty of production and fanmers' well-~eing. 
• Development of computer-Dased models of tre 
env,ronmental and socioeconomic processes in the 
agroecological systeOls of inland valleys. 
• Design of technologies or nterventions to Improve 
land use and manage,'T1ent practices for inland valleys, 
and testing and modification ofthe technologies atthe 
expermental sites. 
The group began to tackle the first th--ee oblectives 
during 1990. with a time frame of about three years for 
completion ofthe expected results. The main problems 
with increasing crop production in inland valleys 
emerged from a detailed review of the literature in 
1990. Weed competition Wier, crops was the greatest 
problem, followed by low soil fertility, and vanable 
water avai ability. Availability of SUitable types of nee 
for those ecosystems was not a major problem. 
I 
i 
Root, tuber, and plantain ___ _ 
improvement 
The starchy staples of cassava, yam and plantain supply food energy for most of tropical Africa's 400 million people each day, Cassava, a tuber-like 
root crop, provides for half the energy needs of over 
200 million people. Yam is consumed by some 150 
million people within this region-a~hough production 
costs have put yam beyond the reach of the poorest, 
Plantain is a mainstay food forabout 70 million people. 
The lilA root. tuber, and plantain improvement 
program breeds improved varieties of cassava, yam, 
and plantain, focusing on problems of 
• pest resistance 
• adaptation to specific environmental conditions 
• processing and eating quality. 
The program works closely with national programs 
throughout tropical Africa, and with many research 
groups from other parts of the world, in fulfilling those 
aims and in developing processing systems forcommun-
ity industries and households. (See Research Highlights 
article on postharvest processing, page 12.) 
Cassava 
Cassava (Manihot escu/enta) is native to South 
America and was domesticated at least 10,000 years 
ago. In the sixteenth century AD the Portuguese first 
brought cassava to Africa, where it flourished in the 
humid, forested lowlands, 
Among the staple root and cereal crops, cassava 
tolerates drought best, is the most productive in poor 
soils and requires the least labor in cultivation. But the 
labor requirement in processing after harvest is very 
high, equalling the labor put into crop production. 
Because of its low cost and convenience in food 
preparation after processing, cassava will remain the 
biggest single source of calories for the foreseeable 
future, especially forthe poor, Cassava is expected to 
play an ever greater role in feeding the expanding 
cities as African economies develop. 
Tailoring breeds to suit needs. IITA began breeding 
high-yielding varieties in the I 970s, starting out with a 
few local varieties. some Latin American introductions 
and one line resistant to cassava mosaic virus disease 
that had been developed in East Africa, More genetic 
materials forthis research came from African sources 
as well as Latin America. the home of cassava, Over 
the past 20 years IITA cassava specialists, worl<ing in 
multidisciplinary teams with colleagues in national 
programs, have developed high-yielding, pest-resistant 
varieties with good processing and eating qualities. 
In 1987 11TA gave to its sister institute in Latin America, 
Centro Intemacional de Agricultura Tropical (ClAT), its 
best 21 lines. ClAT crossed some of those lines with 
Latin American and Asian lines to improve them with 
othertraits. ln 1990, ClAT retumed over 87,000 hybrid 
seeds to rITA'S collection of cassava germ plasm, or 
genetic material for breeding punposes. Evaluation of 
breeding lines produced from those seeds has since 
begun, 
Cassava, unlike yam and plantain, can be grown in a 
range of environments in the tropical and adjacent 
subtropical zones of Africa (see map on page 2): 
• humid forest and forest-savanna transition (high 
rainfall) 
• coastal areas (high rainfall. sandy soils) 
• moist savanna (moderately humid to semi-arid) 
• mid-altitudes (800-1,500 meters above sea level; 
moderately humid to semi-arid), 
Africa's most widely 
grown staple food, 
cassava is being 
. adapted to suit 
dive",e farming and 
food systems. 
33 
IITA'S goal for cassava has been to adapt the crop to 
conditions in these agroecological zones and to the 
farming and food systems there. Breeding schemes for 
these zones are dedicated to improving resistance to 
pests (partcularly t he cassava green m~e and cassava 
mealybug), increasing the yield, enhancing cookjng 
quality and nutritional value (through more carotene), 
and reducing the potential for cyanide in the flesh, (See 
"M~es meet a hairline defeat" and "Cyanide in cassava" 
insets in these pages.) IITA'S improved cassava is 
resistant to the two major diseases of African cassava, 
mosaic virus and cassava bacterial bl ight 
Five improved lines of cassava germplasm. being 
tested in several zones in Nigeria, were evaluated 
during 1990. The new lines, w~h pest resistance and 
prefenred consumer qualities, showed high and stable 
yields over the three-year t rials. Intemational testing, 
in collaboration with six West African countries, 
entered its second yearof operations, of identifying IITA 
lines suited to the particular agroecological conditions 
in each country. 
Two improved lines produced more than three times 
the harvests of local varieties, in a 1990 survey of 
farmers' fields in five states of eastem N igeria. (See 
accompanying diagram.) Such high yields are due in 
large part to resistance to the major cassava diseases, 
as attested by comparative disease scores. 
Comparative performances of UTA-improved cassava and local variet ies 
in farmers' fields in eastern Niger ia, 1990 
Variety Yield (tons per hectare) 
TMS JOS72 
TMS JOSSS 
Local 
TMS J0572 
TMS J0555 
Local 
34 
o 10 20 30 
,============r 360% I 356% 
Disease score 
o I 2 3 4 5 
----------------------------
African cassava mosaic virus o cassava bacterial blight 
Cyanide in cassava -
Cyanide poisoning from cassava is rare, although 
hundreds of mi ll ions of people depend on cassava as 
a staple food, New findings about cyanide in cassava 
and the detoxification process are helping to explain 
why poisoning is so rare. They also suggest new 
breeding strategies to improve cassava, determined 
by the different ways in which cassava: is prepared for 
eating, 
The cassava plant does not accumulate cyanide in ~ 
t issues, Cyanide in cassava is a breakdown product of 
a reaction w hich takes place in the course of preparing 
the leaves or roots for eating, (See the accompanying 
diagram,) The plant accumulates two compounds 
known as linamarin and lotaustralin, in the proportion 
of I 0 to I , They are synthesized in the leaves and 
stored in the cytoplasm of the plant's cells, in different 
concentrations in different parts of the plant For 
example, the peel or cortex of the cassava root retains 
much more linamacinllotaustralin than does the edible 
portion of the root the p~, 
Cyanide is produced when linamarin and lotaustralin 
are hydrolyzed by the enzyme called linamarase, 
Normally linamarinllotaustralin do not come into 
. contact w~ linamarase in the living plant because 
they reside inside vacuoles w~hin the cell's cytoplasm, 
while linamarase is localized in the cell walls of the 
plant However, when the plant is damaged by bruisin~ 
grating, orb~in~ for example, the integrity of the cells 
is lost and the content of the vacuoles comes into 
contact with the cell wall components, including 
linamarase, The enzyme w ill hydrolyze the two 
compounds, producing acetone cyanohydrin which is, 
ata pH above 5,0, converted to acetone and hydrogen 
cyanide, 
Cassava varieties can be classified as "high-cyanide" or 
" low-cyanide", High-cyanide varieties seem to 
accumulate more linamarin and lotaustralin in the 
edible p~h than in the peel or root bark The oppos~e 
seems to be true w~ low-cyanide varieties, which 
store a greater proportion of the two compounds in 
the pe'e/. In any case, the concentration of linamarinl 
lotaustralin varies considerably w~in each part of 
.every plant 
Fit to eat 
When the roots are grated or "chipped" in the first 
steps of preparing cassava to eat most ofthe linamarin 
and lotaustralin is converted to free cyanide-the 
smaller the chips, the greater the conversion. Being 
volatile, the cyanide will evaporate, especially when 
it's not there, it just happens 
heated, (The boiling point of hydrogen cyanide is 
25.7°e.) The same process occurs when cassava 
leaves ane pounded and then boiled, 
However, fermentation of the grated cassava. an 
intermediate stage befone frying in the pneparation of 
West African gari, itself contributes little to 
detoxification, The diffenence between nesidual cyanide 
contained in non-fermented gari, and gari fermented 
for four days, is not significant 
Detoxification of cassava pnepaned whole or in large 
pieces follows diffenent pathways, 
In the making of the Nigerian lafun or Central African 
kwanga. peeled or unpeeled pieces of cassava ane first 
left to ferment in water for several days, During this 
period almost all of the linamarin and lotaustralin is 
eliminated from the fermenting cassava through 
leaching, or converted by enzyme activity to cyanide, 
which evaporates, Heating of the fermented dish 
removes the remaining cyanide. 
In the pneparation of fnesh cassava roots to be eaten 
without fermentation, such as in Ghanaian ampesi, the 
pieces ane simply boiled for IOta 30 minutes, As soon 
as the temperatune neaches 70°e. the linamarase is 
inactivated, Cyanide thus has no chance to form, In 
boiling, about half of the linamarin and lotaustralin is 
leached into the water, The smallerthe size of cassava 
pieces putto boi l, the gneaterthe leaching oflinamarinl 
lotaustralin, 
Paths to.improvement 
Large diffenences in linamarase activity do exist among 
cassava varieties, Bneeders can take advantage of the 
high-activity trait by bneeding it into new varieties for 
processing, Cassava varieties will theneby acquine this 
capacity to expedite the degradation of linamarinl 
lotaustralin to cyanide and, eventually, its elimination, 
IITA bneeders used to aim at producing "low-cyanide" 
varieties by selecting for low levels of linamarinl 
lotaustralin in the roots, Henceforth, they will in 
addition test varieties forthe pnesence of the enzymes 
nesponsible for synthesizing those two compounds in 
the first place, Low-cyanide varieties in the futune will 
be bnedfora minimal potential for cyanide pnoduction, 
for low linamarin levels and high enzymatic activity to 
bneak down what linamarin thene is, 
Cyanide in cassava - a breakdown product of two chemical compounds stored In cassava plant cells 
Linamarinllotaustralin 
Reaction catalyzed by 
linamarase 
•••• Glucose 
Acetone 
cyanohydrin 
pH > 5 
o 0 0 0 
Acetone 
•••• 
Hydrogen cyanide 
35 

Procedures for culturing mature embryos from 
interspecific crosses are being adapted for the rescue 
of very young embryos which might otherwise be lost. 
Embryos have been generated from young leaf tissues 
of several IITA cassava varieties in a liquid culture 
medium. Tissue culturists are exploring different ways 
to develop plantlets from these somatic embryos. 
Bread without wheat. 'ITA food technologists have 
produced bread w~h a flour mixture of cassava (80%) 
and soybean (20%), together with other materials 
produced in African countries. Low-cost (using cassava 
instead of imported wheat) and nutritious (using 
eggwhite and soybeans), such a bread should answer 
a growing demand. To the flour is added margarine, to 
produce a spongy texture and trap air which prevents 
the bread from collapsing after It has risen. The 
research is funded by the Belgian govemment. 
Research for bread-making also involves breeders, 
who select improved cassava varieties with particular 
flour-making properties, 'fTA'S partners in flour studies 
include Katholieke Universiteit Leuven, Belgium, with 
Belgian govemment support. 
A green vegetable, too. Cassava leaves are also eaten, 
in sauces which supplement the staple dish, providing 
nutrients in the form of protein, vitamins, and minerals. 
In preparing cassava leaves for eating, in a 1990 study, 
the first, traditional step of pounding the leaves was 
confirmed to be crucial in eliminating cyanide. 
Cassava germplasm was screened for linamarase 
activity, which is keytothe cyanide elimination process. 
Large differences in linamarase were found among 
varieties, a useful distinction in breeding of new 
varieties for safe processing of both leaves and roots. 
Plantain 
West and Central Africa produce about 60 percent of 
the world's plantains (Muso species), Because of ~ 
long history of Widespread Muso cultivation, the 
region has been host to the evolution of at least I 16 
different varieties so far identified. 
Plantain frts well into the agroecological conditions of 
the humid forest zone, And as a backyard crop which 
receives kitchen and garden wastes for its fertilizer 
needs, it can provide a year-round source of food. 
Long thought to be disease-free because of an abiding 
resistance to the main banana diseases. plantain has 
proved to be highly susceptible to the fungal disease 
of black sigatoka. About 15 years ago, black sigatoka 
was accidentally introduced into Africa and has spread 
w~h such virulence that ~ appears to threaten all 
existing plantain varieties. None of the I 16 varieties in 
IITA'S germplasm collection has shown resistance to or 
tolerance of the disease. 
'ITA launched the first breeding program for African 
plantain in 1987, w~h the primary aim of producing 
resistance to black sigatoka. The genetic improvement 
work at IITA'S high-rainfall station in Onne, southeastem 
Nigeria, has succeeded beyond all expectations. During 
the three years since breeding commenced, 200 
The loaf on the 
right was made 
with cassava flour, 
eggwhne, and 
margarine (locally 
made in African 
countries), and has 
a light texture wrth 
a fine crumb 
structure. 
The middle loaf 
was made with 
cassava flour and 
xanthan gum. an 
imported additive 
which is less 
successful and 
economically not 
the best solution, 
The lefthond loaf is 
an experimental 
control with no 
odcjjtives. 
Cassava leaves 
are a popular 
vegetable in Zaire. 
37 
Yom is a preferred 
but expensive 
staple, which needs 
improvement 
research in order to 
make it more 
economical to 
grow, handle, and 
process. 
38 
hybrids between plantain and wild banana have been 
established. Among them, 24 hybrids of 8 different 
families show exceptional promise, with a combination 
of good bunch qualities and resistance to blacksigatoka. 
Seven plantain hybrids and a cooking banana hybrid, all 
resistant to sigatoka, began trials in 1990 to assess 
performance, fruit quality and consumer acceptance 
in comparison with those of regular plantain. 
Indefinite preservation of gemnplasm is vital to the 
success of all breeding plans. During 1990 IrrA's plant 
tissue culturists succeeded in doubling the life of 
plantain cultures in test tubes, to one year or more. 
Research at Onne has tumed up five cooking bananas, 
a distinctly different sister group to plantains, which 
showed black sigatoka resistance ortolerance. During 
1990 IrrAproduced 5,000 plants of the resistant cooking 
bananas and distributed them in Nigeria to family 
farmers and to agricultural institutions for further 
multiplication and distribution. This exercise is testing 
whether consumers will accept the taste and cooking 
qualities of these bananas, as an altemativeto plantains. 
Laboratory tests for cooking quality in 1990 showed 
that cooking bananas and plantain hybrids have not yet 
attained the standards of regular plantain which are 
generally preferred. Cooking bananas become very 
soft and sweet on ripening. whereas ripe plantains 
remain relatively firm and half as sweet. Plantain 
hybrids come halfway toward the preferred quality: 
their medium firmness and sweetness provide an 
acceptable fried product, but an unacceptable boiled 
product. 
Yam 
A crop synonymous with a full belly and general well-
being, yam (Dioscoreo species) requires much laborto 
cultivate. Cultivation is expanding northward into the 
forest-savanna transition lone, as land in yam's native 
forests becomes scarcer under increased cropping. 
The promise of significant retums to research, as well 
as the importance of yam in the diet and in the social 
cu lture itself. more than justify IrrA'S continued effort. 
(See "Tomorrow's role foryam ancestors" inset in this 
section.) 
The goals of yam breeding are to: 
Research directions 
Cassava 
• Breeding of cassava genotypes for 
agroecological zones: the humid forests. 
coastal zone, moist savanna, and mid-
attitudes zone. 
Manipulation of ploidy levels and evaluation 
of the resulting genotypes to be continued. 
relationships, and impnoving efficiency in 
selecting for desirable genotypes. 
• Evaluation and improvement of exotic 
breeding materials from specific agro-
ecological conditions in Africa and Latin 
America. 
Cassava, plantain 
Cassava, plantain, yam 
• Resistance levels to several pests to be 
increased. as part of a new integrated pest 
management strategy. 
• Efficiency of breeding methodologies to 
be improved. especially for yams and 
plantains. 
• Cytogenetic and b iotechnological 
techniques to be applied in characterizing 
genotypes. e lucidating phyl ogenetic 
• Invest igation s of the inheritance. 
b iochemist ry andlor physiology of 
agnonomic and qual~ characteristics. and 
stress reactions of the plantto be continued. 
• Basic research to be conducted In 
partnership w~ advanced laboratories on 
somatic embryogenesis. somatic hyb-
ridization. anther and pollen culture. and 
genetic transfonmation and regeneration. 
• Investigation of the reproductive biology 
and the processes of polyploidization. 
• Incnease tuber yields. 
• Make yams look and taste better to consumers and 
keep longer before spoiling. 
• Build up genetic resistance to major diseases and 
nematodes. 
• Improve the tuber's shape in order to make it easier 
to harvest and handle. 
The first steps toward attaining these goals are collecting 
yam genmplasm, characterizing ~ and evaluating the 
results for usefulness. and preserving it for breeding 
nesearch. IITA preserves 1.200 samples of yam genetic 
material in test tubes. and others in the field. 
By 1988 breeders had succeeded in their quest to 
produce high-yielding varieties of "water" yam that 
can resist foliar necrosis. a disease which causes 
premature loss of leaves. Tests of water yam and 
"wMe" yam in four different zones in 1990. with the 
National Root Crops Research Institute (NRCRJ) in 
Nigeria. have shown yields of 30 tons per hectare. 
which is more than half again as large as yields of the 
best local varieties. 
A new aid to yam characterization was confirmed with 
the 1990 results of tissue culture research. Biochemical 
pnofiles of five yam enzymes were clearly defined 
under electrophoresis. 
International collaboration 
Cassava. yam. and plantain genmplasm has been 
exchanged among Latin American. Asian. and African 
(cassava only) countries during more than two decades. 
In Cameroon. Rwanda. and Zaire since the I 970s. 
IITA has trained over 40 sCientists. 1.000 technicians 
and extension agents. and 4,000 farmers' association 
members in Its largest-ever collaborative root crop 
prolects. In Nigeria. NRCRJ and the National Seed 
Service have worked with IITA in developing and 
releasing improved cassava and sweet potato. IITA 
scientists have been working on root crop improvement 
in those countries, as well as in Ghana and in Malawi. 
Intemational collaborative testing of cassava has 
become a regular part of research pnocedure. Apart 
fnom that activ~y. dunng 1990 IrTA distributed over 
75.000 tnue cassava seeds to research programs In 20 
African countries for their evaluation and selection 
under local conditions. Vinus-free plantlets of 39 
cassava lines in test tubes were distributed to I 6 
African countries. In the same way. 7 plantain lines 
were shipped to 8 African countries. Five wh~e yam 
varieties were propagated and sent to 21 African and 
Pacific countries-mari<lng a milestone in yam research. 
Networking scientists. technicians and policymakers 
throughout tropical Africa have promoted root crop 
research through infonmation exchange. study tours. 
and other activities. IITA variously participates in and 
helps coordinate activ~ies of the Eastem and Southem 
African Regional Root Cnops Network (ESARIRJN). the 
Cassava Biotechnology Networik the African Plant 
Biotechnology Network and the Intemational Plant 
Biotechnology Network IITA collaborates with the 
Intemational Networkforthe ImpnovementofBananas 
and Plantains (INIBAP). 
During 1989 IrTA tumed over Its responsibil~ for the 
improvement of sweet potato to a sister instrtute, 
Centno Intemational de la Papa (ClP). 
39 
40 
Tomorrow's role for yam ancestors 
Discovery of the genetic forebears of the two most 
widely grown food yams of West Africa opens the 
way to new research for breeding improved yam 
variet ies. IITA analysis of yam genetic material has shed 
new light on the relationship between today's cultivated 
yams and their wild relatives, and suggests leads for 
improvement work 
Different species of the yam (genus Oioscorea) ori-
ginated independently in three tropical zones of the 
world-three species in West Africa (D. rowndata, D. 
cayenensis. O. dumetorum), two in Southeast Asia (D. 
aloea, D. esculenta). and one in America (D. tJif/da). The 
"yam zone" in West Africa. stretching eastward from 
the Bandama river in central Cote d'ivoire to the 
western flanks of the Cameroon mountains, yields 
about 90% of the world's yam harvests. (This zone 
includes the most densely populated parts of tropical 
Africa.) Nigeria alone is responsible for some 70% of 
global harvests, and probably cradles the center of 
origin of Africa's varieties: in the several valleys along 
the N iger river. Over the many centuries of 
domesticating the yam, the various peoples who 
cu~ivated the crop developed complex social systems 
that gave yam a prominent role. 
Scientists have devoted relatively litte research to 
yams for several reasons. Most varieties rarely flower, 
which limits opportunities forbreed ingby conventional 
methods. The countries which depend on yam cannot 
afford budgets of the scale required for basic research. 
Other staple crops exist such as cassava, which can 
less expensively meet the rising demand for food 
caused by population growth. 
New approaches have created new opportunities for 
breeding research to penetrate such problem areas. 
Analysis of yam DNA and genetic structure can point 
the way to improvement of varieties, in terms of 
improved yields, resistance to pests (diseases, 
nematodes, and insects), and other desirable 
characteristics. 
IiTA scientists have applied the analytical techniques of 
restriction fragment length polymorphism (RFLP) to elu-
cidate the relationship between the two types of yam 
most widely consumed in the African yam zone: the 
"white" yam (D. rowndata) and "yellow" yam (D. 
eayenensis). They analyzed chloroplast DNA and ribo-
somal DNA in 26 plant samples from cultivated varieties 
and wild species. From the similarities evident in the 
genetic structures, they concluded that the white yam 
was most probably domesticated from one of three 
wild species: D. abyssiniea, O. praehensifis, or D. 
liebrechtsiana. The yellow yam was most likely a hybrid 
of the white yam and one species from another set of 
wild relatives: D. burkilliana, D. minud~ora, D. smifacifolia, 
or D. togoensis. 
Since those wild progenitors normally reproduce 
themselves sexually, breeders are hopeful that the 
"shy flowering" habit of cultivated yam can be overcome 
through use of genetic material from them. Other 
desirable genetic traits may likewise be introduced 
into the domesticated species, through both 
conventional and biotechnological methods of gene 
transfer. 
Because wild species hold new value for improvement 
work. their conservation becomes an evermore 
important objective for agricu~ural scientists. IITA began, 
during 1990, to add wild yam species to its collection 
of cu~ivated yam genetic materials. The task is all the 
more urgent because the habitat of most wild yams 
lies within the lowland forests, which are rapidly being 
cutdown for farming by an expanding rural population. 
Grain legume improvement __ _ 
Protein-rich grain legumes (pulse crops)- mainly cowpea. peanut. bambara groundnut. field beans. and. in recent years, soybean-are important in 
many parts of Africa where diets are otherwise scanty 
in protein and other essential nutrients. Because they 
can produce their own nitrogen requirements from 
the air and can leave a substantial deposit in their 
stems and leaves as fertilizer for the next crop. these 
legumes are key components of sustainable agriculture 
in the savannas of Africa. 
lITA'S grain legume improvement program conducts 
research to improve cowpea and soybean crops and 
their utilization by small-scale farmers in the range of 
agroecological zones from the humid forest to the dry 
savanna (see map on page 2). 
Cowpea 
Cowpea (Vigna unguiculaw) in Africa is traditionally 
grown as a subsistence crop. It is drought-tolerant and 
thrives in poor soils. 
In the mixed farming systems of the arid Sahelian 
regions, cowpea is the main legume and a major 
source of human food and livestock fodder. It is a 
secondary crop in the moist savanna or semi-arid 
zones. grown together with other food or fiber crops: 
millet, sorghum. maize, cassava, and cotton. 
In food preparation. cowpea is utilized as dry seed. 
green seed. green pods. and green (young and tender) 
leaves. Livestock. particularly cattle. eat the haulms 
(dried stems and leaves. gathered after the seeds are 
harvested). 
Cultivation of the crop has become more attractive 
with the results of research by national programs of 
African countries and IITA. Cowpea varieties with 
improved yields. early maturity. and resistance to 
some diseases and insect pests are being grown over 
larger areas and in more different zones than before. 
from arid to humid. leTA has the global responsibility 
among intemational institutes to conduct research on 
cowpea. 
Reducing risks. The aim of cowpea research at IITA is 
to reduce the risks in cultivation forthe farmer, whose 
productivity and income will thereby increase. 
IITA scientists look at cowpea as part of a cropping 
system with its particular requirements for adaptation 
to various stresses and for resistance to insect and 
disease pests. From 1988. the main breeding objectives 
have been: 
• Adaptation in form. structure. and organic functoning. 
for suitability in intercropprng with cereals. 
• Improved drought and heat tolerance. especially for 
the millet cropping system of the semi-arid zones. 
• Multiple pest and disease resistance to be bred into 
varieties adapted to local growing conditions. 
Because conventional breeding and sources of genes 
from cowpea collections have not been successful 
against insect pests in some cases, the program is 
placing greater reliance on genetic improvement 
through crossbreeding with wild species-or "wide 
crosses". Wide crosses with a wild cowpea (V. 
dekinddana) for resistance to pod-boring and pod-
sucking bugs have been advanced to the sixth 
generation. Some of the resu~s looked promising in 
1990 field evaluations. 
Akoro, a fried coke 
of cowpea rour, is 
a popular street 
food in Nigeria. 
41 

Research directions 
• Investigation of the biology of the parasitic 
weed striga. leading to implementation of 
a striga control project. under a cross-
program team. The strigd population to be 
neduced and nesistance to be bned into 
cowpea as well as maize varieties. 
Cowpea 
• Improvementoflocal cowpea genotypes 
to continue, incorporating a stable 
nesistance to diseases and insect pests; for 
mixed cropping with cereals (millet. 
sorghum. and maize) in the savanna. 
• Improvement in cowpea grain types 
wrth a wide range of maturity periods to 
continue: to meet diverse needs in different 
agroecological zones. 
• Technical support for national programs 
and networks of cowpea scientists in 
western, central, and southem Africa: 
emphasizing technologies forincorporating 
resistance to diseases and insect pests into 
local varieties. Priority given to collaboration 
Cowpea viruses predominant in selected 
African locations 
In relalJon wrth agroecologlcal zones, by 
length of ramfed growing season (In days) 
o Cowpea aphld-bome mosaiC VIrUS 
• Cowpea yellow mosaic ViruS 
" Cowpea mottle mosaiC ViruS 
• Southern bean mosaJC VJrl)S 
wrth the Semi-Arid Food Grains Reseanch 
and Development (SAFGRAO) cowpea net-
worl<.and support forthe South em African 
Development Coordination Confenence 
(SAOCC) cowpea project 
Soybean 
• Breedingto combine resistance to insect 
pests and early maturity (to provide an 
80-130 day range of maturities) with other 
desirable traits. for diffenent zones. 
• Identification of sources of resistance to 
frogeye leaf spot disease. and of the diffenent 
strains of the causal organism. Mode of 
inheritance of nesistanceto be detenmined. 
• Maintenance bneeding to netain the traits 
of stable and high yield. good nodulation 
with bacteria in the soil. nesistance to t he 
main diseases, nine-month storage 
capability of seeds. nesistance to buckling 
under the weight of high pod yields. and 
resistance of pods to shattering and 
dispersing seeds befone harvest. 
• Development of ways and means of 
combining soybean wrth traditional food 
pneparations. for domestic and small-scale 
industrial use. to continue in Nigeria and 
Ghana with national programs. supported 
by the Intemational Development Reseanch 
Centne (IDRC) and the Japan Intemational 
Cooperation Agency OICA). Simple. low-
cost processes also to be developed for 
soybean products simulating meat. fish. 
and cheese. 
• Joint neseanch on intencropping sorghum 
and soybean. and on crop rotation systems 
with soybean. to continue wrth the Institute 
for Agricultural Research (IAR). Zaria. 
Nigeria. and the International Crop 
Reseanch Institute forthe Semi-Arid Tropics 
(ICRJSAT). with field testing in the Nigerian 
dry savanna. 
• Investigation of soybean production. 
utilization. and marketing by Nigerian 
fanmers and small-scale industries. 
43 
44 
With advanced laboratories in Italy (Univer.;ity of 
Naples and the Genmplasm Institute. at Bari) and the 
USA (Purdue Univer.;ity). UTA in 1987 began bio-
technology research for resistance to postfowering 
Insect pests and to the cowpea bnuchid. a storage 
weevIl. The Italian govemment has supported this 
basiC research. UTA has contracted the biotechnology 
research w~h Purdue Univer.;ity as a joint project. 
GenetJc mapping has started at the Univer.;ity of 
Minnesota. Purdue Univer.;ity. and IITA. using the 
restnction fragment length polymorphism (RfLP) meth-
od. To date. 69 linkages of the genetic code have been 
marked on cowpea DNA Botanical classification of Vigna 
species also continues on an RFLP basis. When the map 
is completed. the research team will identify which 
marker.; pertain to which particular tra~s-primarily 
the desired genes for resistance to insect pests and 
diseases. 
The results will prepare the way for prodUCing new 
hybnds- and make the crop less risky and more 
profrtable to fanmer.; in the tropiCS. 
Soybean 
UTA has always attached great importance to 
improvement of soybean (Glycine max) for the trop-
ics. and more recently to research on soybean 
processing and rts utilization in human diets. (See 
Research Highlights article "Making a home for the 
soybean in Africa".) 
In setting research aims. IrTA grain legume scientists 
have given priority to: 
• Resistance to the main diseases and insect pests. 
• Matunty periods which accord w~h climate and 
cultivation patterns in each agroecological zone where 
soybean is grown. 
• Processing technologies su~ble for home and small-
scale Industnal use. 
If people know what foods soybean can be used in and 
how to make them. this nutritious legume (40% 
protein and 20% oil) will generate a strong demand in 
the marketplace. Fanmer.; will need to produce greater 
amounts of soybean for the benefit of all. 
The best agroecological environments for soybean 
production are similartothose for maize and sorghum: 
the moist savanna and "mid-altitude" zones in the 
savanna in particular. 
In 1990. several lines were identified w~ a high level 
of resistance to the fungal disease of frogeye leaf spot 
and to bacterial pustules. both of which are spreading 
and becoming economically damaging in most soybean· 
growing areas. Over half the potential yield of one 
susceptible local variety was lost to frogeye leaf spot 
in trials, while the improved resistant variety maintained 
its high yields under heavy disease pressure. 
Dietary need. The importance of improving the 
protein content of African diets has been the guiding 
principle of work on soybean utilization. IITA scientists 
have aimed to improve technology for household and 
small-scale uses. as well as the food products made 
w~h such technology. 
Soy flour has been used to improve the protein 
content of low-protein trad~ional foods without 
increasing the cost or the cooking time. and without 
changing the appearance or taste of the dishes. In 
many parts of N igeria. soy flour IS becoming very 
popular in home cooking. 
Research on medium-scale industrial processing has 
led four companies in Ghana and N igeria to collaborate 
w~h IrTA in designing and building screw presses for 
soybean oil extraction. By 1990. three companies in 
Nigeria were using such 10caJly made 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 IrTA and collaborating partners over the past 20 
years. Soybean is nelatively 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. 
M aize is an attractive crop for small- and large-scale farmer; alike. It takes relatively little laborto grow, yet retums high yields, especially if fertilizer; are 
used. In the Nigerian moist savanna zone. maize (Zea 
mays) is enjoyinga "boom" as a cash crop, and is taking 
over much of the southem range of the millet and 
sorghum belt. (See Research Highlights article "A new 
maize modernizes savanna farming".) 
lIT A'S maize research program aims to develop varieties 
that will reduce the risks of intensified production for 
fanners. Maize scientists can do so through: 
• Improving their understanding ofthe main pests and 
environmental stresses, through "pathosystem" 
research . 
• Breeding resistance to those pests and stresses into 
high-yielding plant types w~h good grain qual~ and 
the right mix of growing characteristics. 
Nat ional program scientists in the region collaborate 
closely with lerA scientists in all aspects of this research. 
New technologies from these joint efforts will thus be 
acceptable to target user groups. 
Durable prize-winner 
UTA'S development of resistance to maize streak virus, 
which won the King Baudouin award for intemational 
agricultural research in 1986, is a well-known example 
of the "pathosystem" approach. In a I O-year team 
effort, entomologists and virologists studied the life 
cycle and ecology of the vinus and ~ vector, the 
leafhopper Cicadufina, to provide breeder; w~h the 
tools to devise novel screening techniques and a 
breeding strategy which identified a highly stable kind 
of resistance. The success of this effort lies in the 
durability of the resistance, which was based on a 
combination of many genes. 
New strains of maize streak virus could evolve from 
viruses in native grasses surrounding maize fields, and 
overwhelm the IrfA resistance. Against that possibility, 
wild grasses showing symptoms of the virus were 
collected during 1990 in Nigeria. N one of the vinuses 
isolated from those specimens was as vinulent as the 
maize isolate itself. and none was able to overcome 
the resistance In the maize. Moreover, samples of 
maize streak virus collected from western, eastern, 
and southem Africa have shown a remarkable genetic 
Maize research 
similarity, which indicates that the IITA resistance can 
be expected to remain durable. 
Collaborating programs in other African countries are 
beginningto use the research technologies in orderto 
adapt the results to their own settings. Zaire joined 
Togo in 1990 as one of the first countries to succeed 
Maize harvests are 
increasing in 
western Africa's 
moist savanna-
here. in Burkina 
Faso. 
45 
46 
Please save the savanna from that witch 
Taw ny maize fields ripple in the w ind at harvesttime. 
across the moist savanna of northem N igeria. Twenty 
years of maize breeding for Africa have yielded varieties 
well·adapted to th is region. and fanmers have found 
that they can tap new markets with their expanding 
harvests. This scene is ripe for devastation by the 
"witchweed" striga. against w hich maize has little na· 
tural defense. But Irr A breeders have already delivered 
varieties with moderate resistance to the weed, and, 
teamed with other scientists, seem well on their way 
to developing effective striga control for the savanna. 
Striga parasitizes the region's main cereals (sorghum. 
millet, maize. upland rice) as well as grain legumes 
(cowpea. soybean. groundnut). The whole crop can 
be lost in a severely infested field. forcing the fanmer 
t o abandon it 
The threatto maize is greatest of all. Most of the other 
crops which striga preys on evolved in Africa together 
with the parasite. and thus developed a measure of 
genetic resistance long ago. Maize came to the African 
savanna only 30years ago. and has little native resistance. 
W hatever protection science can give it must come 
from extemal sources. 
Although it is a plant striga resemblesa fungal pathogen 
in many ways. It produces hundreds of thousands of 
in using UTA-style screening for maize streak virus with 
minimal facilities.IITAalso assisted Cameroon and Ghana 
in developing their screening capability. 
"W itchweed". The parasitic weed Strigo hennonthico 
threatens the new successes of maize in the Nigerian 
savanna. the zone holding highest potential for large· 
scale maize production. and is a growing threat in 
Zaire. Research and breeding for resistance ortolerance 
to striga. on the pathosystem model, have high priority 
in IITA'S maize work. (See "Please save the savanna 
from that witch" inset above.) 
Downy. The pathogen cunrently ravaging forest·zone 
maize is downy mildew. a fungus. Plants infected early 
suffer a 100% loss in yield, since ears cannot form. The 
disease has become epidemic in southern Nigeria-
by 1990. it had struck in several states. In central Zaire. 
downy mildew is likewise becoming epidemic. 
t iny seeds. each weighing only 5 micrograms. in just 
one square meter of an infested field. The seeds 
remain donmant until chemically triggered by the host 
plant to genminate. The striga root attaches itself t o 
the roots of the host plant w ith a haustorium. a foot· 
like appendage similar to fungal attachments. The 
"witchweed" can then flourish at the expense of its 
host. which it slowly poisons. 
Research in advanced countries has found several 
means of controllingstriga. such as nitrogen applications 
at a high rate. hemicides. managed fallows. and 
fumigation of the soil to induce a suicidal germination. 
These means are too costly for African farmers. so in 
1982 IrrA launched a search for cont rol t eChnologies 
w hich suit the region. 
UT A breeders have screened thousands of maize lines 
from al l over the world for genetic material resistant 
to or tolerant of the most w idespread species in 
Nigeria. Strigo hennonthico. Selection for tolerance or 
resistance has succeeded-moderate levels are already 
available in hybrid and open·pollinated varieties of 
different grain types and maturity periods. well·adapted 
to savanna growing conditions. 
But these resistant or tolerant variet ies sti ll 
accommodate some striga in their midst, so striga 
Excellent genetic resistance is available, however, 
developed jo intly by IITA and N igeria's Institute of 
Agricultural Research and Training ( IAR& T) . and breed· 
ers continue to work on improvements in varieties for 
the forest zone. In t rials of large (half·hectare) plots. 
yields of the resistant varieties are not reduced. while 
susceptible varieties- which are widely grown- are 
severely affected. IrrA helped IAR&T hold a worl<shop 
during 1990 to infonm local authorit ies about the 
epidemic and how to combat it with resistant varieties. 
Fungi are notorious for their ability to evolve new 
strains that can overcome existing types of genetic 
resistance. Understanding of a fungus's potential for 
mutation or variability of strain can help in preventing 
a breakdown of the resistance. In 1990 IrrA began a 
worldwide study with the University of Cali fomia at 
Davis on strain variability of downy mildew. on maize 
and sorghum. 
seed continues to build up in the soil. a risk to future 
crops. Hence. a new phase had to open in the quest 
for protection. to include a multi-sided attack on the 
striga plant. Breeders were joined by other scientists: 
agronomists. pathologists. economists. bio logists. 
computer modellers- to onchestrate a set of plant 
characteristics for maize, farming practice s, and 
biological control actv~ies. reinfonced by improvements 
in scientific knowledge and reseanch techniques. w hich 
together will contro l the striga threat 
In the first year of shared effort. 1990. the earl ier 
breeding advances were complemented with new 
reseanch on farming practices which promote or dis-
courage the pest and w~h models of striga populat ion 
dynamics and of the su~bi l~ of control technologies. 
Resistance breeding continues togetherw~h reseanch 
in the other striga disciplines. Priorities for reseanch 
activ~ are listed below. 
Research priorities 
• Expand the work t o include other important striga 
species. particularly S. asiatica and S. aspera. 
• Increase the number and divers~ of field sites by 
developing more collaborative links w~h affected 
countries. 
Grain drain. Stored maize suffers huge losses from 
insect pests. particularly in the forest zone. W ith the 
help of a visit ing scient ist from the Republic of Benin. 
D. K. Kossou. studies of Sitophilus grain weevils found 
that maize stored on the cob- the t radit ional 
method-suffers less damage from weevi ls than shelled 
maize. The longer husk leaves of trad~ional varieties 
hug the cob more t ightly than do the shorter. looser 
husks of modem varieties. thus affording the stored 
ear better prot ection from pests. Accordingly. breeding 
strategy in 1990 included selection for longer husks. 
and characteristics that contribute to weevil resistance 
in the grain ~el f. 
In the past decade another storage pest of maize. the 
larger grain borer (Prostephanus truncatus). entered 
West Africa from Central A merica. It has become a 
serious problem in Togo. and has spread t o neighboring 
Ghana and Benin. Two UTA programs, on maize 
improvement and on biological control, are working 
• Increase the level of tolerance/resistance to striga, 
and broaden ~ genetic base by screening land races 
and wild relatives of maize. 
• Improve our understanding of resi stance 
mechanisms, and devise screening techniques for 
them. 
• Continue on-farm diagnostic studies to leam how 
farmers ane cumently coping w M striga. and how striga 
is adapting to the recent changes in cropping pattems 
in the savanna. That w ill yield more clues for control 
methods. 
• Study the mechanisms by which n~rogen appears to 
inhiM striga. and find ways to increase the efficiency of 
control using small. economic doses of nitrogen 
fertilizer. 
• IdentifY more "trap plant" species that cause suicidal 
germination of striga and are economically viable for 
savanna farmers. 
• Gain a better understanding of the basic bio logy. life 
cycle. and epidemiology of striga, to reveal novel 
opportun~i es for its control. 
• Assess the potential of biological control strategies 
against striga, uti lizing insects and nematodes . 
• Explore the opportunities for using biotechnology 
t o (a) transfer resistance genes from indigenous grasses 
into maize. and (b) measure strain variability in striga 
populations atthe molecular level. to assess ~ chances 
of ovencoming resistance through genetic change. 
with national and international institutes in Togo, 
Benin. and N igeria to find ways to head off t he threat. 
Organisms possibly useful in biological control are 
being hunted in South America. where the pest 
originated. 
Bio logical and ecological studies of other pests- stem 
borers and ear borers- and their natural enemies 
continued during 1990. Resistance to stem borers 
poses one ofthe most difficult challenges to breeders. 
Breeding for forest-zone maize included resistance to 
these pests, with several maize populations showing 
modest progress in selection. To date. only moderate 
levels of resistance are within reach: hence, IITA breeders 
are exploring the possibilities for biotechnological 
means to obtain a novel type of resistance. 
D ieting. Low nitrogen levels in the soil and the high 
cost of nit rogen fertilizers persuaded "TA in 1988 to try 
breeding varieties which require less nitrogen to grow. 
47 
Green or new 
maize provides 
food to be eaten 
fresh, not stored, 
during the "hungry 
season" before 
other crops are 
mature enough to 
be harvested. 
48 
Yields of tnallines under high and low applications of 
fertilizer ane being companed, and measunements 
which neflect the plant's efficiency in using soil nitrogen 
ane being analyzed. 
Good eating? Eating quality has not been a big issue in 
developed countres, where maize is fed to livestock 
or used as an industrial material. It is a key issue for 
research in Africa, however, where maize is a main 
dish In people's daily diet 
IITA started to characterize maize varieties in 1990 for 
their grain traits---.,;uch as oil content ease in milling, 
types of starch. The first year's wonk neveals that maize 
contains enough genetic variation to enable bneeders 
to produce diffenent combinations of grain quality 
charactenstics. Oil content appears to be high in most 
vanetles, so they would be prone to deteriorate in 
storage, Bneedlng can overcome such a defect 
In bneeding work. conversion of the grain type of some 
improved varieties to a softer kemel continued, utilizmg 
the "floury" gene from traditional, unimproved types 
of maize. A soft grain is preferred in many areas for Its 
ease in milling and high flour yield. Started in 1987, this 
project benefited from the wonk of Ghanaian visiting 
scientist Baffour Badu-Apraku, who neported in 1990 
on his genetic findings from his year-long stint. 
Uses. The nesults of pathosystem nesearch find their 
practical use in the hands ofthe bneeder, who utilizes 
them In developing new varieties with the deSined 
characteristics. The bneeder wonks with two types of 
maize: open-pollinated varieties, which fanmers can 
propagate on thelrfanms each year. and hybrid varieties, 
which yield better but which cannot produce their 
own seed for the next year's crop. The two com-
plement each other in bneeding strategies, From 
open-pollinated populations come lines with genes 
for specific traits. Desirable genes can be "fixed" in 
these lines into unchanging form, a genetic resource In 
developing new hybrids or open-pollinated varieties. 
Research directions 
o Improvement in understanding of the 
biology and control of striga, through a 
cross-program project with a twofold 
approach: to neduce the striga population 
and improve host plant nesistance, 
o Stnengthening of national programs and 
regional maize networks, emphasizing 
Outreach projects 
transfer of technologies for screening for 
resistance to maize streak virus and striga 
o Improvement in understanding of small-
scale farming systems, through close 
collaboration between lITA'S maize 
program and savanna systems group, 
o Development of maize varieties adapted 
available where the demand is, 
to negional growing conditions, emphasizmg 
high yields with stable neSistance to foliar 
and ear diseases and maize streak ViruS, 
nesistance to stem boners and storage 
insects, improved grain types and a range 
of maturity periods, to meet the needs of 
the lowland and mid-altitude tropics, 
An maize scientist is linking colleagues in Sahel ian 
countnes In a regional network sponsored by the 
Semi-Arid Food Grains Research and Development 
(SAFGRAD) project, Institutions in the dlffenent countres 
serve as "lead centers" for particular research tOPICS, 
and share their findings with the rest of the network. 
In 1990 IITA'S SAfGRAD maize coordinator assembled 
trals of early-matunng, drought-tolerant vanetles and 
dlstnbuted them among 16 countnes in West and 
Central Arnca. He also organized various study tours, 
exchange VISits. and training programs for SCientists 
and technicians. 
In Nigena, IITA,has helped establish two successful seed 
companies and, In 1990, was requested to support a 
national project to strengthen seed mul\Jplication and 
distribution, by supplying breeder's seed of downy 
mildew-resistant vanetles and assisting With training In 
seed production, 
In Cameroon. an UTA maize breeder has worked with 
the National Cereals Research and Extension (NCRE) 
project for seven years, helping to train counterpart 
SCientists as they developed high-yielding varieties for 
the mid-altitudes lone, where most Cameroonian 
maize is grown. IITA assistance has helped NCRf to 
succeed In developing maize genetic materials to the 
final testing stages, 
In Zaire, the national program has recommended an 
IITA Improved variety, "Babungo 3", to neplace an 
earlier variety susceptible to maize streak virus, for the 
vast southem Shaba mld-aMudes, In the last year of 
collaboration With the bilateral aid project, Recherche 
agronomlque appliquee et vulgarisation (RAV), an IfTA 
breeder and entomologist completed their work In 
developing high-yielding varieties resistant to maize 
streak ViruS, using IITA materials. The shared efforts 
have helped to stabilIZe yields especially in late plant ings, 
which are customary for poor smallholders with little 
labor at their dISposal. Babungo 3's streak resistance 
pays offin late plantings because the dISease builds up 
as the season progresses. 
Reaching the farm, IITA provides bneeder's seed, 
training, and technical advice to seed producers 
nominated by govemments, as a way to help push 
new vanetles out the end of the research pipeline 
toward farmers' fields, Seed companies help to extend 
the impact of the research by making the newvarieties 
Rice with maize is 
a successfuJ 
combination for 
some farmers in 
northern Nigeria. 
49 
Rice research ________ _ 
During its last year of existence, the IITA rice research program concentrated on con serving the advanced germplasm, or genetic materials, it has developed 
overthe past 20 years, and on duplicatingthe collection 
Rice research head 
at NCRI. £. /ma/ehin. 
swdies the African 
rice gall midge 
problem in an IITA-
designed 
screenhouse at 
Badeggi, 
50 
for transfer to the West Africa Rice Development 
Association (WARDA) at Bouake, Cote d'ivoire, Some 
breeding work during 1990 maintained the momentum 
of improvement research during this transfer period. 
WARDA is placing a breeder of irrigated rice at IITA, in 
order to take advantage of the field and laboratory 
facil~ies and keep in close contact w~h Nigeria, 
WARDA'S biggest rice producer, The breeder will also 
help in linking leTA'S inland-valley research group with 
WARDA'S program. 
Breeding, For inland valleys, 24 promising new 
advanced breeding lines were identified during 1990, 
which have high-yield potential, good eating qual~, 
resistance to the fungal diseases of blast and hull 
discoloration, and, in some, resistance to iron toxicity. 
For upland areas, five new lines were selected. For 
irrigated areas, six new lines were selected. One 
inrigated line shows moderate resistance to rice yellow 
mottle vinus disease, Enough of ~s seed has been 
produced for interested countries to test on their 
own. New germplasm sources of resistance to the 
virus have become available from Kenya. 
Many national programs were drawn closer into the 
breeding process as second-generation rice hybrids 
were distributed to them for testing and selecton 
under local conditions intheirown environments. The 
Rwandan and Cameroonian programs received 
products ofllTAgenetic crosses with global sources for 
cold tolerance. for adaptation to their mid-aMude 
zones, Similarly. populations of advanced breeding 
lines for resistance to iron toxicity were sent to Cote 
d·lvoire. Ghana, Guinea. Liberia, Nigeria. and Sierra 
Leone after review and selection of the seed by their 
own breeders. 
Gall midge. The African rice gall midge was first 
recorded in Nigeria 3S years ago. but did not become 
a major pest until 1988 when it devastated 50,000 
hectares of rice fields in eastern Nigeria, Together. leTA 
and the National Cereals Research Institute (NCRJ) at 
Badeggi, IITA'S chief local collaborator in rice, mounted 
a campaign against the pest from 1989 onward, 
leTA has spearheaded research on the ecology of the 
pest and ~ natural enemies. and begun developing a 
strategy for managing the threat. NCRJ leads the dev-
elopment of rice varieties nesistant to the pest's attack. 
State agricu~ural development projects provide land 
and manpower for expenments, A total of I I local. 
state, federal. and international agencies, as well as 
individual farmers. have linked up w~ networkactiv~, 
sharing information and conducting joint surveys, 
training. and public awareness drives, In 1990. the first 
"monitoring tour" for all Nigerian collaborators was 
held at Ikot Obong. the most badly attacked area that 
year. in the eastern state of Akwa Ibom, 
Networking. UTA continued to support rice improve-
ment work for the region by providing reseanch 
facilities to the International Network for Genetic 
Evaluation of Rice (INGER-Africa). which is based at the 
International Rice Reseanch I n~ute (lRAl), During 1990. 
27 African countries received seeds of upland. lowland, 
inrigated, and mangrove swamp types of rice, INGER w ill 
analyze the results of their trials, for their use in 
breeding work. 
B 'Iclogical cortrol at IlIA began 'In 1979 as an urgent expenmeltto combat the cassava mealybug and the cassava green mite, t\\'o ul'Nelccme 
Immlgra1ts from South Amenca. Uncontrolled, the 
two pests were spreading rapidly n Africa's cassava 
belt-an area larger than the Unrted States of 
America-threaten ng )lie d losses as ligh as 80 percent 
to the sJb-Saharan region's '!lost 'mpo'tant crop, a 
staJle food of some 300 mi lion people, The 
con'vent1cnal, chemical respo'lse-frequelt dousings 
vvith potentinsedc;des-woLld h3ve Jeen ecologlcal'y 
brutal, socially' ulacceptable, expensive, a:-Id most 
probably unworkable. 
A Jiological altemative, erlisting nature's own agelts 
and mechanisMs to <eep pest popJla:lons in tolerable 
ba ance, appea ed to liT A as the "nght" sdutior. On 
their rome ground in South America, 'IlealyJug and 
mite populations are naturally ccntrol"ed by SJch 
an:agonists as parasitic wasps ald lady beetles. 
A decade of A.frica-wide research end campaign 
action was crowned In 1990 with tite King Baudouin 
award for intemational agricultural research, shared 
vvith liT A's sister institute Centro Intemacicnal de 
Agricu tura iroplcal (ClAT). Meanwhi,e, the IITAbiological 
control program has come to playa key role n IITA 
research strategy. The appllcatior of biological cortrol 
strategy to other crop/pest problems must rest on a 
fJll understanding of the ecology and Ife cycle of che 
various pests and their antagonists. In 1990, computer 
programs at IITA simulc..ted the wor<.ings of such eco-
systems, and inclL..ded a!1 living and environ'llental 
componems that the crop and pest interact with. Field 
and laborato,)' researCl are adding to th s new holistic 
understandilg of ecosystems, which Will form the 
basis for sustainable systems of plant protection beilg 
designed. (See "Plalt protection" nset in this article, 
overleaf.) 
Making a meal of mealybug larvae 
The mealibug (,Dhenococcus rTianlhcti) is pr-esent at 
low levels in its native ecosystem. Arduous field 
resea"""Ch in South America hac identif ed that pest's 
prim2J-:( natural antagonist: Epidii""iOcarsis Icpezi. a 
paras,tic waSQ, which lays Its eggs in mealybug larJae. 
Tre wasp's larv2e consume t'le'lr mealybug hosts as 
tley develop. The successful esteblisflment of this 
Biological control 
wasp 'In Afr'lca prom'lsed prompt, self-perpetuating, 
end self-regul2.ting meal/bug control. 
The biological strategy 'was also attractive because 0""" 
its simplicity. Success in distribut ng E. ,lopez,: req ... lred 
no effort from networks of extens'lon agents, norfrom 
individJal ..carmel:;. IITA entomolog sts brec many 
thousands of wasps, 'Nhlch wer-e bro2.dcast from 
airplanes or released on the ground with gove'T1mental 
collaboration in the affected countries. 
3iobgical control of the cassava mealybug worked 
..crom the start: the introdL..ced wasps, multiplied at 111."-, 
and released in cassava-growing regions. readil)" 
es-.:ablished themselves in the African ervironment 
and promptly set about iCduCl1gmealybcgdepredatlon 
by half or be:ter, to virtual y subecol0mlc levels in 
many areas. By 1990, natJral enemies of the meal/bug 
had beeo released at aboJt 160 sites ie 20 tropical 
Afican countries. The parasitiC wasp E. iopez; las 
made tself at home over 1T'0rethal 2.7 Iiillion square 
kilometers in the 25 coultries of the continert's 
casscva be t. 
Over tne pc..~ few years control efforts have eimed 
increaSingly at easte'1l and sout~em A..cr-ica, the last 
areas of the Iiealybug's invasion. During 1990, national 
programs in eight cOJntries conducted mealy:Jug 
surveys, re eases of natural enemies, and follow-up 
cctivity with ITA guicance anc support. Good control 
with E. lopezi is reported from most treated are2.s. 11 
four countr es of West and Central Afrca, national 
programs made follow-up assessments wi"'.:r, 1'-."-, 
assistance in 1990. Biological cortrol sciertists sta'iec 
to Investigate a few of the mealybJg predators which 
have est2blished tremselves in only some of the 
ecologies in which cassava grows. 
Stalking the spider mite 
The spider mite lv1ononyche.llus tonajea, or C2ssava 
green mite, IS the mos"'.: importaflt pest of cassava after 
tle mealybug, and likew'lse came to Afr"lca from the 
American tropics. Exploration for natural enemies in 
ts home ground dUring the 1980s tumed up more 
than 50 Mite predators a~ld Ole pathogenic fungus as 
pocential ageets of biological control-of which 10 
precaceoJs rr'lte species were brought to Afr'lca for 
expe1mental release. 
5f 
52 
Plant protection -
sustaining protector as well as plant 
All living organisms. plants. and animals on earth are 
related by their interactions: whatthey take from each 
other and the environment. and what happens as a 
consequence of taking. The different demands of 
each one have implications for the activity of all the 
others within its sphere of interaction. 
A plant's interactions as part of a cropping system are 
depicted in the accompanying diagram. Farmers are 
part of those interactions as they exploit the plant 
world in order to harvest crops. If scientists want to 
help farmers to increase their harvests, the first step 
should be to understand all the related elements in 
the cropping system being manipulated. On the basis 
of this understanding. scientists can devise efficient 
ways to increase the "take" and to sustain that 
improved harvest for the Mure. 
We human beings need to know how to sustain our 
improvements for the indefinite future. if we want to 
keep things within our control ecologically and to stay 
on top within the system. 
Pest/plant interactions 
In solving a pest problem. the importance of an 
understanding of the whole picture of plant/pest 
interactions becomes apparent. Both pest and its 
natural enemies interact with a plant in different ways. 
which vary according to the plant's growing habit. its 
stage of development. and its environment and climatic 
conditions. 
The plant's ability to withstand pest attacks and 
compensate for damage depends on many aspects 
which govem its growth--among them. length of its 
growing cycle (particularly of the plant parts t hat are 
damaged). the number and kind of diseases and/or 
insect pests attacking it. any form of resistance 
mechanism it may have. type of growing habit (whether 
annual or perennial. early- or late-branching. or leafy! 
non-leafy). its age. vigor. and the actual soil and other 
environmental conditions which prevail. 
The way the pest feeds is very significant for the plant 
in compensating for damage and recovering. The 
cassava mealybug, for example. taps the plant's sap. 
After seven years of campaign effort two of the mites. 
Neoseiu/us idaeus and Typhlodromalus limonicus, both 
from northeastem Brazil, have become established in 
Benin. West Africa. and have already brought down 
which can be highly detrimental over a long period 
because it reduces plant growth. The damage caused 
by the variegated and the elegant grasshoppers. on the 
other hand. which feed directly on the leaves and bark 
over a short season, might be more easily overcome, 
depending on the length of exposure to the pest and 
growing habit ofthe plant (whether profusely branching 
and leafy or not). 
Indeed. the growing habit of the cassava plant is crucial 
to its response to attack and recovery. If plant growth 
is affected by a leaf-feeding enemy (the grasshopper, 
or the cassava green mite) or a sap-sucker (cassava 
mealybug). the plant will respond by producing new 
leaves on lateral shoots. How fast this response comes. 
and how many shoots the plant produces, depend on 
its growing habit 
Growing habit: key factor. Generally. among cassava 
species, two different types of growing habit can be 
distinguished: a late-branching type and a profusely 
branching type. 
The first type. whose branches form late. tends to 
produce the right amount of leaves it needs for the 
roots it is developing underground. The second. early-
branching type tends to put out far more leaves than 
it needs for producing its potent ial volume of root 
flesh. This latter type can. therefore, afford to lose 
more of its leaves to pests or drought. for example. 
without sacrificing its root growth. than the first type 
can. 
As growing conditions improve. the late-branching 
type does not produce more branches or leaves; 
instead. its energies go to developing the root. The 
early-branching type. however. does produce more 
branches and leaves with improvement in growing 
conditions. So. in the absence of pests and diseases in 
a favorable environment. the late-brancher is the 
superior yielder. But in that same setting the early-
, brancher produces proportionately more organic 
matter. in the form of stems and leaves. which can be 
left in the fields afterthe harvest and help in maintaining 
soil fertility. 
the numbers of cassava green mite. Duringwetseasons 
when their target species becomes scarce. both find 
alternative food: N. idaeus another mite species, and T 
limonicus a plant product exuded by cassava leaves, 
Consequences 
When cassava plants grow poorly, mealybugs do not 
grow big. In t um, the parasitic wasp E.lopezi, which UTA 
has released in an Africa-wide program to control 
mealybug populations, spawns males inside its host 
mealybug larvae, if the hosts are small. (It spawns 
females if the hosts are large enough to support the 
usually greater demands of female development) 
Naturally, the fewer females that are produced, the 
smaller is the population of parasites and the better 
the mealybug fares. 
Thus, poor plants show higher degrees of mealybug 
infestation and of plant damage than does vigorously 
growing cassava The efficiency of biological control is 
reduced on plants with severely reduced growth. 
The plant and the biological control agent are also 
directly related in respect of cassava varieties- those 
"susceptible" and those "resistant " to pest attack. 
Susceptible cassava varieties show the highest densities 
of cassava mealybug in the field, but the lowest 
The ecological basis of agriculture: 
parasitization rates; because the "quality" of the 
mealybug populations (smaller-sized mealybugs) 
reduces parasite fecundity by inducing the wasp to 
breed males rather than females. On the other hand, 
resistant cassava varieties have the lowest mealybug 
densities, which show the highest extent of 
parasitization. 
Basic research 
Such basic research will guide future .iTA strategies for 
crop protection and help in planning for farmers to 
exploit agricultural production in an efficient and 
sustainable way. 
The practical side of crop protection involves sharing 
of the research results as feedback to breeders, 
agronomists, and other scientists who are participating 
in the design of new farming technologies. Everyone 
involved in manipulating the sphere of cropping 
interactions should also contribute in interpreting 
feedback and bui lding up understanding of the 
interactive system. 
( OimateNv'eather 
.. 
Consumer 
Govemment 
Researcher 
Other.; 
t 
..... 
..... 
+ 
+.-
Farmer 
-:+ 
) 
HIGHER 
TROPH IC 
lEVELS 
SECOND 
TROPHIC 
LEVEL 
FIRST 
TROPHIC 
LEVEL 
\ I i Co. . .... 
SOCIOECONOMIC 
PLANE 
AGRONOMIC 
PLANE 
( 
The predaceous mites appear to have become 
established in East Africa as well: N. idaeus in Kenya and 
T. fimonicus in Burundi. 
SoilANater 
ECOLOGICAL PLANE 
W ith th is breakthrough; cunrent losses of as much as 
one-quarter to one-third of the cassava harvest can 
possibly be saved, according to South American 
experience. National programs in other countries are 
) 
53 
Research directions 
o Reorganization of plant protection 
activities institute-wide into a new biological 
and integrated plant protect on program. 
o Cassava mealybug: follow-up wonk in 
areas already controlled. Special efforts to 
be mounted in the few remaining pockets. 
Technical assistance in rearing to be given 
to national programs. 
o Maize pest complex: importation and 
testing of natural enemies of larger grain 
borer and others. Reid trials to begin for 
systems management practices mostly crop 
rotation. Striga research: basic systems 
analysis, and identification and analysis of 
factors infiuencing outbreaks, to be 
conducted. 
for pathogens to be prepared for transfer 
to national programs. 
o Selective support to national biological 
control programs. Special funds available 
to assist eight countries, with additional 
requests pending. 
o Technical training (five-week sessions) 
for 48 specialists during 1991 under a 
training project sponsored by the Orgariza-
tion for African Unity (OAU) and funded by 
United Nations Development Programme 
(UNDP) and Food and Agri-culture 
Organization (FAO). New project to be 
prepared for 1992 
o Cassava green mite: releases of predators 
in main agroecological zones. Multipl ication, 
release, and monitoring activities to begin 
in several national programs. Integrated 
control projects for mites and for cowpea 
pests to begin in three or more countries. 
Degree and technical training to reach 25 
and 50 people, respectively, 
o Banana and plantain pest complex: 
completion of diagnostic survey in East 
Africa and initiation in West and Central 
Africa 
o Weed biological control projects: 
initiation of preliminary research, including 
Imperota and Chromoloena. 
o Exploration, quarantine, introduction and 
experimental release of naturai enemies of 
cowpea thrips. 
o Locust and grass hopper project: 
advanced implementation of field trials. 
Development of multiplication techniques 
o Training to continue for MSC and PhD 
degrees; at least four new students per 
year. 
54 
releasing new batches of predators in different 
agroecological zones, and are studying the biology, 
behavior, and ecology of the cassava green mite and 
its natural enemies. 
To the original pair of enemy targets, liT A has added the 
complexes of cowpea pests and maize pests, the 
mango mealybug, and locusts and grasshoppers, which 
are pests of a number of crops in the savannas. 
Possibilities for biological control of the parasitic 
weeds Strigo and Imperato, and the banana and 
plantain weevil, are being explored. 
New findings from ecosystem analysis indicate that 
classical biological control is a possibility for many 
species ofthe cowpea pest complex. Natural enemies 
of thrips, major cowpea pests, were identified. A 
computer model of the plant has been developed and 
was superimposed with thrips during 1990. Studies of 
postfiowering pests, diseases. and striga have 
commenced, to provide data for a comprehensive 
plant/pest model. 
The maize pest complex, including stem borers, cob 
borers, diseases, and weeds, especially striga, poses a 
devastating threat as maize cultivation intensifies in 
forest and savanna zones across West and East Africa 
Research is revealing the extent of the damage caused 
by stem borers and cob borers in West Africa. 
Research on stem borers was extended to eastem 
and southem Africa in 1990 at the request of 
govemments. Centro Intemacional de Mejoramiento 
de Maiz y Trigo (CIMMYT) and IITA are planning a joint 
control program against the larger grain borer, an 
insect pest introduced from Mexico or Central America 
to East and West Africa a decade ago and which now 
causes significant losses in stored maize in many 
African countries. 
Using campaign methods and national programs from 
the cassava mealybug project, control of the mango 
mealybug has succeeded from COte d'ivoire to Zaire, 
with few exceptions. Detailed follow-up studies are 
assessing biological and economic impacts. The few 
remaining pest pockets are a\so being studied in 
preparation for a final assault in 199 \ with a new 
natural enemy introduced from India. 
Microbial control of locusts and grasshoppers was 
planned during 1990 as a joint project with the 
Intemational Institute of Biological Control, uK. 
Laboratory and field tests are under way to identify 
effective fungi, bacteria, and other pathogens. Simple 
multipl ication and application techniques are being 
developed for national program use. The biology and 
ecology of grasshoppers and their natural enemies are 
being studied. 
____ Research support services 
Genetic resources 
Thegenetic resources unit is responsibleforllTA'S genn-
plasm collections of food legumes, cereals, and root 
and tuber crops. II-A has a world mandate to preserve 
and document germplasm of cowpea and yam, and of 
the African land races of two cultivated rice speCies, 
Oryza glaberrima and 0 sativa. To improve the genetic 
diversity aVailable to plant breeders, IITA'S genetic 
resources specialists collaborate with national programs 
in Africa to collect the wild relatives of cultivated 
species. 
The unrt maintains a germ plasm collection of 15,200 
accessions of cowpeas (Vigna species) and 1,500 of 
wild Vigoa, 12,500 of rice speces, 2,000 of yams 
(Dloscorea species), 1,400 of soybean (Glycine max), 
1,200 of maize (Zea mays), 2,000 ofbambaraground-
nut, and hundreds of miscellaneous species, A separate 
collection intheroot tuber, and plantain improvement 
program holds 2,000 lines of cultivated and wild 
cassava (Manlhot esculenta), I,ClOO clones of sweet 
potato and over 400 clones of Jlantain and banana 
(Muso species) in in-vitro cultures. 
Exploration and collection. In Nigeria dcnng 1990, 
eight wild yam species were surveyed and collected In 
eight of the southem and eastern states, along with 
cultivated species from Gongola state. An exploration 
project In Ghana collected samples of wid cowpea, 
and cultivated yams and cassava. Exploration for 
cassava will continuethere during 199 1.ln the Republic 
of Benin, a collaborative survey with national scientists 
collected a total of75 I samples of cultivated legumes, 
cereals, and root and tuber species and their wild 
relatives. 
Germplasm diversity. Study of agrobotanical and 
physiological characteristics of the two Afncan rice 
species in 1990 revealed a clear separation of 0. sativa 
into DNO groups, corresponding to the indica and 
japonica differentiaton in Asian rice. Differentiatior, in 
0. glaberrima has not yet been establIShed. 
Collaborative studies are bnnglngto lightthe extent of 
diversity in the pnmary gene pool of cowpea and i1 
the gelletic evolution of the species, Findi'lgs indicate 
that wild Vigna has much to contribute to cowpea 
improvement So:ne of the genetic materials are 
potential sources of resistance to pod-sucking bugs, 
fiower thrips, and leaf miner. (See the grain legume 
improvement artic e.) 
Genetic inheritance. Knowledge of how plants inhert 
specific traits or characten'stics can provide useful 
examples for application in related species, 0"" help in 
developing strategies for using the genetic materia s 
concemed. 
ITA SCientists have begJn to study how the genetic 
immunity of 0. globenima to rice yellow mottle virus 
is inherited, in orderto gain a1 understanding of how 
the high suscept billty of O. sativQ to the vires can be 
supplanted with immu'lity. For cowaea, II-A 
entomologists have found that hainness of the pod 
can discourage pod borers and pod-sucking bugs, so 
the plant geneticists are investigating how the hairy 
trait can be bred into cowpea varieties which are 
smoot'l, 
Biotechnology research 
The new IITA biotechnology research laboratory, funded 
mainly by the Italian government, was formally 
dedicated in November 1990. The unit wi! help in 
I nking African research needs and facilities with 
advanced laboratories in developed countries. The 
dedication of the unit coincided with a workshop on 
the theme of "Blotechno':ogy: enhancing research on 
tropical crops In Africa", with 120 participants from 24 
countries. T 1e workshop heard 50 papers dunng eight 
technical sessions, Recommendations were adopted 
wrich will guide IITA in setting priorities for its 
biotechnological research activities. 
Some objectives of IITA'S com'Tiodity 'mprovement 
programs cannot be easily realized by conventional 
breeding; for example, host-plant resistance to insect 
pests, which requires biotechnological transfer of 
genes from wild species or even unrelated organisms 
to cultivated plants. 
The unit 1as fOJr broad areas of research: 
• cell and tissue culture 
• cytogenetcs and wide crosses 
• diagnostics 
• restriction fragment length polymorphism (mp) 
techniques. 
55 
56 
The unit is partici:Jating in the collaborative studies to 
explore possibilities oftransferringtne resistance genes 
from the wild species V.,exiliato and others to 
cultvated cowpeas. Since an increasing number of 
wild species will be used in breeding programs, several 
wild cowpeas have been tested for virus resistance. 
Excellent sources of resistance to cowpea mottle vir JS 
have been identified In V. vexiliato, whereas only 
tolerance to this ViruS has been found so far in certain 
cultivated cowpeas, It should be possibleto seiectwild 
species as donors with combined resistance to insect 
pests and viruses whenever wide crosses are possible. 
Work on yam gemeplasm during 1990, With the root 
tuber, and plantain improvement program, involved 
study of DNA. variability i1 yam, using "FLP analysis. It 
resulted in a new understanding of the origins and 
evolution of cultivated yam species. (See "Tomorrow's 
role for yam ancestors" inset on page 40.) 
Recent developments in botechnology pemeit the 
Jroduction of reagents for detection of pathogens, in 
the form of monoclonal antibodies and cloned 
complementary DNA (CDN.I\). Moreover, the sensitivity 
and specificityofdtagnostictests can be highly improved 
by the use of these reagents. In collaboration With 
Agriculture Canada, Vancouver Station, 12 cowpea 
aphid-borne mosaic virus isolates from Nigeria have 
been used .n characterzlng strains of the virus using 
polyconal and monoclonal antibodies. A panel of 
mouse monoclonal antibod'ies was also raised. Using 
this system, four serotypes of the ViruS have been 
differentiated. IITA is helpir,g national programs on the 
use of monoclonal antibodies in their own laboratories 
to identliY locally prevalent strains of the cowpea 
ap'lid-bome mosaic virus. 
Wito the Scottish Crop Research Institute, Dundee, 
many weed species and crops with typical whitefly-
transm'tted diseases have been tested using a panel of 
monoclonal antibodies developed against African 
cassava mosaic virus. Several plants reacted with 
monoclonal antibodies samples which can detect 
whitefiy-transmitted geminiviruses. However, these 
geminiviruseswere not identical with that virus. Further 
stJdies a'"e i1 progress to characterize geminiviruses in 
weed species. 
With the Universityoflilinois, Ponicum streak virus has 
been cnaracterized and compared with maize streak 
ViruS, 
Virology 
The virology unit conducts research on virus diseases 
occurring in IITA'S mandated crops in Africa. The unit's 
activities are closely linked w'~h the work of breeders, 
pathologists, and entomologists in each of IITA'S crop 
improvement programs, 
Virology at IITA focuses on two different but 
complementary fields of interest. The first Includes 
studies on the etiology and epidemiology of virus 
diseases as well as research which supports the 
development of new disease-resistant varieties. (See 
"Putting cowpea viruses on the map" inset on page 
42.) Quarantine aspects of crop tmprovement and 
intematlonal transfer of improved gemnplasm also fall 
Within this field. 
The second concemsvirus 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 
fomn, the IITA virologists try to identiiY and puriiY it. 
develop antise"", and describe the pathogen in temns 
ofisolate characteristics for reference and comparison. 
Achievements. During 1990, the un'~ continued to 
test the resistance of elite cowpea and rice genotypes 
from the breeding programs to new:y recognized 
viruses or virus strains. 
Collections of wild rice as well as 0. sativa gemeplasm 
resistant to rice yellow mottle virus were tested 
against the IITAstandard isolate of this virus and another 
isolate obtained from a rice-growing region within 
Nigeria. An isolate earlier obtained from O. 
fangistaminota was included in the studies. 
Results have shown that the new isolates of rice 
yellow mottle virus do not differ significantly from the 
IITA standard isolate for resistance screening purposes. 
However, there were significant differences b~tween 
isolates in respect of reactions to certain accessions of 
O. iongistominata, 0. barThii, O. giaberrima. O. punctata, 
and O. eichingeri, the originally African Oryzo species. 
Comparative studies of locally occunring strains of the 
cowpea aphid-bome mosaic virus have shown that 
the types of viruses which occur in the main cowpea 
groWiflg areas of the dry savanna differ, to some 
extent. from isolates of this virus routinely used at IITA 
for resistance screening studies. The majo1ty of 
accessions, however, have reacted in a com~arable 
manner. 
IITA virologists made significant progress during 1990 
in characterizing viruses occurring in bananas and 
plantains (Musa species). The cucumber mosaic virus 
was found to be the most commonly encountered 
and has been shown to be responsible forconspicuous 
chlorosis and mosaic symptoms. 
Some apparently new viruses isolated from IITA'S man-
dated crops and associated weed species were 
characterized orpunfied forthe production of antisera 
to be used for diagnostic purposes. Several antisera 
have also been made available to natonal program 
scientists on their request. 
A project with the International Development 
Research Centre (IDRC), Canada, IS assisting national 
programs in Africa in identifying viruses in their major 
food crops. Once national program scientists have 
been trained in the use of monoclonal antibodies, 
they should be in a better position to conduct reliable 
virus identification specifiC to their own areas. After 
locally prevalent virus strains have been identified. IITA 
and national program breeders can adopt strategies 
to incorporate appropriate vi'1JS resistance in improved 
crop varieties. 
Biometrics 
The biometrics unit advises allliTA scientists and grad-
uate students doing thesis research here on the 
applications of mathematics and statistics to agricultural 
research. Scientists and students are assisted by the 
unit in designing surveys and experiments, analyzing 
and interpreting data, using statistical information in 
publications and presentations, and apply ng 
appropriate mathematical and statistical techniques in 
their particular research. 
The unitalso designs and teaches the statistics compon-
ents of most IITA training courses, and conducts 
occasional, more specialized courses in statistics and 
statist cal computing. As resources penmlt, the ITA 
biometrician provides assistance to other research 
institutions and to Nigerian universities. 
During I 990the statistical claSSification of experimental 
sites continued, using results from 18 intemationally 
conducted series of maize trials. Data from three 
large-scale sample surveys were fi~ered and analyzed, 
while other varied and nonrout ne experiments were 
also analyzed. 
The unit depends on continuous improvements in its 
computer software to keep up with the volume and 
complexity of liT A'S mathematical and statistical work. 
In 1990, further extension and improvements were 
made to programs for the analyses of smaller sample 
surveys, genetics studies, and design generation. 
In March 1990, the IITA biometriCIan attended the first 
East African biometrics group meeting at Nairobi, 
Kenya. 
Analytical services 
The analytical senvices laboratory analyzes soil, plant, 
and water samples submitted by IITA researchers and 
their collaborators for various physical and chemical 
properties, which ultimately affect the success of crops 
grown in the originating areas, Plant samples are 
analyzed for primary and secondary nutrients, and for 
micronutrients, which determine plant grovvth and 
indicate species adaptibility to the environment. 
Training in soil and pla'lt analysis was given to 30 
laboratory supentisors, technicians, research scholars, 
and students. 
Acquisition and processing of data wi'l be further 
auto'Tlated in order to establish a laboratory 
information management system. 
The SOil and plant analytical laboratories networx of 
Africa (SPALNA) was inaugurated in 1990. The network 
will help improve soil, water, and plant analytical 
senvlces in Africa, through equipment 'Tlaintenance 
and repair services, supply of chemicals and spare 
57 
West African 
research farm 
managers learn 
survey techniques 
in the /990 course. 
58 
parts, training, quality contnol, and promotion of good 
laboratory practices. 
Research farms 
The research farms unit canries responsibility for the 
development and management of IITA'S experimental 
farms and test locations in the various agroecological 
zones of West Africa: at Onne, Kano, and Ikenne in 
Nigeria. Cotonou in the Republic of Benin, and 
Mbalmayo in Cameroon, and numerous smaller sites 
in all lones. 
The reseanch farms staff collaborates with resounce 
management scientists on studies of soil-conserving 
tillage methods. For sustainability of IITA farms, most 
trials are planted with no-till methods that reduce soil 
enosion and degradation. Gully enosion is contnolled 
by the use of graded contour banks. Sheet enosion is 
minimized with the use of no-till planting and also of 
tied ridges for noot and tuber crops. Good soil 
structure and acceptable levels of organic matter are 
maintained by planted fallows of Mucuna utilis every 
second or thind year. but where soil erosion and 
degradation are extreme, the use of Pueroria 
phase%ides as a fallow crop for several years has been 
found effective. 
The unit also multiplies improved crop varieties 
developed by IITA scientists and their collaborators, 
I 
,,1 , 
.. ~. -.~.~ 
distributing up to 50 tons of seed annually to 
government seed services. seed companies. and farmers 
in N igeria and other African countries. At Ibadan, the 
research farms unit maintains a demonstration area, 
where the latest cnop varieties and farmingtechnologies 
were demonstrated to around 1,000 visitors during 
1990. 
West African training. A three-week course was held 
in 1990, on surveying for soil conservation. maintenance 
and calibration of machinery, and farm wonkshop 
planning and management. The goal was to impnove 
support for experimental farms of national reseanch 
programs in the region. Seventeen research farm 
managers participated, who came from five countries 
of West Africa. The University of Arkansas. USA and 
the Intemational Cnop Research Institute forthe Sem-
Arid T nopics (ICRISAT) assisted IITA in nunning the 
course. Follow-up visits, several months after, revealed 
the considerable usefulness of the course. Similar 
courses are planned for 199 I and 1992. 
A screen house construction team is being organized 
to cater for the numerous requests for assistance in 
constructing IITA-designed screen houses for the 
institute's research sites and national research farms. 
International cooperation 
The special role ofintemational cooperation at IITA is to enhance the collaborative process with national agricu~ural research systems of adapting 
and applying improved technologies for farmers' needs. 
Cooperation strategies ... 
The principal means by which IITA strengthens agri-
cultural research are training. information dissemination, 
germplasm exchange, and other collaborative project 
activities which convey IITA technologies. 
Fourmechanisms have been designed forthe strategies 
in the IITA medium-term plan ( 1989- 1993) to enhance 
usefulness of collaborative research and training 
activities, and enable IrrA to respond with greater 
sensitivity to perceived needs. They are: 
• Networking. Collaborative networks link IITA with 
national and regional research institutions in Africa, to 
address common problems and issues. 
• Research liaison scientists. The medium-term plan 
provides for three research liaison scientists, each with 
specific responsibilities for a group of countries. 
• Resident scientist teams in specific countries 
collaborate w~h national colleagues to meet research 
problems and needs, and to strengthen research 
capabi l~ies. 
• Training. The training program comprises graduate 
research fellowships, short-term courses, and short-
term attachments to acquire specific ski lls in IITA 
research programs. Short-term fellowships are also 
arranged for visiting scientists from national programs 
for collaborative research over periods of up to 12 
months. 
During 1990, IITA operated 19 special projects in 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 
Networking projects include the second phase of 
SAFGRAD, and ESARRN and AFNETA. These networks have 
elected steering comm~ees which coordinate and 
plan their activities. 
AFNET A organized a trainers' workshop forfour regional 
and one national center during 1990, and published 
three issues of The Arneton newsletter. AfNETA 
commenced collaborative research projects with 20 
African countries aimed at the development of 
sustainable cropping systems based on alley farming 
principles. (See "Alleys across Africa" inset. page 26.) 
ESARRN act iv~ies during 1990 included germplasm 
exchange, workshops, and scientific exchange visits 
among member institutions. In Malawi, IITA cassava lines 
were hybridized with the best local selections. IITA 
provided additional lines in tissue culture fonn for 
mu~i plication for various projects. Two graduate 
students completed their MSC degrees w ith ESARRN 
support. Altogether 47 technicians were trained in-
country and at IITA. 
The SAFGRAD maize research network supported 
several ofits member countries in testing ofimproved 
germ plasm and crop management techniques. It 
sponsored technical training and exchange visits. 
The SAfGRAD cowpea research network received 
feedback on 42 regional trials. Those repeated in 
national programs during 1990 performed well. 
National scientists benefited from group training, 
exchange visits, and interaction with IITA scientists in 
research planning. New varieties continued to gain 
wide acceptance in West African countries after being 
Training course 
participants 
demonstrate yam 
nour sifting with 
IITA-designed 
equipment at a 
farmers' field day, 
at fwo, Nigeria. 
59 
Table I. Bilateral and multilateral special projects, 1990 
Project Donor(s) Total Life budget 1990 budget 
staff US$ rrillion US$ 'Tlillion 
Institution-building NCRE II/Cameroor (terminated December 1990) USAID 19 14.31 3.93 
RAv/Zaire (-:erminated September 1990) USAD I 8.12 1.44 
Resident scientist teams Ghana grains development CD' 1.12 0.11 
Ghana smallholder If AD 0.80 0.25 
Cameroon root crOJS (terrni'"'ated Ju"'e 1990) G::F 2 0.70 O.IL 
Congo k ndarTba IFAD 0.40 0.11 
SADCC cowpea project CEC 3 1.78 1.34 
Research networks SAFGRA:J U5AIO 2 4.08 loiS 
ESARRN USAIO/IDRC 2 270 0.40 
AFNElA ClONIDHC 2 3.17 0.66 
USAID 1.00 
DANIDfI, 007 0.46 
IFA~ 1.20 
Other research On-farm/adaptive research EEC 3 2.79 1.53 
Soybean utilization IDRC 0.16 0.05 
Legume viruses IORC 0.46 0.13 
Utilization of cassava flour "',GeD 0.64 0.23 
Dynamics of soi I organ c matter ,A,GCD 0.16 0.12 
Posthaf','est technology 'F 0.21 0.15 
Training projects Human resources development UNDP 0.78 0.35 
Women agricultural professionals FF 0.28 0.17 
(East/Southem Africa) 
\Nomen agricultural professionals FF 0.79 0.34 
(West/Central Africa) 
Totals 46 45.72 13.04 
60 
developed in the network Including Suvita-2 which Acronyms cited in the text 
was developed In Bumna Faso and IS being widely ---------------------------
cultivated in Mali. AFNETA Alley Farming ""Jetwork for Tropical Afn'ca 
Research liaison. Dunng 1990. thelrTA nesearch liaison 
scientist helped to start operations for an on-farm 
adaptive research project on cassava, cowpea, maize, 
rice, and soybean varieties which nad been developed 
in an earlier EEc-supported project Fourteen West 
and Central African countries are participating with 
trials of a selection of the crops, mo51: of which began 
durng the year. Two nesearch projects on cowpea 
insect pests also com'llenced in the dry savanna of 
Nigeria. in collaboration with the Institute for 
Agricultural Research, Samaru: a survey, as a bas s for 
control measures, and aminimum pesticide protection/ 
yeld-Ioss tnal. 
11-,.... finished Its tenth year of continuing Involvement 
with Cameroon's NCREproject, which has had adocble 
impact 'lelping Cameroon to strengthen its own 
research capacity and to become a producer of 
technologies which can benefit other African countries 
as well as itself The IITA team of scientists works on 
four staple cereal crops~maize, rice, sorghum, and 
millet-at stations in Cameroon's six diffe'"'e'lt 
agrociimatic zones, Among many research achieve-
ments to date, two maize and five rice varieties have 
been improved. adapted, and neleased to famne,,;, 
Twe'lty-one staff scientists have received fellowships 
for higher degree 5I:udy, while many more techniCians 
''lave received training at IITA. 
Completion of liT A's role ir. Zaire's RAV project (1985-
1990) marked the seventeenth year of collaboration 
with Zairian research programs that have produced 
high-yielding, d isease-resistant cassava, maze, and grain 
legume varieties, Hundneds of village groups neceved 
planting materials and training through extension 
agencies linked with the RAY research effort, ITA COl lab-
oration with Zairian scientists continues on cassava 
problems, including crop Improvement and plant pro-
tection, and on maize, soybean. and cowpea research. 
IIT.A. completed its part in Cameroon's natiorlal '"Dot 
crops improvement Drogram in June 1990. The 
program succeeded in developing a large quantity of 
improved cassava and sweet potato as planting material 
AGCD General Administration for Cooperation and Development 
ClAT Centro Intemacional de Agricultura Tropical 
CIDA Canadian International Development Agency 
::::1" Cent..-o Intemacionc.1 de a PapC. 
COSCA Collaborative Study of Cassava in Africa 
CA Technical Centre .."or Agricultural and Rural Cooperation 
DANIOA Danish I.-,terational Development Agency 
EEC European Econom c Community 
ESARRN East and Southem Africa Root Crops Research Network 
FAG Food and Agriculture Organization of the United '\lations 
FF Ford Founcation 
IBSRAM Irterational Board fa'" Sod Research and Management 
leRAF Ir,terra:ional Council for Research in Agro-Forestry 
ICRISAT Intema:ional Crops Research Institute for the Semi-Arid Tropics 
I:JRC Intemationa Development Research Centre 
I~,A.D Intemational Fund for Agn'cultural Develop'llent 
1L.-c:A Intemational Livestock Center for Africa 
INIBAP Intemat anal Netvvork for the Improvement of Bananas and Plantains 
I'o,CRE National Cereals Research and Extension Project 
RAV App'ied Agricultural Research a.-,d Outreac"l Projec: 
SADCC Southem Africa" Deve opment Coordination Conference 
'~,t>.FG'V\C Semi-Arid Food Grains Research and Development Projec: 
c..INDP United Natio"ls Development Programme 
USAID United Sta:es Agency for Inte:rational Development 
6' 
62 
for further multiplication and distribution to farmers, 
The improved cassava showed yields twice as high as 
those of local vanetles, although some problems with 
root rot, "cookability" and taste remained for furtner 
investigation. Improved sweet potato was ail over-all 
success in performance and acceptability. Researchers 
and technicians received in-service trailing. 2.400 
farmers were :rained. and 500 extension agents 
attended training courses. 
In the legume component of the Ghana grains 
development project, IITA ger-nplasm was screened 
for selection of early-maturing. high-yielding. disease-
resistant cowpea varieties which combine erect or 
semi-erect plant type, acceptable seed color, and 
cooki'lg quality, suitablefort1e maize-cowpea rotation 
system in Ghana.IIT.A and local germ plasm was screened 
forthe developmentofhlgh-yielding, bf1Jchid-resistant 
vaneties. The project has resulted In release of three 
cowpea varieties. Exotic soybean varieties were also 
screened for the selection of high-yielding, early-to-
medium-maturing varieties which combine traits 
favorable for tropica' cultivation, including disease 
resistance. Resea"Chers and technicians received in-
service training and 30 extension staff attended in-
country training courses. 
In the Ghana smallholder rehabilitation and develop-
ment program, highlights of 1990 included selection 
offour IITA cassava varieties fortnals in farmers' fields 
by Ghana's crop serv'lces/extens'lon department. 
T wentyvarieties of"poundab e" cassava were selected 
from seedlings for fuiher evalcation. The program 
sponsored in-country and extemal training courses, 
ncluding a I O-week root crops course. 
The soybean utilizat on project aims to develop and 
ntroduce improved soybean utilization technology 
for Jse in hO'Jseholds and in small-scale processing 
enterp1ses in rural Nigeria. A marketing survey 
Measured the acceptability of soybeans In Ibadan 
produce markets. revealing that the total cumber of 
soybean retaile'"S had increased from I in I 987to 419 
. n 1990. Extruded soybean products were introduced 
for home use in selected areas and development of 
smal-scale processing technology continued. 
The SADec cowpea research project was launched 
dunng I 990wi:h the signing of an agreement between 
IITA and the Mozambique govemment Tie project 
aims to develop cowpea genotypes with suitable 
resistance and eati1g qua ity characteristics. Research 
began at Maputo and nurseries were distribJted to all 
national col'aborators. 
lIT A IS wor<ing with the Katholieke Universite t Leuven 
in formulating a cassava fiour for making bread. 
Preliminary work In 1989 had included screening of 
cassava clones for making composite flours and 
developl ngtechnologies forwheatless bread for Afncan 
consumers, The project completed its second year in 
1990, and a second phase is being developed. 
Self-development 
To realize the potentials in their own programs, 
national agricultural research institutions in tropical 
Africa are sharing with liT A the responsibilites for 
research and forself-development in human resources. 
Such a collaborative orientation in training should 
enable national programs increasingly to carry out 
their own research and training. 
T rain,ngin research for Afncanagricultural professionals 
has always formed an essential part of IITA'S outlook. 
No proposal to develop or transfer technology from 
IITA fails to consider the training objectives of the 
participating countries, 
"TA'S strategic plan (1989-2000) set the follOWing 
guidelines for development of Its training program: 
• Shifting emphasis at IITA from group to individual 
graduate training. 
• Decentralizing group training to national programs. 
• Raising the proportion of core IITA resources 
devoted to training. 
Improving training materials. 
• Increasing women's participation i1 training. 
Since 1971 IITA has organized indiVidual and group 
training for close to 7,000 researchers. most of whom 
have come f"Dll Afncan countries . 
Individual training seeks to enhance research abilities 
thnocgh doctoral, masters and non-degree levels of 
training tailored to specific needs in national programs. 
To promote the increase of graduate researchers i1 
Africa, IITA i n~iated the graduate research fellowship 
program in 1988, to support graduate students in 
conducting their research with IfTA scientists. During 
1990, 14 new graduate fe llowships were awarded, 3 
of them towome, . Six fellows concludedtheirresearc1 
at IITA During the year IITA. scient ists supervised 50 PhD 
and 30 MSC trainees. of whom 16 were women. 
Intemships provided special ized training in research 
dUring 1990 for 21 intems (one of them a womar) 
from national p""grams. ranging in length from two 
weeks tD six mDnths. 
Group training. During 1990, 25 I technicians and 
scientists participated in 14 group training courses at 
IITA, which collectively amounted to 55 weeks of 
trai , ing. Some 179 persons partici~ated in regional or 
in-country courses in Be1in, Ghana, Guinea, Malawi, 
Niger, and Sier-a Leone. (See t able 2 for a summary 
of courses and trainees.) 
The majDrityofgroJP course participants were Afri cans, 
of whom 80% came from West and Central Africa. 
The trainees ca-ne from 32 African countries: 18 in 
West and Central Africa, 13 elsewhere in the re~Dn. 
About 29% of all group coLrse participants at IITA came 
from French-speaking countries. 
Of the total of : 90 tra nees at Ibadan, IITA provided 73 
with scho iarships, principally from West and Ce, tral 
Africa. fAO and UNO' provided funding for the 61 
trainees at Cotonou. Demand for off-campus training 
came pri1cipaily throug, twD networks: AfNETA and 
ESARRN. The netwonks fundec traning for about 10% 
of their participants. 
Evaluation activities, part of a new evaluatiDn and 
impact assessment process being established in the 
t rain ing program. covered 10 of the courses given 
during 1990 in various locations. Together with 
University Df Arkansas staff, IITA made follow-up visits 
to participants in the 1989 group course in research 
famn management from Ghana, Gambia, and Nigeria. 
Women in training. During 1990,31 women (over 
12% of t he participants) took part in liT A group training 
cou-se~ while I 9 women (I 1%) oarticipated in regional 
or in-country courses. Of the 80 graduate trainees at 
IITA in Ibadan, CotonDu, and elsewhere durng 1990, 
16 were WDmen (25%). 
In 1990 IITA obtained funds for a project to train 
African women for leadership roles. Ten agricultural 
professionals from We'tt Africa Will receive grants to 
'ttudyfor HSC or pho deg-ees in African universities. leTA 
Will collaborate with Winrocklntemationa: in execJting 
this Ford Foundatlon-fur,ded project. Awardees will 
participate in Win"Ock's African women leaders In 
agriculture and environcnent program. 
Besides t he effDrts to include women participants in 
training, IITA is aware that simply increaSing numbers is 
not enough. Gender perspective and gender sensitivity 
must become part of t raining curricula. liT A is studying 
ways to program its training activities and materials 
which wi ll promote ts objectives for women in 
agricultural research. 
Collaboration with international centers. For sev-
eral years, IITA has worked with CiAT and CIP in a joint 
t raining project on human resource development for 
ge~eration and transfer of root and tuber crop 
technologies, funded by UN~P. IITA also collaborates 
with I~RAF , ICLA.IBSRAM, INIBAP, ICRISAT, CTA, Univers~ of 
Arkansas. and other institutions in coerse planning, 
development of training materials, course presentation, 
and evaluatior.. 
Future directions in training. leTA'S training orogram 
ai",sto 1eb nati01al programs and research , etworks 
eventually to do fDr themselves all : he field-level 
training that is needed to support their own research 
efforts. National programs and IITA together offer 
training that is increasingly organized. conducted, and 
susta ned by those programs, with the goal of 
strengthening national and regional capacities for 
-esearch and tranlng. 
ITA'S approach to t he "training of trainers" in nat ional 
prDgrams is evolving and varied according to the 
needs and opportunities in those programs. Training 
of researchers to train others is a central part of ITA'S 
decentralization strategy. For full-t ime training officers 
in national programs, I TAarranges two-to-thnee-month 
attachments tD enable them to work alongside IITA 
training staifto acquire on-the-iob experience. 
Table 2. UTA group training in 1990 
Weeks Trainees Countries* 
total women 
IITA Ibadan 
Advanced soil and plant analysis 4 13 2 10 
Alley falTlling for research trainers 3 20 0 5 
Biotechrology trai"'ing workshop 18 5 8 
coseA village anc institution-level cassava survey 2 16 2 7 
Cowpea and soybean research and :echnology tansfer 6 18 3 10 
Maize research and techno log)" transfer 8 16 3 II 
On-farm experimentation 2 19 9 
Plantain "esearch and technology transfe'" 3 13 4 8 
Research farm -nanagemen: 3 17 0 5 
Roo: crops research and technolcgy transfer 8 24 2 12 
Sustainable food production systems 3 16 3 10 
Ibadan sub:ctal 51 253 51 
IITA Cotonou 
Biological control (3 courses) Cotonou subtotal 12 61 6 23 
Regional/in-country 
Alley farming research (anglophone 'vVesV'Central Africa) 2 29 0 5 
Alley farming research (francophone Wes-.JCentral Africa) 2 24 4 10 
Alley farTning research (Nigeria) 2 27 2 
Roo: a.1d tuber crop production research (Guinea) 2 18 0 
Roo:: and tuber crep production research (Malawi) 2 34 4 
Roo: and tuber crep production research (Sierra Leone) 31 2 
T rain,ng 2nd communication skills (UNDP; regio"al) 2 16 7 5 
regioral/in-cou"try sub:ctal 13 179 19 32 
Group training total 68 430 50 32 
*T otal nUlT'ber of countnes n each instance 
64 
______ Information services 
N ger an print ard. electronic med'3 represe. ntatives were enilsted as supporters of agricultural developnent In the newly forrred media forum 
for agnCJlture. While mas: merrbe"S of the foum are 
joumalists, some are researchers, extension pe--sonrel, 
po icymakers, and agricultural inform3tion speCialists. 
Members represen: a wide range of organizations 
I1YO ved in agricultural deve opment including research 
ilstltutes, banKs, farmers' organizations, extension 
agencies, and commercial farms. 
Through the forum, lilA s tryirgto iryo ve both public 
ard privc..te sectors in dissemlna:ion offlndirgs by the 
various agricu tural research Drganizatiors in Nigeria, 
thereby helpl1gto promote farmers' adoption of new' 
ard improved technologies. The forum laurched the 
food action media se'-\/Ice (F,tlJ-1S) during 1990, with 
three a'Tns: lAMS BJlletins fo r t1e print media; 1Ai'1STEL 
for television, anc Radio IAi"1S for radio. 
IITA cchievements received extensive coverage dLring 
1990 in Nigeric anc, to some extent, internationally 
International coverage included feature programs o~ 
the Bntish Broadc2.stng Serv ce C')l)c) ald Deutsche 
\Nelle (the Voice of Germany). Select ons from IITA'S 
press coverage were reprocuced in tnree volumes of 
r:TA in t,l,e News which have beel distribL ted widely. 
Ii;'>, par::icipation in fairs, exhibitions, and other public 
events In Niger'a included, for the first time, the 
Kacuna inte'T1atioral tracefaw, and the She I Petroleum 
health anc environme1t wee< in V./arri. Many 
businessmen, farmers, and representatives cf agro-
allied indus:nes visited IITA to obtain advice, infonatlon, 
and samples of Impcoved seeds .. AboJt 60 groups of 
students from polytechnic institutes and faculties of 
agriculture visited IITA durng 1990. 
Library services, The n-house database "vas enhanced 
through the addition of3,029 retrospective and 9,359 
current records of various types of publications, The 
library acquired 1,898 bOOkS anc 5,218 jour'lal issues, 
Four additional databases on compact disk (CD-ROM) 
were ccquired. Use o':-librar'j'fac,lites during I 990'l'l2.s 
reflected inthe I 15 recipients of selective dissem nation 
services, ar,d 93 scientists \Iv'ho receive the weekly 
journal serv ce contents. The rumber of books 
borrowed Incceased from 10,138 In 1989 to 17, 152,n 
1990, as a result of increased aWC.reness of services 
and revision of ending policy. 
Toining in library' mc.nagement and automatiorl was 
gillen to s-':aff of other libr'aries, ard to some lecturers 
and students ofhig~erinstitutions in Nigen'a. Assistance 
to national research Institutions contirued in the form 
of iter2.ture searches, inter,ibrary loans, preparation 
and sup:>ly of bibliograph es, donations of duplicate 
publ c2.tions, and provision o~ general in~orma:ion. A 
total 0; 482 entries was con:ributed to the AGRIS data-
base and 332 of tnem have al--eady appeared in 
AGRINDEx-the irternational agricultJral information 
system coordinated by the Food and Agnculture 
Organization of the United i'-.ations (FAC~'. 
Publications. DLr ng 1990, four editors were 
resp:::nsible for issuing 5 I publications with a total of 
about 2,700 prirted pages, ,Anotrler 35 titles were 
being processed at the close of the year. The edi:ors 
irformally reviewed and ed ted several thousard manu-
script pages ofsc ent fie and admi1istrative documents, 
-he publications urit acts as secretariat for the ITA 
pUJlicaticns review panel, wnich received 63 
manuscripts during I 990for review before submission 
to scientific journals, or presentatior at conferences 
Graphics OLtput curing 1990 amounted to some 
4,000 pages of c2meca-ready artwork. The prntshop 
producec 2pproxlm2.tel)" 2.5 millior plate impressions 
dur ng 1990, being aboJt 200,000 i"""'lpressions per 
month on average, 
During 1990 staff photographe"S went on 180 f eld 
ShOOls. They processed SO'lle '0,000 slides of their 
own shots ard those of other 1IT.t>. staff Nearly' 5,000 
color prints and 20,000 black and wh,ce prints were 
produced. Users of the slide col ection, incil~di:lg 
trainees and editors bOoth local and foreign, made a 
total of 155 consultations With the staff to select sl des 
for lectures, derronstrations, 0-- pub1:cations, 
Mail ng list entries wel-e upcated and fle\vaddressees 
recruited wth a qJestionnaire survey, The unit began 
selective dissemination services 'with mailings OofCowpeo 
Genetic Resources tOo 1,500 adoressees, as well as a 
regular mai ling of the rwst issl,Je of the periodical ,ITA 
Research to 7,000 addresses. 
65 
Annexes 
66 
67 Extracts from financial statements for the year ended 
31 December 1990 
(The full Financial Report and the Report of the Auditors 
Arthur Andersen and Company are avalfable (rom IITA on request) 
71 Professional staff 
74 Consultants 
75 Publications by IITA staff 
80 IITA publications 
JITA 
STATEMENT OF FINANCIAL POSITION 
31 December 1990 
ASSETS 
Cash a.ld short-term depoSits 
Accounts receivable: 
D010rs 
Others 
Inventor:es 
Other assets 
Property, p an: and equipment 
LIABILITIES AND FUND BALANCES 
W,BILITIES 
Accounts payable and other lia::>ilities 
Accrued salaries and benefits 
Payments in advance - donors 
FUND BALANCES 
Capi:al 
Capital development 
Operating 
1990 
8,644 
7,862 
363 
2,544 
209 
58,356 
77,978 
7,639 
3,071 
3,974 
14,684 
58,356 
1,224 
3,714 
63,294 
77,978 
Expressed in us$ thousands 
1989 
6,936 
8,058 
503 
3,627 .~ 178 
55,768 
75,070 
8,094 
3,053 
3,465 
14,612 
55,768 
976 
3,714 
60,458 
75,070 
67 
IITA 
STATEMENT OF ACTIVITY 
For the year ended 31 December 1990 
REVENUE 
Grants 
Other inccme 
EXPENSES 
Research prog--ams 
Conferences anc' training 
if'formation services 
General administration 
General operations 
pcoperty, plcnt and equipment 
Exchange (gains) / losses 
Total expenses 
Alloc2.tion -:0 capital development DJnd 
Allocation to ope--ating fund 
68 
1990 
35,333 
613 
35,946 
21,694 
2,290 
1,039 
3,593 
3,248 
3,054 
380 
35,298 
648 
35,946 
Ex,;xessed in u')$ t~ousQnds 
1989 
31,218 
619 
31,837 
18,342 
1,883 
1,432 
3,522 
2,886 
3,634 
(263) 
3 1,436 
401 
31,837 
IITA 
STATEMENT OF CHANGES IN FINANCIAL POSITION 
For the year ended 3 I December 1990 
SOURCES OF FUNDS 
Excess of revenue over non-capital expenses 
Decrease in accounts receivable - doncrs 
Decrec.se in accounts receivable - other 
Decrease in ,nventories 
Decrease in other assets 
Increase in accounts payable and other liabilities 
Increase in accrued salaries and benefits 
Increase in payments in advance - donors 
APPLICATION OF FUNDS 
Purchase of propertY'. plant and equipment 
Increase in other assets 
Decrease in accounts .Jayable and other liabilities 
Decrease in accrued salaries and benelts 
INCREASE/(DECREASE) IN FUNDS 
CASH, BEGINNING OF YEAR 
CASH, END OF YEAR 
1990 
3.702 
196 
140 
1,083 
18 
509 
5.648 
3,45" 
31 
455 
3,940 
1}08 
6,936 
8,644 
Expressed In Uj $ ~hcusonds 
1989 
4,035 
432 
60 
834 
59 
1,096 
349 
6,865 
4,634 
588 
5,222 
1,643 
5,293 
6,936 
69 
DONORS 1990 
Donors 
African Deve opment Bank 
Australia 
Austria 
Belgium 
Canada 
China 
Comrrission of the European Commun ties in Nigeria 
Denrark 
Finlaod 
Food Industry C'1Jsade Agalns: Hunger 
Ford Foundation 
-ranee 
Gatsby Chantable Foundation 
Germany 
India 
Intematioral Development Research Centre 
International Fund for Ag1cultural Development 
Itay 
Japan 
Netherlands 
Nigeria 
Norway 
Roc<efeller FOJndation 
Sweden 
Switzerland 
United Kingdom 
United Nations Development Programme 
United Nations University 
United States Agency fer Interrationai Development 
University of Hohenheim 
World Bank 
Other cont-ibutions 
Closed and r,iscellaneous projects 
Total 
70 
Core funding 
350 
119 
90 
548 
,698 
10 
91 
151 
251 
100 
295 
1,420 
24 
632 
2,963 
761 
57 
731 
531 
327 
792 
823 
206 
5,485 
4,073 
22,528 
Expressed in us$ thousands 
Special project funding 
500 
544 
145 
738 
77 
25 
98 
203 
53 
734 
923 
808 
596 
6 
224 
2 
6,615 
175 
13 
319 
7 
12,805 
• 
Professional staff ____________ _ 
Management and support services 
Executive management 
L. 3race .... , PhD. director general 
L. D. 5tlfel, phD, director gereral '* 
A AdetunJi, Fhc" s;JeCiai assistant to director general 
J. Cremer. 3A. executive assistant to direct:w genera: 
J. H, D'Nles. lise director, office 0':- the d recto .... general 
J. P. Eckebil, coho, deputy director genera, 'ntemation2.1 :::ooperation 
K. S. Fis:::her, phD, deput~1 cirector general. research 
F. C. McDonald. MS, assistant to dep~ ty director general, research 
\/V. P. Powell, 5SC deputy di .... ector general, management 
Administrative and auxiliary services 
C. A Enahoro, l1anc..ger, Ikeja guest house 
C. Inniss-Palmer, specialist english teacher 
A. Jad~sol, deputy head. intem3tional seheal of ITA 
~~. Jackson head, Intematlcnal school of IITp, 
A. R. Middleton, sse, manager, intemational house 
R. I. Olorode, secunty manager 
D. J. Sev'Iell, ma~ager, aircraft operc.tions 
O. Sh:)10 a, ACA, audit senior 
Budget and finance 
D. A. Covemey, =CA, diredor, budget and finance 
B, A. Adeol2., COS, aCCO'Jntant 
O. E. Adepoju, ACp" senior analyst, accounting :Jrocedures 
A. A. Aklnbola, 55C, seni::Jr technical analyst 
C. A. Babalola. ACA, senior analyst. accounting procedwes 
P. O. Balogun, FCCA, fnance manager 
J. E. Bclarinwa, r1SI\, payroll accountc.nt 
P. O. Etuk. '1SA. budget end planning coordinator 
E. D. Greene. M5C, materials nanager .*" 
G. R. Mclnt::Jsh, CM,.'!." procedures manager. firancial inf:::lIl11ati::Jn 
systerrs 
R, Obikudu, r1SI\, materials ma,'"'ager 
S. J. Udoh, Af'lNI'1. chief accountant 
D. 'vVheeler, CP."", project manager, financial informaticn systems * 
Computer services 
L. J. McDo~ald, LLB, corrputer manager 
1\. N. Eguzozle. 3SC, computer JrograMmer 
T D. Oluyemi, 1'-1SC, computer programmer 
Human resources 
J. Thackway, MA, director, human resources 
T P". Akintevve, MD, senior medical officer 
J. O. Badakl, 115A. emp oyee relat ons manager 
J B Elegbe, M5(' manpower develoJment m2.nager 
F. O. A. OsinuJebi-Cole, MD. med:cal officer 
* Left durng the yew (I Aprii ,'990 - 31 March 1991) 
Information services 
S. M. A. Lawc.ni, PhD, director 
Y. A. Adedlgba, [""A, head, library services 
.t>.., 0. Adekun e, MSC, ed tor 
R. O. Adeniran, r1L~, princpal librarian 
K. At<inson. MSC, editor and head, publications 
A. A. ,A.z.ubulke. ML5, principal librariar 
T, Babaleye, M::::A. public informatlo'"' manager 
E. \Jwu U, M5C, audiovsual specialist 
B. O. OJurcngbe, sse, production manager 
T. T. OV'lOeye, t1LS. editor 
J. O. Oyekan, 35C, head, public affairs * 
D. R. '1ora'l Raj, phJ, senior science writer anc ecitor 
F. N. Ubogu, MLS, principal librarian 
R. Umelo, BA, editor 
Physical plant services 
J. G. H. Craig, director 
E. O. Akintokun, research vehicle serv'ICes cff.cer 
A. K, Bhatnagar, 2.ssistant direct:Jr 
A. C Butler, building and site 5e~vi[es officer 
P. G. Gualinetti, corstruction site engl'"'eenng services cfficer 
E. Ojlnere, heavy equipment.lfabricc.tion services engineer * 
A. Oyedejl, electrical services engineer 
S. \/'1. Quader, electronic services officer 
71 
Research and support services 
Biological control program 
H. P.. HeJTen, phc, director 
D. T. Aklbo-Betts, Eas:iSouthem Africa regional coordinater * 
J. B, Akinw ~ml, MS(, engineer 
V'l N, O. HaMmond, phc, en:cmclogist VVest'Cen:ral Africa regional 
coordi,lator 
T. t1. Hcug, MSC, mass reanng 5pecialist 
B. rvegevanc. M5C, mite ard !lass rearing special st 
P. Neuenschwander. pMO. e~tomologist 
F. Schulthess. rho, bloecologls: 
A. Vy1odage'leh, phD, train ng officer FAO 
. S. Yarlnek. PhD, entoMologist 
ASSOCiate experts 
C. Boavlca. MSC, eco ogist 
H, M. Creyer, MSC, ecologist 
C. Gold, phD, associate scient st 
M. T amo, '1S(, ecologist 
P')stdoctoral fellows 
,A" Paralso. "'ho, pathologist 
T G. Shanovver, rho. en':omologist 
Grain legume improvement program 
S. R. S,ngh, rhQ, director *" 
K, F, Cardl,vell. rho, pla:t pathologist 
P Q, Craufurd, phD, crop physiologist Kano station 
K, E. Dashiell, rhD, breeder 
D. A. Fiorini, phD, plant pa:ho oglst 
L. E, N. Jackai, "'ho. entomcioglst 
O. Nakayama, phD, JICA expert (soybean posth2.rvest scientist) 
B, R. Ntare, FhD, Jreeder and liaison SCientist to c=\ISAT, Niger"* 
G. 0, Myers. rho, b~eeder 
r-. 0. Ogunclpe, MSC. feod technolog'lst 
B B. Singh, PhD, oreeder and cfficer-in-charge, Ka:'o station 
I, Watanabe, rho. pl2.nt :Jhysiologist Kano station 
Postdoctoral fel;ow 
C. N. Akem, FhD, pathologist/breeder 
Maize research program 
M, v\/i .... slov'l rhJdirector 
r'-l. A. Bosque-Perez, rho, entoMologist 
S, K, Kim. phc, breeder 
G. Kling, ::>ho, breeder 
H. Mareck, phc, breeder 
Postdoctoral fellows 
A. E. Awad, phD, striga biologist 
~ Mestin, PhD, vector entomologist 
72 
O. M. Olanya, phD, plant pathologist 
VisiIillg scie";tJsts 
L. Everett, phD, maize breeder 
S, N. C Okonkwo rho, stnga biologist 
Resource and crop management program 
D. S. C. Spencer, ph:), director 
I. O .. Akobundu. phe, weed scientist 
A. N. Atta-Krah, rho. coorcinator, I\FNETA 
K. Dvorak. ph:), agricul:ural economist 
H C Ezumah. ::>ho, agronomist t 
M. P. Gchuru, PhD, agroromist 
A. E. Ikpi. phD, economist * 
A-M. N, Izac. phJ, agricultural economist. inland valle/ s>,'Sterls 
S. S, Jagtap, PhD, agroclimatologlst 
B. T. Ka~g, PhD, soil scientist 
K. Mulo~goy, FhD, s8il microbiologist 
H. J VI!, Mutsaers ph], agronomis:, humid forest s/stems 
N, Sanginga, FhD, assist2nt coordinator, AFNETA 
J. Smith, '-'ho, agricultural econcmlst. savanna systems 
M, j. S''Ivift, p"o. leacer, resource management research 
B. Vanlauwe, ssc, junior exper: 
G, K, VVe'Jer. PhD. agronomist. savan"a systems 
Collaborative studv of cassava in Africo 
F. I, Nweke. rho, agncultura economist team leader 
G. R r1ullins, PhD, East./Southem Africa regional coordinator"* 
Y. C. Prudencio. PhD. regional coorcinator 
Postdoctora,' fellows 
R. J. Carsky, Fhoagronomist 
G, Fairchild, rh=:>, soil micro~iologlst * 
Y. Moh2.m8ud. phc, agronomist 
R. A. Polson, rho, ag"icLltura econornist 
E. Tucker, phc, weed sCientist 
VISJMg scientists 
S. Hauser, phD, agronomist 
R Markham, FhD, entomologist "* 
AssoCiare experts 
J, Foppes, Ir, agrkultural economist. Onne station * 
rv. C Van der Meersch, Ir, rTicrobiologist"* 
Rice research program 
K. Alluri, ::>ho, coord nator, I'JGEP,-AfricaiIRR.1 liaison scientist 
T. M. Masajo, "'ho. program leader and breeder * 
Postdoctorol fellow 
tOn saboaricai * Left- dun'ig the year (I April 1990 - 31 lv10rch 1991) 
R. C jcshi. phD. entomologist 
Root, tuber, and plantain improvement program 
S. K Ha-n. phD. director 
R. ASIt?CU, phi l , plant breeder 
F. Cauh . 'hD. plan: p'-t hologist 
S Y. C Ng, r1$C, t ssue cultJre specialist 
D . S. O. O siru. PhD, p lant phySIC oglSt • 
C Pasberg-Gauhl ph) . plant pa:ho ·oglSt 
M. C M. ::)orto ph::>. CI.~T- l'TA ph}'sio:ogist/Jreeder 
G. D. Se:-y, P~D. West/Central Afrca --egiona coordinator, If'..IB.AY, 
O nne station * 
R. L A. Swenr e r., '>ho. agror,omlstib reeder and otTrcer-in-cha--ge. 
Onne station · 
D . R. Vuylsteke. Ir, : issue cu l:ure scientist 
P:stdoctoral ;e,'bw£ 
M. Bokanga. FhD. oiome""ist 
A. G. O . D ixon, :.flD. breeder 
G. Eggleston, phD. food technolcgisUblochemlst 
R. T erauch. :nD. yam geneticist ..,. 
\frS/lmg soentis1S 
K. V. ~a , PhD, cytogene:ic ist * 
1. Ikctun, PhD. pathologi;t .. 
H . Kanno phD, entomo agist. JICA ... 
Postharlest unit 
L. S I-a as, M$C , research specialist 
Y. 'vv. Jean. ph:l, po~tharvest techno logist 
Analytical services laboratory 
J. L. Pleys ier, ~hD, l abor~tot)· serv'ices Lpervsor 
Biometrics 
P. 'Nalker, "'lA. biometrician 
Biotechnology research unit 
G Thottapp illy. ph :::.. VI''D logist 
Genetk resources unit 
N . Q . Ng. PhD, head. genetic re50urces uni-: 
S, Padulosi. Dott. plant explorer 
Research farms unit 
P. D, Austin, B::'C. research fa:Tfls deve lopment officer 
D C. ::ouper. "1sc. head, re5.earcR farms unit 
P. V. Hartley, esc research farms engineer 
• Left dunng the yecr (I Apnl 199C - 3; March 199 1) 
Virology unit 
H. VV. Rossel. Ir, lilro logist 
International cooperation 
Support services 
S . .A.uerhan, interpreteritranslator!li 
B. Auvarc , interpretcr/tri.mslator 
S. Bai ley. interpreter/transla-:cr .. 
E. F Deganus. sse. VOJect development coord inator 
O. B. Haun'lou, In<:erp rete r/transla1or 
C. Lord n terpreteritranslato '-
E. Moli 'le"'o. head, interpretat ion/transla:io1 
0 , M. Ogunyin<a, '1sc. ccord in:tt o "'. monito'" ng anc· evaluation 
8. F 531·, nterpreter/translator 
J. C Sentz, phI), USAiD 112. 150" SCientist ",. 
j. B. Suh, rho, research liaison scientist 
A P. Unyo, PhD, project de'le l o~ment coordinator 
Training program 
H. Gasse r, rho. c ireccr , training 
J. L, GJiley, ph D, group tra in ng coo~:jjnatD r 
P .. Zachrrann. Fh ), training matenal5 speciali st 
Cooperative programs 
CIDAlCIMMYTIiITA Ghana grai ns development proiect, Ghana 
,A." M, Hossain. PhD, grair legume breeder 
Gatsby charitable foundation/IITA/Cameroonian national root crops 
improvement pr~gram (CNRCIP). Cameroon 
J. B Abaka-Wlyte. PhD. breeder and project leader' 
M. 0. A kon)d.::., jho, agro~om istlbr'eeder -.I 
EEclliTAiSADCC cowpea project 
R. AmaJle, ?he, CO'NJea agronomIst 
j. D . N.,k. pr,D. leg. me breede-
IFAD/IITA Ghana smallholder rehabilitation and development program 
O. O . Oko)i, rhc, creeder and root crops coordinator 
Semi-arid food grains research and development (SAfGAAO) proiect, 
Burkina Faso 
J. M, Fajemlsln, ph:J, pathologlstlbreeder, project leader and maize 
network coorcinator 
N. Muleba, phc . agronomist and ccwpea network coordinator 
USAIOflDRclllTA East and Souttlern African root crops research 
network (ESAP.P.N) . Malawi 
M. N . A lvarez. rho, breeder .::.nd netwolt coordirator 
j. A Otoo. ' -0. agronollist 
USAID/111A1National cereals: research and extension (NCRE) pro;ect. 
Cameroon 
73 
E. A. Atayl, PhD. cr.lef of party a~d agr·lculturc..1 economist 
S. \/V. Almy, Fhc:, socia econorl'ist "" 
D. C. Baker. rh~. agricultural economist 
\'. Balasubraman:am, phD. agronoMi3t "" 
N. F. Beninati, PhD, maize breeder 
O. P. :>angi. ph~, :'reeder * 
_. Everett, P."10. breeder "" 
M P. jO."1es. rh~. breeder 1<-
M. Kc.muanga, F·ho. agricultural economist 
j. Kikafunda-Twine, rho. agronom st * 
D. McHugh, "vISe. socloeconom st 
O. A. Os inane, ~'hD, farming systems cgr::momist 
j. A. Pcku, PhD. extenSion agronomst 
A. C. Roy, PhD, agronomist -oj: 
J T. r\ussell , phD, extension agronor'list * 
L. Singh, phr;, breeder * 
T. C. Strlwel, =>hD, deputy chief of party 
H. T aile/rand. -'ho, cereals agronomist 
C. Y. Yamoc.h. phD, soil scient:stlagroforester 
USAIOJIITA Applied agricultural research (RAV) project, Zaire 
F. E. i3rockman, phD, chief of pa1:y and agrono'Tli3t t 
M. S. Alam, rho, entor-ole-gist "" 
C. D. S. Bartlett, PhD, agnc-.JltL .. ral economist *" 
T Berhe. PhD, agroromist * 
L. H. Canacho, phD, breeder .. 
8. Chrti-8abu. farm manager >t-
.A. D. Florn·l. mo. regloral oLtreach spec'lallst * 
<. M ... ohnson, PhD, breeder * 
:J. Kelta, outreach specialist '< 
G F. Montalban, plant superintendent "* 
A. O. Os name, rho, agronomist '" 
M. Seye, MA, aem nistrative officer "* 
D ? .. Shannon, rno, agro~omist * 
VI./. O. Vogel, phD, 2..gncultJral econoTlist * 
IITA Benin station 
J. N. A. Quaye, MI" leader, rranagement unit and offlcer-in-charge 
M. N. Versteeg phD. agronomist and leader 
IITA Cameroon station (Mbalmayo) 
S. L. Claassen, MSC, faml nanager 
P. G. Gillman, phD. soil chemist 
r"J. R. Hul'Jgalle, PhD, 5011 phY3ic st 
PostdDctoral (eiiovVs 
D Russell. P"lO, anthropologist/Rockefeller fell 0\\1 
N. \/v'. MenZies, PhD, 5011 chemist 
74 
Consultants 
r. M. 0. Ag:m, wild yam collection 
A. ?gboola, research eVcluat on 
M. S. Alam. maize research 
C L. A. Asadu, research evaluat"lon 
P. AI, cassava research 
R. A. Boxall, grain storage research 
8. DnJk-<er, biologica control 
C. S. Gold, biclogical control 
L. S. Ha'os, p03tharvest -::echnology 
V. T. Joh,1, rce pathology 
j. A. Kwarteng, training materials 
A VV. Mocre. eciting 
S. Ncke-e training rI',aterials 
C. Par<er, strigc.. biology 
L. V..J. R.oone>" meize research 
O. l.;th'Tlan, cassava research 
t On s~btoucol .. Lef. duri'";g the Veor (I April 1990 - 31 lv10rch 199/) 
Publications by I ITA staff _________ _ 
Contributions by IITA staff to scientific literature that 
became available during 1990; including journal articles, 
papers in monographs or conference proceedings. and 
edited monographs. 
A kobundu, 1.0. 1990. The ro e cf weed cont ' o l in integrated pest 
r anagement for tropica ' roo: and tuber crops. Pages 23-2.9 in 
Integrated pest management for tropical root and tuber crops, edited 
by SK Hahn and FE. Caveness, . - A, Ibadan. Niger a. 
A kpokodje. G.O., JA Odebiyi, R.S. Ochieng. and H.R. Herren. 
1990. Fund onal responses of Neoseiul'us Idaeus and Iphiseius 
degenerans (Acarina: Phyt05e iidae) feeding on the caSSJ'/a green mite, 
. Mor-:onyc~IJus tc"ajoa (Acarir a: Tetranychidae). Bullet in de 12. societe 
entomo'ogique suisse 63: 327-335. 
Akundabwen i. L S. , C. Peter-Paul, and B.B. Singh. 1990. Evaluation of 
eJite lines of cowpea ('vlgrtO unguiculoro (L.) \Nalp.) fo r leaf/fodder plus 
grain (i .e .. dual purpose). TropICal Agliculture 67(2): 133- 136. 
Almazan. A. 1990. Utilization of cassava and its prcd'..-cs. Pages I 13-
120 i" CasSeva in tropical Africa: a reference m anual. ITA, Ibadan, 
N iger a. 
Atta-Krah, A N. 1990. Alley farming V'Jlth leucaena: effect cf short 
grazed fallows o~ soil fertil ity and crop yields Experimental 
Agricu t ure 26( I): I- 10. 
Atta-Krah , AN. 1990. Ava llabili:, and use of fodder shrubs and t rees 
In trop i::al A frica. Pages 140-1 62 In Shrubs and tree fodders for ferm 
animal5. ed ited by C. D evendra. Proceedings of a Workshop in 
D enpasar.lndo"e;ia. 24-29 Ju l 1989. DRc·276e. lntem at onal 
Development Research Centre, Canada. 
Atuahene-Amankwa, G., MA Hossain, and A Assibi. 1990. 
Groundnut production and improvement in Gh ana. P2.ges 45-46 Ir: 
Summary Proceed ings, Fi '"5t ICRISAT Regional G roundnut Meeting for 
\t'/est Africa. 13 · 16 Sep 198E, ICRISAT Sarelian Center, N iamey. N iger. 
Ayanaba. A .. and D.S. Jenkinson. 1990. Decomposition of Carbon- I 4 
label ed ryegrass and maize under tropical cJnd tions. So I Sc ience 
Society of America Joumal 64: I 12-1 15. 
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Plantc:ir: 
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CowDec; 
Annual Report of the International Institute of 
Tropical Agriculture 1990 
ss," 0331-4340 
VVntlng/editing 
Kim Atkinson 
Bibliographic compilation 
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Design and production 
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Phot:)graph siill u strat ions 
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