Cover: CIP's research organization reflects the full range of problems encountered by national programs and farmers in developing countries, ranging from distribution of new germplasm to studies on potato marketing and consumption. Here, a Rwandese farmer brings her potatoes to a local market. International Potato Center Annual Report 1985 INTERNATIONAL POTATO CENTER P.O. Box 5969, Lima, Peru 1986 The International Potato Center (CIP) is a nonprofit, autonomous scientific institution established in 1972 by agreement with the Government of Peru for developing and disseminating knowledge for greater use of the potato as a basic food in the developing world. CIP is one of 13 nonprofit international research and training centers supported by the Consultative Group for International Agricultural Research (CGIAR). The CGIAR is sponsored by the Food and Agriculture Organization (F AO) of the United Nations, the United Nations Development Programme (UNDP), and the International Bank for Reconstruction and Development (World Bank), and comprises more than 45 countries, international and regional organizations, and private foundations. CIP received funding in 1985, through the CGIAR, from the following donors: the governments of Australia, Belgium, France, Germany , Ireland, Italy, Japan, Mexico , Netherlands, Norway , People's Republic of China, Philippines, Spain, and Switzerland ; the Canadian International Develop- ment Agency (CIDA); the Danish In ternational Development Agency (DANIDA); the European Economic Community (EEC) ; the Inter-American Development Bank (IDB) ; the International Fund for Agricultural Development (IF AD) ; the Swedish Agency for Research Cooperation with Developing Countries (SAREC) ; the United Kingdom Overseas Development Administration (UKODA); the United States Agency for Inter- national Development (USAID); the OPEC Fund for International Development ; and the World Bank (IBRD). The 1985 Annual Report is published in English and Spanish by the International Potato Center (CIP). This report covers the period from 1 November 1984 to 31October1985 . Mention of specific products by trade name does not imply endorsement of or discrimination against such products by CIP. Citation: International Potato Center. 1986. Annual Report CIP 1985. Lima, Peru. 176 p. Printed by the International Potato Center, P.O. Box 5969, Lima, Peru, July 1986. Copies printed: 3072 Foreword Board of Trustees Staff List of Abbreviations and Acronyms Impact of CIP Research 1985 Summary of Research and Regional Programs Agroecological Zones of Peru RESEARCH THRUSTS Maintenance and Utilization of Unexploited Genetic Resources II Production and Distribution of Advanced Breeding Material III Research on Bacterial and Fungal Diseases IV Potato Virus Research v Integrated Pest Management VI Warm Climate Potato Production VII Cool Climate Potato Production VIII Postharvest Technology IX Seed Technology x Potatoes in Developing Country Food Systems ....__ National Manpower Development Publications Research and Consultancy Contracts Financial Statement CGIAR Information Contents 5 7 8 12 15 20 29 31 37 47 63 73 83 95 105 115 133 144 157 163 167 175 Foreword Change has to be a part of any institution that is keeping its program adjusted to the evolving priorities of rapidly emerging developing countries. Although the research to produce needed technologies requires stability and continuity, an institution's ability to react quickly to oppor- tunities for progress in developing countries must be maintained within its program. This is not always easy. Some unwanted changes cannot be avoided such as the retirement of Dr. Orville Page, CIP's first and only director of research during the past 15 years. His dedicated service at CIP started with a sabbatical from Canada Agriculture Research Station in Alberta. His capability for organizing research was quickly demonstrated and he was asked to become the director of research. Dr. Page was instrumental in developing the successful research thrust strategy at CIP, which uses interdisciplinary teams of scientists to address priority research areas. Also under his direction, research and con- sultancy contracts on core funding became a unique cost-effective method of increasing the research capacity at CIP and within the CGIAR system. He will continue to be available for short-term consultancies and is already scheduled to help develop CIP's new regional program in China during 1986. CIP's new Region VIII was established in China on September 7, 1985, in association with the Chinese Academy of Agricultural Sciences. CIP is the first CGIAR center to have a regional base in China, which is the result of many exchange visits between scientists during the past seven years. With 25°/o of the world's population and over four million hectares of potatoes produced annually , there is more than adequate justification for a CIP regional base to be located in this country. With the large number of institutions and scientists working on potatoes in China, strong collaboration is anticipated on programs that will be of mutual benefit to China and the rest of CIP's client countries. China needs the broad base of germplasm available at CIP and we need to learn of their experiences in intercropping and commercial use of true seed technology. During 1985, CIP's Board of Trustees looked carefully at the possibility of CIP becoming involved with sweet potato. The idea was brought to CIP by several donors and members of the Technical Advisory Committee as a result of the CGIAR priorities study, which indicated that sweet potatoes were not being given enough attention in the CGIAR system in relation 5 to their importance in the developing world . CIP's Board of Trustees , at their annual meeting in 1985 , formerly approved the inclusion of sweet potato in the Center's mandate. The relationship between CIP and the other international agricultural centers working on this commodity is being established, based on the comparative research advantages of each center. The advantage of being located in the area where the sweet potato originated has enabled CIP to assume leadership in gathering a world collection of sweet potato germplasm. Today, CIP is on the cutting edge of science in developing techniques for the identification and elimination of potato viruses and viroids , an ability that can be transferred quickly to sweet potato viruses, which have not yet been adequately researched. CIP's regional network could be used equally for potatoes and sweet potatoes in helping to distribute the technologies of the other centers working with this commodity. The sweet potato will complement the potato as CIP continues to serve clients living in regions of the world with scarce resources, marginal soils, and hot climates. As CIP goes into 1986, the CIP Profile, the long-term plan, is being updated. This plan, the fourth updating of this vital and valuable document , provides goals and strategies that will take C!P through to the year 2010, long after I will have completed my task as director general. If increases in potato production continue in developing countries as they have since CIP was first funded in 1972, the potato will have become by 2010 a major staple food in many tropical countries, helping to solve the problems of famine such as the situation that occurred in Rwanda during a recent crisis. Potato and sweet potato, as a combination, will probably be outranked only by rice as the major food and cash crops and they will have a wider range of climatic flexibility than any other major food commodities in the developing world. The potato alone will have more climatic flexibility than any other major commodity addressed by the CGIAR system. I would like to thank the loyal donors who have supported CIP's collaborative efforts with national programs to make this highly nutritious tuber - the potato - become a major staple food in the developing world. Director General 6 Board of Trustees Executive Committee DR. JACK MEAGHER, Chairman Chief, Division of Plant Research Department of Agriculture , Victoria P.O. Box 4041 G.P.O. Melbourne, Vic. 3001, Australia DR. FLAVIO COUTO, Secretary President Empresa de Assistencia Tecnica e Extensao Rural do Distrito Federal C.P. 04 235 70.770 Brasilia D.F., Brazil DR. RICHARD L. SAWYER Director General International Potato Center P.O. Box 5969 Lima, Peru Program Committee DR. MAGNHILD UMAERUS, Chair Professor of Plant Breeding Swedish University of Agricultural Sciences Department of Plant Breeding P.O. Box 7003 S-750 07 Uppsala, Sweden DR. DAVID CALL Dean College of Agriculture and Life Sciences Cornell University Ithaca , New York 14853 U.S.A. DR. DELY GAPASIN Director Crops Research Department PCARRD Los Banos, Laguna , Philippines DR. VICTOR PALMA VALDERRAMA Victor Matirtua 526 San Isidro, Lima, Peru DR. KLAUS RAVEN National Agrarian University P.O . Box 456 La Molina, Lima, Peru DR. MAX RIVES Senior Breeder Geneticist INRA 289 rue Lecourbe 75015 Paris, France DR. NOBORU T AKASE Sugar Crop Development Fund Sukai Building West 7 Ave., South 1 St. Chuo-ku, Sapporo, Japan 7 Staff SENIOR MANAGEMENT Richard L. Sawyer, Ph.D., Director General Jose Valle Riestra, Ph.D., Deputy Director General William A. Hamann, B.S., Assistant to the Director General Orville T. Page, Ph.D., Director of Research (until June 1985) Peter Gregory, Ph.D., Director of Research (from July 1985) Kenneth J. Brown, Ph.D., Director of Regional Research Primo Accatino, Ph.D., Associate Director, Transfer of Technology Adrian Fajardo, M.S., Executive Officer Leonardo Hussey, Controller RESEARCH THRUSTS (Leaders and Co-Leaders) 1. Maintenance and Utilization of Unexploited Genetic Resources (P. Schmiediche-Z. Huaman) II. Production and Distribution of Advanced Breeding-Material (H. Mendoza-M. Iwanaga) III. Research on Bacterial and Fungal Diseases (E. French-C. Martin) IV. Potato Virus Research (L. Salazar-U. Jayasinghe) V. Integrated Pest Management (F. Cisneros - P. Jatala) VI. Warm Climate Potato Production (D. Midmore - H. Mendoza) VII. Cool Climate Potato Production (J. Landeo-D. Midmore) VIII . Postharvest Technology (R. Booth- R. Rhoades) IX . Seed Technology (P. Malagam~a-A. Monares) 8 X. Potatoes in Developing Country Food Systems (R. Rhoades - D. Horton) R ESEARCH DEPARTMENTS Breeding and Genetics Humberto Mendoza, Ph.D., Head of Department Enrique Chujoy, Ph.D., Geneticist Ali M. Golmirzaie, Ph.D., Geneticist Zosimo Huaman, Ph.D., Geneticist Masaru Iwanaga, Ph.D., Cytogeneticist Juan Landeo, Ph.D., Breeder Fermin de la Puente, Ph.D., Breeder+ Deborah Rabinowitz, Ph.D ., Biologist+ Franr,;oise Rousselle, Ph.D., Breeder*+ Patrick Rousselle, Ph.D., Breeder* + Roberto Ruiz, Lie., Breeder+ Peter Schmiediche, Ph.D., Breeder Maria Scurrah, Ph.D., Breeder Nematology and Entomology Parviz J atala, Ph.D., Head of Department Javier Franco, Ph.D ., Nematologist K. V. Raman, Ph.D., Entomologist Severino A. Raymundo, Ph.D., Plant Protection Specialist Luis Valencia, M.A., Entomologist (Reg. I) Pathology Edward R. French, Ph.D., Head of Department John Elphinstone, Ph.D., Bacteriologist Enrique Fernandez-Northcote, Ph.D., Virologist Jan Henfling, Ph.D., Mycologist (Reg. I)* Upali Jayasinghe, Ph.D., Virologist Carlos Martin, Ph.D., Pathologist Victor Otazu, Ph.D., Pathologist Luis Salazar, Ph.D., Virologist Physiology Patricio Malagamba, Ph.D., Head of Department Cornelia Almekinders, Ir., Physiologist + Robert H. Booth, Ph.D., Physiologist John H. Dodds, Ph.D., Tissue Culture Yoshihiro Eguchi, B.S., Physiologist+ Peter Keane, B.S., Processing Specialist David J. Midmore, Ph.D., Physiologist Riccardo Morpurgo, M.S., Physiologist + Noel Pallais, Ph.D., Physiologist Siert Wiersema, Ph.D., Agronomist Taxonomy Carlos Ochoa, M.S., Head of Department Social Science Douglas E. Horton, Ph.D., Head of Department (on sabbatical) Robert E. Rhoades, Ph.D., Acting Head of Department Peter T. Ewell, Ph.D., Economist Anibal Monares, Ph.D., Economist Vera Niiiez, M.A., Anthropologist + Gordon Prain, Ph.D., Anthropologist+ Gregory J. Scott, Ph.D., Economist Norio Yamamoto, Ph.D., Ethnobiologist+ Research Support Fausto Cisneros, Ph.D., Head of Department Dennis Cunliffe, Ing. Agr., Field & Greenhouse Supervisor, Lima Lombardo Cetraro, B.S., Field Supervisor, San Ramon Miguel Quevedo, Ing. Agr., Field & Greenhouse Supervisor, Huancayo Pedro Ruiz, Ing. Agr., Field Supervisor, Yurimaguas Marco Soto, Ph.D., Superintendent, Huancayo REGIONAL RESEARCH AND TRAINING Headquarters James E. Bryan, M.S., Seed Technologist Region I- Andean Latin America Apartado Aereo 92654 Bogota 8, D.E., Colombia Oscar Malamud, Ph.D., Regional Representative Fernando Ezeta, Ph.D., Co-leader Potato Program (Peru)+ Cesar Vittorelli, Ing. Agr., Seed Production Team Leader (Peru)+ Juan Aguilar, Ing. Agr., Seed Production (Peru)+ Claude Auroi, Ph.D., Economist (Peru)+ Karin Luther, Agr. Eng. ETH, Virologist (Peru)+ Urs Scheidegger, Ph.D., Agronomist (Peru)+ Region II - Non-Andean Latin America c/o Centro Nacional de Pesquisa de Hortalir;:as, Caixa Postal ( 11) 1316 70.000 Brasilia, D.F., Brazil Oscar Hidalgo, Ph.D., Regional Representative Anna Strohmenger, M.S., Agronomist+ Region III - Tropical Africa P.O. Box 25171 Nairobi, Kenya Sylvester Nganga, Ph.D., Regional Representative Gerrit De Vries, Ir., Agronomist (Burundi)+ Angelique Haugerud, Ph.D., Anthropologist (Rwanda)+ Anton Haverkort, Ph.D., Agronomist (Rwanda) George L. T. Hunt, T. Eng., M.I. Agr. E., Storage+ Michael Potts, Ph.D., Agronomist (Burundi)+ Region IV -Near and Middle East P.O. Box 2416 Cairo, Egypt Sidki Sadik, Ph.D., Regional Representative Cristoph Engels, Ph.D., Agronomist+ Region V - Nor th and West Africa 11 Rue des Orangers Ariana, Tunis, Tunisia 9 Roger Cortbaoui, Ph.D ., Regional Representative Jurgen Benz, Ir., Storage+ Roland von Arx, Ph.D ., Entomologist + Region VI - South Asia c/o NBPGR Indian Agricultural Research Institute New Delhi, 110012, India Mahesh Upadhya, Ph.D ., Regional Representative Bharat L. Karmacharya, Ph.D., Agronomist (Bhutan)+ Lyle Sikka, M.S., Seed Technologist (Bangladesh)+ Region VII - Southeast Asia c/o IRRI P.O. Box 933 Manila, Philippines Peter Vander Zaag, Ph.D ., Regional Representative. Jeroen Kloos, Ir., Agronomist + Ponciano Batugal, Ph.D ., Coordinator- SAPPRAD + Region VIII - China Chinese Academy of Agricultural Sciences Bai Shi Qiao Rd., No. 30 West Suburbs of Beijing People's Republic of China Song Bo Fu, Dr., CIP Liaison Scientist TRAINING AND COMMUNICATIONS DEPARTMENT Manuel Pina, Jr., Ph.D., Head of Department Linda Peterson, B.F.A., Senior Editor Carmen Podesta, M.A., Librarian Hernan Rincon, Ph.D., Communication Support Coordinator Garry Robertson, M.A., Training Program Coordinator Carmen Siri, Ph.D., Training Materials Specialist+ Rainer Zachmann, Ph.D., Training Materials Specialist ADMINISTRATION Office of the Executive Officer Carlos Bohl, Transportation Supervisor 10 Gustavo Echecopar, Ing. Agr., Plant & Equipment Supervisor Ana Dumett, Asist. Soc., Social Worker Juan Iladoy, Recreation Supervisor Lucas Reano, C.P.C., Administrative Supervisor German Rossani, M.D., Medical Officer Jacques Vandernotte, Pilot Office of the Controller Oscar Gil, C.P.C., Assistant Controller Blanca Joo, C.P.C., Accountant Edgardo de los Rios, C.P.C., Accountant Guillermo Romero, Head Accountant SCIENTIFIC ASSOC IA TES Manuel Canto, Ph.D., Nematologist (Peru) Romulo del Carpio, Ing. Agr. , Taxonomist (Peru) Nelson Estrada, Ph.D., Breeder (Colombia) Cesar Fribourg, M.S., Virologist (Peru) Alfredo Garcia, M.E.S ., Biometrics Consultant (Peru) L. V. Turkensteen, Ph.D., Micologist (Netherlands) Sven Villagarcia, Ph.D., Physiologist (Peru) SCIENTIFIC AND OTHER ASSISTANTS (By Department or Region) Walter Amoros, M.S., Breeding & Genetics Luis Calua, M.S., Breeding & Genetics Jorge Espinoza, Ing. Agr., Breeding & Genetics Rosario Galvez, M.S., Breeding & Genetics Luis Manrique, Ing. Agr., Breeding & Genetics Jose Luis Marca, Ing. Agr., Breeding & Genetics Rodomiro Ortiz, Biol., Breeding & Genetics Roger Vallejo, M.S., Breeding & Genetics Jesus Alcazar, Ing. Agr., Nematology & Entomology Rosa Canicoba, B.S., Nematology & Entomology Arelis Carmen Garzon, B.S., Nematology & Entomology Alberto Gonzales, M.S., Nematology & Entomology Angela M.atos, Ing. Agr., Nematology & Entomology Raul Salas, Ing. Agr., Nematology & Entomology Maria Villa, Biol., Nematology & Entomology Jorge Abad, M.S., Pathology Ilse Balbo, Biol., Pathology Carlos Chuquillanqui, B.S., Pathology Wilman Galindez, Ing. Agr., Pathology Liliam G. Lindo, Ing. Agr., Pathology Charlotte Lizarraga, B.S., Pathology Josefina Nakashima, Biol., Pathology Ursula Nydegger, Tech. Dip., Pathology Hans Pinedo, Ing. Agr., Pathology Herbert Torres, M.S., Pathology Ernesto Velit, Biol., Pathology Nilda Beltran, Ing. Ind ., Physiology Donald Berrios, Ing. Agr., Physiology Fausto Buitron, Ing. Agr., Physiology Rolando Cabello, Ing. Agr., Physiology Nelson Espinoza, Biol., Physiology Nelly Fong, M.S., Physiology Rolando Lizarraga, B.S., Physiology Norma de Mazza, Q.F., Physiology Jorge Roca, B.S., Physiology Daniela Silva, Biol., Physiology Dora Tovar, Biol., Physiology Jesus Amaya, Tech. Dip., Taxonomy Matilde Orrillo de Jara, Biol., Taxonomy Alberto Salas, Ing. Agr., Taxonomy Adolfo Achata, Ing. Agr., Social Science Pierre Bidegaray , B .S., Social Science* Beatriz Eldredge, B.S., Social Science Hugo Fano, B.S., Social Science Rosa Antunez, B.S., Research Support* Nelson Melendez, Tech. Dip ., Research Support Luis Zapata, Ing. Agr. (Reg. I) Jorge Queiroz, Ing. Agr. (Reg. II) Stan Kasule, B.S. (Reg. III) John- Kimani, B. S. (Reg. III) M. Shahata, B.S. (Reg. IV) M. Sharkani, B.S. (Reg. IV) M. Kadian (Reg. VI) K. C. Thacur (Reg. VI) Richarte Acasio, M.S. (Reg. VII)* A. Demagante, M.S. (Reg. VII) V. Escobar, M.S. (Reg. VII) B. Fernandez, M.S. (Reg. VII) C. Montierro, M.S. (Reg. VII) B. Susana, B.S. (Reg. VII) Qin Yu Tiang, B.S. (Reg. VIII) Jesus Chang, M.S. Ed., Training & Communications Martha Crosby, B.A., Training & Communications Jorge Palacios, Dip., Training & Communications Christine Graves, M.A., Writer/Editor, Director General's Office Luis Cabanillas, B.S., Executive Office Eleana Bardales, C.P.C., Controller's Office Jorge Bautista, B.S., Controller's Office Jose Belli, B.S., Controller's Office Vilma Escudero, B.S., Controller's Office Alfredo Gonzalez, B.S., Controller's Office Alberto Monteblanco, C.P.C., Controller's Office Djordje Velickovich, Copilot, General Operations Rocio Jimenez, B.S., Auxiliary Services Staff as of December 31, 1985 are listed by Department or Region. * Left during the year. +These positions are separately funded as Special Projects by the fo llowing donor agencies: Australian Development Assistance Agency Belgium , General Administration for Cooperation and Development (AGCO) Canadian International Development Agency (CIDA) Fed. Rep . Germany, German Society of Technical Cooperation (GTZ) Food and Agr iculture Organization of the United Nations (FAO) Netherland s, Ministry of Foreign Affairs Rockefeller Foundation Spain, Ministry of Foreign Affairs Swiss Development Cooperation and Humanitarian Agency United Kingdom, Overseas Development Administration (ODA) United States Agency for International Development (USAID) W. K. Kellogg Foundation World Bank 11 List of Abbreviations and Acronyms AMV APLV APMV avg AVRDC BARI BW CEC CGIAR CIAAB CIAT CIP cm CNPH CPE CPRI CV CV. d DLS DNA EB ELISA EMBRAPA FAO FDR g GA GCA h ha IADS IBPGR IBTA ICA IDRC IITA 12 alfalfa mosaic virus Andean potato latent virus Andean potato mottle virus average Asian Vegetable Research & Development Center (Taiwan) Bangladesh Agricultural Research Institute bacterial wilt cation exchange capacity Consultative Group on International Agricultural Research Centro de Investigaciones Agricolas "A-Boerger" (Uruguay) Centro Internacional de Agricultura Tropical (Colombia) Centro Internacional de la Papa (Peru) centimeter Centro N acional de Pesquisa de Hortaliyas (Brazil) centrally planned economy Central Potato Research Institute (India) coefficient of variation cultivar day diffused-light stores deoxyribonucleic acid early blight enzyme•linked immunosorbent assay Empresa Brasileira de Pesquisa Agropecuaria (Brazil) Food and Agriculture Organization of the United Nations -first division restitution gram gibberellic acid general combining ability hour hectare International Agricultural Development Service International Board for Plant Genetic Resources Instituto Boliviano de Tecnologia Agropecuaria Instituto Colombiano Agropecuario (Colombia) International Development Research Centre (Canada) International Institute of Tropical Agriculture (Nigeria) INIA INIAP INIPA INPT INRA INRAT INTA IPO ISABU L lat. LB LER long. LSD LUE m meq min MJ ml mm mo NASH ND nm ns NS ODD OP Pf/Pi PLRV PNAP ppm PRACIPA PRAPAC PRECODEPA PROCIPA PSTV PTM PTV PVM PVS PVV Instituto de Investigaciones Agropecuarias (Chile) lnstituto N acional de lnvestigaciones Agropecuarias (Ecuador) lnstituto Nacional de Investigaci6n y Promoci6n Agropecuaria (Peru) Institut National de la Pomme de Terre (Togo) Institut National de la Recherche Agricole (Senegal) lnstitut National de la Recherche Agronomique de la Tunisie lnstituto Nacional de Tecnologia Agropecuaria (Argentina) Research Institute for Plant Protection (Netherlands) lnstitut des Sciences Agronomiques du Burundi liter latitude late blight land equivalent ratio longitude least significant difference light use efficiency meter milliequivalent minute mega joule milliliter millimeter month nucleic acid spot hybridization test not determined nanometer not significant not studied Ouch terlony double diffusion open-pollinated final population density /initial population density potato leafroll virus Programme National de l'Amelioration de la Pomme de Terre (Rwanda) parts per million Programa Andino Cooperativo de Investigaci6n en Papa (Andean region) Programme Regional d'Amelioration de la Culture de Pomme de Terre en Afrique Centrale (Central Africa) Programa Regional Cooperativo de Papa (Central America-Caribbean) Programa Cooperativo de Investigaciones en Papa (southeast region of South America) potato spindle tuber viroid potato tuber moth Peru tomato virus potato virus M potato virus S potato virus V 13 PVX PVY RH RNA SAPP RAD SD sec SEO t TPS UNA UNDP var. vol vs. wk wt yr 14 potato virus X potato virus Y relative humidity ribonucleic acid Southeast Asian Program for Potato Research and Development standard deviation second standard error of difference ton true potato seed Universidad Nacional Agraria (Peru) United Nations Development Programme variety volume versus week weight year Impact of CIP Research A CIP anthropologist is studying farmer reaction to technological innovation in Rwanda 16 1985 When CIP and the other international agricultural research centers became a part of the CGIAR (Consultative Group on International Agricultural Research) , it was known that the system was looking toward a medium- to long- term investment in terms of achieving technological impact in the devel- oping world. After 14 years, CIP has started to record examples of tech- nology adoption and national potato program development that are having significant impact at the farmer level. The major developments recorded during 1985 are highlighted below. Technology Rapid multiplication techniques and true potato seed (TPS) technology have complementary features - both have been used effectively to provide planting materials in several devel- oping countries. In Vietnam, both of these technologies have resulted in two aggressive programs by farmers on the use of sprout cuttings and TPS for producing potatoes. In the 1984-85 season, 14 hectares of potatoes were grown from sprout cuttings and TPS, thus stimulating the planting of over 100 hectares by each method in the 1985-86 season. Looking to the future, the government of Vietnam is now anxious to expand the area under TPS to many thousands of hectares. Rapid multiplication is also a feature of other national seed pro- grams; for example , the basic seed production project in Peru, which started in 1983, has enabled the national program to produce more than 200 tons of high-quality potato seed in 1985. Given the good climatic conditions at the start of the 1985-86 season, the program expects a sevenfold increase in seed production during 1986. Other countries where these tech- nologies are making a significant impact on supply of seed are the Philippines, South Korea, Ecuador, Cuba, and Guatemala. Ecuador adapted the rapid multiplication system originally developed at CIP, and with a few simple modifica- tions, particularly in the handling of mother plants, has reduced the original seed multiplication program by three generations, or by about two years. This has enabled more rapid dissemination of new varieties to farmers, putting the first seed in the hands of farmers in 1985. Adoption of a rapid multiplication program based on in vitro propaga- tion has also permitted the Centro Nacional de Pesquisa de Hortalic;:as (CNPH) of Brazil to produce , for the first time, small quantities of basic seed in the areas around Brasilia. Antisera production for virus detection in seed improvement programs has been another technol- ogy where CIP has given strong technological support to national programs. Several countries have already been trained in how to produce their own antisera and are now beginning to use this antisera in latex and ELISA serological tests. In Brazil, CNPH has produced latex kits and distributed them to several seed producers to complement visual inspection of crops for symptoms of virus infection. Colombia and Tunisia are two other countries who are also producing their own antisera . The adoption of diffused-light stores (DLS) by national programs has already been well documented in other CIP reports. Following an earlier program of DLS training and demonstrations in Thailand, a 1985 survey of the adoption of DLS technology showed that more than 200 stores had been constructed by farmers in the potato-producing areas of Thailand. In North Africa, failure to control potato tuber moth (PTM) in storage can completely destroy the produce within three months. A collabora- tive study on the epidemiology of PTM in Tunisia, by CIP and the Institut National de la Recherche Agronomique de la Tunisie, has con- firmed that effective control of this pest requires early harvesting (before June 7) , since the moths rapidly increase their egg laying after this period. Early harvest combined with the use of a synthetic pyrethroid insecticide in stores reduced losses after three months of storage to less than ten percent. Even more important, this new system has made it possible for the government of Tunisia to ban the use of the toxic chemical parathion as a pest control in stores. For more than ten years, CIP has been studying the problems of potato production in warm climates. This research, starting with the selection of heat-tolerant clones, has passed through several years of testing improved agronomical methods for potato production as well as the control of potato pests and diseases. In the lowland plains of the Philip- pines, three to five farmers in each of five communities grew potatoes using a technological package that combined the use ofDLS for seed, and agronomic practices such as mulching, optimum planting date, frequent irrigation, and planting in rice paddies after harvest to avoid bacterial wilt. These practices had already been evaluated by CIP's regional team headquartered in the Philippines. Farmer yields ranged from 16 to 25 tons per hectare on the best farms, with only 6 out of 26 farmers getting less than 5 tons per hectare. After harvest, there was a ready market for this crop in nearby towns. Presently, the lowland crop is new, quite small, and is harvested before the main highland crop , thus the the urban consumer must pay high prices for lowland potatoes, or wait until the mainland crop becomes available at lower prices. If a more stable potato supply could be available throughout the year by 17 18 producing a lowland crop, the market supply could be extended by an extra two months. When a greater number of farmers adopt lowland production, increased supplies should result in lower market prices for this crop. The success in the Philippines in demonstrating the feasibility of lowland potato production has become one of the important tech- nologies that SAPPRAD, the Asian potato research network, is trans- ferring to its member countries. Several countries released new varieties in 1985 or now have advanced clones ready for release, selected from segregating mate- rials supplied by CIP. Bolivia ( 1), Burundi (1) , and Peru (2) released new varieties, while Cuba and the Dominican Republic both have selected advanced clones, which are being multiplied prior to official release as varieties. In the Philip- pines, the first selections of bacterial wilt-resistant progenies, with resist- ance derived from crosses using four wild species, have shown excellent resistance to bacterial wilt. This resistance is considerably better than that derived from Solanum phureja, which was the only source previously available. Country Network and National Program Development The cooperative national research networks, which are an integral part of CIP's regional research pro- gram, have further consolidated their research and transfer activities during 1985. The oldest of these, PRECODEP A (Programa Regional Cooperativo de Papa), an associa- tion of programs in Central America, Mexico, and the Caribbean, has now completed seven years of operation. One of the outstanding successes of this association is that the national programs with no previous research results of direct benefit to other group members have now matured and are producing practical tech- nologies through their research, and are therefore contributing actively to solving production problems of member countries. Much of the credit for the research strength that now exists in Honduras, the Dominican Republic, and El Salvador must be given to the active technical support received from other group members in the earlier years. Another achievement of this asso- ciation has been to offer technical assistance to other nonmember coun- tries located within the geographical area. In 1985, the association invited Haiti to become a member, even though Haiti will require a large sup- portive effort from the group to help develop its potato program to meet the farmers' priority needs. SAPPRAD (Southeast Asian Program for Potato Research and Development) started from a rela- tively small scientific base when it first formed in 1980. By 1985, Thailand had an active national potato program, which is making considerable impact at the produc- tion level, particularly in seed storage and germplasm selection. Sri Lanka is already well advanced in TPS research and its use by farmers, and in the Philippines, lowland potato production is beginning to show impressive results. PRACIP A (Program a Andino Cooperativo de Investigaci6n en Papa) , an association formed in 1983 between five countries in the Andean zone of South America, is still devel- oping a stronger interaction between its member national programs. Research results from member coun- tries have amply demonstrated this year that it is of great importance to choose research projects that are specifically related to the needs and within the capabilities of national programs. Bolivia chose to study an urgent problem on how to improve the seed stock of its poorest farmers, who could not afford to buy certified seed. The study showed that these small-scale farmers can improve their own seed by learning how positive selection of healthy plants in existing seed stocks can greatly increase yields. The results were very impressive, and two other member countries are now incorporating this approach into their own programs. The brief summary presented above on the impact of CIP's research in 1985 has focused on the transfer and adoption of practical measures to improve potato production in both the traditional and nontraditional potato-growing areas in developing countries. This is a collaborative experience between CIP and national scientists, however the credit for successful adoption of improved technologies must go to the scientists themselves. CIP's regional scientific team, charged with the task of evaluation, adaption, and transfer of new tech- nologies arising from CIP's research program, numbers less than 15 scien- tists worldwide dealing with more than 70 countries. The country network systems for cooperative research reinforce the horizontal contact between group members, enabling them to benefit from each other's research, and complement CIP's regional research activities. 19 Summary of Research and Regional Programs World Potato Germplasm Collection A project designed to simplify the taxonomy of the series Tuberosa has been concluded. The species Solanum canasense and S. multidissectum were found to be synonyms of S. bukasovii, and S. gourlayi and S. spegaz- zini were found to be synonyms of S. leptophyes. Excellent frost resist- ance was confirmed in S. bukasovii, and several genotypes of S. bukasovii and S. leptophyes exhibited useful levels of resistance to potato cyst nema- tode (Globodera pallida). The useful traits of these two wild species can be exploited in breeding since there are no crossability barriers between them and diploid cultivated potatoes. Resistance to early blight ( Alternaria) was found in the tetraploid wild species S. acaule, thus adding one more useful trait to the relatively long list of tolerances and resistances already identified in this species. More than 6400 seedlings, representing 27 species and 44 specific hybrid combi- nations, were evaluated for resistance to bacterial wilt (Pseudomonas sola- nacearum). The 32 genotypes that survived the screening tests have now entered CIP's regular breeding program for bacterial wilt resistance. As a result of collecting trips in Ecuador, 146 accessions comprising 65 genotypes were added to CIP's world potato collection. This germplasm was collected as a joint effort between CIP, the Instituto Nacional de Inves- tigaciones Agropecuarias (INIAP) in Ecuador, and the International Board for Plant Genetic Resources (IBPGR). The total number of accessions of native Andean cultivars now preserved in vitro is 955; of these, 92 are virus-free and 53 are being freed of viruses. Formal agreements to main- tain duplicates of the in vitro pathogen-tested collection have been made with the Institute of Resistance Genetics in West Germany and with INIAP in Ecuador. A computerized data-management system is now in operation at CIP for the in vitro potato collections. Somatic embryo culture has been improved by the development of a new liquid medium that promotes rapid, vigorous growth of cultured em- bryos and facilitates the culturing and rescue of embryos from seeds of interspecific hybrid combinations. In a research contract with Louisiana State University (U.S.), genetic engineering has been used to improve the quality of potato protein. Synthetic DNA fragments were constructed that code for proteins with a high content of the five essential amino acids, which are normally deficient in plant-derived proteins. The synthetic DNA 20 fragments were inserted successfully into a number of potato clones by using Agrobacterium sp. plasmid vectors. Sweet Potato Collection An international genebank for sweet potato has been started at CIP with an initial acquisition of 1808 cultivated and 297 wild accessions, representing 20 lpomoea species. Collecting expeditions in Peru and Ecua- dor contributed 341 cultivated and 297 wild accessions of sweet potato, which included 20 Jpomoea species and 3 natural hybrids. A total of 150 selected genotypes have already been transferred to in vitro cultures. A field-management system for evaluating and describing the sweet potato collection has been established; and yield performance and morphological characteristics have already been described for 1704 cultivated accessions, of which 660 are of hybrid origin. All data on the sweet potato collection are now stored in a computerized data bank and are available for use. Breeding and Distribution of Advanced Clones A new clone that is high-yielding, early maturing, heat tolerant, and virus immune, code-named LT-8, has been introduced into CIP's seed pro- gram. After being freed from diseases it will be ready for regional distribu- tion in early 1987. Research on the inheritance of resistance to early blight (A. solani) has indicated that rapid progress can be achieved in selecting for resistance to this disease. Although lateness and resistance to A. solani are generally associated, a few early maturing progenies have been found that are re- sistant, e.g., Maine 47 x 378015.16. Several clones that transmit good levels of resistance have been identified, but the most resistant progeny is 65.ZA.5 x 378676.6, which, even though late-maturing, also shows a high level of resistance to late blight (Phytophthora infestans). In the international trials for selecting late blight-resistant clones, 120 of 1541 clones were selected in Colombia for resistance, yield, and earli- ness. The highest-performing clones yielded up to 4400 grams per plant. The top-yielding progenies were P-13 x India 1035 and 73.13.16 F 2 x bulk Phy. 21 In Peru, the use of CIP's materials with resistance to bacterial wilt (P. solanacearum) has increased . For example, in the Department of Caja- marca, the area planted to potatoes, using the Peruvian variety Molinera (released from CIP's germplasm), increased from 19°/o in 1982 to about 78°/o in 1984. A sister clone, BR63. l 5- resistant to late blight, bacterial wilt, powdery scab, and potato leafroll virus-has been selected by the University of Huanuco to be released as a new variety. Significant progress has been made through contract research at Cornell University (U.S.) in combining resistances to potato viruses X, Y, and potato leafroll virus (PLRV). Also at Cornell , experiments have shown that glandular trichomes on the foliage of potato cultivars give protection against both primary and secondary spread of PVY and other nonpersist- ent viral diseases. In another research contract with the Potato Research Institute in Poland, six selected clones - two diploids and four tetraploids - with .combined resistances to PLRV, PVY, PYX, and PYM were sent to Lima for use in CIP's virus breeding program. At CIP, progress has been made in the area of ploidy level manipulation. The number of diploid clones that produce FDR (first division restitution) 2n pollen has increased to more than 200; many of these clones carry resistances to potato pests and diseases. In the use of true potato seed (TPS) for commercial potato production, advances have been made in breeding for yield, earliness, and tuber uni- formity , with three clones being identified as good general combiners for these characteristics. These clones are being freed from diseases and will be available for distribution as parental material in early 1987. CIP distributed pathogen-tested germplasm to 65 countries during the year, which included tubers and in vitro plantlets as well as TPS progenies. The present list includes 182 advanced cultivars and varieties free from dis- ease, 28 advanced cultivars and varieties being freed, 95 primitive cultivars free from disease, and 52 primitive cultivars being freed from diseases. Disease Research Following the successful development of a population bred for resist- ance to bacterial wilt disease in cool climates, CIP is developing a new pop- ulation designed for use in warm climates. This population will include heat tolerance and resistance to root-knot nematode (Meloidogyne spp.), which interact synergistically with the bacterium. Field trials of these ma- terials in both Peru and the Philippines have indicated good progress with respect to resistance and yield; however, extreme earliness in this popula- tion - required for most tropical lowland situations-is lacking, thus em- phasis will be placed on crosses with the best early, heat-adapted clones. In 1985, 1582 clones and 296 tuber families from CIP's late-blight breeding program were sent to ten countries. In Peru, 12 good general 22 combiners were selected for future crossing work on late blight research. Plans were made to establish a second population exclusively for field resistance to late blight. This population would be free of the major genes that are vulnerable to changes in the pathogen. In Burundi, two advanced clones with late blight resistance have been selected for use in multiloca- tional trials. A CIP clone, recently approved as a variety in Kenya, is being considered for release in seven other African countries. Collaborative research with the University of Wisconsin (U.S.) on de- veloping control measures for bacterial pathogens has now confirmed that calcium fertilization of potato plants can increase their resistance to Erwinia soft rot. Good progress has been made in selecting PLRV-resistant materials for breeding work. Through an intensive screening effort, high levels of PLRV resistance were identified in 4 clones from CIP's world germplasm collec- tion and in 20 from the Sturgeon Bay Potato Introduction Station in Wis- consin. Seedling screening for PLRV resistance has been refined by care- fully evaluating the number of viruliferous aphids required per plant for infestation. By using this methodology, it may be possible to reduce the number of susceptible plants escaping into the field during seedling screening. International trials on virus resistance , carried out in several Latin American countries, have made important advances. A clone originally selected in Argentina, B71-240.2, is now being named as a variety in sev- eral countries worldwide because of its resistance to PLRV and PVY. Another clone, 380507 .1 , has been selected in Chile for high resistance to PLRV and good agronomic characters. Three clones selected in Brazil are being multiplied for inclusion in the 1985-86 national potato trials. Modifications to the ELISA test for detection of PLRV and PVY have resulted in a 30°1o increase in sensitivity. During 1985, 40 ELISA and 30 latex kits for virus detection in I 00,000 samples were sent to several de- veloping countries. This represents a hundred-fold increase in the use of serology between 1984 and 1985 by national potato programs. Use of nucleic acid spot hybridization (NASH) for detection of potato spindle tuber viroid (PSTV) has streamlined CIP's ability to guarantee the health of exported and imported germplasm. The number of samples tested for PSTV by this test increased from 5000 in 1984 to 35,000 in 1985. During the year, 40 NASH kits for testing 3865 samples were sent to ten devel- oping countries. To facilitate more efficient immunological detection of potato viruses worldwide, CIP has implemented two approaches to help national pro- grams produce their own antisera. In the first , a country is selected from a region to produce antisera for other countries in the same region, and excellent progress has been made in Brazil, Colombia, and Tunisia. In the second, organizations such as the national potato program ofINIPA (Peru) 23 and the country network PRECODEPA (Central America-Caribbean) have been producing their own antisera by contracting the use of CIP facilities. Integrated Pest Management In Ecuador, six clones with resistance to potato cyst nematode (G. pallida) have been selected for yield and good tuber characteristics. Simi- larly, in Peru, seven clones were selected by the national potato program for G. pallida resistance and good agronomic characters. In screening clones for resistance to potato tuber moth (Phthorimaea operculella) in rustic and diffused-light stores at CIP's San Ramon site in Peru, 43 of 445 resistant clones were identified. Eleven clones were also identified in Colombia as having different levels of resistance to P. oper- culella. Repellent plant barriers continued to give stored potatoes excel- lent protection against tuber moth damage . For example, dried crushed leaves of Eucalyptus globulus layered over tubers were very effective against Symmetrischema plaesiosema, and layers of Eucalyptus globulus or Lantana camara leaves were effective in controlling P. operculella. Use of sex pheromone traps in Egypt significantly lowered tuber moth infestation in the field, and in Tunisia, several formulations of the biological control agent Bacillus thuringiensis and two synthetic pyrethroids were effective against this pest in stores. Mass rearing techniques have been developed in Peru to multiply the wasp Dibrachys cavus-an ectoparasitoid of tuber moth-for testing its potential usefulness in controlling P. operculella. Warm and Cool Climate Potato Production In warm climates the generally recommended application of mulch at the time of planting to improve crop emergence and establishment has hin- dered the customary side-dressing of a split nitrogen application. Experi- ments at two sites in Peru , however, have shown that splitting nitrogen applications does not benefit tuber yield . For the soil characteristics at these two sites, the application of all nitrogen fertilizer at planting was satisfactory. Such a practice would obviate the need to hill-up and would therefore reduce the possible entry of bacterial wilt or other pathogens into the crop. The quantity and temporal distribution of water are major determinants for achieving high potato yields in warm climates. Through detailed studies on the use of irri~ation water for potato production in these climates, the optimal practices for maximum growth have been quantified. In studies on intercropping potato and maize, the most beneficial asso- ciation was when these two crops were planted simultaneously and sys- tematically at a proportion of 9: 1. Equidistant spacing between maize plants in the mixed plots gave minimum clustering, and therefore maxi- mum shading late in the potato crop cycle. The incidence of several pests 24 and diseases, including bacterial wilt and potato tuber moth, was reduced by this intercropping system. Two major constraints to warm-climate potato production are lack of seed tubers and field space due to demographic pressure; however, these constraints can be managed by beneficial systems that assist small-scale farmers in improving their production needs. For example, a new low- input system, with little or no reliance on seed tubers, has been developed that can satisfy the year-round potato production requirements of a six- member family . This system is based on the use of stem cuttings and TPS seedlings. Screening and selection for heat-tolerant materials has shown good re- sults in the countries of Africa, Southeast Asia, Latin America, and the Caribbean. Progeny testing of second generation clones at CIP's lowland site in Yurimaguas, Peru, has reemphasized the breeding values of LT-7 and 7XY. l as parents. Also, two new clones have emerged as good parents in a sample of 700 first generation clones. In Senegal, clones LT-5, LT-6, and CFK-69. l had comparable yields to those of Desiree and acceptable tuber characteristics. On-farm evaluations of recently released varieties in Burundi have confirmed their superiority over local varieties, the early bulking variety Muziranzara was particularly outstanding. In Southeast Asia, the cultivars Serrana and B71-240.2 are widely adapted throughout the area, but the lack of seed is a major constraint to increasing their use. Efforts have been made to solve this problem by promoting rapid multi- plication techniques in the individual countries concerned. In Cuba, two clones have been selected from the heat-tolerant tuber families supplied by CIP and are being rapidly multiplied by in vitro techniques. In research on potato production in cool climates, collaborative breed- ing work in Colombia has resulted in the development of new clones with frost resistance. The highly successful collaborative project with the Chilean potato program, on the evaluation of the adaptability of the high- land tropic population to long days, has resulted in the selection of 32 clones for local use . The national program has reported that 72°/o of these clones had marketable yields equal to or greater than those of the locally adapted cultivars. Postharvest Technology As a result of three years of on-farm storage trials in Peru, it has been shown that storage losses in small quantities of consumer potatoes can be reduced from an average of 3.8°/o a month in traditional storage systems to 1.4°/o a month by using simple storage boxes and a chemical sprout inhibitor. Storage research in Tunisia has resulted in the development of an excellent, inexpensive alternative to cold storage of seed tubers. The new system comprises a sequential combination of storage in traditional 25 stores (dark storage under straw) and diffused-light storage. The new sys- tem provides seed for the early planting season and is rapidly gaining farmer acceptance. The dried potato mixture M-6 continues to receive good acceptance in consumer tests in Peru. Various mixture formulations of potato and other locally available products, as well as alternative products and processes, are being evaluated for use in Peru and other developing countries. Seed Technology The production and use of TPS have received major emphasis through- out the year. Research on TPS production in Peru and Chile has shown that factors such as the amount of nitrogen, pruning of excessive flowers, and stem density significantly affect TPS quantity and quality. In Chile, through a collaborative project with the national potato program, massive production of hybrid seed was achieved under optimum environmental conditions in Osorno, located in the southern part of the country. The average production was about 8 grams of hybrid seed per square meter. The five kilograms of seed produced at Osorno will be distributed to other national programs around the world. In Peru, newly selected hybrid and open-pollinated (OP) progenies to be used as seedling transplants showed an improvement in average tuber size and yield. Selection for rapid recovery from transplanting shock has also progressed and modifications in agronomic practices have improved tuber bulking in this material. Highly promising results have been obtained in intensive TPS progeny testing and related agronomic research carried out in Peru and other Latin American countries, as well as in Africa, and South and Southeast Asia. For example, in Chile, two hybrids transplanted as seedlings (Atzimba x RI 28.6 and DT0-33 x RI 28.6) gave better yields than the two varietal controls. In Bangladesh, Atzimba x Rl 28.6 and OP progenies CIP 800226 and P-111 were among the highest yielders, with yields equal or superior to yields of standard seed sown from seed tubers. TPS progenies evaluated in the Philippine lowlands gave good yields, but the hybrid LT-2 x I gave yields of more than 30 tons per hectare (on a per plant basis). In Vietnam, at least 8 kilograms of OP seed of two cultivars, CFK 69.1 and Atzimba, will be collected for distribution to farmer cooper- atives during 1986. Potatoes in Developing Country Food Systems In I 985, dot maps were developed and overlaid with agroclimatical and socioeconomic maps, giving the most up-to-date information on potato- production areas in the developing world. Analysis of country-level sta- tistics indicated that the potato ranks among the top five food crops in tonnage and in monetary and food value. Total potato production in the 26 developing world has tripled since 1960, with the greatest increases occur- ring in Africa, Asia, and Central America. Since 1960, potato production has tripled in Rwanda, Bangladesh, India, and Pakistan, and more than doubled in Madagascar, Cuba, Mexico, and several North African and Mid- dle Eastern countries . China alone now produces more potatoes than all of Western Europe . Potato consumption in most developing countries has grown somewhat more rapidly than production since 1960, and better technology has reduced postharvest losses, while increasing yields have lowered the proportion of the crop that must be reserved for seed. Potato yields are now, on the average, 80°/o higher in developing countries than in the 1950s and have increased, except for the Far East, by at least as much as cereal yields and much more than yields of other root crops. Studies on adoption and use of potato varieties by farmers in Peru and Rwanda showed that farmers ' decisions are strongly influenced by socio- economic factors. Marketing research has suggested that the potato has an unexploited potential for helping to satisfy the growing rural demand for food in sub-Saharan Africa; while in Bhutan, the national program, through collaborative work with CIP, is now beginning to identify and solve potato marketing problems for that country. 27 28 Arid ------.J Highlands ---------' Mid-elevation tropics ---------~ Low, humid tropics --------------' Agroecological Zones of Peru T he cultivated potato originated on the high plains ( altiplano) in what are now parts of Peru and Bolivia. This center of diversity is not only for the potato but also for its major pests and diseases. CIP has four experimental stations located between latitudes 6° and 12° S that represent the four major agroecologi- cal zones of Peru : Lima-La Molina, arid; Huancayo, highlands; San Ramon, mid- elevation tropics; and Yurimaguas, low, humid tropics. The small range of lati- tudes gives little variation in daylength, but the geographical location of CIP's sta- tions ensures wide variation in altitude, temperature , rainfall regimes, soil types, and incidences of pests and diseases. All major climatic characteristics of tropical zones found in the developing world are represented within Peru's four agroeco- logical zones. CIP research sites in Peru and the potato-growing seasons, with meteorological data for 1985. Site : Lima-La Molina Huancayo San Ramon Yurimaguas Latitude : 12° OS'S 12°07'S l 1°08'S 5°4l'S Altitude: 240m 3280 m 800m 180m Growing season: Jan-Mar May-Nov Oct-May Nov-Mar May-Aug May-Aug Air max (°C) 28.25 20.41 19.69 28.88 28.60 30.77 Air min (°C) 19.20 13.72 6.63 18.21 15.02 20.52 Evaporation (total mm) 600.S 711.81 1096.0* 736.61 562.2 260.1* Rainfall (total mm) 2.5 6.9 703.7 1062.9 304.7 521.7 Solar radiation (daily MJ/m2 ) 19.14 10.73 18.73 18.75 14.49 no data *Evaporation using Piche evaporimeter. 29 THRUST I Maintenance and Utilization of Unexploited Genetic Resources Valuable new sources of genetic resistance to bacterial wilt, early blight, soft rot, potato cyst nematode, and frost have been identified in CIP's potato germplasm collection. Six important species of the series Tuberosa were shown to represent only two good species. The taxonomic simplifica- tion of this material will streamline its use in breeding. In 1985 CIP's world potato collection received 146 new accessions as a result of INIAP/IBPGR/ CIP collecting trips in Ecuador. Work continues on identifying and elimi- nating duplicates. In both the newly acquired and world potato collections, 904 duplicates were identified. Of the 955 native Andean cultivars now pre- served in vitro, 92 are virus-free and 53 are being freed of viruses. A comput- erized data-management system for the in vitro collection has been developed. Formal agreements for maintaining duplicates of this in vitro collection have been made with the Institute of Resistance Genetics in West Germany and also with the National Institute of Agricultural Research in Ecuador. Prelimi- nary findings suggest that the use of in vitro tubers may dramatically improve germplasm conservation by increasing storage time before vegetative renewal of the material is required. Through genetic engineering, synthetic DNA fragments that code for amino acids, which are normally deficient in potato, have been inserted into the potato genome by using Agrobacterium plasmid vectors. The production of the corresponding messenger RNA and synthetic protein with the potato has been confirmed. A sweet potato gene bank with 1808 cultivated and 297 wild accessions, representing 20 Jpomoea species, has been established at CIP. Data on mor- phological characteristics and yield are being accumulated and stored in a computerized data-management system. Work in the newly established sweet potato germplasrn collection at CIP. 31 n. p1VJV1,.,l VH UJV,)y,)u:::Uldll\. ... dHU l!llYlU~ genetic studies in the taxonomic series Tuberosa was successfully concluded in 1985, reducing a group of six species to two, which simplifies the taxonomy of the series considerably. The species So- lanum canasense and S. multidissectum were found to be synonyms of S. buka- sovii; and S. gourlayi and S. spegazzini were found to be synonyms of S. lep- tophyes. In several evaluations, the high frost resistance of S. bukasovii was con- firmed and , in addition, various genotypes . of this species were found to have resist- ance to several pathotypes of the cyst nematode Globodera pallida. Resistance to G. pallida was also identified in several genotypes of S. leptophyes . Since there are no crossability barriers between these two wild species and diploid cultivated potatoes, this gene pool is available for breeding. UTILIZATION STUDIES Sixty accessions representing ten species were evaluated for their resistance to early blight (Alternaria sp.). Relatively good re- sistance was found in the tetraploid wild species S. acaule, adding one more resist- ance to the relatively long list of toler- ances and resistances already identified in this species. A total of 6500 seedlings, representing 27 species and 44 specific hybrid com- binations, were evaluated for their re- sistance to bacterial wilt (Pseudomonas solanacearum). In the first step of this screening program, the seedlings were in- oculated with strain 204 (biovar II, race 3) from Peru; the resistance of the survivors of this test was challenged in a second test against the same pathogen strain by using plants grown from tubers. The sur- vivors of the second screening were tested 32 L'-VV'111U'1. v111y JL,, Ul Lilt:: UJVV gt::IIULypes survived the rigors of these three screening tests, and this material has now entered the regular CIP breeding program for re- sistance to bacterial wilt . In a continued search for further sources of resistance to bacterial wilt, we conducted a second set of screening tests in which evaluation was done on 800 seed- lings from ten progenies of S. sparsipilum (until now the major source of resistance in wild species), 800 seedlings from nine progenies of S. bukasovii, and 750 seed- lings from seven specific hybrid progenies (each involving S. sparsipilum as one par- ent) . All progenies tested exhibited resist- ance. In S. sparsipilum, resistance ranged from 25°/o to 85°/o of resistant genotypes per seedling progeny and in S. bukasovii from 20°/o to 70°/o per progeny. The hy- brid combinations generally exhibited a higher degree of resistance than the pure S. sparsipilum progenies. In the combina- tion S. marinasense x S. sparsipilum, the proven resistance of the S. sparsipilum parent did not find expression, and the hybrid progeny exhibited extremely low levels of resistance. These results provide CIP's breeding program for resistance to bacterial wilt with well-tested parental material. From a group of native Andean culti- vars with a high level of resistance to soft rot (Erwinia sp.) , 22 progenies were pro- duced for further evaluation and eventual incorporation into germplasm adapted to warm climates where Erwinia is a serious constraint to potato production. GERMPLASM MAINTENANCE, DISTRIBUTION, AND EVALUATION New potato germplasm was collected in Ecuador in a joint effort by CIP, the Na- tional Institute of Agricultural Research (INIAP), and the International Board for Plant Genetic Resources (IBPGR). A to- tal of 146 accessions, comprising approxi- mately 65 genotypes, were added to CIP's world potato collection. Duplicates were identified in a collection of Andean cul- tivars that had been received in 1983 from the Bolivian Institute of Agricultural Technology (IBT A) and the University of Ayacucho in Peru . These two donors pro- vided 1218 accessions, of which 528 were identified as duplicates of 170 different cu ltivars. CIP has provided these two do- nor institutions with evaluation data on this new material. During clonal propaga- tion of the world potato collection , 376 additional duplicates of 105 genotypes were identified on the basis of morpho- logical and electrophoretic data. The total number of accessions of native Andean cultivars now preserved in vitro is 955; of these, 92 accessions are virus-free and 53 are in the cleanup process. During the year, CIP developed a computerized data-management system for the in vitro collections. Duplicates of the in-vitro pathogen-tested collection have been maintained for several years at the Institute of Resistance Genetics in Gri.inbach, West Germany, on an infor- mal agreement with CIP, and in 1985 the agreement to maintain this duplicate col- lection was formalized. Another arrange- ment has been made to store a duplicate set of the in vitro cultures of the germ- plasm collection in an INIAP laboratory in Ecuador. The use of in vitro tubers is being studied in several experiments such as the yield of these tubers in seedbeds, meth- ods of breaking dormancy, and their pos- sible use in germplasm distribution and conservation. In vitro tubers were shipped to nine national programs in 1985 on an experimental basis as a collaborative pro- I I I Figure 1. In vitro tubers induced on the c lone Mariva, mean diameter of tubers is approxi- mately 5mm. The tubers are induced by adding chlorocholine chloride to the culture medium. gram to test the potential of using these tubers for international germplasm distri- bution (Fig. 1). Some important advan- tages to exporting germplasm in vitro are year-round availability, further and rapid propagation of the material in vitro after receipt, and reduced shipping and hand- ling costs. In the germplasm conserva- tion studies, in vitro tubers from a se- lected number of genotypes were stored on growth-restricting media at 6° -8° C. Preliminary results indicated that this procedure could add an additional year to 33 the time needed between vegetative re- newals and transfers of this material. IN VITRO TECHNIQUES FOR GERMPLASMIMPROVEMENT A new liquid medium was developed for the culture of somatic embryos. Use of the medium results in rapid and vigor- ous growth of cultured embryos and has also been successful in the culturing and rescue of embryos from seeds of inter- specific hybrid combinations. The tissue culture rescue of these embryos is of val- uable assistance to both potato breeders and taxonomists in producing progeny from crosses that would otherwise be im- possible . Plants have been regenerated from cul- tured roots of four potato clones, and the morphology of plantlet regeneration has been studied in detail. Plant regeneration from leaf disks has also been successful: when leaf disks were cultured on an ap- propriate medium, small calluses formed around the cut edge of the disk and two weeks later plantlets began to regenerate. In 1984, contract research with Loui- siana State University (U.S.) led to pro- duction of a series of synthetic DNA frag- ments that were constructed to code for proteins with a high content of the five essential amino acids-methionine, lysine, isoleucine, threonine, and tryptophan - which are deficient in plant-derived pro- teins. During 1985 the tissue culture com- ponent of this project was conducted at CIP where we successfully inserted DNA fragments into a number of potato clones by means of Agrobacterium sp. plasmid vectors. The insertion of these fragments into the potato was confirmed by bio- chemical methods. We also proved that the plant produces the corresponding mes- senger RNA and the final synthetic pro- tein, rich in essential amino acids. 34 ESTABLISHMENT OF SWEET POTATO COLLECTION An international gene bank for sweet potato was established at CIP in 1985, with the acquisition of 1808 accessions of cultivated material, of which 1467 were donated to CIP and 341 were col- lected through IBPGR-sponsored expedi- tions. Sources of the material are shown in Table 1. Fourteen collecting expedi- tions were completed by a CIP scientist during 1985: 12 covered large areas of Peru and 2 were in Ecuador. In total , 638 accessions were collected in 314 localities, and areas of high genetic diversity were identified. The total collection consisted of 341 cultivated and 297 wild accessions, comprising at least 20 Jpomoea species and 3 natural hybrids. Table 1. Sources of sweet potato germplasm assembled at CIP . ·No. of Sou rce Country accessions R . d el Carpio (private) Peru 1119 Ayacucho Un iversity Peru 306 T acna University Peru 19 U .S. Vegetable Labo- ratory (So. Carolina) USA 23 CIP/ IBPGR Collection Peru 308 CIP/ IBPGR Collection Ecuador 33 Total 1808 All available information on the collec- tions donated to CIP as well as informa- tion obtained from the IBPGR-sponsored collections have been stored in a com- puterized data bank. A total of 150 se- lected genotypes have been transferred to in vitro cu ltures. A field-management sys- tem for the evaluation and description of the sweet potato germ plasm collection has been set up at CIP. Morphological evalua- tion has already advanced on a large part of the cultivated collection. Yield per- formance has also been evaluated and de- scribed for 1704 cultivated accessions, of which 660 are of hybrid origin. All infor- mation is readily available to breeders, na- tional programs, and research institutions working with this crop. 35 JJ1Dt;t.:;, _5,., ,.,,,_,Lr J2 d<:» THRUST II Production and Distribution of Advanced Breeding Material A new clone, LT-8, which is high-yielding, early maturing, heat tolerant, and immune to potato viruses X and Y, was introduced into CIP's seed program for disease cleanup and regional distribution. Genetic research on resistance of potato to early blight ( Alternaria solani) has indicated that rapid progress can be made in selecting desirable material. Early maturing clones with resistance to A. solani have also been identified. Considerable progress has been made in selecting clones for resistance to late blight and bacterial wilt and to a combination of both. In the area of ploidy manipulation, an increased number of clones have been selected that produce FDR (first division restitution) 2n pollen and carry resistance to pests and diseases. Great differences in general combining ability for yield and other attributes have been found within a set of highly selected diploid clones that produce 2n pollen by the FDR mechanism. The international true potato seed (TPS) progeny evaluations, carried out in six countries, permitted the identification of three promising progenies that have shown stability of performance and good tuber uniformity. Three new clones have been introduced into the seed program for disease cleanup; they have a very high general combining ability for yield and tuber uniformity and are to be used for production of TPS progenies. CIP genetic materials were distributed to 65 countries in 1985, where there is an increased interest to use CIP's advanced germpJasm. LT-8, a heat-tolerant and early maturing clone (1.2 kg/plant in 82 days), immune to both PVX and PVY. 37 DEVELOPMENT OF ADV AN CED CLONES During the 1985 summer and winter sea- sons in Lima, 2400 clones at various stages of selection were tested. In the summer evaluations, the performance and early maturity of clone 379706.27 (LT-Ix XY bulk) was confirmed, with a yield of 1560 g/plant in 90 days. This clone, with the code LT-8, has been introduced into the seed program to be cleaned from dis- eases and should be ready for regional dis- tribution in early 1987. LT-8, under heat stress, does not show tuber cracking or secondary growths and is also immune to potato viruses X and Y (PVX and PVY). During the winter evaluations, over 100 clones yielding more than 3000 g/plant were identified. The top-yielding clone was C83-245 x Yur bulk, with 11 plants producing 4300 g/plant in 120 days. In Bangladesh, two clones, CIP 720088 and Kufri Lalima, have been selected by the Bangladesh Agricultural Research In- stitute (BARI) after extensive evaluation and have been recommended for official release in 1986 . Both possess a high de- gree of field resistance to late blight and are high yielding; CIP 720088 also has long dormancy and excellent storability. GENETIC RESEARCH Early blight (Alternaria solani). Several experiments, including three diallels, three line x tester designs, and one North Caro- lina Design I , were evaluated at San Ra- mon to investigate the inheritance of re- sistance to early blight (A. solani). Plants from these experiments were inoculated with a suspension of A. solani spores 45 days after transplanting, and no pesti- cide was applied during the entire 90-day growing season. From the diallel experi- ments an estimate of narrow sense herit- ability of h 2 = .72 was obtained for A. 38 solani, indicating that rapid progress is possible in selecting for resistance to this pathogen. Although lateness and resistance to A. solani are generally associated , a few early maturing progenies with resistance (e.g., Maine 47x 378015.16) have been found. From the experiments at San Ramon, a number of clones were identified that transmit a good level of resistance, the most remarkable ones being 378676.6, LT-7, BL 2.9, and 7XY.l. The progeny 65.ZA.5 x 378676.6 was the most resist- ant to A. solani, and even though late- maturing, it also showed a high level of resistance to late blight . International collaborative research. Argentina. Through a research contract with the National Institute of Agricul- tural Technology (INTA) in Balcarce, a collection of 15 highly selected tetraploid clones with field resistance to potato leaf- roll virus (PLRV) and PVY or both has been made available to CIP for use in its virus breeding program. Canada . New collaborative research with the Agriculture Canada Research Sta- tion includes studies on environmental ef- fects on the nutritional value of breeding materials. Sixteen clones, including tuber- osum cultivars and sel!'!ctions of andige- na, tuberosum x andigena , diploid-haploid and 4x-2x hybrids, were evaluated in New Brunswick during 1985. Agronomic data, yields, specific gravities, and boiling and chipping scores have been recorded, and nutritional analyses are in progress. Addi- tionally , 29 more clones have been multi- plied for 1986 trials in Peru and Canada. Netherlands . The Department of Plant Breeding at the I.V.P. Agricultural Uni- versity, Wageningen, has started a highly promising breeding program using wild potato species. Different accessions of Solanum brevidens (a source of high lev- els of resistance to PLRV and PVY), S. jamesii Pl 275265 (a potential source of resistance to Pseudomonas solanacearum), S. verrucosum (a source of late blight re- sistance) are being combined with S. tu- berosum cultivars chosen for earliness and complementary resistances. Pseudo- gamous apomictic seed production has been observed in diploid as well as in tetraploid genotypes by using S. phureja as pollinator. Research on the use of cytoplasmic male sterility (ems) for effi- cient TPS production is in progress. Two accessions of S. verrucosum crossed to a dihaploid and a homozygous diploid clone have produced F1 progenies show- ing eclipse and tetral cytoplasmic steril- ity, respectively. Inheritance studies on both types of ems at the diploid level are being conducted. Poland. At the Potato Research In- stitute in Koszalin, diploid clones have been produced that combine resistance to PLR V with 2n pollen production. In an effort to combine resistance to PLRV with other viruses in diploid material , 60 clones were selected for good yield and tuber characteristics in a preliminary eval- uation. In 27 of these clones, resistances to PLRV, PVY, and PVM were found , and in the remaining 33 resistances to PLRV and PVY were recorded . Six selected clones, two diploids and four tetraploids, with combined resistances to PLRV, PVY, PVX, and PVM were sent to CIP for use in the virus breeding program. United States. Significant progress has been made at Cornell University, New York, in combining resistances to PLRV, PVX, and PVY. The five traits of heat tolerance and resistances to bacterial wilt, root-knot nematode, late blight, and PVY are being combined in a population for warm environments. For this purpose, four specific sources of germplasm have been used: S. sparsipilum, S. phureja, tu- berosum, and neotuberosum. In trials testing for resistance to ear- ly blight (A. solani), clones N503 .158, NY67, and NY72, and the variety Elba showed high levels of resistance. In re- search on insect resistance, larvae of the Colorado beetle, confined to the wild Bo- livian potato S. berthaultii, suffered slow growth, retarded development, and high mortality compared to larvae feeding on the cultivated potato S. tuberosum. Ex- perimental field and greenhouse work has shown that the glandular trichomes of S. berthaultii limit spread of PVY. The re- sults of these experiments indicated that a potato cultivar with glandular trichomes is protected against both primary and sec- ondary spread of PVY and other non- persistent viral diseases. Through contract research at North Carolina State University, diploid clones, highly selected for various traits such as heat tolerance, high dry matter content, and resistances to early blight and Erwi- nia, have been assessed for pollen produc- tion. Several of these clones produce FDR (first division restitution) 2n pollen and are thus very valuable for breeding purposes. High levels of resistance to ear- ly blight have been found in progenies of 4x -2x crosses between susceptible tetra- ploids and resistant diploids. Resistance in the diploid clones to soft rot and black leg was studied in the laboratory as well as in the field . The field results revealed a high degree of correlation with the labo- ratory data. Field evaluations conducted by the Uni- versity of Wisconsin on selected haploid- wild species F1 hybrids showed that these hybrids had a high yield potential; in some cases they yielded as much as tetra- ploid cultivars. The yield of 2x parents has not been found to correlate to the yield of the 4x hybrid following 4x -2x crosses. Consequently, a careful assess- ment of the parental value of 2x parents 39 is necessary. Research on the evaluation of haploids (2n=2x=24) as a method of gametic sampling, enabling the researcher to draw conclusions on how a character is genetically controlled, is underway. Stud- ies on the inheritance of specific gravity, on reducing sugar accumulation, and dor- mancy are being conducted with the hap- loids extracted from Merrimack, Chippe- wa, and W23 l tetraploid cultivars. These studies will provide the basis for further improvement of these characteristics in commercial potato varieties. Also at Wisconsin, studies relating to the use of TPS were conducted by using tetraploid clones that have low to varia- ble male fertility and that produce tubers with white flesh. These clones were inter- planted with diploid clones that produce tubers with yellow flesh as well as FDR 2n pollen with no crossover. Since yel- low flesh is dominant over white flesh, hybrids had yellow flesh and selfed geno- types had white. Only 24 of the 445 progenies (about 5°/o) grown from the open-pollinated (OP) seeds produced by the tetraploids had yellow tuber flesh, indicating their hybrid origin. These hy- brids yielded on the average 0.69 kg/hill, while the plants that originated from self-pollination yielded only 0.31 kg/hill. Open-pollinated fruit set was higher on the hybrids, which had 2.75 fruits per plant versus 0.05 fruits on plants that had originated from self-pollination. Thus the hybrids, which constituted only 5°/o of the first generation OP progeny, produced 78°/o of the second generation OP fruit. These results will help to improve the use of TPS technology in commercial potato production for the developing world. POPULATION DEVELOPMENT Late blight resistance. International test- ing and selection of clones with resist- 40 ance to late blight (Phytophthora infes- tans) continued in Colombia. A sample of 1541 clones grouped in 118 families was sent to Colombia for testing at ICA's research station in Rionegro. At harvest, 120 days after planting, 120 clones were selected for earliness, yield, and resistance to late blight. The highest performing clones yielded up to 4400 g/plant; the top-yielding progenies were P-13 x India 1035 and 73.13.16 FxbulkPhy. Bacterial wilt resistance. The use of CIP materials with resistance to bacte- rial wilt (Pseudomonas solanacearum) has increased in Peru. Farmer cultivation of the variety Molinera-previously re- leased from CIP's advanced germ plasm - increased from 19°/o in 1982 to an esti- mated 78°/o in 1984 in the Cajamarca De- partment (northern highlands). A sister clone of Molinera, BR63.15, has been se- lected by the University of Huanuco to be released as a new variety. In addition to being resistant to P. solanacearum, it is resistant to late blight, powdery scab, and PLRV. In the South Pacific, farmers on Fiji continue to grow the bacterial wilt- resistant variety Domoni, released from CIP's materials in 1983. In Sri Lanka, the potato program of the Department of Agriculture, after five years of testing clones for bacterial wilt resistance, has selected CIP clones 800224 and 800226 for resistance to races 1 and 3 of P. so- lanacearum. Three more clones selected from tuber families also showed prom- ise: 3778475, 377850.2, and 377852.2. All three were resistant to race 1, while 3778475 and 377852.2 were also resist- ant to race 3 and still remain resistant to late blight. Development of 2x populations with 2n pollen production and specific attri- butes. The goal of potato breeding at the 2x level is to select 2x clones with a specific attribute, good agronomic char- acters, and FDR 2n pollen production. Until last year, only several clones were available with both 2n pollen production and specific attributes. Thus a new 2x population was created by making crosses among selected diploids with specific re- sistances and/or FDR 2n pollen. More than 5000 seedlings from 206 families with different attributes and genetic back- ground were checked for 2n pollen pro- duction, which was found with different frequencies in 689 seedlings. Of these, 288 seedlings had more than 1°/o of 2n pollen frequency and will be useful for 4x-2x crosses; however, at harvest some were eliminated due to poor tuber traits. From the original group of 5000 seed- lings, a total of 216 clones were selected as 2n pollen producers with potential re- sistance to important pests (Table 1 ) . This year's progress was highly signifi- cant in two aspects. First, the number of clones with 2n pollen production was increased from 7 or 8 for 1984 to 216 Table 1. Clones selected for production of 2n pollen with specific resistances to pests or dis- eases. Resistance No. of clones Root-knot nematode (RKN) 63 Bacterial wilt (BW) 4 Late blight (LB) 12 Cyst nematode (CN) 13 Potato virus Y (PVY) 10 Potato leafroll virus (PLRV) 16 BW/RKN 24 LB/RKN 28 PLRV/RKN 6 PVY/RKN 15 CN/RKN 4 PLRV/LB Early blight/others 20 in 1985 . Second, many clones had com- bined resistances such as bacterial wilt and root-knot nematodes, which are im- portant for potato production in warm areas. TRUE POTATO SEED Progress has been made in breeding for yield, earliness, and tuber uniformity for the use of true potato seed (TPS) in com- mercial potato production. After several years of testing, three clones have been identified as good general combiners for these three characteristics. These clones have been introduced into CIP's seed pro- gram for cleanup from diseases and will be ready for regional distribution as pa- rental material in early 1987. The first clone (379706.34) is a tuberosum x andi- gena PVY immune clone, and the other two (378015.13 and378015.16) are heat- tolerant tuberosum clones from the same cross. In 1985, the international TPS prog- eny evaluation trials were started by test- ing a sample of 25 TPS progenies in six countries: Egypt, Tunisia, Brazil, Rwan- da, Philippines, and Peru. Several proge- nies such as Serranax LT-7 (Fig. 1), At- zimbax7XY.1, and C83.551xLT-7 were stable in yield and tuber attributes. Simi- lar trials will be repeated on a yearly basis to permit national potato programs to se- lect in situ progenies adapted to local conditions. At CIP-Lima, the performance of ad- vanced OP progenies (OP2 and OP3 ) was tested against that of OP1 progenies. The results indicated that in most of the OP2 and OP3 progenies, quantitative and qual- itative characters were better than in the OP1. This suggests that it is possible to re- move the effect of inbreeding depression, expressed in vigor and yield, by selecting appropriate genetic starting material. 41 Figure 1. High-performing TPS progeny in the 1985 international TPS progeny evaluation trials . 42 The effect of parental line selection on the earliness of TPS progenies was stud- ied at San Ramon by using two families of the 1984 TPS populations. Progeny No. 1 was rated as very early while No. 2 was rated as early. Harvesting the crop at two different periods only affected the yield of progeny No. 2. The yield of progeny No. 1 ranged from 20 to 24 t/ha at 60 and 90 days, while for No. 2 the difference was much larger (Fig. 2). The results have shown that by selecting very early progenies, the growing period of TPS will be reduced and that the adap- tation to tropical environments of TPS progenies will be increased. Early selection of seedlings for vigor in the performance of OP progenies was very effective in experiments conducted at San Ramon, Huancayo, and Lima. Open-pollinated seed of ten clones was used for the early selection of seedlings. Within each OP seed lot, the following levels of selection were applied: 80°/o, 40°/o, 26°/o, 20°1o and 16°/o. These ex- periments showed clearly that by increas- ing the number of seed in the nursery and Weight/plant (g) 1000 • 800 • 600 400 I 200 0'--=- 2 TPS progenies Figure 2. Comparison of yield per plant for two TPS progenies harvested at 60 and 90 days, San Ramon. kg 9.5 r-------------.---,-~ 7.6 5.7 3 .8 1.9 2 3 4 5 Levels of selection Figure 3 . Effect of the level of selection in tuber yield per plot. by selecting the most vigorous seedlings for transplanting, a significant increase in yield as well as other characters in the OP progenies can be obtained (Fig. 3). GERMPLASM DISTRIBUTION During 1985, CIP distributed pathogen- tested germplasm to 65 countries in both developed and developing countries (Ta- ble 2). The shipments included tubers and in vitro plantlets from pathogen-tested as well as TPS progenies; also distributed were advanced populations segregating for pest and disease resistance as well as stress tolerance. The inventories of tubers and TPS progeny are sufficient to respond to immediate requests, and tuber families are being produced for distribution in 1986. The pathogen-tested list includes 182 advanced cultivars and varieties free from disease, 28 advanced cultivars and varieties being freed, 95 primitive culti- vars free from disease, and 52 primitive cultivars being freed from diseases. In southern Chile , collaborative TPS production with the Agricultural Research Institute (INIA) greatly increased with 43 Table 2. Genetic materials exported from CIP-Lima, October 1-September 30, 1985. Cultivars In vitro plants Tuber families TPS families TPS progeny CIP A cc es- Acces- A cc es- Acces- Acces- region sions Units sions Units sions Units sions Units sions Units 410 7,609 42 359 215 2,947 46 4,980 25 209,000 11 886 10,356 244 1,220 231 8,464 99 11,270 77 358,000 111 268 1,789 30 82 113 4,251 20 4,000 19 92,000 IV 32 359 25 87 87 2,257 48 13,000 30 489,000 v 75 909 2 15 54 1,808 20 4,000 34 202,000 VI 119 1,648 4 33 88 5,203 20 4,000 41 912,833 VII 305 2,498 73 291 295 11,670 78 18,805 42 291,000 VIII 63 251 76 152 20 4,000 6 12,000 Othersa 75 503 302 615 200 7,803 62 13,875 13 46,000 Total 2,233 25,922 798 2,854 1,283 44,403 413 77,930 287 2,612,633 a Developed market economies and centrally planned economies . NOTE: Regions 111 and VI I have also been distributing materials within their regions, but this material is not included in the table. production of over 5 kg seed of six hy- brid progenies. As a result of this last pro- duction, CIP's export of TPS progenies increased fivefold over that of 1984. TRAINING Two CIP germ plasm management courses, one held in Kenya and Rwanda and the other in the Philippines, were attended Participants in the CJP germplasm course in Kenya discuss variety perform- ance with the manager of the Agricultural Development Corporation seed farm at Molo. 44 by 27 scientists from Africa and Asia . This was the first such course in East and Central Africa and the second in South- east Asia. The courses were planned spe- cifically to train scientists from those countries that receive CIP's germplasm from the distribution centers near Nairo- bi (Kenya) and Los Banos (Philippines). Since 1981, eight CIP germplasm man- agement courses have been given through- out the developing world with more than 115 scientists participating. During the year, more than 50 scientists attended CIP courses on tissue culture and rapid mul- tiplication techniques, presented in the Near and Middle East, North and West Africa, and Southeast Asia. 45 THRUST Ill Research on Bacterial and Fungal Diseases A new population bred for resistance to bacterial wilt in warm climates is being developed. CIP's initial bacterial wilt-resistant population is being used in cool climates; however, it lacks resistance to heat and root-knot nema- tode , which interact synergistically with the bacterial wilt pathogen (Pseudo- monas solanacearnm). A rapid method for visually distinguishing strains of P. solanacearnm in culture has been developed. In contract research at the University of Wisconsin, greater strain specificity of antisera for P. solanacea- rum was achieved ; it appears that unique antigenic determinants in the outer membranes of the bacteria are related to pathogenicity. Selection for bac- terial wilt resistance has continued in several regional locations. In Burundi and Kenya, clone 720118 (Cruza 148) and several others are exhibiting use- ful levels of resistance. Clone 720057 has been eliminated due to poor per- formance in multilocational trials. Experiments in the Philippines confirmed that root contact can increase spread of bacterial wilt. Also at Wisconsin, it was confirmed that tuber soft rot can be controlled by applying calcium to the soil. CIP's late-blight breeding program distributed 1582 clones and 296 tuber families to ten countries in 1985. In Peru 12 good general combiners were selected for future crossing work in late blight research. Plans were estab- lished to develop a second population exclusively for field resistance to late blight, without the major genes that are vulnerable to genetic changes in the pathogen. In Burundi, two advanced clones with late blight resistance, 720123 and 720125, have been selected for use in multilocational trials. In Kenya, CIP clone 800224 has been approved as a variety - and is being con- sidered in seven other African countries-but has not yet been named. The screening methodology for field resistance to early blight was refined for both seedlings and plants. Acceptable levels of field resistance have been found in selections. Five clones from various sources in the USA were found to have high levels of tolerance to Verticillium wilt. CIP-INIPA (Peru) screening for late blight resistance in tropical rain forest, Acomayo (2200 m). 47 BACTERIAL DISEASES Breeding for resistance to bacterial wilt (Pseudomonas solanacearum). The initial population bred for resistance to bacterial wilt (BW) disease has been successful in the cooler climates, but not in the warmer climates where tolerance to heat and re- sistance to root-knot nematode (Meloido- gyne spp.) are needed, since they interact synergistically with the bacterium. In the initial population, the cultivated diploid Solanum phureja was used as a source of resistance to P. solanacearum. The need for a second population became appar- ent, and it was developed using the resist- ance to P. solanacearum and Meloidogyne spp. from the wild species S. sparsipi- lum, S. chacoense, and S. microdontum. Mass screening under warm greenhouse conditions was performed with strains of both races 1 and 3 of P. solanacearum during several cycles of selection. Resist- ant diploid selections were crossed with selections from the initial BW-resistant tetraploid population. This was done in tetraploid-diploid (TD) crosses involving unreduced diploid gametes. Tetraploid progenies were evaluated under naturally infested field conditions at Cajabamba and Cauday, in the Cajamarca Department of northern Peru, and are now being tested in the Philippines. In the trials at Cajamarca, 75°/o of the genotypes were significantly more re- sistant than the controls: Molinera, a re- sistant Peruvian variety, and BR 69.84, a resistant farmer selection known as Moli- nera II (var. Domoni in Fiji). In addition, 58°/o of the genotypes were superior in yield. This population lacks the extreme earliness required for most tropical low- land situations, thus it has been crossed with the best early, heat-adapted clones. Screening for bacterial wilt resistance by national programs. Burundi. Bacterial wilt continues to be a serious problem in 48 Burundi; to date the only clone showing useful resistance is 720118 (Cruza 148). A further 68 clones selected from the 1983 CIP introductions were retested by the national program of ISABU (Institut des Sciences Agronomiques du Burundi) and 24 were retained. Sixty-six clones se- lected from the 1984 introductions were retested and 19 retained. Because of heavy BW infection confounded with Er- winia chrysanthemi, it has been difficult to identify BW-tolerant clones. Conse- quently, ISABU devised another method for testing. Five tubers of the test clone were planted in the same row on either side of the BW-susceptible variety Kenya Baraka. The rate of BW progression along the line of test plants was measured, as- suming that disease spread was principally by root contact. The results are shown in Figure 1, where the most susceptible clones show a steep slope, indicating the rapid spread of disease. The most resist- ant clone was 720118, but there were in- dications that some useful variation in resistance exists among the others. Clone 720057 has since been eliminated due to poor performance in multilocational trials. Kenya. Through a research contract with the National Agricultural Laborato- ries (NAL), in Nairobi, additional clones were tested for BW resistance in both pot and field experiments. Both systems gave similar results, with clone 720118 being the most resistant. In the future, this clone will be included in all NAL trials as the resistant control. This con- tract included studies on the relationship between the log dilution of bacterial in- oculum and mean time to wilting, which showed a linear relationship . Brazil. In Brasilia, the Centro Nacio- nal de Pesquisa de Hortali9as (CNPH) is collaborating in the evaluation and selec- tion of BW-resistant clones. Progress in Plants infected (O/o); expressed as loge -1 -1-x 2 .6 Weeks after planting Figure 1. Development rate of bacterial wilt incidence in advanced clones grown in an infected area in Burundi. The slope of the line indicates the degree of sus- ceptibility of a clone: the steeper the slope the more susceptible a clone. selection has been slow due to difficulty in maintaining a constant level of field infection and low temperatures during the growing season. In 1984, 239 clones were tested and 130 clones showing no apparent symptoms were selected; how- ever, climatic conditions during the field evaluation were cooler than usual and the results of this test were inconclusive. The test was repeated in 1985 with similar results, including unseasonably low tem- peratures during the growing period. The effectiveness of field evaluations under these conditions will be reevaluated. 49 Philippines. Bacterial wilt resistant clones selected by CIP showed improved adaptation to the short days in Minda- nao where the disease is severe. Yields of these clones were better than those of currently used varieties; however, by the third generation, these clones exhibited more disease , more latent infection, and increasing infestation by root-knot nema- todes. A new group of heat-adapted prog- enies, incorporating resistance to BW and root-knot nematode derived from three wild potato species, was planted in Min- danao in late 1985. This material should be a valuable source of new clones for the warm tropics. In collaboration with the Central Min- danao University, three experiments were conducted on the effect of intercropping potato with corn or sweet potato on BW incidence in the potato and on the pop- ulation of P. solanacearum in the soil. Intercropping potato with any crop or simply leaving more space between po- tato plants reduced BW incidence. Soil inoculum levels decreased approximately 50°/o, compared with the levels observed after monoculture. Similar results were obtained in Burundi in 1984, indicating that root contact is probably an impor- tant means of disease spread. Ecology of P. solanacearum. A strain of both race 1 and race 3 simultaneously occurred in one plant in a field in Huam- bos, Cajamarca Department (highlands, 2450 m) of Peru, and in another plant as well as independently in several plants in Yurimaguas, Loreto Department (tropical rain forest, 170 m). The strains of differ- ent races were recognized by differences in formazan pigmentation on modified Kelman's medium (Fig. 2) . This tech- nique permitted the separation of the two strains from a given plant and recognition of different strains from a given field. These differences may be useful for fur- 50 ther ecological studies. It is known that many strains of P. solanacearum produce bacteriocins antagonistic to other strains; thus there is an a priori expectation that it would be unlikely to find two strains acting together. Bacteriocinogenicity tests (Fig. 3) were conducted between P. solanacearum strains of similar or different origin, known to be different because they be- long to a different physiological grouping or biovar (Bv). The Bv classification of 180 isolates from different provinces in the Departments of Cajamarca and Loreto are shown in Table 1. Among the high- land Cajamarca isolates, only one of 130 isolates was Bv I (equivalent to race 1), the rest were Bv II (considered equivalent to race 3). The 180 lowland Loreto iso- lates included 37 Bv I and 143 Bv II strains. There was mutual bacteriocino- genicity between three pairs of isolates from similar ecological niches, but none between two isolates from different loca- tions. Among the first three , the bacterio- cinogenicity was greater by Bv I to Bv II than vice versa. No conclusions can yet be drawn on the ecological significance of these observations, because few isolates have been tested so far; therefore, this work will be expanded in the future. Serological specificity in P. solana- cearum. At the University of Wisconsin (U.S.), contract research has continued on improving the strain specificity of anti- sera prepared against whole P. solanacea- rum cells. Because components of the bacterial outer membrane are implicated in the antigenic specificity of many bacte- ria, rabbit antisera were prepared against membranes isolated by sucrose density centrifugation from a Bv I and a Bv III strain from potato and a Bv I strain from banana. The antisera were tested by the Ouchterlony double diffusion (ODD) tech- nique against 57 strains of P. solanacea- Figure 2. Different colony formazan pigmentation that permitted the separation of iso- late 203 (Bv I) on the right, from isolate 202 ( Bv 11) on the left. These strains were together in the same stem of a plant infected with P. solanacearum. Figure 3. Example of a bacteriocinogenicity test. First, colonies of different strains are grown, which may diffuse bacteriocin into the surrounding agar (A). Th is becomes evident when the colonies are overlaid with agar seeded with a sensitive test strain of P. solanacearum. 51 Table 1. Biovars of P. so/anacearum from potato in the highland provinces (2400-3100 ml of Caja- marca Department (C), and in the low, humid zone of Yurimaguas (170 m), Loreto Department (L), Peru. Provinces Years of isolation Huambos (C) 1973-1982 Chota (C) 1974-1984 Cajamarca (C) 1967-1984 Celendin (C) 1978-1984 Total (C) Yurimaguas (L) 1975, 1981, 1984 1977 1976, 1978, 1979 Total (L) Overall total rum isolated from potato, tobacco, to- mato, pepper, and banana. With the antiserum against the Bv I (race 1) potato strain, serological identi- fication of several Bv II (race 3) strains was possible. Apparently all Bv II strains lacked one antigen, probably a lipopoly- saccharide component. When antiserum to the Bv III strain from potato was cross- absorbed with sonicates from the Bv I strain, only the strain used as immunogen, two strains from potato (Bv II), and one strain from tobacco (Bv I) gave positive reactions by ODD. This indicated that the absorbing strain (Bv I) had antigenic determinants in common with Bv I, II , and III strains, and that the antiserum had antibodies specific for antigenic determi- nants in the immunogen but absent in the absorbing strain. When the antiserum raised against the banana Bv I strain was absorbed with the potato Bv I strain, only the banana strains gave positive reactions. This indicated the presence of unique antigenic determinants in the outer membrane of banana strains 52 Number of isolations Biovar I Biovar II Total 44 45 0 38 38 0 29 29 0 18 18 129 130 19 0 19 0 4 4 17 10 27 36 14 50 37 143 180 (race 2). Thus, there are determinants re- lated with pathogenicity in the outer mem- brane of P. solanacearum , which might be determined with more sensitive immuno- chemical techniques such as the use of monoclonal antibodies. This approach will soon be initiated at Wisconsin. Bacterial soft rot (Erwinia spp.). Eco- logical studies were conducted in Peru to assist in planning control measures to combat increasing problems of bacterial soft rot at CIP's San Ramon station. As- says of environmental contamination by Erwinias showed irrigation water was con- sistently contaminated with more than 100,000 cells of E. carotovora pv. caro- tovora (Ecc) per liter (L). The 88 iso- lates collected all caused soft rot in po- tato slices. Irrigation water came from two sources: 1) the Tarma River, which had greater than 10,000 Ecc/L even at its source at 3000 m; and 2) a mountain stream, which had 1,000,000 Ecc/L or more up to an altitude of 1200 m. Com- mon weed species growing in shallow water usually harbored high populations of rhizosphere Erwinias (see Thrust VI). Field soil samples in San Ramon were also contaminated consistently with Ecc immediately after irrigation, but in 5-cm deep samples kept in plastic trays, these populations dropped to undetectable lev- els after 96 hours. Samples of soil, up to 20 cm deep, that had never been irrigated had no Ecc. Similarly, Erwinias were not detected at this depth in nonirrigated fal- low soil. Soil samples taken from depths of 30-90 cm in fields under rotation crops revealed the occasional presence of small Ecc populations. Soft rot resistance by calcium nutri- tion. Contract research at the University of Wisconsin has shown that increasing calcium fertilization of potato plants in- creases the calcium content in tuber tis- sues, and that higher calcium tubers of a given cultivar are more resistant to Erwi- nia soft rot than those of the same culti- vars with lower calcium content. Addi- tional testing was carried out using various sources of calcium. Three application rates were used (100, 200, and 300 lb Ca/ A) and three methods of application (preplant strip, broadcast, and sidedress). Tubers were inoculated with E. caroto- vora pv. atroseptica (Eca) and incubated in a mist chamber at 20° C for 96 hours. Tubers harvested from various treatments were compared on the basis of percent sur- face area decay. In a study on the effec- tiveness of different sources of calcium, triple superphosphate and one source of calcium sulphate (Smith-Douglas) were not significantly different from the con- trols. The treatments that gave signifi- cantly less rot were, in the order of most to least rot, calcium sulphate (U.S. Gyp- sum, sieve), calcium sulphate (Ampel), lime, calcium nitrate, and calcium chlo- ride; however, differences among these were not significant. The use of calcium sulphate (U.S. Gypsum) at rates of 100, Table 2. Bacterial soft rot of Russet Burbank potato tubers in relation to various application methods of calcium sulphate and calcium chlo- ride, shown as percent surface area decayed.0 Calcium source Application Calcium Calcium methodb sulphate chloride Preplant strip 22.3 b 18.5 b Broadcast 22.3 b 22.3 b Sidedress 18.5 b 26.1 b Control 45.5 a 42.5 a 0 Mean of 40 tubers (10 per replicate, 4 repli- cates per treatment) . Values in the same column followed by the same letter are not significantly different at the 5°/o level. bPlots were treated with calcium sulphate (U.S. Gypsum-sieve) and calcium chloride by each ap- plication method at 300 and 200 lb Ca/ A, re- spectively. 200, and 300 lb/ A gave significantly bet- ter control of rot with all three treatments but no significant difference among rates. When calcium sulphate (U.S. Gypsum) was compared with calcium chloride, both applied as either a preplant strip, broad- cast or sidedress, there were no signifi- cant differences among treatments, but all were superior to the control (Table 2). FUNGAL DISEASES Breeding and screening for late blight (Phytophthora infestans) resistance. Dur- ing 1985, about 26,000 true potato seed (TPS) were used in a seedling screening test in Huancayo. Approximately 10°/o were selected and multiplied and sent for field testing at Rionegro, Colombia, in collaboration with the national program of ICA (Instituto Colombiano Agropecua- rio ). Selections from the previous cycle are being tested at Toluca, Mexico-the final testing site in the scheme-prior to being distributed to requesting national programs. In 1985, ten countries received 53 advanced genetic materials with resistance to late blight (LB) and also bred for earli- ness, involving 1429 clones and 4088 indi- viduals in 296 tuber families (Table 3). Collaborative field tests on predomi- nantly andigena materials were conducted in Peru with the national potato program ofINIPA (Instituto Nacional de Investiga- ci6n y Promoci6n Agropecuaria) in Aco- mayo, near the city of Huanuco (2200 m), where LB is severe and predictable, but where the racial complexity is not well known. One hundred clones were ar- ranged in a single lOxlOlattice, and 241 clones in ten-plant observation plots. Of these 341 clones, 113 were selected for LB resistance and desirable agronomic characteristics. Thirty- five clones con- formed to local standards and were se- lected by the national program for further testing. A progeny test for parental line selec- tion was conducted in the LB testing field at Acomayo by growing the progenies in flats arranged in a randomized complete block design with two replications of 100 seedlings each. Parents were 30 advanced Table 3. Advanced clones and tuber families, bred for resistance to late blight and earliness, distributed by Cl P du ring 1985. Country Brazil Colombia Ecuador Guatemala Kenya Mexico Philippines Rwanda Turkey Venezuela Total 54 No. clones 32 51 143 46 388 245 356 168 1429 No. families/ individuals 32/1001 135/1919 17/208 112/960 296/4088 selections (LB-resistant) crossed to two male testers. Results indicated that the general combining ability (GCA) effects associated with the additive portion of the total genetic variation was more im- portant than the specific combining abili- ty associated with the nonadditive genetic variance. Twelve clones were selected as having good GCA effects. A second breeding population with only field resistance, i.e., without major R-genes that can interfere in making selec- tions for durable resistance, is being as- sembled by accumulating field-resistant clones of Solanum tuberosum subsp. andi- gena, S. phureja, and S. tuberosum subsp. tuberosum that have been tested for ab- sence of R-genes. This population will be screened with race zero. Screening for late blight resistance by national programs. Burundi. The national potato program of ISABU continues to select advanced clones and tuber families with adaptation to local growing condi- tions. Of 117 clones selected in 1984 and replanted and harvested in 1985, 50 were selected after being exposed to a moder- ate attack of late blight. Seven CIP tuber families (662 tubers) containing potential LB resistance were screened under a se- vere LB attack in March-July 1985, and only 40 plants were retained. Two ad- vanced clones, 720123 and 720125, will be included in multilocational trials in Burundi for the first time in late 1985. On-farm trials were carried out for two seasons in three districts of Burundi to compare the yield performance (un- der conditions of farmer management) of the new varieties selected by ISABU. An important factor in these trials was that the new varieties, all of which have good LB resistance, were planted early in the season to get maximum yield. This is a new practice for the farmers as they tend to plant late in the rainy season to escape LB attack. A total of 67 trials were har- vested with Sangema as control, the most common variety for which seed is cur- rently available . Early planting of the new variety Ndinamagara (720118, re- ported above as resistant also to BW) gave 50°/o greater yield than the same variety planted one month later. The yield from both plantings exceeded that of Sange- ma by 35-80°/o, due to LB resistance in Ndinamagara. Kenya. The germplasm multiplication and distribution center in Kenya, which CIP operates in collaboration with the Plant Quarantine Station at Muguga, con- tinues to multiply a wide range of po- tato germplasm for testing. The test sites range from the high elevation site at Mau Narok (3100 m) down to the coastal site at Mtwapa, thus clones are challenged with a wide range of climatic conditions and disease complexes. In 1985, the CIP clone 800224 (resistant to late blight, bacterial wilt, and potato leafroll virus) was finally approved as a variety by the Ministry of Agriculture, but has not yet been named. This clone is also under consideration as a variety in Burundi, Ethiopia, Madagascar, Malawi, Rwanda, Tanzania, and Uganda. At medium elevations (1850 m) three advanced clones, 720084, 720088, and 678019, continue to give stable yields. The first two are now included in the Kenya national performance trials. At the coastal lowland site, clone 800938 (moderately LB resistant but re- sistant to BW) was outstanding for yield, tuber size, and early maturity. This clone, originally selected at the Asian Vegeta- ble Research and Development Center (AVRDC) in Taiwan, exhibits adaptabil- ity to lowland tropical climates in other countries, including the Philippines and El Salvador. Philippines. In the Philippine highlands, the Mountain State Agricultural College conducted replicated on-farm trials of LB- resistant clones, confirming that I-1035 and B71-240. 2 were the highest yielders with moderate LB resistance. They are ready for release to farmers as soon as they are officially approved. Trial yields at the farmer level were between 33 and 45 t/ha, 50°/o to 100°/o greater than the local controls Cosima and Conchita. The seed of 46 TPS families with frost and LB resistance was divided and planted during two seasons. From the first (dry) season, 197 clones were selected but LB pressure was only moderate. During the second season, which had higher rainfall and severe LB attack, plant survival was lower but 67 clones were selected. Se- lected clones appeared to be distributed across all families and most had accept- able agronomic characters. They will be evaluated further in 1986. Early blight (Alternaria so/ani) . CIP initiated this project in late 1984 to study 1) Alternaria species causing early blight (EB) in Peru, 2) the identification of re- sistance sources, 3) the development of reliable screening methods, and 4) the de- velopment of resistant clones with good agronomic characters. Studies on conid- ial morphology have indicated the occur- rence of at least three species causing early blight. Isolates from San Ramon fit characteristics described for A. solani, whereas isolates from the Mantaro Valley (central highlands) fit those described for A. solani, A. porri, and A. brassicae (the last two are to be reconfirmed). All these Alternaria spp. were pathogenic on potato seedlings. Of the several media tested for best sporulation of A. so Zani, V- 8 agar medium with constant light at 18° C gave the better result. Isolates from San Ramon, however, sporulated easily in V-8 agar and very slowly in potato dextrose agar medium, as compared to isolates from 55 the Mantaro Valley in which the reverse occurred. Data on EB incidence at San Ramon during the 1985 rainy season agreed with data obtained for the 1984 dry season in showing high levels of incidence that are 43 days after planting Desiree - DT0-33 77 days after planting Desiree DT0-33 0 10 suitable for progeny evaluations and selec- tion of EB-resistant clones. The percent leaf area infected and plant defoliation due to EB were intermediate for plots naturally infected and maximum for plots artificially inoculated with A. solani (Figs. Fungicide control led • Natural inoculum • Spore inoculation t--; LSD (50/o) - 20 30 40 50 Leaf area infected (O/o) Figure 4 . Percent leaf area infected by A. solani on two potato cultivars under three treatments, two dates after planting (1985 rainy season, San Ramon). 56 Desiree DT0-33 0 2 3 Defoliation 4 5 6 Figure 5. Plant defoliation caused by A . solani on two potato cultivars under three treatments, 85 days after planting (1985 rainy season, San Ramon). 1 =no defoliation; 3 = 50'¥o; 6 =dead plant . 4 and 5). From these field trials, data were also obtained on the effective control of EB by alternating fungicide applications such as copper oxychloride, mancozeb, and dithiocarbamate-zinc. During 1985, we also developed and evaluated tests that screen for EB resist- ance at the seedling stage. Seedlings 35- 40 days old were sprayed with an inoc- ulum suspension of 2000 spores/ml. At Lima, TPS were sown in trays under screenhouse conditions, and after inocula- tion the seedlings were kept inside large plastic bags at 22°-25° C for four days. At San Ramon, TPS were sown in large seedbeds ( 10 m 2 ) under field conditions, and after inoculation beds were covered with a plastic sheet for four days at a temperature range of 24°-37° C. Infec- tion and disease development occurred in both tests when TPS from the cultivar DT0-33 were used. TPS from 36 families were evaluated by these two tests and compared with a field evaluation carried out in San Ramon on adult plants. A significant correlation (r = .44 Spearman's coefficient) was ob- tained be tween field evaluation under high inoculum pressure at San Ramon and the seedling test carried out in trays at Lima. Improvements of the seedling tests at both locations are under way. At Lima, TPS from 36 accessions from the germplasm collection were sown in plastic trays inoculated with A. solani and evaluated for their resistance to EB. The seedling test was used for the evaluation. Results indicated that acceptable levels of resistance are available in the germ- plasm collection (Table 4). Also, more extensive research will be conducted with these genetic resources, especially on the relationship between resistance to EB and plant maturity, in order to discover clones that possess both resistance and earliness. Table 4. Early blight readings ( 1 =no infection; 9 = 1 OOO/o infection) of 12 accessions out of 36 tested at the seedling stage (35 days old) under controlled conditions for resistance to early blight (Alternaria solani) . Lima, Peru. Early blight Accession reading Accession HUA-332 1.5 HUA-477 CUA-565 2.5 JAK-77 700882 2.5 HUA-358 700687 2.5 DT0-33 (control) OCH-3527 2.5 HUA-934 SOIL-BORNE DISEASES Early blight reading 2.5 2.5 4.0 6.0 7.0 Verticillium wilt (Verticillium dah/iae). Preliminary greenhouse evaluations in Lima of 12 advanced clones from dif- ferent sources in the United States with tolerance to Verticillium wilt indicated that 5 clones (A-7914.3, A-7914.49, A- 66107.57 , JB-1.3, and Mara) had a high level of tolerance. To study the host range and soil survival of V dahliae in the Mantaro Valley, several fields were sampled under potato as well as fallow fields to collect plants, especially weeds, that could be hosts of this pathogen un- der natural conditions. A total of 65 dif- ferent plant species were collected and 18 were infected with V dahliae in the vas- cular tissue of stems or roots. More than 50°/o of the infected plant species did not show Verticillium wilt symptoms under field conditions. Field evaluations of advanced clones for their resistance to Verticillium wilt were conducted in the coastal city of Canete. Results indicated that the best method of inoculation was to use V dahliae grown for 30 days on perlite, sup- plemented with PDA (2 g agar/L) at the rate of 250 ml PDA/kg ofperlite, applied on top of the tuber at planting time . 57 Potato smut (Angiosorus solani) . Of 53 clones and cultivars tested for re- sistance to potato smut under field con- ditions at Comas, Peru (3100 m), during the 1985 potato season, 17 were highly resistant . Eight of these resistant culti- vars and clones were not infected during three consecutive years at that location; the other nine were tested over two years. Among these highly resistant materials are some well-known cultivars such as Cuzco, Mariva, Mi Peru, Participaci6n, and Revoluci6n, and the advanced clones 376181.5, 6956.52, ASN 69.1, 375587.2, and 376608. 7. No further evaluations of genetic materials for resistance to potato smut will be conducted in this project un- less specific requests are submitted. Pink rot (Phytophthora erythrosep- tica) . On-farm studies were conducted on the residual effects of the fungicides Basa- mid (300 kg/ha)+ Ridomil 5G (30 kg/ha) applied to soil for controlling pink rot. Results indicated that after a second po- tato season, the plots under a continuous application of these products yielded 7 .8 more times (27.8 kg/12 m2 ) than the un- treated control plot (3.6kg/12 m 2). Plots treated in the previous season, but not the second season, yielded between 27°/o to 35°/o less than continuously treated plots, but much higher than the untreated control. Rhizoctonia solani. Coastal (Lima and Canete) , highland (Huancayo, Huanuco, and Cuzco), and tropical rain forest (San Ramon) fields were surveyed for the pres- ence of Rhizoctonia disease symptoms on roots, stems, and tubers, and for seed- ling damping-off. To determine classifica- tion by the Anastomosis Groups (AGs), we used the microculture technique by testing the samples against each of the tester cultures of AGs I to 5. Results indicated that only AG-3 and AG-4 oc- curred in potato in Peru. Furthermore, 58 there was a clear distinction with regard to elevation and distribution of AGs: AG-3 was only found in the highlands as compared to AG-4, which was found at lowland coastal sites as well as in the trop- ical rain forest . In a different experiment, nine soil treatments were tested at Lima to con- trol soil-borne fungi causing damping-off and early dying, a disease complex (where R . solani is the principal pathogen) that causes heavy reduction of plant stands and yields. DT0-33 seedlings were trans- planted to the field and harvested 90 days later (summer season, 1984-85). There were no significant differences among treatments for number of plants/ plot, although plots treated with Rizolex + Basamid +plastic cover , Rizolex +Basa- mid , and PCNB + Benlate + Basamid had a higher number of plants than the other treatments. In most cases, plants showing symptoms of early dying produced some tubers and did not die completely. Final symptoms included early maturity, stunt- ing, and chlorosis. Regarding yield/plot (Fig. 6), the highest yields were obtained from plots treated with Rizolex + Ba- samid +plastic cover (Trt. 2), followed by those treated with PCNB + Basamid + Benlate (Trt. 6), PCNB + Benlate + plas- tic cover (Trt. 3), and Rizolex + Basamid (Trt. 4). The lowest yields were obtained from plots treated with Ridomil (Trt. 7), and PCNB + Benlate (Trt. 9, CIP's normal field treatment at Lima) . SUR VEY OF DISEASE INCIDENCE A survey of fungal and bacterial dis- eases of the potato in Colombia was con- ducted for three weeks during late Octo- ber and early November 1984, as part of an agreement with the Research Institute for Plant Protection (IPO), Netherlands, and in collaboration with the national Yield/plot (g) 14000 12000 10000 8000 6000 4000 2000 'I I I I I I I I I I I 9/ • Without Basamid .. .. .· 2 • 3 PCNB + Benlate 5 1 •···•···•·····•· •·• • Ridomil .. With Basa mid Basamid + plastic cover Figure 6 . Average yield / 27 m 2 of DT0-33 seedlings at 90 days from plots treated with nine different soil treatments (numbered 1-9) to control soil-borne fungi at Lima. potato program of ICA (Instituto Colom- biano Agropecuario) . Late blight (P. infestans) was impor- tant throughout the potato-growing areas, but was generally controlled by the use of fungicide sprays. Verticillium wilt was generalized in the southern Narifio De- partment (bordering Ecuador), and seri- ous in the Boyaca, Cundinamarca, and Antioquia Departments in the central highland region. The causal agents varied: V. albo-atrum was found exclusively in Narifio , this organism and V. dahliae were present in Boyaca and Cundinamarca, and V. dahliae was found mostly in Boyaca and Antioquia. It was concluded that high 59 priority must be given to the control of Verticillium wilts. V. albo-atrum can be controlled more readily than V. dahliae, the latter producing microsclerotia that survive for lengthy periods in soil. For V. albo-atrum , the use of clean seed and the practice of rotation reduces its incidence, but for V dahliae it will be necessary to breed for resistance. Rust (Puccinia pittieriana) and gray mold (Bo try tis cinerea) were restricted to the humid microclimates, located in the highland areas of the departments visited at altitudes above 3200 m. To control these localized diseases it will be neces- sary to explore the use of fungicides. TRAINING The first workshop on bacterial wilt, held in the Philippines in 1978, placed emphasis on the isolation and identifica- tion of P. solanacearum and its epidemi- ology. The 1985 workshop in the Philip- pines included 32 scientists from seven Asian countries, Australia, and the United States. It provided a forum for discus- sions on the current status of the disease in Asia, as well as recent findings on the pathogen variation and control through host resistance and cultural methods. Two mid-career scientists from the Central Potato Research Institute in India studied bacterial wilt at CIP-a patholo- [n addition to workshops and individual training for scientists on bacterial wilt, CIP also supervises graduate-level research and training in th e regions. Above, an M.S. degree student, at the CIP research station in the Philippines, is screen- ing CIP clones for resistance to Erwinia. 60 gist worked on serological identification of the bacterium, and a plant breeder studied breeding and selection procedures for disease resistance. A scientist from Bangladesh studied virological and bac- teriological procedures for seven weeks. Two Chileans, whose principal objective was to spend four weeks at CIP in viro- logical work , spent part of their time learning new methodology developed for serological studies on P. solanacearnm. An Argentine scientist spent one week acquiring a general background on fungal diseases of the potato. 61 0.5µm Ve THRUST IV Potato Virus Research High levels of resistance to the potato leafroll virus (PLRV) were found in four clones from Peru and in 20 clones from the potato introduction station at Sturgeon Bay, Wisconsin. The efficiency of greenhouse screening for PLRV resistance in seedlings was improved by determining the number of viruliferous aphids required per plant for infestation. This will provide for reductions in the number of seedlings from the screened population, which become infected in the first field exposure. Testing for virus resistance is continuing in several Latin American countries. Clone B71-240.2 (originally selected in Argentina) showed good resistance to PLRV and potato virus Y in field trials in Uruguay and is being named as a variety in several coun- tries. In Chile , clone 380507.1 was selected for its resistance to PLRV and good agronomic characters. In Brazil , clone 381027. 2 and three other virus- resistan t clones are being multiplied for inclusion in the 1985-86 national po ta to trials. Stability of resistance to potato viruses PVX and PVY was studied under field conditions during three consecutive cropping seasons. Resistance in im- mune clones was stable, but not in hypersensitive clones. When clones were infected with PLRV, the resistance in those having immunity to PVX and PVY was not altered , but clones normally hypersensitive to PVX and PVY showed immunity to these viruses. Irrespective of resistance levels to PVX and PVY, potato virus S exhibited the highest rate of incidence. Resistance to PLRV infection can be greatly modified by the presence of PVX and PVY. A 3 0°/o increase in the sensitivity of ELISA tests for detection of PLR V and PVY has been achieved. In comparison to 1984, there was a 100-fold increase in the use of serology for detecting viruses. Forty ELISA and 30 latex virus-detection kits were sent to developing countries; excellent results have been obtained from the 100,000 samples examined, and there is growing demand for these kits. The number of samples tested for potato spindle tuber viroid (PSTV) by means of the NASH kit increased from 5000 in 1984 to 35,000 in 1985. This test has been instrumental in guaranteeing the health of exported and imported germplasm. In 1985, 40 NASH kits were distributed to ten different countries to test 3865 samples. Several national potato pro- grams are being assisted in producing their own virus-detection antisera. Ultrathin section of a mesophyll cell of Ph ysalis (loridana infected with virus SB-22. N =nucleus, V=cluster of virus particles, and V c =vacuole. 63 RESISTANCE TO VIRUSES Levels of genetic resistance to potato leaf- roll virus (PLRV) infection in clones. Ma- jor emphasis was placed on determining levels of resistance to PLRV in clones from CIP's world germplasm collection. The objective was to select parents for breeding work; the evaluation method used has been described in the 1984 An- nual Report. Of the 47 clones tested, only 4 showed a high level of resistance to PLRV infection. Forty-nine clones ob- tained from the potato introduction sta- tion at Sturgeon Bay, Wisconsin (U.S.) , were also tested for their resistance to PLRV infection and 20 showed a high level of resistance to infection. These selected PLRV- resistant clones are being evaluated for other agronomic and disease resistance characteristics to be used as par- ents in future breeding work. Interaction of potato viruses. The re- sistance to PLRV infection in potato clones is greatly modified in the presence Potato clone J-853 showing interference of potato leaf- roll virus (PLR V) on potato virus Y (PVY) infection (left). Control plants infected with only PVY showing systemic hypersensitive reaction (right). 64 of potato viruses PVX and PVY ( 1984 Annual Report). This year we studied the interaction of these viruses, using potato clones with immunity, relative resistance, or hypersensitivity to PVX and PVY. All selected clones were graft-inoculated with PLRV and inoculated two weeks later with PVX or PVY, either by mechanical or graft inoculation. Clones exhibiting immunity to PVX and PVY did not alter their -resistance to these viruses when in- fected with PLRV; however, clones that werei hypersensitive to PVX and PVY showed immunity to these viruses when infected with PLRV. It is therefore im- portant that the clones be free from PLRV when evaluating their resistance to PVX andPVY. Screening for PLRV resistance in seed- lings. At Lima seedlings are screened in greenhouses for PLRV resistance by using viruliferous Myzus persicae inoculation. The efficiency of screening has not been optimal however, as a majority of seed- lings from the screened population be- came infected in the first field 'exp'Osbrl Consequently, we performed expenm~nts . ·1 ~ , r· (' I i(f to determine the optimal numbet dfvitu- liferous aphids needed to inocui~te seed'. ling progenies during screening. Proge- nies from the crosses Serrana x XY 7 .6, Serrana x XY 15 .1, and Serrana x bulk XY were used. The experimental design was a split plot with eight potted plants per treatment and with six replicates. The treatments included inoculations made with 5; 15, 25, 35, and 50 viruliferous aphids per plant. No significant differ- ences were found between the treatments with 15, 25, 3 5, or 5 0 aphids per seed- ling, but all were superior to inoculations with 5 aphids per seedling. These results indicated that during seedling screening for PLRV resista~ce, a minimum of 15 aphids per plant should be used as an in- oculum to minimize the escape of suscep- tible seedlings. Stability of resistance to PVX and PVY under field conditions. Potato cul- tivars were tested under field conditions Table 1. Percentage of clones with known resistance to potato viruses PVX and PVY infected with both viruses after three field exposures at Lima. Known Exposure reaction First Second Th ird Clone x y x y x y x y V-2 la 0 0 0 0 0 0 ARSH32 0 0 0 0 0 0 78C11 .5 0 0 0 0 0 0 Bzura 0 0 0 0 0 0 Serrana I nta H 0 0 0 0 0 0 78C8.1 s I 0 0 0 0 23 0 CEX-69-1 H 0 0 0 14 0 0 MEX 750815 H 0 20 0 21 0 3 Heid rum H I 0 0 0 0 10 0 LT-4 s I 0 0 10 0 60 0 T . Condemayta s H 0 20 14 64 7 50 Rosita s s 20 15 43 29 100 27 a I =immune; H =hypersensitive; S =susceptible. 65 in Lima during three consecutive cropping seasons for their stability of resistance to PYX and PVY. The results indicated that clones immune to PVY and PVX were not infected; however, clones CEX 69.l and MEX 750815 with high hypersensitivity to PVY showed 15°/o and 21°/o of PVY infection, and Tomasa Condemayta with low hypersensitivity to PVY showed 64°/o infection (Table 1 ). Irrespective of the resistance level to PVX and PVY in clones and cultivars tested in three field expo- sures in Lima and Huancayo, the highest percentage of disease incidence was due to potato virus S (PVS) (Table 2). Table 2. Percentage of virus infections in 12 se- lected potato clones after three field exposures, two in Lima and one in Huancayo. Clone PVS PLRV APMV APLV V-2 27 3 0 3 ARSH32 30 3 0 0 78C11.5 10 7 0 0 Bzura 7 7 0 0 Serrana I nta 60 0 0 0 78C8.1 13 0 0 0 CEX-69-1 0 7 3 0 MEX 750815 3 7 0 0 Heid rum 100 10 0 0 LT-4 77 60 0 0 T. Condemayta 43 0 0 0 Rosita 63 63 23 0 a PVS =potato virus S; PLRV =potato leafroll virus; APMV =Andean potato mottle virus; APLV =Andean potato latent virus. INTERNATIONAL TESTING FOR VIRUS RESISTANCE Uruguay. During the November 1984- February 1985 season, the stability of re- sistance to viruses in 4 tuber families and 23 advanced clones (a total of 114 clones) was tested in a collaborative project with 66 CIAAB at the Las Brujas experimental station. Seven control varieties were in- cluded in the test. After field exposure , ELISA tests for PLRV and PVY were per- formed on all plants. Four clones were selected showing no serological reaction on two of the three test plants, but no clone was completely virus-free. In a sec- ond field test carried out in 1985, these four clones showed no visual symptoms of either virus in the field. Clone B71-240. 2, originally selected in Argentina and now being named as a variety in several coun- tries worldwide, had the highest level of resistance to both viruses. It should be emphasized that the aphid population was extremely high, and thus exposure to PLRV and PVY was severe. Argentina. Prior to 1984, the field tests for virus resistance conducted by the national potato program of INTA at the San Pedro station showed a similar high aphid population as in Uruguay. Thus the evaluation for resistance is now made only during the spring season (October) . From the tests carried out in 1984-85 , 7 4 selected clones were multiplied and then replanted in October 1985 for fur- ther evaluation. An additional 32 fam- ilies were planted for multiplication in February 1985 and screened for agro- nomic characters. Of these , 83 clones (16°/o) were selected for further field ex- posure in October. Chile. In a collaborative project with the national agricultural research insti- tute (INIA) in Osorno, 46 clones selected for PLRV resistance in the 1983-84 sea- son were retested and 20 were selected for their virus resistance. Within the 20 clones, one clone (380507.1) had good agronomic characters and low (3.2°/o) PLRV infection . Other resistant clones, even with high yields, were not retained due to poor tuber shape. Other genetic materials introduced as true potato seed (TPS) were multiplied in January 1985 for replanting in October. Of these 674 individual progenies, 22 had acceptable agronomic characters. Brazil. Similar projects for selecting virus-resistant materials in Brazil were car- ried out jointly with CNPH/EMBRAPA in Brasilia. CIP clone 381027.2 and three selected by !AC-Sao Paulo are being mul- tiplied for inclusion in the 1985-86 na- tional potato trials. Two field trials for PLRV and PVY resistance were planted at CNPH and on a commercial farm near- by to test infection under natural aphid populations at CNPH and "normal" pop- ulations in a farmer's field subjected to chemical sprays. The aphid population was higher at CNPH than in the farmer's field. Clones DT0-2 and B71-240.2 and the variety Loman gave very high yields. VIRUS SPREAD IN SEED PROGRAMS Colombia. A study of virus incidence in the main potato-growing areas of Colom- bia , conducted by the national potato program of !CA, confirmed that the lower altitude areas in Antioquia had higher in- cidence of PLRV, PVS, and PVY than the higher altitude areas of Cundinamarca. Seed-producing zones within these two important districts showed the same gen- eral trend , but had much lower levels of infection. Unselected third generation tu- bers at ICA's Tibaitata and San Jorge sta- tions in Cundinamarca had between 5°/o and 18°/o infection of the main viruses; whereas selected healthy seed had less than 2°/o of all viruses except for PLRV ( 5°/o in Tibaitata). This illustrates that potato producers in the higher altitude areas can easily keep seed for three gener- ations before replacing it. Tunisia. Three generations of local- ly multiplied seed from the same initial source, planted at the Saida site by the national agricultural research institute (INRAT) , were evaluated for virus con- tent. The infection rate in the first gener- ation was 0.63°/o PLRV and 0.63°/o PVY. The third generation had only 0.5°/o PLRV and 3.0°/o PVY. The yield of seed size tubers was similar for all generations, but the number of main stems produced per tuber increased with successive gen- erations. In a complementary study, one row of seed infected with PLRV was planted with 30 rows of elite seed on either side· (Fig. 1). During the season, the spread of PLRV was evaluated by the number of plants with visual symptoms appearing in the adjacent row, and rows 3, 9, and 27 on either side. Parallel records were made of the number of winged and wingless aphids found on the leaves. The first PLRV symptoms appeared approximately 20 days after the first significant count of winged aphids. Most of the infected plants were in row 1 adjacent to the in- fected row, and only a few infected plants were found in the more distant rows. From these studies, it was concluded that: 1) After three generations the low rate of degeneration in locally mul- tiplied seed is due to the absence of a concentrated and sustained buildup of aphids during the season. Aphid popula- tions fluctuate considerably from week to week, never reaching epidemic propor- tions in Tunisia as in other countries. 2) Spread of PLRV throughout the pota- to crop is relatively slow, therefore early roguing can adequately maintain low in- fection levels. These conclusions support the view that the Tunisian national seed program can successfully multiply seed for at least three generations and main- tain acceptable levels of virus control. Uruguay. A study was made by CIAAB at the Las Brujas station on the yield 67 Figure 1. Field trial in Tunisia to study virus spread by planting a center row infected with PLRV and 30 adjacent rows of elite seed on each side. depression caused by PLRV and PVY in the variety Kennebec. A total of 119 pairs of plants were selected in commercial fields : healthy adjacent to healthy, and Table 3. Effect of potato leafroll virus (PLRV) infection on the yield of the variety Kennebec in a commercial potato crop . Uruguay, 1984-85. Treatment A. Healthy plants adjacent to healthy B. Diseased adjacent to healthy C. Healthy adjacent to diseased Mean of B and C Yield /plant (mean of 120 plants) Total Marketable 590 578 198 (-66)a 188 (-67) 714 (+ 21) 697 (+ 20) 456 (-23) 443 (-23) a Numbers in parentheses indicate percentage of reductions or increases compared with treat- ment A . 68 healthy adjacent to a diseased plant show- ing secondary symptoms of PLRV (Table 3). The results showed that although in- fected plants had lower yields, there was compensation by adjacent healthy plants. The net loss in yield for a crop with 50°1o plants showing secondary symptoms of PLRV was 23°/o. Initial observations on 34 pairs of plants infected with PVY gave results similar to those with PLRV. VARIABILITY OF POTATO VIRUSES Potato virus Y isolates PVY-GL, pyyc_ AB, and PVY- UF, previously reported in the literature as deviating strains of PVY, have been characterized as potato virus V (PW). These three isolates were inocu- lated mechanically or grafted onto sources of Solanum stoloniferum and Solanum tuberosum ssp. andigena, the two sources of immunity available at CIP for PVY. Sources from S. stoloniferum were im- mune to all the isolates tested. Sources of immunity from S. tuberosum ssp. andi- gena were hypersensitive to these isolates when graft-inoculated, indicating a geno- typic difference between these sources of resistance to PVY. PVV isolates can be easily confused with PVY or PV A isolates unless sero- logical identification tests are done. The symptoms caused in potato by PVV and in other indicator host plants commonly used for PVY resemble symptoms of pyyo infection. Studies on the biologi- cal and serological properties of PVV in comparison to a wide range of PVY iso- lates and other related potyviruses indi- cated that PVV is a strain of Peru tomato virus (PTV). The PTV-type strain, how- ever, does not infect the potato. TECHNIQUES FOR DIAGNOSING VIRUS AND VIROID INFECTIONS Serological testing for PLRV. This virus generally occurs in very low concentra- tions in the potato plant, making diag- nosis difficult . We therefore attempted to increase the sensitivity of ELISA for detecting PLRV by changing the sample extraction buffers and slightly modifying the existing procedure. The use of 0.16 M citrate phosphate buffer pH 7 .0 (CP), in- stead of phosphate-buffered saline (PBS), resulted in greater sensitivity of PLRV de- tection in tomato ( Lycopersicon esculen- tum); however, CP buffer was not suitable for PLRV detection in potatoes. Decreas- ing the concentration of each PVP-40 and ovalbumin from 2°/o to 0.2°/o in the PBS extraction buffer increased the sen- sitivity of ELISA for detecting PLRV in S. tuberosum. Postincubation of gamma globulin-coated plates with 3°/o bovine serum albumin (BSA) for 30minutes prior to loading the sap sample into the wells of the microtiter plates increased the sensi- tivity of ELISA for detecting both PLRV and PVY. These modifications resulted in a 30°/o increase in sensitivity over the standard detection procedures for PLRV. During the year, 40 ELISA and 30 latex kits for detection of potato viruses in 100,000 samples were sent to more than 22 developing countries on request. This represented a 100-fold increase over the samples tested serologically in 1984 by national programs. The short ques- tionnaires filled in by kit users indicated good-to-excellent results and a demand for more kits in the future . Experiments were performed to com- pare the routine procedure of latex sen- sitized with whole gamma globulins with latex sensitized with fractions of these gamma globulins (F(ab) 2 fragments). The latter procedure resulted in five times greater sensitivity. The modification is laborious but can be advantageous when high sensitivity is required or when the antiserum quality is poor. Nucleic acid spot hybridization (NASH) for detecting potato spindle tuber viroid (PSTV). The introduction of the NASH test for detecting PSTV has obviated the need for the tomato-electrophoresis test. By means of the NASH test, the num- ber of samples tested at CIP for PSTV increased from 5000 in 1984 to 35,000 in 1985 (Fig. 2). The NASH test also en- abled us to help national programs check their materials against PSTV infection by receiving spotted membranes sent to CIP for testing. The sensitivity of the NASH test and its ability for mass indexing helped us to guarantee the health of CIP's exported and imported germplasm. The experiments we performed indi- cated that the use of chloroform-phenol in the extraction buffer is indispensable for the success of the NASH test. The sample-spotted nitrocellulose membranes 69 No. of samples 36,000 34,000 26,000t 24,000 6,000 4,000 2,000 0 79 • • 80 Tomato test Electrophoresis NASH 81 82 83 84 85 Years Figure 2. Number of samples tested for potato spindle tuber viroid (PSTV) over a seven-year period. remained stable for more than 14 months at room temperature. Membranes sub- jected to -15° C for 24 hours immedi- ately followed by a 24-hour exposure to 37° C remained stable. In potato tubers, the NASH test facilitated PSTY detection in sprouts irrespective of location, how- ever in dormant tubers only the apical re- gion of the tuber flesh should be used for detection. Producing antisera for developing coun- tries. The two approaches CIP imple- mented to help national programs pro- duce their own antisera have been suc- cessful. In the first approach, where a country is selected from each region to produce antisera for other countries of the region, activities in Colombia (Re- gion I) , Brazil (Region II) , and Tunisia (Region Y) progressed well during the year. Tunisia is entering the second phase and will soon produce antisera for pota- 70 to viruses . Brazil and Colombia have pro- duced antisera for PVS, PYX, and PVY. Based on CIP technology, Brazil has also produced and distributed to local seed growers a latex-sensitized kit for detec- tion of these viruses. In the second approach, organizations such as the national program of INIPA (Peru) and the country network PRECO- DEPA (Central America-Caribbean) pro- duce their own antisera using CIP facili- ties. INIPA is already using the antisera produced for them, while a major portion of the antisera needed by PRECODEPA has already been produced. Identification of other virus diseases. A flexuous virus, 750 nm long and code named SB-20, was isolated from wild po- tatoes collected in Uruguay . This virus did not react with any antisera available at CIP, therefore experiments are under- way to identify and characterize SB-20. A bacilliform virus, existing in differ- ent sizes and code named SB-22, was iso- lated from the asymptomatic potato cul- tivar Ticahuasi, grown in Canete on the coast of Peru. In many indicator plants the virus caused a latent infection except in Physalis floridana and Nicotiana gluti- nosa, which reacted with a mosaic. Light and electron microscopic studies of in- fected P. floridana revealed the presence of virus inclusion bodies in the epider- mal and mesophyll cells (Fig. 3). Virus SB-22 has been purified and an antiserum produced. TRAINING CIP has continued its assistance to de- veloping countries that have , or are es- tablishing, national seed production pro- grams. Scientists from various countries have been trained at CIP in serological detection of virus diseases, as well as in other virological techniques such as Figure 3. Light microscopy of the leaf mesophyll S. tuberosum clone DT0-28 infected with virus SB-22 stained with Azure A, showing inclusion bodies (I), nucleus (N), and cell wall (CW). Magnification X3600. virus purification and electrophoresis and NASH for PSTV detection. During the year, eight scientists from Latin America, two from the Caribbean, three from Europe, six from Asia, and one from New Zealand were trained at CIP headquarters. Individual training on the detection of PSTV and serological identi- fication of viruses was given to five scien- tists from Latin America and three from the Indian subcontinent. These scientists are working in the basic seed programs of their own countries. 71 THRUST V Integrated Pest Management Major emphasis was placed on screening potato genotypes for resistance to nematode and insect pests. Through advanced selections, 253 clones representing a wide range of genetic material from wild species were tested for their reaction to root-knot nematode; all were found to be susceptible. In Ecuador, resistance to different races of Globodera pallida, the potato cyst nematode, was found in 39 of 295 clones tested ; 6 of these were selected for yield and good tuber characteristics. Of 37 clones tested in Peru, 7 were selected for resistance to potato cyst nematode and for agronomic characters. Under rustic and diffused-light storage conditions in San Ramon, 43 of 445 clones tested were selected as resistant to potato tuber moth (PTM). In Colombia, 11 clones were selected with different levels of PTM resistance. The efficacy of plants-particularly Eucalyptus globulus- as repellent barriers against PTM infestation was confirmed. The use of sex pheromone traps in Egypt significantly lowered PTM infestation in the field. In Tunisia, several formulations of the biological control agent Bacillus thuringiensis and two synthetic pyrethroids were effective in controlling PTM damage in stored tubers. Observations on leafminer fly damage in 106 selected clones, field- evaluated in Lima, revealed a unique resistance mechanism in some clones in which the eggs were extruded out of the leaf tissue, exposing them to natural enemies. Studies on biological control included: improvement in the mass produc- tion of the nematode-parasitic fungus Paecilomyces lilacinus and the devel- opment of a pelletized formulation; investigations on the fungus Beauveria bassiana as a potential biological control agent for the Andean weevil; and the development of a mass rearing technique for Dibrachys cavus, a parasitoid of tuber moth. Evaluating potato tuber moth damage in rustic stores at San Ramon, Peru. 73 ROOT-KNOT NEMATODE Screening for resistance. A total of 192 clones representing hybrids between wild Solanum species, 24 clones from CIP's pathogen-tested list, advanced selections from tuber families, and 37 clones from the germplasm collection were tested for their reaction to the root-knot nematode Meloidogyne incognita. All were found susceptible. All seedling progenies from six different crosses between susceptible and resistant progenitors were found sus- ceptible in the testing. This contradicted the expected genetic segregation for re- sistance. In reviewing the background of the screening process, we noted that the sources of nematode inoculum were those that survived screening tests during the last four years. Those that were successful in attacking resistant plants had the op- portunity to multiply and increase their numbers by successive propagation on po- tatoes. It is possible that a new race of M. incognita has evolved, hence the discrep- ancies in the expected segregation rate of resistant progenies. Tests are underway to determine the validity of this hypothesis. Biological control. Attempts were made to develop techniques for mass pro- duction of the fungus Paecilomyces lila- cinus by using low-cost waste products as growth media or carriers. Fungal multipli- cation was highest on chopped corncob grit mixed with rice grains or coated with wheat flour. Similarly, through a research contract at North Carolina State Univer- sity (U.S.) , pelletized spores of P. lilaci- nus have been formulated that remain via- ble for a long time. Refinement of these processes and identification of the condi- tions under which the mass production of the fungus is to take place should provide the needed information for the economi- cal mass production of this fungus. Com- mercial production of the fungus, under the name BIOCON, is being carried out 74 by the National Crop Production Center, University of the Philippines at Los Banos, for distribution within the Philippines. In Burundi, the national potato pro- gram of ISABU has continued studies on the biological control of M. incognita. The site of the 1984 experiment on con- trol by chemicals and the biological agent (P. lilacinus) was resown with a suscep- tible pea crop to examine residual ef- fects of the previous treatments but none were found. Advanced clones are routine- ly assessed for any possible nematode re- sistance. Some clones such as Montsama, 720088, Uganda 11 , and Sangema ap- peared best in one trial, but the lower scores for nematode infection did not appear to be correlated with a reduction in bacterial wilt. The problem of un- even infestation in the test sites is being studied, and 0.032 ha of one terrace is being uniformly infested by planting tu- bers of Kenya Baraka with visible nema- tode symptoms. Control by soil solarization. The ef- fectiveness of soil solarization in control- ling nematodes in nursery beds has been confirmed previously. Good results were obtained at San Ramon and Lima with solarization periods of 15 and 30 days, by using new and used transparent plastic sheets of various thicknesses (0.05-0.42 mm). The nematode population and root infection were reduced significantly (83- 97.6°1o) down to a soil depth of 15 cm. The efficiency of solarization increased when layers of plastic sheets with a space of 30 cm between them were used. Sig- nificant raises in soil temperature were re- corded as compared to one layer of plas- tic sheeting (Fig. 1). POTATO CYST NEMATODE Screening for resistance. The high sensi- tivity of the petri dish test for selection Soil temperature (OC) 80 60 60 .3 --·-..........---·-·_,,,,,,.'· /·-·--·--....... ·-·-·-........ 40 - ........ _. ·-- 47.5 ........•.......•.......•. ··•.. . •...•...•...•...•...•. ··•···•· ··•· .. • • ••• •• • 32.2 • 20 ol__~~~-----'-~~~~..L_~~~~l__~~~__J_~~~~l__~~~__J___j 25 28 March 31 3 6 9 12 April Figure 1. Soil temperature at 10-cm depth in nursery beds covered with two layers (.__) and one layer (•-•)of transparent plastic sheeting, compared with bare (• .. •) or noncovered nursery bed . Lima, Peru, March-April 1985. of Globodera pallida-resistant plants was confirmed in 1984 studies. Some discrep- ancies with the previously used pot test were largely due to the new scale used to measure the resistance-susceptibility plant reaction (Table 1). The petri dish test is expected to streamline CIP's breeding program for G. pallida resistance. The se- quential procedure of the screening pro- gram (Fig. 2) includes two possible routes: one is to provide G. pallida-resistant ma- terial for the national potato program of INIPA in Peru, and the other is to export resistant clones to other national programs in the regions. In Ecuador, of the 295 clones tested by the national potato program of INIAP, 39 were selected for resistance to different races of G. pallida. Only 6 of the 39 have been selected for their yield and good tu- ber characteristics. Some of these clones are now being considered for release as commercial varieties. Out of 37 clones tested by the national program of INIP A for resistance to G. pallida and agronomic characters, 7 were Table 1. Types of plant reaction in relation to multiplication rates of potato cyst nematode (Glo- bodera pa/Iida). General Type of plant resistance or reaction susceptibility Resistance Total Partial Susceptibility Partial Total ePf/ePi =egg multiplication rate. cPf /cPi =cyst multiplication rate. Pot test (cPf/cPi) 1.0 > 1:0 < 2.0 < 2.0 O/o female= number of females out of 100 larvae. Petri Pot test dish test (ePf /ePi) (O/o female) <1 0.0 < 1 0 .1-7.0 >1 7.0-14 .0 >1 > 14.0 75 I ~~ Multiplication ~ plot ~ ~ ..... ___ __. Yield trials 383001.4 .8 .20 .41 Regional trials Farmer trials Tolerance and resistance t r ials in naturally infested fields RESISTANT VARIETY BREEDING Evaluation El imination FLOW Material - Information --- Agronomic Nematode tra its resistance c:J t!J ~ ~ , Figure 2. Diagram for screening and selecting CIP material for resistance to potato cyst nema- tode {Globodera pa/Iida). 76 selected. Good levels of resistance and good agronomic characteristics were con- firmed in 3 (279139.5, 279142.12, and 276008.16) out of 9 clones that had been selected previously in Peru. Identification of populations. Fifteen potato cyst nematode populations, col- lected in the potato-growing areas of the central Andean region of Peru, showed predominance of G. pallida, but also the presence of a mixed population of G. rostochiensis , which represents the first record of this species in that area. In studying the races of these nematodes, using cyst nematode multiplication rates ( cPf/cPi) on different clones, we found the following G. pallida races: P1 B (6.70/o), P2 A (6.7°/o) , P3 A (6.7°/o), P4 A (40.0°/o), P5 A (33.2°/o), and a mixed population of R 1 A (6.7°/o). A new set of standard potato host- differentials were selected to determine the races of G. pallida by developing pre- liminary modifications of the existing classification scheme. G. pal!ida (P4 A and P5 A) resistant clones, 278096.10 and 280090.10, were included as new host differentials (Table 2) . Solanum vernei (VI)n 62.33.3 was replaced due to its poor growth and lack of adaptability to diverse climatological conditions. Biological control. Over 50 fungal spe- cies were isolated from soil samples and cysts of G. pallida and G. rostochiensis collected in Arequipa, Peru. Over 54°/o of the fungal species belong to the genus Penicillium . Several experiments are in progress to determine the role of these fungi as possible biocontrol agents of po- tato cyst nematode. ROOT-LESION NEMATODE The susceptible cultivar Revoluci6n and 15 selected clones (resistant to other nem- atodes) were tested in Lima for their re- action to the root-lesion nematode Praty- lenchus flakkensis. Eleven clones were either tolerant or resistant. In the presence of P. fiakkensis, the wilt caused by Pseudomonas solanacea- rum developed faster and was more se- vere than in treatments with the bacteria alone. The resistant cultivar Molinera did not show wilt symptoms at 16°-26°C with the bacteria alone, but it became sus- ceptible when the nematode was present. Attempts were made to develop a Table 2 . Reaction of a new set of standard potato host-differentials to different races of Globodera pa/Iida. A modified race classification scheme. No. Race designations and their reaction designated to Standard differential plants the differential Pl-. P2A P3- S. tuberosum ssp. tuberosum 0 + + + S. multidissectum P55/7 + + S. kurtzianum KTT 60.21.19 2 + + S. vernei G LKS 58.1642.4 3 + + S. tuberosum ssp. andigena 278096.10 4 NT NT S. tuberosum ssp. andigena 280090.10 4,5 NT + NT * Lette r to be designated after the reaction of the nontested plant is determined . +=indicates cPf/cPi and ePf/ePi > 1. P4A + + + + - =indicates cPf/cPi is equal to or slightly higher than 1, and ePf/ePi is less than 1. NT= not tested yet. P5A P6- + + + + + + + + + + + 77 simple extraction method for use in devel- oping countries. The most practical meth- od, although not the most precise, was a modified Baermann funnel method in which the funnel was substituted with a round tray and a plastic ring with the plastic screen placed at 2 cm above the bottom of the tray . The soil was then placed on a facial tissue, which had been placed over the screen, and water was ad- ded to cover the soil. Nematodes were collected every 2 days for up to 8 days. POTATO TUBER MOTH Screening for resistance. Tubers from 445 clones, obtained from crosses using clones resistant to potato tuber moth (PTM), were screened in an infested diffused-light store at San Ramon. Forty-three clones were selected as resistant to PTM (Phtho- rimaea operculella). Several techniques are being evaluated in the laboratory to determine the nature of PTM resistance. In Colombia, 37 clones from the national program of ICA were tested in the labora- tory for PTM pupation, 11 were identi- fied as having moderate to high levels of resistance. Biological control. At Lima, a para- sitoid wasp, Diglyphus sp., an important larval parasitoid of leafminer fly , was found parasitizing PTM larvae. Parasitism of foliar mining PTM larvae ranged from 4°/o to 55°/o. Mass rearing techniques have been developed for another wasp, Dibrachys cavus, an ectoparasitoid of PTM. This biocontrol agent is maintained on Sitotroga sp . larvae, a pest of stored wheat. An entomophilic nematode , Neo- plectana carpocapsae, that was multiplied using Galeria sp. larvae, was tested under laboratory and field conditions for PTM control. In the laboratory tests, the nem- atodes were very effective in causing PTM larval mortality. In the field , PTM ropu- 78 lations and damage were too low to per- mit a proper evaluation of this nematode. Control with sex pheromones. A less expensive, unpurified sex pheromone, PTM 1 + PTM 2 at 1. 25 mg loading per dispenser in a 2 :3 ratio , was found to be as effective as the purified pheromone in trap capture. A microencapsulated phero- mone spray, formulated in collaboration with Imperial Chemical Industries (U.K.) was tested in diffused-light stores at San Ramon at 0.26°1o, applied four times at one-month intervals. Mating disruption was over 95°/o. Larval population in pheromone-treated stores was reduced sig- nificantly (1.8 vs. 3.0 larvae in untreated stores). Tuber damage was reduced by 15°/o. Tuber protection, however, was not total as stores were not completely mothproofed to avoid entry of mated fe- males from outside . Control of PTM in the field by sex pheromone traps was studied in two areas of Egypt - Minia (upper) and Kalubiah (delta)-during the spring season. Ten pheromone traps per one feddan plot (about 0.04 ha) were used. The percent- age of infested tubers at harvest in Ka- lubiah was 8.6°/o in the treatment field and 27.5°/o in the control field ; the fig- ures for Minia were comparable at 10.6°/o in treated and 31. 2°/o in untreated fields. Significant differences were recorded also in tomato fruit infestation but not on eggplants. Control in stores. Repellent plant bar- riers and insecticides were tested for PTM control in Huancayo, San Ramon, and Lima. The predominant PTM species were Symmetrischema plaesiosema in Huanca- yo, and P. operculella in San Ramon and Lima. In Huancayo, dried crushed leaves of Eucalyptus globulus, layered at 2 cm and 1 cm over tubers, and the insecticide Phenthoate were the most effective treat- ments. In San Ramon and Lima, a layer Table 3. Effect of Phenthoate insecticide and insect-repellent plants on Phthorimaea opercu- fella damage in stores, San Ramon. Tubers Sprouts damageda damaged Treatmenta (O/o) (O/o) Ph enthoate 36.3 e 44.22 d Eucalyptus globulus 0.5 cm 29.6 cde 14.30 abc 1.0cm 29.9 de 15.20 abc 2.5cm 17.8 abc 1.42 a 5.0cm 13.5 a 3.45 a Lantana camara 0.5cm 24.2 abc 26.00 c 1.0cm 19.8 abc 14.17 abc 2.5 cm 17.1 ab 7.75 ab Barley straw 0.5cm 39.8 c 21 .25 be 1.0cm 40.3 c 12.72 abc 2.5 cm 25.3 bd 11.77abc 5.0 cm 27.5 bed 12.62 abc Control 90.0 f 58.27 d a Dried crushed weeds were used to cover stored tubers at the depths indicated (cm). bMeans followed by different letters withi n each column are significantly different at the 50/0 level. · of 2.5 cm or thicker of E. globulus or Lantana camara was effective in control- ling P. operculella, but Phenthoate gave poor control (Table 3). In Tunisia, other methods of control tested at Saida included biological con- trol with Bacillus thuringiensis and chem- ical control with two synthetic pyre- throids, Deltamethrine and Permethrine. PTM damage on stored tubers from an early harvest with low initial infestation ( l.6°1o) was well controlled with Bacillus application, while the same control agent did not sufficiently control PTM damage on stored tubers from a late harvest with a high initial infestation (25.1°/o). There- fore , the use of this biological control agent must be integrated with an early harvest for effective PTM control. Formu- lations of the two synthetic pyrethroids also gave excellent control of PTM dam- age in stored tubers, with no increase in infestation on the early harvested crop and only slight increase in the already se- verely damaged tubers. Population dynamics/ economic injury levels. The results of 1985 studies on the population dynamics and economic dam- age caused by PTM in Tunisia confirmed previous findings that harvest must be timed carefully to maximize yield and to have, at the same time, a low initial PTM infestation in tubers. During the 1985 main season crop at the Saida site, tuber bulking ceased in early June. Crops har- vested at that time had a low level of ini- tial infestation in the tubers, and subse- quent PTM damage evolved slowly while these tu be rs were being stored for con- sumption. Delaying the harvest beyond early June would, therefore, be uneco- nomical since 1) the higher initial infesta- tion lead to higher storage losses from PTM damage, and 2) a later harvest did not increase tuber yields. To demonstrate these differences, samples of potatoes from the same field were harvested May 25, June 5, and June 18 and stored in traditional dark stores (in heaps covered with a layer of straw) for three months. By September 11, the sample from the first two harvest dates showed less than 10°/o tuber damage, whereas the sample harvested on June 18 contained 82°/o damaged tubers. LEAFMINER FLY Screening for resistance. A total of 106 CIP pathogen-tested clones were evalu- ated in the field at Lima for leafminer fly ( Liriomyza huidobrensis) damage. Ovi- position was usually inside the leaf tissue . In a few of the resistant clones the eggs 79 were observed to be extruding out of the leaf tissue thereby exposing them to nat- ural enemies; the percentage of eggs ex- truded was over 80°/o. Larval antibiosis (effect of resistant clones on larval mor- tality) is being studied in these selected clones. Biological control. Parasitoids acting as important biological control agents of the larval and pupal stages ofleafminer fly in- cluded Chrysocharis sp., Ganaspidium sp., and Opius sp. Parasitism by these natural enemies was monitored on unsprayed po- tatoes planted during June, July, August, and September at Lima. Parasitism was initially low (12°/o) in June, however, it reached 75°/o during the later period of September. ANDEAN WEEVILS Screening for resistance. A laboratory screening method to identify resistance against the Andean weevil Premnotrypes suturicallus has been developed at CIP. Weevils collected from the field at Huan- cayo readily lay eggs when maintained at 10° C in a refrigerator. First instar larvae hatching from these eggs are used to infest tubers placed in plastic containers. This test eliminates escapes found under field conditions. There appears to be no cor- relation between foliar damage by adult feeding versus tuber damage by larvae. Biological control. A fungus, Beau- veria bassiana (Balsamo) Vaillemin, was found infecting the weevil population in Huancayo (Concepcion area). Infection reached 60°/o of the weevil population, including adults, larvae, and pupae. In greenhouse tests at Lima, 34°/o adult mor- tality was observed. Further field tests, using this fungus for weevil control, are underway in Huancayo. Socioeconomic studies. In the high- lands of Peru, studies were conducted in 80 relation to farmers' perceptions of insect pest problems and their pest management strategies. Most of the farmers recognized common key pests such as Andean wee- vils, noctuid worms, and tuber moths, as well as large, highly distinctive insects such as blister beetles. Many confused the various lepidopterous larvae, but clearly recognized different types of damage. Leaf-infesting insects such as Diabrotica spp., aphids, leafhoppers, and thrips are regarded as serious pests but only in cer- tain areas and years. The importance of insects as disease vectors and the role of natural enemies do not seem to be part of common traditional knowledge among highland farmers. The intensification of potato produc- tion methods and the rapid growth in urban demand, plus other changes in the structure of the rural economy, have led to the introduction of new potato varie- ties, chemical fertilizers, and other pur- chased inputs. Fallow periods have been reduced and a range of traditional cul- tural practices has been simplified. Pesti- cides are increasingly used as a kind of insurance to protect the cash investment in production. This process of intensifica- tion is more advanced in the Mantaro Val- ley than in Cuzco (Fig. 3). The cost of applied chemicals varies over a wide range, from US$18. 00 per hectare for a single dusting of Aldrin to over US$150.00 for soil application of carbofuran plus four or five sprays. Expenditures on insecticides are correlated with the use of chemical fertilizers. The single, most important source of information about pesticides in Peru is radio advertising by chemical companies followed by the recommendations of sales people. Observations suggest that inte- grated pest management programs - com- bining adaptations of traditional cultural practices and the rational use of pes- 0 Percent of farm families who consume all or most of their potato production in the home Percent of farmers who sell a significant proportion of their potato harvest Percent of farmers who hire in significant amounts of labor Percent of farmers who plant at least part of their land with improved potato varieties Percent of farmers who use chemical fertilizers Percent of farmers who use some form of chemical pest control Percent of farmers who treat seed before planting Percent of farmers who apply insecticide to the soil at time of planting Percent of farmers who spray or dust their plants at least once during the growing season One spray application Two spray applications Three spray applications Four spray applications Five or more spray applications Mantaro Valley; • = Cuzco ---o • ....------o • .--------- 3.5 cm) of six clones planted at San Ramon and Lima, with tuber seed from two origins. San Ramon Origin of tuber seed 0/o Reduction due Huancayo San Ramon to replanted seed Clone TY O/o COM TY 0/o COM TY O/o COM 1. Desiree 1964 96 .1 1619 91.2 18 5 2. DT0-33 1747 92.0 1276 85.8 27 7 3. LT-1 1643 96.4 970 96.3 40 0 4 . 871-240.2 2622 92.9 1839 90.9 30 2 5. CGN 69-1 2489 96.4 6. 278072.10 1357 93.7 SEO (clones 1-4) : for TY, between origin means= 176, between variety means= 191; for 0 /o COM, between site means= 2.04, between variety means= 1.14. Dashes (-) indicate no data available. Lima Origin of tuber seed O/o Reduction due Huancayo Lima to replanted seed Clone TY 0 /o COM TY O/o COM T Y 0 /o COM 1. Desiree 3157 91 .6 1249 88.0 60 4 2. DT0-33 3608 92.1 2108 87.6 42 5 3. LT-1 3059 93 .1 1971 92.8 36 0 4 . 871-240.2 4238 95.3 2548 91 .9 40 4 5. CGN 69-1 4270 91.3 2357 88.2 45 3 6 . 278072.10 3124 58.1 203 42.3 94 27 SEO (clones 1-6) : for TY, between origin means=597, between variety means=204, between any two means= 500; for 0 /o COM, between site means= 2.0, between variety means= 1.4, be- tween any two means= 3.4. CIP's warm sites, San Ramon and Lima. Yield decline was measured against tuber yield of freshly introduced, good quality seed tubers. Although the objective was to study physiological decline in seed tu- ber quality, this cannot be separated from pathological decline. Therefore, general virus resistance in clones adapted to warm climates is of particular importance. The data from the first replanting of seed produced at San Ramon (Table 2) and replanted two months after harvest in- dicated an 18-40°/o yield reduction and 0-7°/o reduction in the proportion of commercial size tubers with marked dif- ferences between clones (Table 2). Re- ductions in yield (36-94°1o) and the com- 90 mercial proportion of yield (0-27°/o) were even greater at Lima (Table 2). SCREENING AND SELECTION FOR HEAT TOLERANCE Peru. The efficiency of light interception, LUE, and harvest index should be im- proved to increase tuber yields in warm climates. Data from Huancayo and San Ramon indicated that short leaf longev- ity (15 vs. 5 0 days in warm vs. cool field conditions), less leaf growth after tuber initiation, and an earlier onset of senes- cence in warm climates all contributed to short canopy duration following tuber ini- tiation. Therefore , light interception and tuber growth were restricted. Selection for faster rates of leaf appearance and ex- pansion and delayed senescence may lead to yield improvements. Preliminary re- sults already show a good correlation be- tween yellowing of leaf discs at high tem- peratures and a known lack of tolerance to heat susceptibilities. Similarly, an in- verse relationship was found between dry weight production per plant and thermo- stability of cell membranes (as measured by ion leakage of cell discs) at high tem- peratures (35° C day, 22° night). Progeny testing of second generation clones at Yurimaguas has reiterated the breeding value of LT-7 and 7XY.l as par- ents , and two new clones, 377887.35 and 377904.10, emerged as good parents in a sample of 700 first generation clones. At San Ramon, 1100 first generation clones were evaluated at three harvest dates. Five percent of the population was harvested at 75 days, 20°/o at 82 days, and the rest, whether mature or not, at 90 days. As expected, the best selected clones from the last harvest date outyielded the ear- lier harvested clones: however, one clone (377935.2xLT-7) from the first harvest yielded 1650 g/plant. Further evaluation of this material is in progress to identify superior clones with adaptation to warm, humid conditions. West Africa. Senegal requires heat tol- erance in its potato varieties in order to cultivate the crop during the warmer sea- sons (October and April plantings). In trials carried out by the national agricul- tural research institute (INRA), selected advanced clones were compared with De- sin~e during the main season (January planting). CIP clones LT-5 , LT-6, and CFK-69.1 had comparable yields to De- sin~e with acceptable tuber characteristics. These selected clones will be tested in Oc- tober 1985 and April 1986. In another main season trial (February-April) of cul- tivars previously selected in 1984, Greta and DT0 -28 had acceptable yields and tuber characteristics. In Togo, 13 of the 89 clones tested for heat tolerance were retained and will be incorporated into a cropping sequence to evaluate the feasibility of producing two crops annually. Six of these 13 clones were included in variety trials in Septem- ber and gave yields between 13 to 17 t/ha. The highest yield was from A VRDC- 1287. l 9, a clone which has shown good heat tolerance in other regions of the world. The remaining clones will be re- tested in 1986. In Cameroon, 11 clones were received in 1985 from CIP's late blight resistance program and have been multiplied at the Bambui station of IRA, together with clean seed of Sangema. These materials will be stored and used for variety trials in 1986. Burundi. On-farm evaluations of ISA- BU's newly released varieties confirmed their better yield potential, compared with that of local varieties. The supe- riority of Muziranzara, an early bulking variety, was particularly outstanding (Ta- ble 3) . Far East. Evaluation of germplasm adapted to warm climates is a major ob- jective of potato research in Asia, South- east Asia, and the Pacific. Variety trials have been conducted by national potato programs in the lowlands of the Philip- pines, Thailand, Vietnam, Laos, Indone- sia, and Fiji . Initial evaluation of a large range of germplasm, primarily received from CIP, is being evaluated in the Philip- pines. In December 1984, five trials were planted in the Philippine lowlands. Four of these included 15, 19, 22, and 40 culti- vars, and the fifth included 1 700 clones of tuber families . The two cultivars Serrana and B71- 240.2 are widely adapted throughout the Far East, but the lack of seed is a major 91 Table 3. On-farm trials of newly released varieties in Burundi, 1985. Mean yield (g/plant) No. trials Test Control Test variety as Test variety harvested variety San gem a O/o Sangema Muziranzara 15 747 476 157 Ndinamagara 19 576 453 127 Kinigi 6 475 353 135 Local variety 20 125 375 33 constraint to increasing their use . To overcome this problem, great efforts are being made by the Far Eastern countries to adopt rapid multiplication techniques. It is important that the storability of all selections be tested, since, for example , in Vietnam nine months of storage are re- quired from season to season. In collaborative work with BARI , the national agricultural research institute in Bangladesh, five heat-tolerant clones planted in October and grown under mulch and high temperature conditions gave yields from 16.6 to 23 .5 t /ha 65 days after planting. These results indi- cated that early maturing varieties with heat tolerance can grow well under warm climates and help regulate the supply of potatoes in the markets by spreading the harvest period. Non-Andean Latin America and the Caribbean. In Central America, the Carib- bean, and Brazil, several national pro- grams have been seeking ways to produce potatoes under heat stress conditions. In Cuba, the Ministry of Agriculture is try- ing to increase the availability of potatoes at other times of the year by planting later in the season (February-March) in- stead of October-November. Two clones have been selected from the heat-tolerant tuber families supplied by CIP and are being rapidly multiplied by in vitro tech- niques. 92 The national programs in the Domini- can Republic, Costa Rica, and El Salvador have each been testing a wide range of heat-tolerant germplasm at altitudes close to sea level. The Dominican Republic se- lected clones LT-4 and N.565 .l as a re- sult of tests in 1983 and 1984. A member of the national team sent to CIP in 1984 for training in rapid multiplication and tis- sue culture returned home with seven ad- ditional clones for multiplication during the 1985-86 season. In Costa Rica, six clones were tested at Finca Blanco (80 m). Temperatures ranged from 21°C min to 30° C max in this high rainfall environ- ment with 3460 mm per annum . At har- vest (77 days after planting) , DT0-28 was the highest yielding clone with approxi- mately 10 t/ha. In El Salvador, six clones previously selected for yield and drought tolerance , were again tested; three clones, DT0-33 , AVRDC-1287.19, andB71-240.2, were se- lected for adaptation to warm lowlands ( 460 m). Through collaborative work with CNPH-EMBRAPA in Brazil, lowland trials were conducted at the Itaguai Ex- perimental Station near Rio de Janeiro. A wide range of clones and tuber families have been tested over the past two sea- sons, and from the original 1200 clones tested, 27 were selected. From 34 tuber families, 4 promising clones have emerged. In agronomic trials at the same site , yields improved 70°/o due to mulching treat- ments. Several clones have shown adaptabil- ity to warm lowland conditions world- wide. The most outstanding of these is the clone B71-240.2, which is being mul- tiplied in China, Dominican Republic, Peru , Thailand, and Vietnam. It is al- ready named as a variety in all of these countries except Thailand and is now being cultivated by small-scale farmers. This clone originated from the INT A breeding program in Argentina with which CIP has maintained a research contract for more than a decade. 93 THRUST VII Cool Climate Potato Production T wo populations developed for genetic tolerance to frost have been im-proved, one for the Andean region and the other for the non-Andean region. They will provide a basis for the development of frost-resistant cultivars in various parts of the developing world . In the populations for the Andean highland region , frost tolerance is combined with major virus and cyst nematode resistances. Early maturity is being built into the population for the tropical and subtropical non-Andean countries where early and late frosts are problems. Considerable potential for adaptability is indicated in the frost-resistant population for the non-Andean region. Genotypes within this population appear to be capable of tuberizing under extremely long days. Collaborative work in Colombia has resulted in the development of new clones with excellent frost resistance. In several Andean countries, potentially valuable clones with resistances to frost and late blight have been selected. Clones with resistances to cyst nematode and late blight were also identified. A collaborative project with the national potato program in Chile has strongly indicated the adaptability of genotypes within the highland tropical population to long days. Good progress has also been made in the search for nitrogen- efficien t clones. Highland tropic population being tested for frost tolerance at Usibamba, Peru (3800 m). 95 AND ADAPT ABILITY Frost tolerance. Two populations are being developed to provide a base for selecting frost-tolerant cultivars. In one population, geared toward the develop- ment of improved genetic material for the Andean highland region, frost toler- ance is being combined with resistances to major virus diseases and cyst nematode. The second population is being improved to meet the tuberosum crop standards in tropical and subtropical non-Andean countries, where early and late frosts are problems and early maturity is required. Advances during 1985 were the result of successful crosses within both popu- lations, seedling screening below freezing temperatures, and clonal selection in repli- cated and nonreplicated trials under frost and nonfrost conditions. A total of 102 crosses were made, between advanced sources of frost tolerance and early ma- turing clones from the population being developed for the lowland tropics, with a yield of more than 200,000 seeds. An- other 62 intercrosses, between frost re- sistant sources from the population un- der improvement for the Andean region, yielded over 180,000 seeds. At Lima, 9222 seedlings from the frost-resistant population for the non- Andean region (FRNA) were screened at - 3°C in a growth chamber with a sur- vival rate of 21.5°/o. From the frost- gion, more than 10,000 seedlings were screened at - 4°C with l 6.3°1o survival (Table 1). All survivors were transplanted to the field at CIP's station in Huancayo (3200 m) for multiplication and single plant hill selection at harvest . Selections in nonreplicated trials in- cluded 485 single plant hills in Huancayo, and 259 selections from ten-hill observa- tion plots tested for frost tolerance in two other locations, Usibamba (3800 m) and Puno (3870 m, southern Peru). The latter location has been established for the first time in collaboration with the national potato program of INIPA (Peru) , which is highly interested in developing frost-tolerant cultivars based on the ad- vanced sources developed at CIP. The extensive area of potato production in this location (about 30,000 ha) is under frost stress and is providing us with the most severe test to select for adequate cultivars for the Andean region. Replicated trials included two simple 10 x 10 lattices and two randomized com- plete block designs of advanced selec- . tions in Huancayo and Usibamba. Yields of advanced clones at both Huancayo and Usibamba were almost 2 kg/plant, and the yield averages of all clones in both locations were over 1.0 kg/plant. The average yields of 100 more recently selected clones in both lattices were 0.97 kg/plant in Huancayo and 1.56 kg/plant Table 1. Seedling screening.for frost resistance in a growth chamber. No. Frost screeninga Survival No. families seedlings -40C/-30C rate (O/o) Andean population, 65 10,663 1,742 16.3 Non-Andean population, 55 9,222 1,984 21.5 Total 19,885 3,726 Avg 18.7 a Andean population, 2 hat -4DC; non-Andean population, 2 hat_ 3oc. 96 A visiting scientist from France is evaluating plant growth of frost-resistant varieties being grown at Usibamba, Peru (3800 m). in Usibamba. The yield potential of these newly selected clones shows a general trend toward further improvement over earlier selected clones. The high yields of clones under selection for frost tolerance were obt~ined during a year when frost was not severe at Usibamba. Mild frosts (- 2° C), recorded in January and March 1985, hardly damaged the clones under evaluation at that site . A joint project with the national po- tato program of ICA in Colombia to de- velop clones with frost resistance has given excellent results. The source of re- sistance came from Solanum acaule, but new crosses using clones from the Inter- regional Potato Project (IR-1) collection in Sturgeon Bay, Wisconsin (U.S.), have genes from 11 wild-species incorporated into their genetic background. Advanced clones had excellent cooking quality , no taste of alkaloids, and gave good yields. Advanced clones from the joint CIP- ICA project were sent for regional germ- plasm trials specifically for Andean con- ditions in Bolivia, Ecuador, Peru, and Venezuela for selection of clones with resistances to late blight and frost. Each country has made initial selections of potentially valuable clones for compari- son with the best local cultivars. In Ecuador the principal objective of the trials was to screen clones resistant to cyst nematode (Globodera rostochiensis). Forty-six clones were selected in the first test and 50°/o of these yielded twice that of the currently used European varieties. The selected clones from Ecuador also had a good level of resistance to late blight. An additional 5000 genotypes .J.rere introduced into Venezuela spe- cifically for their late blight resistance. These were derived from S. tuberosum, S. andigena, and S. phureja parents. The best ten selections in one trial outyielded the local varieties Granola and Baraka. 97 Widening adaptability of the frost- resistant population. To assess the adapt- ability of the frost-resistant population under improvement for the non-Andean region, we tested a sample of 14 families and 5 early maturing tuberosum controls (with no resistance to frost) for tuber- ization response at 18 hours of day length. A single leaf-node cutting technique was used under artificial daylength. There was on the average a 19°/o tuberization response in the frost-resistant families and 58°1o in control families (Table 2). How- ever, whole plant tuberization grown at 18-hour daylength from planting to har- vest yielded a 37°/o overall family aver- age for the frost-resistant population and 80°1o for the control families. Several specific frost-resistant crosses had a tuber- ization response as high as 42°/o with the single leaf-node test. These preliminary results are quite encouraging in providing frost-resistant genotypes capable of tuber- ization under extremely long daylengths. The adaptability potential of this popu- lation to a wider range of environments is evident. In a collaborative project in Chile, the national potato program of INIA eval- uated the adaptability of the highland Table 2. Tuberization response of a sample of the frost-resistant populations and early tuberosum controls to an 18-hour daylength . Leaf-node Whole plant cutting tuberization Family (Cfo) (O/o) Frost-resistant population F6 x ABPT bk 18.8 51 F6 x DT0-28 40.6 73 F7 x DT0-28 41.7 73 375057.9 x bk early 20.0 24 375057 .39 x 0.0 0 375528.2 x 21 .9 55 375596.6 x 37.5 47 377427.1 x 9.4 24 377924.1 x 6.3 28 379115.2 x 6.3 36 HFF 2.2 x 4.3 20 HFF 19.2 x 18.8 36 HFF 21.3 x 3.1 25 HFF 23 .7 x 34.4 29 Average 18.8 37 Early tuberosum controls Serrana x 377904.1 O 37.5 95 377904.10 x Katahdin 43.8 71 (BR-63.74 x Katahdin)9 x 378015.16 87.5 87 377959.9 x 377888.8 83.3 95 378011.23 x (377887.17 x L T·7) 21 37 .5 53 Average 57.9 80 98 Jn Chile, workers of !NIA are harvesting long-day adapted clones from the highland tropic population. tropic population to long days, which resulted in the selection of 32 clones for local use . Evaluation of the selected clones in a replicated trial with a density of 47,619 plants/ha indicated that 72°/o of them had marketable yields equal to or greater than the local adapted cultivars (Table 3). 99 Table 3. Performance of the best ten clones as compared to local controls under long daylengths, Osorno, Chile (lat. 4005).a Tuber Skin CIP no. shape color 381079.41 Red / flat Purple 381102.13 Red / flat White 381127.43 Oval Wh ite 381132.21 • Oval /flat Pink 381114.202 • Oval /f lat Red 380554.130 Oval/flat Wh /pink eyes 381116.7 Red Wh /pink eyes 381081 .21 Red Cream 381135.3 Oval /long Russet 380553.81 Oval/flat Wh /pink eyes Controls Mirka Oval /l ong Cream Yagana Oval /lo ng Yellow Ultimus Long Red Desiree Oval / long Red CV (O/o) a Data from INIA, Chile. AGRONOMIC AND PHYSIOLOGICAL STUDIES Soil management. Contract research with the Soils Department of the National Agrarian University in Lima is directed toward determining basic fertilizer require- ments for potato in the diverse soils and environments within Peru. In the Mantaro Valley, a study was made to measure the potato plant's efficiency of uptake of various levels and sources of nitrogen (N). No difference in tuber yield between sources of N (urea, ammonium nitrate or ammonium sulphate) was detected; how- ever, tuber production increased asymp- totically over the range 0-240 kg/ha N. Analysis of the radioactive plant and soil samples is underway. A similar experiment was conducted on the sources and levels of potassium (K) fertilizer. Tuber yield increased from 35 .4 t/ha without applied K to 45 .7 t/ha 100 Marketable Total Flesh yield yield color (t/ha) (t/ha) Cr 77 .6 78.8 Wh 71 .8 74.3 Wh 69.9 72 .3 Cr 69.7 71 .1 Cr 69.4 70.7 Wh 68.8 69.9 Cr 67 .9 69.1 Wh 67.4 68.3 Cr 67 .3 70.3 Wh 66.3 67 .1 Cr 46 .8 49.3 Cr/Yel 42.7 44.4 Cr 41 .2 44.4 Cr 40.2 41 .2 15.2 with 240 kg/ha K2 0 in the form of po- tassium chloride, which was a more ef- ficient source of K than potassium sul- phate , particularly at the lower levels (80 and 160 kg/ha) of application. Earlier work indicated that potassium may play a role in reducing plant injury due to frost since concentration of K + ions was greater in resistant than suscep- tible clones. In a field study at Usibamba with three levels of K2 0 (0, 100, 200 kg/ha), and fo ur clones ranging from highly frost-resistant to susceptible and maturing in 160 days, a frost at 128 days damaged leaves of the susceptible clone. Yield of the susceptible clone was not im- proved by the higher K rate, suggesting that under mild conditions of frost, K fertilizer does not differentially increase the yield of susceptible clones; however, its direct fertilizer effect on yield was observed in all four clones studied. Screening for efficient use of N fer- tilizer. Fertilizer application is frequently beyond the financial means of farmers in developing countries; consequently, po- tato varieties efficient in their use of re- stricted quantities of fertilizer are of great importance. Such varieties should also be able to respond to applied fertilizer if financial conditions permit. We have concentrated initially on the search for N-efficient clones in a field experiment in Huancayo on soil that without fertilizer applications wpplied approximately 60 kg N through mineralization during the season. Treatments applied were low N (100 kg/ha) and high N (200 kg/ha) to 64 clones and cultivars. Differences in tuber yield between N treatments were not sig- nificant ; however, the effect of the clones and their interaction with the treatments were both significant at the 1°/o level. Yield of high N treatment as O/ o of low N 190 ', 0 ' '~ o.., ' 0 ' o, o' 0 0 ' ' o, 0 .... Clones that gave good yields in low N did not respond to the higher N rate (Fig. 1). Some clones were an exception to the general relationship ; those that yielded well under low N and responded to the higher N were of particular interest. The light use efficiency (LUE) was greater in the high N treatment (1 .81 g MJ- 1 ± 0.04 vs. 1.34 ± 0.03), as was total light energy intercepted (1709 vs. 1533 MJ m-2 ) . Fur- ther evaluation of representative clones from within this group, together with a new set of clones , is in progress. A second experiment in Tarma that in- cluded 17 native cultivars and 8 selected hybrids indicated that approximately 60°/o of native clones and all hybrids re- sponded positively to the application of high levels of NPK fertilizer (Fig. 2). Most hybrids, however, yielded higher tu- ber fresh weight than native clones under 0 0 0 0 0 y = 189.06 - 0 .04x r2 = 0.16 0 150 0 .... , 0 0 110 0 0 1000 0 .............. 0 00 '-....,2i 8 - .... -- 8 0 1500 2000 Tuber yield (g /plant) , low N treatment -- --- 2500 Figure .1 . Relationship between response to high nitrogen (N) and tuber yield (g/plant) at low N for 64 clones and cultivars : fitted regression and 950/0 .confi- dence limits. 101 102 g/plant 1200.--~~~~~~~~~~~~~~~~~~~~~~~~~~~ 1000 800 600 400 200 SA- 1310 Adg . Low NPK . High NP K Senorita Stn SA-388-A Adg Tollocan Hyb Atzimba Hy b P-3 Hyb Figure 2 . Tuber yields from a sample of three native cu l t ivars (Adg, Stn, Adg) and three hy brids (Hyb) under low and high NPK in the soil , Tarma, Peru . DW g/plant 40 30 20 10 0 L H ~ Puca quitish • Total DW • Tuber OW ~ L H ~ ~ Ccompis P-3 Y ungay Figure 3. Dry w eight (OW) of potato plants grown in two nutrient media with low (L) or high (H) NPK. both low and high levels of NPK. A simi- lar experiment in Huancayo, using nu- trient solutions (NPK) applied to plants growing in sterile media in pots, indicated large differences between clones in pro- duction and partitioning of dry weight into plant organs (Fig. 3). Further studies on the relationship between both tech- niques are underway to provide a screen- ing method to identify suitable genotypes under variable nutrient conditions in the soil. Kenya . Agronomic experiments done by the University of Nairobi at a mid- elevation site (Kabete , 1800 m) indicated that yields were severely depressed when potatoes were interplanted with cowpeas or green grams. The cowpea variety (Vita 4) was extremely vigorous and competi- tive with the potato crop, but green grams, while less competitive than cow- peas, still depressed potato yields. Mulch, however, proved to be an extremely ef- fective treatment for improving potato yield. When mulch was applied two weeks after planting (the best treatment), a maximum yield of 19 t/ha was obtained. Burnndi. The national potato program of ISABU has continued agronomic trials to improve potato production : dates of planting of the new late blight-resistant varieties and the use of farmyard manure practices were the principal treatments used. It was again demonstrated, at dif- ferent research stations, that early plant- ing in both seasons (mid-September and mid-February) gave the highest yields in all areas, except in the south of Burundi where the rains started later. There was a linear relationship between yield and rates of manure applied in the range of 0 to 30 t/ha. Thus, even such small applica- tions as might be available to subsistence farmers (e .g., 2 t/ha) improve production when applied in the planting hole below the seed tuber. Further trials are needed to investigate methods of application in the range of 8-15 t/ha of manure. In 1985 , nitrogen fertilizer trials confirmed that there was no benefit to be gained from split applications of nitrogen in the seedbed and at hilling over a single initial fertilizer application. TRAINING Ten months of training was given to a scientist from Spain at CIP headquarters on breeding and selection of potato va- rieties for cool climates. A Canadian stu- dent from the University of Toronto, studying for her M.S . degree, was also trained at CIP for six months on the use of single leaf-node cuttings to screen seed- lings for frost tolerance and long-day adaptation. 103 THRUST VIII Postharvest Technology Three years of on-farm trials in Peru have shown that losses in storage of small quantities of consumer potatoes can be reduced from an average of 3.8°/o a month in traditional storage systems to 1.4°/o a month by use of simple storage boxes and a chemical sprout inhibitor. Research on the stor- age and management of small seed tubers in diffused-light stores, particularly seedling tubers produced from true potato seed (TPS) in beds, has given extremely positive results. The follow-up study on the transfer and impact of diffused-light technology for storing seed tubers in Peru indicated that the application of this technology has continued to spread. In Tunisia, an excel- lent , inexpensive alternative to cold storage of seed tubers has gained farmer acceptance. The new system comprises a sequential combination of storage in traditional stores and diffused light. In Peru, the use of dried insect-repellent foliage of local plants continues to show promise within an integrated pest-management scheme for control of potato tuber moth in storage, which will significantly reduce tuber soft rot. Application of calcium sulfate to field soils and to tubers after harvest tended to reduce soft rot, but further research is required before recommendations for its use can be made. Studies on the extent of virus spread in stores have shown that severe buildup of both potato leafroll virus (PLRV) and potato virus Y (PVY) can occur in stored tubers, but PLRV can be controlled by regular insecticide spraying. The dehydrated potato-based mixture M-6 continues to show broad ac- ceptability in consumer tests in Peru. Several small processing plants have been projected by cooperating national institutions in strategic communities throughout Peru. Variations in mix formulations and alternative products and processes are being evaluated for use in developing countries worldwide. Emphasis is now on the transfer of knowledge gained from CIP's simple potato-processing experiences. Acceptance test of home-processed potato products in the central Peruvian highlands. 105 STORAGE OF CONSUMER POTATOES Peru. During 1985 the third and final se- ries of on-farm trials to evaluate improved technologies for storing small quantities of consumer potatoes in cool environ- ments was conducted. As in previous years, the effectiveness of simple, 500 kg, naturally ventilated storage boxes and a sprout inhibitor in reducing storage losses under farm conditions were evaluated and compared with traditional farm storage methods. The traditional storage practice is to simply pile the potatoes in the cor- ner of an existing room and sometimes cover them with loose straw or Muna (Minthostachy s spp.). Due to pricing pol- icies and market uncertainties, the stor- age period in 1985 was shorter than in previous years and ranged from 2.2 to 2.7 months with a mean storage period of 2. 5 months. Despite this short storage period, the losses recorded with different storage systems were similar to those reported previously (1984 Annual Report) . As a result of parallel studies on stor- age practices in Peru, we reported in 1984 that an estimated 75°/o of farm house- holds in Peru that produce potatoes stored at least 500 kg of potatoes for var- ious home uses such as home consump- tion, sale in local markets, gifts, and bar- ter. On a national basis this amounts to about 650,000 tons of potatoes or about 40°/o of the national production. During 1985, two new experimental stores, encompassing four possible storage environments, were being constructed for the storage of consumer potatoes at San Ramon. Each storage environment con- tains ten small storage bins with a capac- ity of 250 to 300 kg of tubers. All the stores have the possibility of trickling water through the walls to permit passive evaporative cooling. These stores will be used to evaluate control methods for po- 106 tato tuber moth and soft-rotting during the experimental storage of consumer po- tatoes in warm climates. East Africa. On-farm experiments by several national institutions have contin- ued in several countries in East Africa to test farmer acceptance of storage tech- nology for consumer and seed potatoes. In Kenya, there appears to be a general reluctance on the part of farmers to store consumer potatoes for an extended pe- riod, indicating that the present mar- keting flows for consumer potatoes are efficient, and large-scale storage for an extended period is unlikely to be profit- able. There may, however, still be the need for small-scale storage by farmers for family use or sale in local markets. The Ministry of Agriculture is settin,g up additional trials in areas not presently included in the current program such as in Taita Hills and Bungoma. This study continues in collaboration with the Rural Structures Unit of the Ministry of Agri- culture and an agricultural economist from CIMMYT in Mexico . In Malawi, there is a storage project financed by the government of the Netherlands, with which the CIP storage specialist, based in Nairobi, has been serving as a consultant. The first phase consisted of eight consumer potato stores built for trial purposes, which proved in- valuable in training extension officers. By the end of 1985, 50 consumer and 50 seed stores were under construction throughout the potato-producing areas. In Tunisia, storage of consumer pota- toes for four months after harvest was possible provided that sprout inhibitors such as IPC or CIPC were applied. The potatoes were first sprayed with Decis (pyrethroid) to protect them from potato tuber moth (PTM), then dusted with the sprout inhibitor, and covered with news- paper (to reduce the fast evaporation of the product) and a thick layer of straw. Weight losses in these tubers were less than 4°/o compared with more than 11°/o for other treatments without inhibitors. STORAGE OF SEED TUBERS Latin America. Research in Peru during 1985 focussed on evaluating the storage behavior of small seed tubers, particularly of seedling tubers produced from true potato seed (TPS). The postharvest dor- mant period was studied in six size grades of second generation seedling tubers of Table 1. Effect of tuber size on length of the postharvest dormant period in diffused-light and dark stores. Tuber size (g) 1-3 3-5 5-10 10-20 20-40 40-60 Mean Postharvest dormant period (days)0 Diffused I ightb 49 ± 1.3c 44 ± 1.1 44 ± 0.9 40 ± 0.8 42 ± 0.8 40 ± 0.6 43 ± 0.9 44±1.1 42 ± 0.9 42 ± 0.9 41±1.0 41±0.6 39 ± 0.5 42 ± 0.8 a Means of two TPS progenies of 100 tubers each. b At ambient temperature during summer in Lima. cstandard error of the mean. DT0-33 OP and Atzimba x DT0-3 (Table 1). The length of the postharvest dor- mant period tended to increase with de- creasing tuber size, resulting in a differ- ence of about one week between 1-5 g and 40-60 g tubers. The dormant periods in diffused light and in dark stores were similar. The number of eyes per tuber was about 50°/o higher in 40-60 g tubers com- pared with the number in 1-3 g tubers (Table 2). The maximum number of sprouts per tuber that was obtained after desprouting was 1.8 in 1-3 g tubers and 6.8 in 40-60 g tubers. On a per unit weight basis, however, the 1-3 g tubers produced over four times more sprouts that 40-60 g tubers. The percentage of sprouted eyes at 29 days after harvest was similar in all size grades despite the large differences in numbers of eyes per tuber. This suggested that tubers of all size grades experienced a similar degree of apical dominance. In diffused light stores (DLS), the number of sprouts per tuber showed little increase with increasing storage time. Although desprouting in- creased the number of sprouts, the effect varied with tuber size and storage period. In large tubers desprouting had a greater effect on sprout number than in small tubers. Table 2. Effect of tuber size on the number of eyes and sprouts per tuber0 in diffused-light stores. Tuber size (g) No. eyes/tuber No. sprouts/tuberb No. sprouts/kg tubers 1-3 4.4 ± 0.9c 1.8 ± o.02c 3-5 4.6 ± 0.9 2.4 ± 0.08 5-10 5.6±0.14 2.9 ± 0.06 10-20 5.5 ± 0.09 3.7 ± 0.14 20-40 5.8±0.12 5.0 ± 0.31 40-60 6.5 ± 0.11 6.8 ± 0.46 a Means of two TPS progenies of 100 tubers each. bNumber of sprouts obtained after desprouting eight weeks after end of dormancy. cstandard error of the mean. 667 ± 7c 522 ± 17 372 ± 8 266 ± 10 201±12 147 ± 10 107 Results from desprouting tubers af- ter different periods of storage indicated that tubers of all size grades showed their maximum resprouting capacity af- ter eight weeks from the beginning of sprout growth. The subsequent decline in sprouting capacity was greater in tu- bers of the smaller size grades, suggesting that larger seed tubers maintained higher levels of sprouting capacity for a longer time when compared with small tubers. Tuber weight loss after 5.5 months of storage tended to decrease slightly with increasing tuber size. Although weight loss in tubers stored in DLS was two to three times higher than those stored at 4° C, field emergence was not affected. This finding demonstrated that relatively high weight losses can be tolerated in seed potatoes provided that sprouts are maintained in adequate condition. The overall variability in the storage charac- ters recorded tended to be somewhat higher in the smaller tubers as indicated by higher standard errors. During 1985 a follow-up survey on the transfer and adoption of DLS for storing seed tubers was conducted in the Mantaro and Tulumayo Valleys of Peru. The ob- jectives of the study were to 1) verify if diffusion had taken place, 2) deter- mine how and why farmers adopted and adapted the technology, and 3) deter- mine benefits of adoption and reasons for non-adoption. A questionnaire was given to 45 farmers and information on an additional 106 farmers was collected. Forty-three of the 45 farmers stored in diffused light, 28 of these had con- structed new stores, while 15 had adapted existing farm buildings. Although the total number of DLS adopters in Peru is not known, an overall growing adoption rate was illustrated by 37 of the 45 farmers surveyed, who reported the date when they had adopted the technology. 108 As far as the actual adoption process is concerned, two different patterns can be appreciated from the survey: 1) farmers working directly with national ex ten- sionists tended to progress from storing in complete darkness directly to specially built DLS (Fig. 1), and 2) farmers who either attended a course or field day, or saw the rustic seed stores at neighbors' houses, tended to show more interest in the principle of DLS and tended to adapt, with available resources, the most suitable places in their dwellings or in other farms building (Fig. 2). Farmers, in general , showed a very clear understanding and knowledge of the benefits this new tech- nology could offer them (Fig. 3); how- ever, the reasons for nonadoption were more varied but are not reported here. In Chile, the national agricultural in- stitute INIA has continued research on the use of DLS for seed tubers. Tubers of four cultivars (Yangema, Fueguina, Spartan, and Ultimus) were stored for 150 days: the emergence of seed tubers stored in DLS was faster than seed stored in the dark and, as a result, plants from DLS tubers matured two to three weeks earlier. In seed crops this is an advantage as the plants are exposed to aphids for shorter periods and have lower virus in- fection rates. These plants also produced a larger number of seed-sized tubers, al- though yield was similar to the crop of normal duration. DLS technology is now being adopted by farmers in southern Chile, who are modifying traditional wooden stores by replacing side walls with double-layered plastic sheets. A study in Uruguay, conducted by the national agricultural institute CIAAB, is assessing the use of DLS on its own and in combination with refrigerated stor- age. Tuber weight losses were higher in DLS storage, partly due to the removal of apical sprouts; however, there were no Figure 1. Large-scale diffused-light store built within existing building, Ocopa, Peru. Figure 2. Small-scale farmer 's diffused-light store adapted to local house design . 109 In storage c B In the field* B A= less water loss B = less weight C = less sprouting D = better control E = lower attack by insects n = 102 farmer responses A= higher yielding B = higher resistance C = early emergence n = 77 farmer responses *Fewer answers were recorded for "in-the-field benefits" as 9 farmers were only planting their first green seed and 8 farmers were just in their first year of DLS trial. Figure 3. Benefits resulting from the use of diffused-light stores as reported by potato farmers in Peru. significant differences in yield whether the seed was stored in DLS, refrigeration , or a combination of the two. This in- dicated that considerable energy savings could be made by combining the two storage methods under the climatic con- ditions of Uruguay. 110 North and West Africa. The first phase of storage investigations in Tunisia has been completed and is being written up in collaboration with the staff at Saida. It was concluded that seed har- vested in the main season and stored in a combination of traditional stores (T) (dark storage under straw) with diffused- light storage (DLS) in the ratio of 80 d T + 70 d DLS was an excellent and low cost alternative to cold storage. This system provides seed for the early (mid- November) season and farmers have com- mented that it fits well with their own management strategies. Seed stored un- der this system will probably outyield the physiologically very young imported seed. Methods of long-term storage, from June until the following February (230 days), were examined. It was found that there were large varietal differences in storage performance. Spunta and Atica, without mechanical cooling, gave virtual- ly no yield, whereas Claustar and Desiree yielded more than 20 t/ha. Cold storage over the hottest three months (June, July , and August) gave much higher yields regardless of subsequent storage treat- ments. Long periods of DLS storage caused hardening of the sprouts and ex- cessive branching. Desprouting of tu- bers ten days prior to planting improved emergence and yield in most varieties. In conclusion, future work on combined methods of storage for long periods will have to involve differential varietal re- sponses. Since 1984, CIP has been working in the Cape Verde Islands to help estab- lish a seed multiplication program. Im- ported seed was multiplied in 1984 dur- ing the spring (March-June) crop on a small scale and stored in specially con- structed DLS on government farms ; how- ever, potato tuber moth (PTM) caused considerable storage losses. The usable seed was planted in October 1984 and gave satisfactory yields (17 to 22 t/ha) . In 1985, DLS were built at different sites on government, cooperative, and pri- vate farms, and seed multiplication was extended to cooperatives and farmers' fields. Better control of PTM was applied for the 1985 trials. As a result, ten tons of locally multiplied seed were available for the November planting. A FAO pro- ject will take over the work in 1986 and expand the program. A seed multiplication program similar to that in Cape Verde has been established in Senegal by the national agricultural institute INRA. There is also ongoing storage research, similar to the Tunisian program, in which determination of va- rietal response to local storage conditions will be an important factor. In Togo, the storage program has reverted to the ex- perimental stage after severe losses in DLS due to soft rot. Methods of soft rot control and varietal performance are being assessed. CONTROL OF POSTHARVEST PESTS AND DISEASES Potato tuber moth and tuber soft rot in stores. Research continued on Erwinia soft rot in tubers during a rainy season in San Ramon, yielding results similar to those reported previously in the field; the cultivar Desiree had a significantly higher (5.0°/o Duncan) number of rotting tu- bers, higher number of plants with symp- toms, and higher number of plants killed prior to harvest than the cultivars Revolu- ci6n or Rosita. There were no significant differences, however, between final yields of the three cultivars. The application of either 12 t/ha or 24 t/ha of calcium sul- phate had no significant effect on either reducing tuber rotting or increasing yields. During storage there was a constant and highly significant (1.0°/o Duncan) difference in the percentage of tubers showing symptoms of PTM and/or soft rotting between treatments protected against PTM attack with Phenthoate and Lantana foliage and nonprotected treat- ments as recorded in previous seasons 111 Table 3. Influence of biological and chemical protection against potato tuber moth on tuber damage and soft rot in stores, San Ramon, Peru. Tuber damagea (O/o) Storage period 2 mo 4 mo 6 mo Protected against PTMb 2 b* 7 b 13 b Non protected 95 a 99 a 100 a aTubers damaged by PTM attack, soft rotting, or both . bTreated with Phenthoate and covered with Lantana sp. *Numbers in each column followed by different letters are significantly different at the 1°/o level . (Table 3). Postharvest application of cal- cium sulphate resulted in significantly less (5 .0°lo Duncan) tuber damage after two and four months of storage but this effect was not evident after six months. There were no significant differences between the three cultivars with respect to the per- centage of tubers damaged throughout the storage period. It is evident that protection against PTM during storage is reducing tuber damage to a more acceptable level, i.e., 13°/o after six months of DLS storage un- der San Ramon conditions. The applica- tion of calcium sulphate both in the field and to stored tubers appears to reduce rotting slightly, although further research is required before general recommenda- tions on its use can be made . Potato leafroll virus and potato virus Y in stores. In trials on the occurrence of PLRV and PVY in storage, there was con- siderable buildup of both viruses in the susceptible cultivar 69-47-2 at two sites, one on the Peruvian coast (lea) and the other in the central highlands (Huancayo). No buildup of either virus was recorded in the cultivar Serrana at either storage location. With the cultivar B71-240.2, reported to be resistant to PLRV and 112 susceptible to PVY, some PVY buildup was recorded at the highland location. These results indicated that the reaction of cultivars to these severe viruses is simi- lar in storage to that reported under field conditions. In the susceptible cultivar 69-47-2, the level of PLR V infection reached between 98°/o and 100°/o in both locations. This virus buildup was well controlled by regu- lar spraying with the insecticide Tamaron every 7 or 14 days. The use of dried foli- age of the plants Lantana sp. and Euca- ly ptus sp. did not provide adequate con- trol, although less buildup was observed than in control treatments. Although the buildup of PVY was not so great and was more erratic , none of the treatments eval- uated gave control in susceptible cultivars. National potato programs are now being encouraged to evaluate the importance of virus spread and buildup during the stor- age phase of seed tuber production under their specific conditions. POTATO PROCESSING Production implications and evaluations of alternative techniques and costs, with respect to the manufacture of the potato- based mixture M-6 at different scales, have now been completed. Both the family scale and small factory scale described in the 1984 Annual Report show promise of acceptance in Peru. Additional hand-operated equipment is being developed jointly with a local engineering training institute (SENATI), where prototypes are being manufactured for evaluation in the various processing alternatives in the CIP pilot plant in Huancayo. The M-6 mixture has con- tinued to show consumer acceptance in daily use by a communal kitchen located in one of Lima's pueblos j6venes, where free lunches are provided for about 100 children each day. Consumer acceptance was also confirmed in a large-scale school feeding test with 2000 schoolchildren. This test, involving six tons of M-6, was conducted by the Ministry of Health in several schools throughout the central highlands of Peru. Major emphasis is now on transferring these simple processing and product tech- nologies, in cooperation with several na- tional institutions, to private enterprises and farming communities. To assist in these national transfer efforts, CIP held a four-day workshop in 1985 at the Huan- cayo pilot plant, with 16 participants from many collaborating institutions in Peru. In a collaborative effort , CIP and researchers from different countries, for- merly trained at CIP in processing tech- niques, are using CIP's experiences and pilot plant to formulate and produce processed food mixes that recognize lo- cal market acceptance , food preferences, costs, and availability of native food crops. For example, a test product for- mulated with a trainee from Bangladesh has shown initial promise in acceptabil- ity trials in Bangladesh. Additional test products, involving other Andean root and tuber crops, are being investigated by Peruvian and Bolivian trainees. The processing of alternative products such as dehydrated french fries for different consumer groups in Peru is also being initiated by CIP. CIP's emphasis will continue to be on the transfer of these technologies to assist national institutions in researching loca- tion-specific market needs and opportu- nities for the development of a viable po- tato processing industry. This will require continued research support in product development and testing, as well as ad- ditional research at the CIP pilot plant on reducing costs for processing. In Peru, one national institution (Centro IDEAS) has been successful in obtaining external funding to establish one small potato- processing plant, and possibly others. These plants will be built directly with the private sector in strategic locations throughout the country. Also, INIPA, the ·national institute for agricultural re- search and extension, is to develop its own pilot plant for the processing of Andean crops including the potato. An organization based in the United States, Compatible Technology, has been cooperating with the NAVE Institute in Bareilly to develop a small, village-scale processing plant in India. Technical sup- port for the project has been provided by CIP, including a visit by the sponsors to CIP's pilot processing plant in Peru. This project will be used as a model to start similar projects in South Asia after one or two years of full-scale operation at Bareilly. TRAINING Two group training activities on storage were held in Tanzania and one in Malawi, with a total attendance of 57 researchers and extensionists. The majority of the instruction for all three courses was pro- vided by the national program staff. Also in East Africa, 48 Ethiopian government personnel, who are involved in potato production and use , attended a three-day workshop in Addis Ababa on low-cost storage technology that CIP is using in developing countries. Three scientists from Bolivia studied CIP's storage and processing methods at CIP headquarters to assist them in devel- oping a postharvest project. Colombia also sent one of its scientists to study the production of potato-based mixes at CIP's pilot plant in Huancayo. 113 THRUST IX Seed Technology Research has continued to focus on the production and utilization of true potato seed (TPS). Studies on TPS production in Peru and Chile indi- cated that factors such as stem density, pruning of excessive flowers, and the amount of nitrogen significantly affect TPS quantity and quality . In south- ern Chile, under optimal environmental conditions, the average production was about eight grams of hybrid seed per square meter, indicating that, in an area of 15 square meters, sufficient TPS can be produced to plant one hectare with seedlings. In Peru, TPS progeny testing with seedlings or seedling tubers has con- tinued under different climatic conditions. Improved performance was ob- served in newly selected hybrid and open-pollinated progenies used as seed- ling tubers and transplants. Progress was also made in selecting for rapid recovery from transplanting shock. Tuber bulking has been improved by de- velopment of new agronomic practices. The use of TPS for seedling tuber production has improved rapidly and represents an excellent short-term solu- tion for developing countries, while the primary, longer-term goal of devel- oping seedling transplant technology is being achieved. Intensive TPS progeny testing and related agronomic research was carried out in Peru and other Latin American countries, Africa, and South and Southeast Asia. Highly promising results are being obtained and TPS tech- nology is rapidly gaining farmer acceptance, particularly in South and South- east Asia. Seedbeds for seedling tuber production in a farmer's field , Sri Lanka. 115 POTATO SEED Since many practices required for proper performance of the potato crop from true potato seed (TPS) are well defined and are under evaluation in the regions, re- search in two areas, seed physiology and production, has grown in importance during 1985. This increase responds to the need for defining efficient methods of quality TPS production. The availability of high-quality TPS could expand con- siderably the potential area of adoption as well as the range of users. Massive hybrid seed production of im- proved combinations was attempted in three locations during the year: Lima (12.05°S) , San Ramon (ll.08°S), and Osorno, Chile ( 40.5° S). The latter work represents a cooperative project with INIA, the national agricultural research institute. Great differences in the effi- ciency of TPS production were obtained among locations when comparing results obtained with the same genotypes used as parents of various hybrid combinations. In Osorno, suitable daylength and other optimal environmental conditions allowed for the production of more than 5 kg of hybrid seed for distribution to many na- tional potato programs worldwide. The average production in Osorno was about 8 g of hybrid seed per m2 . Under short daylengths and less favorable environmen- tal conditions, such as those in Lima and San Ramon, TPS production efficiency was reduced to 10°/o of that in Osorno. Several projects were implemented in Lima and San Ramon to improve the efficiency of TPS production under sub- optimal environmental conditions. Em- phasis was on practices that could be proposed to national programs located in warm tropical areas. Additional N appli- cations resulted in enhanced flowering , delayed plant maturity, and also length- 116 - - r ---- - - - - -- the vines. The increase in flower produc- tion was an indication that N rates greater than those required to produce tubers might be essential to efficiently produce large quantities of TPS. Flower produc- tion was increased by 2.7 and 3.5 times, when three additional applications of 80 kg and six of 40 kg of N/ha were added to the normal N rate of 150 kg/ha recom- mended for high tuber yields (Fig. 1). Berry weight and seeds per berry did not vary significantly. The 100-seed-weight, possibly the closest estimate of TPS qual- ity, did not vary significantly across berry sizes, except for seed produced in small berries, where the higher number of par- tial N applications resulted in heavier seed. Fully ripe berries were small be- cause they contained a lower number of seeds, and berry size was highly corre- lated to the number of seeds per berry. Therefore, the size of fruits should not be used as a selection criteria for large-scale hybrid seed production, but rather for Percent (0 /o) of control 400 300 200 100 No . in- florescences per plant • 150 + 80 x3 • 150+40 x6 Berry weight No. seeds per berry Figure 1. Flowering, fruit, and seed setting as affected by three and six additional weekly ap- plications of 80 and 40 kg /ha of N, respectively, in addition to the normal 150 kg/ha of N. Percent (O/o) of control 1000 800 600 400 200 o~-----'--­ Flower production 1000 ppm GA • 2000ppm GA j 500 ppm GA+ 500 ppm BA • 2000 ppm GA+ 500 ppm BA Pollen fertility Figure 2 . Flower production and pollen ferti lity as affected by various rates and combinations of gibberellic acid (GA) and benzyladenine (BA) (values relative to the control). Treatments were applied on DT0-28. conditions that promote a longer seed- bulking period. The effect of several growth regulators on flowering and seed characteristics of a sparse-flowering male parent (DT0-28) was also evaluated in Lima. Among the most effective treatments, gibberellic acid (GA) at rates of 1000 and 2000 ppm, or a combination of 500 ppm GA with 500 ppm of benzyladenine (BA), produced not only an increase of about tenfold in the number of flowers, but also a con- siderable improvement in pollen fertility (Fig. 2). Several field practices for TPS produc- tion were evaluated in Huancayo on three potato varieties. Considerations included the effect of 1) pruning axillary branches, 2) stem number per plant, 3) position of first (FDI), second (SDI), and third (TDI) developed inflorescences, and 4) number of berries per inflorescence. Axillary branches were removed week- ly during a five-week period, starting two to three weeks after emergence; after this period, no new branches developed. With- out pruning, the total number of flowers per plant was higher, but the number of flowers on main stems was lower. The presence of axillary branches mainly de- creased the number of SDI and TDI on the main stem, and pruning increased the length of the flowering period of the in- florescence on the main stem. There was generally no significant effect of pruning on berry size distribution. 117 With respect to the number of main stems per plant, three-stem plants had the same number of branches as one-stem plants but had less flowers on the main stems. The total number of flowers per plant was only slightly higher in three- stem plants than .in one-stem plants. In three-stem plants, a lower proportion of flowers originated from TDI compared to that in one-stem plants. Three-stem plants started to flower one week earlier than one-stem plants and terminated flowering two weeks earlier; they also produced more large- and medium-sized berries on the main stems, although the proportion of large berries and 100-seed-weight was lower. Pollination of flowers in other than FDI reduced the average size of berries produced in the first position in two out of three varieties, suggesting competition between inflorescences of the different positions. When berries from all positions were left for the same period on the plant, berries from SDI were larger than those from FDI . The 100-seed-weight obtained from FDI and SDI tended to be higher than that from TDI. The variations in physical characteristics of the seed ob- tained by applying these field practices may produce favorable changes in the seed quality. The greatest potential for the adoption of TPS technology is in the warm areas of the tropics, where also environmental stresses on the crop are far more demand- ing. For TPS to be used extensively in these areas, seedling vigor must be im- proved. In potatoes, the long history of cultivation involving selection for tubers probably had a strong influence on the sowing value of TPS. Tubers that are rap- idly storing assimilates may cause an ar- rested development of embryos and result in low-quality TPS. Very few plant spe- cies that are vegetatively propagated, e.g., 118 the potato , are known to develop func- tional sexual organs. Dormancy is a major factor affecting the use of TPS. Preliminary evidence from work at CIP suggests that dormancy is induced in the embryo during seed ex- traction or immediately after. Prelimi- nary experiments were conducted using excised embryos from Atzimba and DT0- 33 OP seed, imbibed and left in the light or in the dark, with or without GA . In the light, in both progenies, GA inhibited embryo growth as compared to no GA. In the dark, GA promoted embryo growth of Atzimba seed but not of DT0-33 seed. Since a difference in the progeny response to GA was observed in these experiments, the use of GA to break dormancy should be investigated further. In an experiment using Atzimba OP seed that was imbibed for 48 hours in GA solution, either in the dark, or in a combination of 24 hours light and 24 hours dark, the speed of germination was favored by the use of GA. But seedling growth 30 days after germination was reduced by 30°/o in the 24 hours light + dark combination and by 20°/o in the dark treatment. In seed of other proge- nies, opposite results were observed. In other experiments, we found that when TPS was dried properly immediately af- ter extraction, GA use was not necessary and might even reduce the speed of germination. In 1984, we reported on the advan- tage of using fermentation as a method of extracting freshly harvested TPS. An eval- uation of the seed obtained from fermen- tation was performed during 1985 after 8 and 12 months of storage. The speed of germination was reduced with fermen- tation periods of 72 and 96 hours. No apparent damage to germination was ob- served when seed was fermented for pe- riods of 24 and 48 hours. Pollen selection, an area of research recently initiated at CIP, appears to be a promising alternative for manipulating the proportion of genotypes responsible for improved seedling vigor. In the project with INIA in Chile, the first stage of massive TPS production was carried out at the Remehue Experimen- tal Station in the southern part of Chile . Detailed socioeconomic information was carefully recorded on six progenies: Ser- rana x DT0-28, Serrana x DT0-33, CFK 69.l x DT0-33 , CEX 69.1 x DT0-28, At- zimba x DT0-28, and Atzimba x DT0-33 . The average production cost per kilogram (including data from all progenies) was US$283 . However, costs varied drasti- cally among progenies: from US$233 for Serrana x DT0-33 up to US$350 for CEX 69.1 x DT0-28. Production costs were lower when 1) a higher number of seeds per berry were produced, 2) a higher number of berries per plant were set, and 3) a smaller number of female plants were needed to produce 1 kg of TPS. Of the total production cost, emasculation was the most costly activity, representing 63°/o , with pollination as the second at 12°/o. The two most expensive inputs were technical management (64°/o) and labor (22°/o) . The costs can be reduced when more experience is gained on TPS field production practices. AGRONOMY OF TRUE POTATO SEED Agronomic research has concentrated on two alternative methods of TPS use: 1) production of consumer potatoes by transplanting seedlings to the field , and 2) production and use of seedling tubers for further propagation. Seedling production and transplanting. The simplest and most direct method of using TPS is to produce potatoes for con- sumption from transplanted seedlings. With this method, the most extensive ex- ploitation of TPS could be realized, par- ticularly for subsistence potato growers in warm areas. Research is concentrating on the eval- uation of improved progenies and on agronomic practices for enhancing tuber bulking. Different groups of hybrid and open-pollinated (OP) progenies are being systematically evaluated. A set of 47 im- proved progenies was evaluated in Lima, Huancayo, and San Ramon, and the yields of the best 12 progenies across environments are shown in Table 1. This set was also tested for resistance to late blight and Rhizoctonia. Another group of 12 selected proge- nies, propagated either by transplanting seedlings to the field or by using seedling tubers, were evaluated in Huancayo and San Ramon. Various field practices were investigated that might reduce the num- ber of tubers produced or improve the tu her-bulking capacity of plants from transplanted TPS seedlings or a combi- nation of both. Experiments included transplanting methods, hilling, fertilizer applications at different stages, and use of growth regulators. Selected progenies must be improved with respect to average tuber size and yield when transplanted seedlings are used. Average tuber size is an important trait for areas where TPS will be used every season for growing potatoes for consumption. In San Ramon, the three highest-yielding progenies from trans- planted seedlings were also the highest when seedling tubers were used. One of those three, Atzimba x 380700.79, had an additional advantage in producing a high proportion (85.5°/o) of large size tubers (> 3.5 cm diameter) when trans- planted. In all progenies tested, the yield was higher from seedling tubers than from transplants. 119 Table 1. Total and percent marketable (Mktb) yield (t/ ha) of the best 12 hybrid progeniesa in eval- uations conducted in three different agroecological locations during the 1984-85 seasons, Peru. San Ramon Huancayo Lima Average Mktb Mktb Mktb Mktb Progeny Total (O/o) Total (O/o) Total (O/o) Total (O/o) Atzimba x R 128.6 37 .8 84.3 43.2 76.6 48.1 87.9 43.0 82.9 Atzimba x 380701.12 33.0 76.1 49.7 83.0 43.2 75.6 41.9 78.2 R128.6 x 7XY.1 37 .3 88.7 39.8 85.0 41.6 78.4 39.6 84.0 Atzimba x 380700. 79 24.5 87.0 38.5 79.0 52 .3 73.4 35.6 75.1 CFK 69.1x380701.12 33.9 83.0 40.2 85.5 26.8 66.0 33.6 78.2 CFK 69.1 x 380700.79 25.7 84.0 42.1 84.1 37 .6 82.3 32.6 80.5 377935.27 x 377964.5 39.3 78.9 22.2 73.5 39.7 82.8 33.7 78.4 CEX 69.1 x 380701 .12 27.5 82.5 42.5 77.0 27.8 73.2 32.6 77 .6 CGN 69.1 x 380701.12 26.8 78.0 46.8 80.0 23.6 67.8 30.2 72.9 Atzimba x DT0-28 30.1 69.0 32 .8 83.0 34.6 70.7 32.4 74.2 LT-1 x R128.6 20.8 83.0 34.6 73 .0 40.0 84.0 31 .8 80.0 377935.27 x L T-7 32.8 85.0 29.7 75.2 26.7 66.7 29.7 75.6 a Highest yielding among 47 hybrid progenies tested. Recovery index (Or /Wi ) 9 6 3 Another characteristic of great im- portance when selecting TPS progenies is their ability to recover rapidly from transplanting shock. We studied the re- sponses of three groups of progenies to an induced shock at transplanting of -15 bar water potential , using a polyethylene glycol (PEG) M.W. 6000 solution for 15 minutes at 20° C. A seedling recovery index based on the amounts of roots regenerated and the speed of recovery from wilting for three response classes are shown in Figure 3. Preliminary experiments for defining fj rates and time of application of two 0 1-0'-----~----~-----' growth regulators, chlormequat chlo- 2 4 6 8 ride (CCC) and GA, were conducted in Days after treatment Lima. The experiments were designed to Y F = -2.5 + 1.84x - 0.075x 2 (r = .76) provide information applicable to the YM = -0.46 + 0 .36x + 0.007x 2 (r = .80) selection of materials and practices for Ys = 0.17 + 0.23x-0.012x 2 (r = .91) h f b improving t e average size o tu ers pro- Figure 3 . Recovery index, expressed as a ratio of roots regenerated (Or) and degree of wilting (Wi), at different dates after an induced trans- planting shock in TPS progenies, representing fast (YF), intermediate (YM), and slow (Y5) recovery response groups. 120 duced by plants grown from TPS. Fifty percent higher yields and a 50°/o greater number of tubers larger than 3.5 cm diameter were obtained when approxi- mately 50 ppm of CCC was applied around 75 days after transplanting. With GA, a rate of I 0 ppm caused a 45°/o in- crease in total yield and a 41 °lo increase in the number of large size tubers. The best time of application for similar effects on yield was approximately 60 days after transplanting. More detailed studies are in progress. SEEDLING TUBER PRODUCTION AND USE This is the system of TPS utilization in which the fastest progress has been achieved. It is the most practical system in the short term for many developing countries. Complementary experiments on nursery production of seedling tubers indicated that high temperatures during the summer are responsible for the pro- duction of lower numbers of tubers and favor bulking to a larger average weight (Table 2) . Studies using a broad range of seedling densities ( 6-96 plants/m2 after thinning) during both the winter and summer sea- sons in Lima confirmed that reducing seedling density is not effective in in- creasing the number of relatively large tubers(> 10 g). At low densities the pro- portion of large tubers as a percentage of total tuber number was higher, but the total number of large tubers produced per unit area was lower. Experiments also confirmed that the highest number and weight of usable tubers were obtained at 96 plants/m2 . Densities above 100 plants/m2 appeared to be impractical for proper hilling. Studies were conducted on the effect of thinning (a practice normally done with seedlings growing in nursery beds) and on the effect of natural selection of the most vigorous seedlings on the pro- portion of harvested hybrid genotypes. Two mechanical mixes (A and B) of seed containing hybrid and selfed seed in ratios of 50:50 and 25:75 ofhybrid:selfed TPS were sown in the normal sowing pattern of 10 x 10 cm in nursery beds. The posi- tions of the hybrid seeds were well identi- fied at sowing time. After normal thin- ning, by which the weakest plants were discarded leaving only one plant in each position, and after the natural selection that occurs by strong competition at such Table 2. Evaluation of TPS progenies for tuber production in nursery beds during win ter and summer seasons in Lima. No. tubers/m 2 > 1 g Mean tuber weight (g) Progeny Winter Summer Winter Summer Atzimba x DT0-33 1070 b* 506 a 12.6 16.6 Atzimba x 7XY.1 1365 a 492 a 9.6 17.9 Participaci6n OP 1019 c 486 a 12.5 16.7 DT0-33 OP 808 c 450 ab 9.7 14.1 Murca OP 1306 a 397 b 9.4 15.0 Atzimba x R128.6 993 c 252 c 15.1 23.8 Anita OP 1355 a 216 c 11.5 17.9 4.1 DI OP 833 c 174 c 17.6 16.7 Mean 1094 372 12.3 17.2 *Means followed by the same letter within a column are not significantly different at the 50/0 level. . 121 At sowing A At harvest TPS 1 ____ _ At sowing mix _ _________ _._ B At harvest 0 50 1000/o • Hybrid - Selfed Figure 4. Proportion of hybrid and inbred genotypes before and after natural selection in densely sown nursery beds (mean of four progenies). a plant density, the proportion of remain- ing plants from hybrid or selfed seed was recorded at harvest. A significant increase in the proportion of hybrid genotypes was found at harvest (Fig. 4), which could favor the planting value of the tubers pro- duced. This result would also indicate that when seedling tubers are produced in beds, some contamination during the hybrid seed production process can be acceptable, since weak genotypes from selfing could be eliminated either natu- rally or by normal management practices. Several experiments were conducted on how to use small seedling tubers. In one experiment, plant density was kept con- stant by manipulating the distances be- tween and within rows. Results indicated that closer spacing between the rows was better for early ground cover than closer spacing within the row when using small- sized tubers (1-5 g). Closer row spacing approaches a square arrangement of plant distribution, which compensates the slow growth rate of plants from small seed tu- bers by an earlier ground cover and more efficient light interception. In cooperation with CIP virologists, plants from first generation seedling tu- 122 bers produced in nursery beds at Lima were serologically tested for potato viruses Y, X, S, potato leafroll virus (PLRV), Andean potato latent virus (APLV), and Andean potato mottle virus (APMV). Seedling tubers produced during the win- ter season generally showed lower virus incidence than in the summer; for exam- ple, PLRV incidence during the winter was 2°/o, while in the summer it was 35°/o. Considerable differences, however, have been observed in virus contamina- tion of TPS progenies, particularly in the summer season when aphid-transmitted viruses were more prevalent. PATHOLOGICAL STUDIES Two fungicides, Benlate 50 WP (Benomyl at 4 g a.i./m 2 ) and Rizolex 50 WP (Tol- clofos Methyl at 3.5 g a.i./m 2 ) , and a soil fumigant Basamid 98°/o (Dazomet at 35 g/m 2 ) were tested to control Rhizoctonia damping-off in nurseries sown with At- zimba x DT0-33 TPS for the production of seedling tubers at two TPS planting densities. The three products significant- ly controlled the disease as measured in per.cent of seedling survival at 15 days af- ter sowing ; however, there were no signif- icant differences among products at the two ·planting densities. Based on results from previous ex- periments for controlling TPS seedling damping-off in San Ramon, field seedbeds were inoculated with the pathogens Rhi- zoctonia solani + Pythium sp. and received applications of Rizolex and Rixolex + Ri- domil. Trays with natural field soil were also sown with TPS and kept in a screen- house. Trays kept in the screenhouse had the lowest incidence of damping-off (8°/o ), as compared to results from field seed- beds, either inoculated or noninoculated, which had a similar and rather high pro- portion (above 65°/o) of seedlings affected by damping-off. In inoculated seedbeds, Rizolex gave the best control of damping- off, whereas in seedbeds with natural soil, Rizolex + Ridomil gave the best control. This indicated that under these condi- tions, Pythium sp. might be more impor- tant than R. solani. However, studies on isolates from infected plants have sug- gested the presence of a still unidentified causal agent or a combination of agents. In an attempt to evaluate TPS proge- nies for susceptibilities to diseases, we inoculated 46 progenies from the TPS breeding program at the seedling stage with the same mixture of Phytophthora infes- tans races used normally in the interna- tional late blight trial (8000 zoospore/ml). The response of the progenies to P. in- f estans was evaluated using the CIP late blight scale of 1- 9. Of the 46 proge- nies, 5 (Atzimba x 380700. 79; Atzimba x 380701.12; 796-8.7x380700.79; 796-8.7 x 380701.12; and CFK 69.1x380701.12) had a late blight reading of less than 4; the remainder were highly susceptible. TPS from 34 of the 46 progenies were also sown in soil artificially inoculated with R. solani AG-4 (7 g infected wheat grains/kg of soil) to test their susceptibil- ity to damping-off. At 30 days after sow- ing none of the 34 progenies had more than 15°/o seedling survival. The noninoc- ulated control had a score of 93-100°/o survival. Progenies with the highest per- cent seedling survival were 377891.19 x 378017.2 (15°/o), 377887.59x377877.9 (11 °lo), Serrana x 380700.79 (11°/o), and Serrana x RI 28.6 (9°/o ). Due to the very high inoculum pressure, these progenies probably have some resistance to R. so- lani damping-off that should be consid- ered in future evaluations. Four chemicals were tested at different concentrations for disinfecting TPS prior to sowing: Dimanin (10, 20, and 30°/o), sodium hypochlorite (0.5 , 1.0, 1.5, and 5.0°/o), Streptomycin (100, 200, and 200 ppm), and alcohol (50, 70, and 99°/o). Sodium hypochlorite at 0.5 , 1.0, and l .5°1o gave the best control of biological contaminants (close to 100°/o as com- pared to a control) and did not affect germination. Even though Dimanin gave 100°/o control of contaminants at the three concentrations, it severely affected germination. FARMYARD POTATO PRODUCTION FROM TPS The use of TPS for potato production in tropical farmyards, where an assortment of vegetables are usually grown, has been under evaluation for the last two seasons in San Ramon. Of the different planting structures and propagation methods eval- uated, the best results were obtained with progressive sowing of TPS in beds, which could expand to year-round availability of freshly harvested potatoes for family- level consumption. Beds were made of materials available on the farm and the substrate used was soil from the upper horizon of the local tropical forest. In a different experiment, conducted 123 Spac ings (cm) 20 x 20 > 3.5 cm a a a 18 x 18 • 2.8 -3 .5cm - - • < 2.8cm a a b 16 x 16 - - a a b 14 x 14 a a be 12 x 12 b a c 0 2 4 6 8 kg /m 2 Figure 5. Tuber size distribution of potatoes produced in nursery beds from trans- plants at different seedl ing spacings (the same letters indicate no significant dif- ference among tuber sizes by Duncan 's Test at P =0.05) . under rainfed conditions, seedlings were transplanted into beds to study the effect of different spacings on tuber size dis- tribution. The amount of consumer-sized tubers (> 3.5 cm) produced was similar for all spacings wider than 12 x 12 cm (Fig. 5). The highest density treatment produced the lowest amount of large- sized tubers, while the lowest density pro- duced the lowest amount of small tu- bers. The amount of small-sized tubers produced decreased as plant density also decreased. In three farmyards in San Ramon, the technology of producing potatoes for consumption from TPS in beds was eval- uated under farmer-management condi- tions. Four 2-m 2 beds were sown sequen- tially, with one bed being sown every month. In addition to the production of consumer-sized tubers, as a by-product , small-sized tubers ( > 2.8 cm) were used for planting small plots on the farms, 124 which in turn produced potatoes for selling in the local market . ON-FARM EVALUATION OF TPS TECHNOLOGY On-farm experiments and observations were conducted in three regions of Peru: in the central highlands, representing a typical seed tuber-producing area; in the warm tropical region of San Ramon, where potatoes are not cultivated ; and in two coastal vegetable-growing areas. The possibility of using TPS in tradi- tional seed tuber-producing areas in the highlands (Huancayo, 3280 m) was as- sessed in two farmers ' fields and at CIP's experimen ta! station. Transplanted seed- lings, seedling tubers, seed tubers from the farms, and clean seed of the variety Yungay were compared in their produc- tivities. Also , the production of seedling tubers in an area densely transplanted with seedlings (seedling tuber plot) of 12 m2 was included. At the experimental station, highest yields were obtained by the highest quality seed tubers ( 4 7 .5 t/ha) and by seedling tubers ( 44.4 t/ha) . Trans- planted seedlings had highest yields ( 45.4 t/ha) in the on-farm experiments, but with a considerably lower proportion of marketable tubers (53.4°/o), compared to more than 70°/o marketable tubers when seed tubers were used. About 6800 usable tubers were produced in the seedling tu- ber plots at the farmers' fields and 8500 usable tubers at the experimental station. In San Ramon, eight farmers received seedling tubers for planting a plot of either 100 m 2 or 200 m2 , depending on whether or not farmyard production of vegetables for family consumption was practiced on the farm. The seedling tu- bers distributed had been produced at two other farms in nursery beds. The fea- sibility of a system of TPS use in similar climates is being studied in these on-farm activities. On the coast of Peru, potatoes are cul- tivated twice a year. In the first season, imported seed tubers from the highlands are used for planting, whereas in the sec- ond season locally produced tubers are used as seed. No further multiplications are possible due to high virus contamina- tion. Due to limited availability of labor in one location (Canete), farmers intro- duced the use of direct sowing of TPS in furrows, at 45 x 5 cm spacings between and within the furrows, respectively, for producing seedlings tubers. This spacing, although it may not be as efficient as the high density stand in nursery beds, permitted easier and less expensive man- agement. In a second location (Callao), an area with abundant and skilled labor in vege- table growing practices, the most accept- able system for seedling tuber production has been transplanting into a relatively large area . Tubers produced in both lo- cations, Canete and Callao, were partly kept as seed for the following season and partly sold for consumption. In Callao, a 20-m 2 seedbed produced seedlings that were transplanted to a 1500-m2 field (seedling tuber plot) . The seedling tubers produced in that area were used for plant- ing about 1.5 ha the following season. PROGRESS IN TPS RESEARCH IN DEVELOPING COUNTRIES Latin America. In Chile, yield tests of TPS progenies as seedling transplants were made at INIA's Remehue Experimental Station in Osorno. There were ten OP progenies, five hybrids, and controls con- sisting of seed tubers from two commer- cial varieties, Yagana and Desiree. The two CIP hybrids (Atzimba x Rl 28.6 and DT0-33 x Rl 28.6) gave better yields than either of the two varietal controls. Uni- formity of foliage and tubers of these two hybrids were not as good as the standard varieties. The best progenies will be tested in on-farm yield trials during the 1985-86 season. Through a collaborative project be- tween INIA, the Universidad Austral de Chile (UACH) and CIP, the UACH is car- rying out agronomic experiments in Val- divia on the influence of soil type and sowing depth on seedling tuber yield. The optimum substrate for the seedbeds was examined and mixtures of sand, manure, and soil in various combinations gave ex- cellent results. In terms of weight and number of tubers produced in the seed- beds from TPS transplants, spacing of 10 x 10 cm or 8 x 8 cm gave optimum results averaging 7-8 kg/m 2 . There were no significant differences between these two spacings, although in terms of tuber number, the 8 x 8 cm spacing gave 411 125 Table 3. Average yield performance of four TPS families and two clones at ICA's experi- mental station at Tibaitata, Colombia . Family / Yield clone Genetic makeup (kg /plot) Pu race tbr x tbr 33.0 F4 Purace x R128.6 (neo tbr) 27 .0 F15 Atzimba x R128.6 (neo tbr) 20.0 F12 Monserrate x 380073.2 (tbr x (tbr x adg)) 15.0 Pastusa adg x adg 14.0 F8 Tequendama x FDR-71 (phu)25 (tbr x adg) x adg 12.0 tubers/m 2 compared with 306/m2 for the 10 x 10 cm spacing. In Colombia, four TPS families se- lected from tests in previous seasons were planted as seedling tubers by the national program of ICA, at the Tibaitata experi- mental station. Small tubers with an aver- age size of 10 g were used and compared with the two cultivars Pastusa and Purace. Two families gave yields better than Pas- tusa, but less than Purace (Table 3). Egypt. In collaboration with the Min- istry of Agriculture at the Kafra El- Zayat station, CIP studied methods for raising high-quality seedlings in nurseries for transplanting, and appropriate field cultural methods for potato production through direct seeding in the field. Yields of transplants were compared with those of small seedling tubers in two grades (1-5 g and 6-20 g) and those of normal- sized seed tubers of the cultivar Alpha. In autumn, seedlings were transplanted during the hot period in October, how- ever they survived well and recovered in seven days. After December, low tem- peratures and early blight inhibited fur- ther foliar development. Relative yields from the autumn transplants were simi- lar to those from small tu be rs (1-5 g) as might be expected, as they are both es- 126 sentially single-stem plants. Transplant yields were 30°/o to 50°/o lower than those from larger tubers (6-20 g) and reg- ular seed tubers of Alpha, both of which form multiple-stem plants. An earlier transplanting period (September) will be tested to advance the date of complete foliar cover. In the spring season (Feb.-June), initial low temperatures after planting caused slow early growth and weakened the plants that were later attacked by early blight. Seedlings sown in December were not transplanted for 60 days due to the cold and then they tuberized prematurely. There was a heavy loss(> 80°/a) of seed- lings as recovery after transplanting was very slow. Ex tending the day length to 18 hours in the nurseries by artificial light re- duced premature tuberization, shortened the recovery period after transplanting, and increased final tuber yield. The spring season (cold/ short days going in to warm/long days) is the most difficult at present for TPS hybrids. They do not seem to be well adapted to this growing regime, and better adapted hybrids need to be developed for this purpose. Seedling tubers were produced in nurs- eries at four periods throughout the year (Dec.-April, Jan.-May, Jan.-June, and Feb.-June) to test the applicability of using this system to produce planting ma- terials. During the first period, plants were affected severely by cool weather and early blight, thus the yield was low. The optimum period for seedling tuber production in nurseries was the January- May period when 5.67 kg/m 2 was ob- tained. The yield decreased as date of planting was delayed. This probably re- flects the lack of adaptation of the gen- etic materials to the hot/long-day condi- tions at bulking. Tubers produced were stored and tested for viability by planting in October. Autumn-planted seedlings in nursery beds gave tuber yields of 2.5 to 5 kg/m2 . However, between harvest (Dec. 1984) and planting (Feb . 1985) there was insufficient time to break dormancy. Use of chemicals such as Rindite improved sprout production, but full emergence was not achieved until 40 days after planting. Investigations will continue on how to improve sprouting. In Tunisia, a collaborative study be- tween CIP and CPRA, the Ministry of Agriculture's training center at Saida, was made on the possible applications of TPS for each of the three growing seasons, planting in September, November, and January-February. Direct production of consumer potatoes from seedling trans- plants in all seasons had little potential. Climatic conditions at planting and in the early weeks were either too hot or too cold, and seedling survival was poor. Also, there was early tuberization of seedlings before transplanting. The best possibility studied was seedling tuber production in the main season (Feb.) to produce plant- ing material for the following September and November plantings. This fits with the general policy for local seed produc- tion, which is to concentrate on the late season (Sept.) crop, for which the only seed available is the farmers' own seed or that currently being produced by the na- tional program. In Senegal, preliminary trials were car- ried out by the Centre pour le Developpe- ment de !'Horticulture (Dakar), in which four possible nursery substrates were tested for seedling tuber production. The best results were obtained from a mixture of two parts sand and one part peanut husks . At planting, a basal amount of fer- tilizer (equivalent to 120, 360, 150 kg NPK/ha, respectively) was mixed with the substrate. The yield was 4.76 kg/m 2 or 532 tubers/m 2 . The size of the tubers can be varied by adjusting planting date and the particular seed progeny; however, a compromise will be necessary between number of tubers and average size to pro- duce a size acceptable to local farmers. The tubers produced in 1985 were stored in a combination of cold storage followed by diffused-light storage for six months and will be planted in 1986 for further evaluation. Rwanda. Ten on-farm trials were set up to evaluate the potential use of TPS technology by farmers. The objectives were 1) to evaluate the applicability of this technology in different ecological zones and 2) to compare advantages of seedling tubers of hybrid and OP seed with farmers' own seed. Farmers showed that handling heterogenous populations posed no problem, and they selected the types normally preferred with respect to tuber size , quality , and vegetative cycle. In fact , this process introduced them to the idea of positive selection, which could benefit their home-grown tuber seed. The mean yield of all plots with farmer seed was 16.3 t/ha compared with the yield from seedling tubers of 22.3 t/ha. India. TPS as a technology to form part of the research program of the Indian Council for Agricultural Research was of- ficially approved in 1985. CIP's regional scientist was designated as the coordina- tor for the project and will initiate trials at various institutes throughout India and supply the necessary TPS. A comprehensive program for investi- gating optimum agronomical methods for TPS production was conducted during the year. A seedbed substrate composed of subsoil and biogas sludge was the best medium for promoting vigorous emer- gence of seedlings. For transplanting in December, either in nursery beds or fields, the main difficulty encountered was high seedling loss due to low night tempera- tures (min 1°C), and it was not until late 127 January that normal plant growth re- sumed. Average seedling establishment was about 50°/o. Transplanting could not be delayed or the season would have ex- tended into May when extremely high temperatures prevail. A collaborative research project with a farmers' association at Mandra, Calcutta, investigated the potential role of seedling tubers as planting material . Seedling tu- bers harvested in 1985 and kept in a cold store were graded as either medium (> 20 g) or small ( < 20 g) . These were planted in the field in November 1984 with normal fertilizer applications , but the within-row planting distance was 20 cm for medium-sized tubers and only 10 cm for small sizes. The percentage of emergence was 92°/o for medium and 73°/o for small sizes. At harvest, the fol- lowing conclusions were drawn: the me- dium size seedling tubers gave a higher number of large- and medium-sized tubers than the small seedling tubers. There was no significant difference between mean yield per unit area and size of seedling tu- bers. In a study on transplanting meth- ods, the use of banana leaf cups for rais- ing TPS seedlings and then planting di- rectly to the field improved both stand and yield, compared with normal trans- planting methods. The mixture in the cups was the subsoil/biogas sludge men- tioned previously. Plants were extremely vigorous with an average yield of 2.25 kg/m 2 , equivalent to about 22 t/ha. A trial for seedling tuber produc- tion was planted at the Jawaharlal Nehru Agricultural Research Station, Chindwara, using transplanted seedlings and three planting densities ( 60 x 10, 60 x 20, and 60 x 30 cm). For both progenies tested, the closest planting (60 x 10 cm) gave the highest yield per m 2 . Bangladesh. A number of TPS proge- nies were evaluated by the Bangladesh 128 Agricultural Research Institute (BARI) , at four substations representing differ- ent ecological environments. The hybrid progeny Atzimba x RI 28.6 and the OP progenies CIP 800226 and P-111 were among the high yielders, equal or supe- rior to the yields of the standard varieties Patrones and Lalpakri, planted as seed tubers. All TPS progenies displayed satis- factory standards for plant and tuber characters as determined by market pref- erences. These selected progenies , and suitable agronomic practices to produce potatoes from TPS, which were devel- oped during the last three years, will be evaluated with farmers in 15 locations in 1986. Southeast Asia. Throughout this area, various national potato programs have been studying the potential for TPS pro- duction. In the Philippine lowlands, near Los Banos (Canlubang) , it was not possi- ble to produce hybrid seed, whereas sev- eral clones had OP berries and the seed was viable. Thus, it may be possible to produce OP seed for farmers even under these extremely difficult environmental conditions. TPS progenies, produced by CIP in Lima and the Mountain State Agricul- tural College (Baguio) and Sta. Lucia in the Philippines, were evaluated at the PCARRD/CIP germplasm center at Sta. Lucia. Three trials were planted between January 23 and February 22. Yields were good in all trials, but one hybrid (LT-2 x I) gave yields of more than 30 t /ha (on a per plant basis). Large differences were ob- served between progenies in the trials with respect to adaptability to tempera- ture and changing daylength. Seedling tu- bers are being stored for further evalua- tion of the general performance of the different crosses. In Vietnam, at the Food Crops Re- search Institute at Dalat, at least 8 kg of OP seed of two cultivars, CFK 69.l and Atzimba, will be collected for distribution to cooperatives in November and Febru- ary, 1985-86. TPS is best suited to the mid-elevation areas of Southeast Asia, where bacterial wilt is present, and also to the new wilt- free areas in the warmer lowlands. Farm- ers in the traditional potato-growing areas at present show little interest in TPS tech- nology since effective production systems already exist in these areas. RAPID MULTIPLICATION The CIP regional germplasm center at Sta. Lucia in the Philippines has maintained 80 clones and cultivars in vitro using very simple techniques and without the benefit of controlled temperatures as the station has no connection to the public electric- ity supply. This operation is an example of what other countries in Asia can do at very low cost and with minimum facili- ties. Approximately 27 shoots with a to- tal of 68 nodes were maintained per flask , using a manually operated shaker. The in vitro cuttings were transferred to a soil mixture in wooden boxes and became mother plants. The installation maintains, on the average , 100 mother plants per clone at any one time, and cuttings are harvested weekly. To improve rooting, light intensity was lowered 50°/o by the use of a double layer of net screening, and lighting was extended to 14 hours, with artificial illumination provided by a small portable generator. Density of cut- tings was 30 to 40 plants/m2 in the beds. Harvest varied from 80 to 250 tubers/m2 and yield from 2.0 to 4.5 kg/m2 . Virus testing of plants was carried out monthly on mother plants. Pathogen-tested tubers have been dis- tributed to Mindanao (Philippines), Fiji, Indonesia, and Western Samoa for evalua- tion of bacterial wilt resistance . In Mindanao, CIP and the Bureau of Plant Industries (BPI) have started pro- jects to evaluate the use of cuttings by farmers. Although farmers are willing to use cuttings as planting materials, they show little interest in maintaining mother plants. It appears that specialized farm- ers, such as those in Vietnam, will have to maintain the mother plants and produce the cuttings on a commercial basis. Alter- natively, in Mindanao, TPS progenies can be used to produce small seedling tubers for planting. This has advantages over the cutting technique as it reduces the risk of latent wilt infection, particularly if the tubers are produced in sterilized seedbeds. However, identification of TPS progenies with bacterial wilt resistance is essential to the success of this approach. SEED TUBER PRODUCTION PROGRAMS Latin America. In Peru, with financial assistance from the Swiss Development Project (COTESU), CIP has been assisting the national potato program of INIPA in establishing its basic seed multiplica- tion program. In 1985, three new screen- houses with a total area of 285 m2 were brought into operation, giving a total area of 3012 m2 for the whole country. These screenhouses are located at six strategi- cally placed centers covering all the main highland areas and Lima. Tissue culture laboratories were put into operation in Lima, Huancayo, and Cajamarca, and vi- rology laboratories were placed at each site plus one in Cusco. The total number of stem cuttings produced was more than 1,180,000, which were planted in 31 sites in the highland areas under the supervi- sion of various official and local organiza- tions. In total, 14.6 ha were planted with basic seed in the 1984 season. 129 A study by INIPA was made at the highland site of Pariahuanca (2800 m) on yield response differences between seed tubers and rooted stem cuttings. At a density of 3 cuttings per hill , and 4 hills per m2 , the yield obtained from cut- tings was not significantly different from normal-sized seed tubers planted at one tuber per hill . With two cuttings per hill , the yield was reduced by 25°/o. Another study at Huancayo (3200 m) compared the yield of bare-root cuttings and cuttings rooted in plastic cones with peat moss and sand (to overcome trans- planting shock) with the yield of normal seed tubers. Success with bare-root cut- tings depended on the variety used, favor- able weather at planting, and length of season. With a long-maturing variety and adequate planting conditions, the bare- root method gave almost equal results to seed tubers. Cuttings in plastic cones, however, accelerated crop development and would thus be preferable when the season is uncertain or transplants are sub- ject to some form of stress. A series of on-farm trials were carried out by the CIP/INIPA team in the Man- taro Valley (central sierra) to determine the agronomic value of basic seed for local farmers. All decisions relating to methods of planting and spacing, fertilization, hil- ling, spraying, and harvest were left to the individual farmer. Farmers' seed and basic seed were treated alike. Only eight trails could be planted although 20 had been planned. Average yields of basic seed ver- sus farmers' seed were 19.5 and 15.7 t /ha, an increase of 24°/o. A similar series of on-farm trials in which varietal perform- ance was tested demonstrated that basic seed of the improved variety Mariva out- yielded all other improved varieties under farmer-management conditions. Part of the objective of these trials was to en- courage national scientists to adopt the 130 methodology of on-farm trials to improve their testing procedures. In Argentina, in collaboration with the national potato program of INT A, CIP has helped to analyze a situation in the potential seed-producing area of the Valle Bonarence del Rio Colorado. In this zone , areas infected by root-knot nematode need to be identified to avoid spreading the pest. Soil samples were taken throughout the area and 63°/o were found free of nematodes and 30°/o had very low levels of infection. Most infected soils occurred where horticultural crops had been previously cultivated ; but where extensive farming for wheat or soybeans was carried out, nearly all samples were free of nematodes. INT A will use the re- sults to define the infected areas and de- velop appropriate inspection standards. In Chile , many farmers use regular seed (uncertified seed lots) since it is cheaper than certified seed. To examine the quality of regular seed, 21 samples were taken and compared with two sam- ples of certified seed of Desiree. Although the mean yield of regular seed samples was about 13°/o less than that of certified seed, there were large discrepancies in yield within the regular seed samples, and uniformity (trueness to type) was gener- ally poor. There was an average of 56°/o off-type tubers in the sample as a whole, and only five samples had less than 10°/o mixture. In Chile , it is generally assumed that regular seed, despite its lack of uni- formity, gives good yields, as it is pro- duced under excellent growing conditions and is in good physiological condition. TRAINING Support to programs for seed tuber pro- duction was continued through collab- oration in seven regional and in-country training courses. A two-week course in Argentina on pathological problems in seed production , and an in-country field- level virology course in Bhutan were ac- tivities designed to enable extensionists and seed inspectors to upgrade the qual- ity of certified seed. Training in the use of different types of planting materials was given in three other group activities. One of the several courses conducted by SAPPRAD, the Southeast Asian country network, on pro- duction technology was held in the Phil- ippines and attended by 20 farmers and researchers. This was a short course on rapid multiplication techniques to pro- duce rooted cuttings for planting directly to the field. A regional course on TPS for South America and a TPS workshop for countries of the Indian subcontinent were held during the year. Individual training was also given to six scientists on the use of TPS for production of consumer potatoes. 131 THRUST X Potatoes in Developing Country Food Systems Research in 1985 generated the most reliable maps to date showing areas of potato production in developing countries. Agroclimatic and production maps were refined. Data on potato production and consumption in 95 de- veloping countries have been organized within country files. Analysis of country-level statistics showed that in developing countries potato production has tripled since 1960 and yields have doubled. These countries now produce nearly one third of the world's output . Diminishing potato prices and rising incomes have stimulated the rapid growth of potato consumption in many developing areas. Studies of adoption and use of potato varieties in Peru and Rwanda showed that socioeconomic factors strongly influence farmers' decisions. Surprisingly, some farmers keep improved varieties for home consumption and sell native varieties because they have a higher market price . Research on traditional seed systems in Peru uncovered complex informal seed flows and helped the national seed program diversify its strategies, enabling them to reach more producers. The findings of a study on Peruvian potato marketing was published by a CIP marketing specialist as a book, entitled Markets, Myths, and Middlemen. Research on potato marketing and demand was also conducted in Madagascar and Bhutan. Research on household gardens in Asia, Africa and South America revealed that root crops often occupy from 30°/o to 80°/o of the land and, along with maize, are the most common and nutritionally significant garden crops. A Bhu tanese farmer transports his potato crop to the market and storage. 133 INFORMATION BASE ON WORLD PATTERNS AND TRENDS IN POTATO PRODUCTION World patterns and trends in potato pro- duction. Analysis of country-level statis- tics indicated that of the world's food crops, the potato ranks among the top five in tonnage and in monetary and food value. Until recently, the impor- tance of the potato has been much greater in Europe than in the developing world due to its adaptation and cultivation in the temperate climates of these coun- tries. The balance of world potato pro- duction is gradually shifting, however, from developed to developing countries and from temperate to tropical and subtropical zones. Nearly one third of the world's potatoes are now grown in de- veloping countries, about 60°/o are still grown in Europe, and 10°/o in other de- veloped countries. Since potato prices are highest in developing areas, roughly 40°/o of the monetary value of world potato production is now concentrated there . In dollar value of production, the potato now ranks fourth in the devel- oping world, after rice , wheat and maize. In developing regions, production in- crease has been greatest in Africa, Asia and Central America. Since 1960, potato production has tripled in Rwanda, Ban- gladesh, India, and Pakistan, and more than doubled in Madagascar, Cuba, Mex- ico, and several North African and Middle Eastern countries. In terms of total vol- ume, more potatoes are now grown in the Far East than in Western Europe, North America , and Oceania combined. China alone now produces more potatoes than all of Western Europe. In Sou th America, where potatoes have long been a staple food , potato pro- duction has grown less rapidly because consumers are diversifying their diets and moving away from traditional staples. 134 Agricultural and trade policies have also discouraged potato production in some countries. Peru is among these . Since 1960, potato consumption in most developing areas has grown some- what more rapidly than production as better technology has reduced posthar- vest losses and increasing yields have low- ered the share of the crop that must be reserved for seed. Although potato con- sumption is expanding in the developing world, most people there still eat less than 10 kg of potatoes a year. Potato consumption levels are lowest in the warm tropics, and highest in countries that have extensive cool, temperate , or highland production zones. Potato yields are now, on the average, 80°/o higher in the developing countries than they were in the 1950s. With the exception of the Far East, potato yields have increased by at least as much as ce- real yields, and much more than yields of other root crops. Population growth, rising incomes, and changing food hab- its have stimulated potato production. Improvements in technology have also helped bring down the farm-gate price of potatoes, improving their competitive po- sition in many developing areas. Potato prices have fallen most, relative to the prices of other foods , in tropical and subtropical lowland areas like the plains of India and Bangladesh, where effective seed production and distribu- tion systems have been developed, new varieties adapted to local food systems have been introduced, and storage capac- ity for seed and consumer potatoes has expanded. ADOPTION OF POTATO TECHNOLOGIES Adoption and impact research concen- trated on both storage technologies and As in other developing countries, potatoes stored by farmers in China are often sold in small amounts to augment family incomes. varieties. Adoption and impact of storage technology is reported in Thrust VIII on postharvest technology. Adoption of varieties in Peru. Five communities with different levels of market integration were studied in the highland Departments of Junin and Cuz- co. They ranged from 96°/o dependency on improved varieties to 100°/o depen- dency on native varieties. In each com- munity, channels of diffusion and farmer strategies for varietal use were studied. Interviews with 159 farmers revealed that most maintain their own germplasm bank, consisting of six or seven main varieties, planted in varying proportions depending on the farmers' production goals. The tendency is clear that farmers value im- proved varieties for yield, early maturi- ty, disease resistance, and marketability, while native varieties are valued for home consumption, processing, barter quality, and market price. _ An in-depth study of farmer use of potato varieties was also conducted in the community of Marcapata, Department of Cuzco, as part of a detailed study of po- tato agriculture. Use of different kinds of cultivars is associated with agroecological zone and ethnicity. Marcapata is divided 135 into a high zone occupied by Quechua- speaking campesinos (peasants), an in- termediate zone occupied by Spanish- speaking mestizos (mixed populations), and a low zone occupied by recent set- tlers from outside the community. Of the 100 potato varieties in the commu- nity, most are grown in the high zone where production is primarily for home consumption and seed tubers. In the intermediate zone, both new and old varieties are found. Native varieties are used for home consumption while most improved varieties are sold after harvest. In the low zone, improved varieties are grown and used for consumption and sale. The study illustrated that in a sin- gle community different strategies are pursued relating to use of varieties, de- pending on agroecological zone and social characteristics of the population. Adoption of varieties in Rwanda. Sim- ilar research on farmer use of potato cul- tivars was conducted by a CIP anthro- Food systems thinking is incorporated into biological science research through training. Above, Rwandese stud- ents are learning about the technical and socioeconomic aspects of potato production and use. 136 Table 1. Farmers' preferences for duration of dormancy and vegetative cycle (O/o of 186 farmers), Rwanda. Dormancy Long Short Both Long 3°/o 43°/o 54°/o pologist assigned to the national potato program of Rwanda (PNAP). This study, which covered 90 households in one sur- vey area and 186 farmers in another, addressed a broad range of questions concerning production, storage, and use. Rwandese farmers grow an average of four or five different potato cultivars; over 80°/o mix cultivars with other crops in the fields, although they sometimes have additional plots, especially of new cultivars, that do not contain mixtures. Farmers find it advantageous to maintain diversity in such traits as maturation and dormancy, disease and drought resist- ances, cooking quality, marketability , and storability. More than 100 different crop rotations involving potatoes were found in Rwanda. The cropping systems are very complex and both long- and short-cycle cultivars play important roles. There is a strong demand in Rwanda for short-cycle varie- ties (early maturing) to meet pressing food and cash needs and to deal with ex- treme land scarcity. In marginal growing areas below 1700 m, short-cycle varie- ties were preferred by 92°/o of farmers surveyed. Most farmers preferred either short or a mixture of long and short in both dormancy and the vegetative cycle, but a few expressed a preference for long dormancy and long or medium vegetative cycles (Table 1). Maintaining diversity is a risk-reducing strategy to deal with such uncertainties as the timing of the rainy season and planting dates. Farmers pre- Vegetative cycle Medium Short All 52°/o 44°/o ferred to maintain diversity, 44°/o wanted mixtures of early, medium, and long cy- cle varieties in their fields. At the time of the surveys, the pre- ferred varieties were Sangema and Mont- sama, introduced from Mexico in 1972, and which form the basis of the PNAP seed multiplication program. There is a different conception of varieties suit- able for home storage and consumption, which ideally should have high dry matter and starch content, and of those for sale in town markets where these qualities are not so important. SURVEYS OF POTATO PRODUCTION SYSTEMS AND SEED FLOWS Surveys of seed flows, production, stor- age, and consumption help determine research priorities, selection criteria for new varieties, and also help to identify channels through which improved seed might be introduced. Peru. Research conducted in the cen- tral highlands, in conjunction with the national potato program of INIP A, iden- tified three main types of seed flows : 1) within specific areas between farmers, kin, or neighboring valleys, 2) between farmers and merchants within the high- land region and between highland and coast, and 3) between commercial seed producers and small and medium-scale farmers (Figs. 1 and 2). Different seed distribution patterns were observed for improved varieties, commercial native and 137 3900 m 3300 m Co~ * Seed grower • • • Community e Small farmer Figure 1. Seed flows within the central Peruvian highlands. ~ --- Coastal valley Annual supply of seed Cheap or loaned coastal seed ~elayed exchange f / ~ith small '"-_.,.......,__.,, upland farmers Highland valley seed production Figure 2. Seed flows between the coast and central highlands of Peru. native home-consumption cultivars. The variety Yungay was the most common improved variety, while Huayro was the most common native variety. Commercial seed growers accounted for only 8°/o of seed flows to small growers, primarily those living in proximity to the commer- 138 cial seed production areas. Furthermore, small producers acquired up to half of their seed through exchange, barter, or share-cropping arrangements. CIP and INIP A researchers planted basic seed with eight farmers and four communities in the highlands. The farmers' reactions to this seed and subsequent seed flows are being monitored by the team to explore the possibility of diffusing the basic seed along existing seed flows. Socioeconomic research has revealed that native varieties are important to small farmers for consumption, sale, and processing. Eighty percent of the pota- to area in Puno is cultivated with native varieties. Further north, but still in the southern highlands, the area with native varieties decreases to 35-40°/o. In the north and central regions of Peru, it is 25°/o and on the coast less than 1 °/o. In some areas, native varieties are disappear- ing and the area of land planted in native varieties is diminishing. Several of the most important native varieties are being cleaned and multiplied in an attempt to reverse this trend. Burundi. A survey of production, storage, and consumption patterns in Burundi was made by the national po- tato program, assisted by two students from the Institut Technique Agricole de Burundi. Table 2 gives a brief summary of the survey results. MARKETING AND DEMAND FOR POTATOES Peru. A detailed study on potato mar- keting in Central Peru, entitled Markets, Myths, and Middlemen, was published during the year in English (by CIP) and Spanish (by the Universidad de! Pacifico, Lima). This study concluded that the food system for potatoes - production, marketing, and consumption - is more complicated than that for most other crops in Peru. Principal reasons include the multitude of planting and harvesting dates, diversity of varieties planted, and number and dispersion of producers and consumers. Contrary to popular opinion, wholesalers' earnings represented a very small share (roughly 2°/o) of the retail potato price paid by Lima consumers. Although the current price rose from 2 to 64 soles per kilo during the last two decades, the real price (i.e ., the current price deflated the consumer price index) actually fell lower at the end of this pe- riod than at the beginning. Whereas it is generally believed that potato consump- Table 2. Summary of data relating to potato production collected from 60 farmers in Burundi (112 fields). Average field size Method of planting Associated crops Tuber skin color Fertilization Seed Harvest Dormancy Storage Consumption Cooking Varieties 300 m 2 Flat, intercropped, several potato varieties Maize, beans, Colocasia, tobacco, and bananas No preference 75°/o of fields received either compost or manure Generally the small leftover tubers selected at harvest; in 50°/o of households women select seed Large tubers removed at weeding and hilling then continuous harvesting of tubers as required Short dormancy preferred 670/o inside the house (theft a major problem) Majority eaten by household Boiled with beans, peas, or cabbage Sangema, Kenya Baraka, Gashara, lranda, Hicintuka 139 Table 3. Estimated potato consumption in Lima: selected years.0 Potatoes Average annual Share consumption of diet Year (kg/capita) (O/o) 1971-72 45 12.2 1976 46 13.1 57 18.9 1977 38 11.1 51 16.1 1978 45 12.4 53 17.9 1979 51 13.7 52 17.5 1980 48 16.4 a Source: Extracted from Markets, Myths, and Middlemen. tion in Lima declined over time, in fact it rose slightly during the 1970s (Table 3). Myths about potato marketing in Peru have distracted attention from the more fundamental production problems of small growers in the central highlands and pre- empted discussion of measures to improve existing marketing arrangements, such as more effective collection and dissemina- tion of market information, and produc- tion and marketing credit programs that are not mutually incompatible. Improved collection and dissemination of informa- tion on the total area planted, potato ship- ments to the capital, wholesale prices, and per capita consumption could help grow- ers, traders, and policymakers better an- ticipate the evolution of supply and de- mand for potatoes in Lima. Madagascar. Collaborative research with the national potato program and the Ministry of Scientific and Technological Research has revealed that potato pro- duction in the country has increased by 140 150°/o since 1972, with production ex- panding by 100,000 tons between 1980 and 1984. Production of potatoes now surpasses that of all other crops - includ- ing rice- in the central highland (Vaki- nankaratra) region of the country. Inter- views with over 900 growers revealed that most potatoes are produced for house- hold consumption and only about 30°/o are sold. These findings point to the po- tato's potential to help satisfy the grow- ing rural demand for food in sub-Saharan Africa, especially where growing condi- tions favor potato production. Bhutan. A CIP follow-up to the 1982 baseline study of potato marketing in Bhutan revealed that the marketing of consumer potatoes through the Food Corporation of Bhutan's auction yard in Phuntsholing has been improved by 1) en- forcing standardized trading procedures and 2) more complete recording and dis- semination of market information. Mar- keting of improved seed potatoes through existing private trade channels has also begun. The original study and follow-up showed that national programs working in collaboration with CIP can now iden- tify and begin to solve both production and marketing problems. HOUSEHOLD FOOD PRODUCTION CIP's strategy is to improve potato pro- duction for both farmers and small-scale home gardeners. A CIP investigation of gardens in Asia, Africa, and South Ame- rica has shown that Peru, because of its great ecological diversity , is an excel- lent laboratory for the systematic study of home gardens. Field research on gar- dens in five agroecological zones revealed that roots and tubers covered 30°/o to 80°/o of the garden area (Fig. 3). Impor- tant garden staples of this category were Solanum tuberosum, Jpomoea batata, Inter- High Andean High jungl e Low 1000 m 5 Coast plateau valley jungle 1000m 5 4 4 3 3 2 2 0 0 Sweet potato, Potato, Potato, Maize, Cassava, maize, grains maize cassava, maize, musa spp., musa spp., musa spp., co locasia colocasia, colocasia, potato sweet potato Figure 3. Ecology of garden stap les in five agroecological zones of Peru. Diascorea sp., Manihot esculenta, and a number of native roots and tubers. Garden research was also conducted to develop and adapt an intensive house- hold or community-level food produc- tion method appropriate for Lima's low- income groups. In Lima, the greatest food expenditure by low-income families was for potato, representing 12°/o of family expenditure for food and drink. Of the 76 Lima gardeners surveyed, 4 7 had tried growing potatoes, but only 2 still grew them; the major reason for dropping being low yield, diseases (par- ticularly Phytophthora infestans), and in- adequate water and space. A control garden (6 m 2 ) was. estab- lished and maintained for two growing seasons in Lima in an actual backyard situation. Input levels were simulated to represent the gardening practices of low-income people with limited space and capital. Promising techniques, re- fined in the control garden , involved in- tensive household or community-level po- tato production for confined backyard areas. Several planting strategies were tested involving potato tubers, true pota- to seed (TPS), sprouts, and sweet potato branches as seed material for in-ground and in-container plantings. Horizontal row planting was tested against box methods in vertical arrangements and other container production techniques (Table 4). The least costly and most promising technique was the potato box method (Fig. 4). With low capital and a one-time outlay (12°/o of monthly household in- come) , a three-tier rack can be built Table 4. Performance of home garden pota- to production (90-day growing season), Lima, Peru. Yield Methods kg/m 2 (g/plant) Regular row 2.6 650 Tire 2.5 250 Potato box 5 .0 250 Potato rack 7.5 250 141 Figure 4. Low-cost potato box rack constructed from rough lumber and fruit crates. covering 12 m2 and accommodating up to 20 boxes. In the control garden, 15 boxes were stacked in three tiers. Individ- ual boxes were harvested every 90 days, giving a yield of 0.5 kg/box or a total "vertical" yield of 30 kg/m 2 per year. POTATO PROCESSING Household potato processing finds its greatest intensity in the· Andes where the potato originated. In an effort to learn more about indigenous methods of po- tato processing and their relevance for other world regions, an in-depth anthro- 142 pological study was conducted in Peru and Bolivia. The various stages of boiling, freezing, soaking, and drying for different potato processes have been described and categorized (Fig. 5). To gain a historical overview, more than 20 Spanish chroni- cles were reviewed to analyze traditional Andean tuber processing technologies. Most of the ancient practices are still fol- lowed by farmers in the Andes. Although native varieties are the most common processed type, some farmers prefer im- proved potatoes for making chufio (de- hydrated potato) and tun ta (water-soaked and dehydrated potato). Process Name of product papa seca (papa sancochada) muraya tun ta (no hay) chuiio kachu-chuiio lojota chuiio toqosh Dryi ng (D) (papa cruda) Geographical distribution Central / Southern Centra l Andes Northern Central Andes Figure 5 . Several types of processed potato products, illustrating their geographical di stribution in Peru . 143 144 I ncreasing food availa-bility in the developing world not only depends on research institutions such as CIP to produce technologies that improve production, but also on the abilities of national pol- icymakers, researchers, ex- tensionists, educators, and agribusinessmen to receive , adapt , and transfer tech- nologies from all sources to their farmers. NATIONAL MANPOWER DEVELOPMENT 145 146 Introduction CIP's collaboration with national programs for manpower development, as mentioned in previous annual reports and profiles, is based on the conviction that national programs are, in general, better qualified than outside organiza- tions providing technical assistance to examine their own potato-growing con- ditions, analyze government agricultural policies, assess research and training needs, and undertake activities to transfer improved technologies to their farmers. In 1985, CIP trained 967 potato workers from 73 countries, mostly in association with key national programs- bringing the total number trained by CIP to over 5000. This report concentrates on the changes that are oc- curring in CIP's strategy on national manpower development as a result of the experience gained in collaborating with national potato programs since 1971. Changes are also taking place, particularly over the past few years, that are based on reviews and evaluations that have appraised CIP's worldwide activities. Staff from national potato programs understand their farmers ' problems and constraints. A former partici· pant in a C/P training program is explaining the use of diffused-light storage to farmers in Fiji. Cf P's training program emphasizes strengthening national capability to con- duct research and to respond to farm-level problems. A national scientist in Rwanda, trained previously by CJP and now involved in collaborative research, is sharing his research experiences with others from East Africa. The training undertaken to enable participants to conduct research and to respond to farm-level problems is reported briefly in this section. More detailed presentations appear in the respective research thrust reports. Development and Coordination of Activities National manpower development activities among CIP's research thrusts, departments, and regions are developed and coordinated by the Training and Communication Department. This Department, through its training program, communications support unit, and information service unit, has the following major responsibilities: • designs programs that enable technology transfer to take place • transforms technology into useful information for developing coun- tries • gives communications support to CIP • provides information services to CIP and collaborating national scien- tists Evaluations and Reviews Since 1984, CIP's manpower development efforts have been continually modi- fied to respond to the changing needs of national programs. This is achieved 147 148 through a f6llow-up system that includes a survey mailed to all former training program participants, evaluations by activity coordinators of all training activ- ities, and on-site follow-up visits by CIP staff as a part of research and transfer activities in the regions. The results obtained from the overall follow-up system have enabled CIP to make continuous adjustments in CIP's strategy for manpower develop- ment. Some adjustments were reported in 1984, and others are reflected in this Annual Report as well as in the activities included in the current training plan for the next five years. A questionnaire survey was conducted of national potato workers who had been trained under a project sponsored by the United Nations Development Programme (UNDP). The responses were tabulated and submitted to a UNDP- contracted consultant for evaluating who will analyze the data and use it as a basis for conducting a number of country case studies to determine the effect that this project had at the national level. 1985 Activities and Trends Training program. Within CIP's overall manpower development effort, the training program exerts the most direct influence on the movement of tech- nology to national programs. Through CIP training activities, potato workers Capable national program staff enable CIP to organ- ize and conduct courses worldwide. In Kenya, a national researcher is explaining virus indexing to course participants. Interaction with farmers is an important part of regional and in-country training activities. In Rwanda, a farmer is explaining to course participants the potato varieties she prefers to grow and why. from the developing world are reached with technologies that can improve potato production in their countries. Of the 967 persons trained under CIP's auspices in 1985, 407 participated in 21 specialized group activities designed to enable participants to conduct research. Also, as a part of specialized training, 181 scientists received training as visiting scientists, scholars, student assistants, or as part of their preprofessional practices. The remaining 379 Course participants in Colombia are gathering data resulting from practical experiences in group training activities. This type of specialized training is on the increase and is usually conducted away from CIP headquarters. 149 Table 1. CIP training activities for CIP headquarters and Regions I-VI, 1985. Region Headquarters-Peru Visiting scientistsa Scholarships Student assistantships Preprofessional practiceb Region I Colombia and Peru Peru Region II Argentina Braz il Uruguay Region Ill Burundi Burundi Ethiopia Kenya and Rwanda Malawi Rwanda Rwanda Rwanda Tanzania Tanzania Zaire Region IV Egypt Turkey Region V Cape Verde Nigeria Senegal Tunisia Tunisia Region VI Bangladesh Bhutan India Nepal Activity True potato seed Production with special emphasis on seed productionc Pathology in seed productionc Productionc Seed production Production Seed production Postharvest workshop Germplasm management Storage Seed production Seed production Seed production Storage Storage North Kivu potato program development workshop Regional conference on seed production Workshop on tissue culture Seed production and storage Tissue culture of root and tuber crops (IJTA/CJP)c Production Potato tuber moth Production Seed production Field-level virology Modern methods of potato production Workshop on true potato seed a 35 trained at headquarters and 25 in the regions. b58 from Peru ; 8 from developed countries. c United Nations Development Programme (UNDP). 150 No . of No. of participants countries 61 25 28 67 9 16 14 18 12 15 18 48 27 35 21 22 25 8 14 14 18 7 21 11 13 15 18 19 26 17 21 30 12 1 5 6 6 3 12 3 6 9 6 6 2 5 4 6 Table 2 . CIP training activities for Region VI I and SAPPRAD,a 1985. No. of Region Activity participants Region VII Laos Philippines SAPP RAD Philippines Production Bacterial wilt workshop Germplasm management Production Rapid multipl ication techniquesb Highland potato research Lowland potato research Production Rapid multiplication techniques Rapid multiplication techniques Lowland potato production TPS production and progeny testing a Southeast Asian Program for Potato Research and Development. bUnited Nations Development Programme (UNDP). 21 20 19 22 15 33 38 32 8 20 51 5 No. of countries 1 8 12 1 5 3 participants underwent production training in 18 group activities designed to help them respond to farm-level problems. The activities conducted, the countries in which they were held, and the number of participants are listed in Tables 1 and 2. It would not have been possible to accomplish such a wide range of activities or train such a large number of people without the collaboration of national program staff, many previously trained by CIP. In 28 of the 39 group activities, 144 (66°/o) of the instructors were from national programs. For example, in a UNDP-sponsored production course with emphasis on seed production, organized and con- ducted by Peru's National Agrarian University at La Molina, 12 of the 16 instructors were national researchers and university professors. In CIP's Five-Year Training Plan, no group activities are planned at head- quarters in Peru after 1986, all courses will take place regionally or in-country. They will continue to receive particular attention and will be of longer dura- tion to provide sufficient practical experience for participants and to increase national program involvement in planning and conducting the training. Specialized training will concentrate on topics concerned with improving the availability of good seed to farmers and on priority research areas such as true potato seed, production of potatoes in warm climates, and germplasm management. Specialized training at CIP headquarters and in the regions, similar to production training, will include more practical experience and be directed at key national programs who can serve as network hubs for future regional training. 151 152 Key national programs such as th e one in Kenya will serve as focal points for future training in the regions. Degree-related training must continue to be made available to national programs so that a constant supply of capable researchers is guaranteed. In this process, particular attention should be given to thesis research that will be conducted under growing conditions similar to the home country and on topics of national priority. For example, the UNDP training project has per- mitted CIP to sponsor 16 advanced degree students from six countries at universities in Bangladesh, the Philippines, and Rwanda. Increasing the avail- ability of well-trained researchers in the developing world will permit CIP to continue with its strategy of having contract research in developing countries. Presently, 23 of the 36 research contracts are held by research institutions in ten developing countries. Communications support. Improved technology must be converted to information before it can be used by national programs. CIP's Communica- tions Support Unit plays an important role in this process, which is essential if national programs are to adapt and transfer technology to their farmers . As mentioned in previous reports, three important areas of CIP's efforts in na- tional manpower development receive direct support from this unit - adminis- tration, research, and training. In 1985, in addition to producing periodical publications such as the CIP Circular, Annual Report, and visual aids, CIP published 20 different documents in English and Spanish, relating to research and the transfer of technology. The total included four Technical Information Bulletins (TIBs) (2 English / 2 Spanish), five Specialized Technology Documents (STDs) , one Technology Evaluation Series (TES), four social science publications, and two planning conference reports. The STD and TES documents describe technol- ogies that have been developed for use in research and are intended for na- tional researchers. Eleven TES titles have been published since 1982, and over 100 STDs have been written and printed for CIP's trainees since 1980. The STDs are used for handouts in courses and are eventually bound, according to related titles, and produced as Specialized Technology Manuals (STM). CIP's training materials are designed to be adapted by national programs to meet their specific needs. Most are prepared initially in English and translated into Spanish. A special effort was made in 1985 to translate all of the TIBs into French, which was accomplished by the end of the year. The translations are being revised by French-speaking scientists. To date , TIBs have been pub- lished by national programs in Hindi, Bengali , Farsi, and Chinese. Also, CIP's field guide entitled Major Potato Diseases, Insects, and Nematodes is being translated into Arabic. Copublication. Translation and publishing by national publishers or co- publishing in the same or different languages by commercial publishers is a method that makes infonnation more accessible to national scientists and policymakers, university students and faculty, university libraries, and food producers as well as farmers . A copublication agreement was reached in 1985 with a publisher in Uruguay to print 17 of the Spanish TIBs for distribution in South America, Mexico, and Spain. At the end of the year, a similar arrangement was being sought for distribution in Central America and the Caribbean. A collaborative publishing agreement between CIP and Cambridge Univer- sity Press has also been established, and three books by CIP authors will be published in English during 1987-88; the first one, The Potato in the Human :::::::::· ::·:::::::'.:.::::::. llll"l .. l\'I" .. ...... _ --=.oo;- '" .... ""- (./:.fu1~·t..iJ/'/.11JAr . rf,~· - -· ..:i~~;l7'......,, ..!.§.~>.:-4 'WA- 1~/Jc;.:if . .-.Je11 Technology must be converted into information in an appropriate language before it can be used by national programs. Several of CIP's Technical Infor- mation Bulletins have already been published in various languages. 153 154 National communicators can play an important role in bridging gaps between national potato programs and farmers. During a production training course in Peru, participants have an opportunity to practice preparing messages for their farmers. Diet, will be released in early 1987. The feasibility of copu blishing these books in other languages is being explored. During the year a special effort was made to update CIP's master mailing list to ensure that regularly mailed publications and documents were reaching potential users and to reduce unnecessary mailing costs. Based on responses to a mailing list survey, the English-Spanish master list was trimmed from 7000 to approximately 5000. Communications training. CIP took preliminary exploratory steps in 1985 to find methods to collaborate with national communication units to im- prove national potato worker's skills in communicating with farmers. The envisioned approach coincides with CIP's current strategy for technology development and transfer, but with increased involvement of national com- municators. In an initial experience in a group training activity in Bolivia, participants, at the end of each day, transformed the information that they considered to be the most important for farmers into messages by selecting the most appro- priate medium for reaching farmers in their areas, e.g., posters and radio. They also outlined campaigns with timely information at key stages of the crop's production cycle. CIP and national communicators collaborated in this effort. The ultimate goal is to bring about the development of support linkages between national potato programs and communication units, thus facilitating the process of reaching the farmer with improved technologies. Information service. In late 1985, special project funds from the Interna- tional Development Research Centre (IDRC) of Canada were received to develop an Information Service Unit that would respond to the long-range information needs of potato researchers in the developing world. This three- year project will incorporate the services offered by CIP's library to CIP and national scientists into a much broader context toward the development of a global communications network on potato . In the follow-up survey of former CIP training participants, mentioned in the section on Evaluations and Reviews, 44°/o of 557 respondents indicated that lack of information was a limitation to conducting research. This study revealed that national programs are conducting research and attaining results that could be of interest to other researchers working under similar potato- growing conditions. As such, the Information Service Unit's objectives are as follows: • develop an automated database of conventional and nonconventional literature of particular relevance to national researchers • assist national researchers to gain access to other databases, such as AGRIS and CAB • provide additional services to national researchers, e.g. , selected dis- semination of information, specialized searches and bibliographies, and acquisition lists • facilitate exchange of information among national researchers through financial and technical support to national scientific journals • assess national program information needs continually At CIP headquarters in Lima, the Information Service Unit is taking steps to develop a worldwide communications network on the potato. 155 156 CIP's continuous follow-up system is intended to provide support to national programs, contribute to research on food systems, and deter- mine impact at the farm level. In Tahiti, a farmer provides us with an insight into the impact of potato research. A Digital VAX 750 with six megabytes of memory was purchased to meet the needs of this project as well as those of other CIP scientific needs. The system includes 17 terminals and 13 printers. The work in this project will be incorporated into CIP's ongoing programs at the end of three years. The Information Service Unit will also coordinate CIP's continuous follow-up system of training. This effort is designed to not only determine the impact manpower development activities are having on national research and exten- sion activities, but to also be a mechanism for providing necessary support to national programs. All information gathered will become a part of Thrust X research. CIP PUBLICATIONS IN 1985 Annual Report CIP 1984. Lima, Peru. 167 p. 1985. In English and Spanish. CIP Circular. Vol. 13 (Nos. 1-4). 1985. In English and Spanish. Evaluacion de Clones de! CIP Mejorados por Resistencia al Nematoda de! Quiste de la Papa (Globodera pallida) [Evalua- tion of Improved CIP Clones for Re- sistance to Potato Cyst Nematode], by J. Franco and M. Scurrah. Technical Evaluation Series 1985-1. Lima, Peru. 1985. 30 p. Evaluation Manual for CIP Courses: Ob- jectives and Implementation Proce- dures, by C. Siri. Lima, Peru. 1985. 60p. Innovative Methods for Propagating Pota- toes. Report of 28th CIP Planning Con- ference, December 10-14, 1984. Lima, Peru. 1985. 342 p. Investigaciones Nematol6gicas en Progra- mas Latinoamericanos de Papa [Nema- tode Research in Latin American Po- tato Programs], Vol. I: Informes [Re- ports], Vol. II: Proyectos y Metodos [Projects and Methods], edited by J. Franco and H. Rincon. Lima, Peru. 1985. 178 p. Markets, Myths, and Middleman: A Study of Potato Marketing in Central Peru, by G. J. Scott. CIP, Lima, Peru. 1985. 184 p. Spanish edit., Mercados, Mitos e Intermediarios. Universidad del Paci- fico, Lima. 304 p. Publications Physiological Development of Potato Seed Tubers, by S. G. Wiersema. Technical Information Bulletin 20. Lima, Peru. 1985. 16 p. In English and Spanish. Potato Atlas, by D. E. Horton and H. Fano. 2d ed. revised. Lima, Peru. 1985. 135 p. Present and Future Strategies for Potato Breeding Improvement. Report of 26th CIP Planning Conference, December 12-14, 1983. Lima, Peru. 1985. 203 p. Principales Enfermedades, Nematodos, In- sectos y Acaros de la Papa [Major Pota- to Diseases, Nematodes, and Insects]. CIP Slide Training Series IV-1 (Spanish ed.). 100 slides with 100-page booklet. Lima, Peru. 1985. Traditional Potato Production and Farm- ers' Selection of Varieties in Eastern Nepal, by R. E. Rhoades. Potatoes in Food Systems Research Series Report No. 2. Lima, Peru. 1985 . 52 p. Transmission of Potato Viruses by Aphids, by K. V. Raman. 3d ed. revised. Tech- nical Information Bulletin 2. Lima, Peru. 1985. 22 p. In English and Spanish. OTHER PUBLICATIONS BY CIP STAFF Alcazar, J., and S. A. Raymundo. 1985. Danos en tuberculos de papa (Solanum tuberosum L.) por Colaspis chlorites Erichson. [Damage to potato tubers 157 (S. tuberosum L.) due to C. chlorites Erichson.] F AO Plant Protection Bull. 33 : 165. Canto-Saenz, M. 1985. Metodos de ex- tracci6n e inoculacion de Pratylenchus flakkensis. [Extraction and inoculation methods of P. flakkensis. ] Nematro- pica 15: 116. (Abstr.) Canto-Saenz, M. 1985. The nature of resistance to Meloidogyne incognita (Kofoid & White, 1919) Chitwood 1949. p. 225-232. In J . N. Sasser and C. C. Carter (eds.), An advanced trea- tise on Meloidogyne. Vol. I. Biology and control. North Carolina: North Carolina State Univ. Graphics. 422 p. Chandra, R., M. D. Upadhya, and K. K. Jha. 1985. Regeneration of plants from rachis tissue of the potato in vitro. J. Indian Potato Assoc. 12:88- 91. Dayal, T. R., S. N. Chaturvedi, and M. D. Upadhya. 1985. Comparative group study of combining ability for differ- ent traits in the potato. J. Indian Po- tato Assoc. 12:31-42. Dodds, J. H. (ed.). 1985. Plant genetic engineering. Cambridge: Cambridge University Press. 3 20 p. Dodds, J. H., and L. W. Roberts. 1985. Experiments in plant tissue culture. 2d ed. revised. Cambridge : Cambridge Uni- versity Press. 272 p. Eguchi, Y. 1985. Preliminary report of study on flower bud differentiation and development in potato. p. 246-24 7. In Reports of the Second Meeting of the Japanese Society for Horticultural Science, Tokyo, Japan, October 14-16, 1985. 619 p. Espinoza, N. 0., and J. H. Dodds. 1985. Adventitious shoot formation on cul- 158 tured potato roots. Plant Sci. Let. 41 : 121-125. Fedalto, A. A., and 0. A. Hidalgo. 1985. Produ9ao de batata (Solanum tuberosum) em canteiros via plantula de semente botanica. [Production of potato (S. tuberosum) in beds using seedlings from true potato seed.] Horticultura Brasileira 3:68. (Abstr.) Fedalto, A. A., and 0 . A. Hidalgo. 1985. Efeito de niveis de fertilidade na ob- ten9ao de plantulas de batata (Sola· num tuberosum L.). [Effect of fertil- ity levels on potato seedling produc- tion.] Horticultura Brasileira 3:69. (Abstr.) Franco, J., and E. Bendezu. 1985. Estu- dio del complejo Verticillium dahliae Kleb y Globodera pallida Stone y su efecto en el comportamiento de al- gunos cultivares peruanos de papa. [Study of V. dahliae Kleb and G. pal· lida Stone complex and its effect on some Peruvian potato cultivars.] Fito- patologia 20: 21-27. French, E . R. 1985. Multiple disease re- sistance in potato cultivars with Sola· num phureja and S. demissum back- ground. Phytopathology 7 5: 1288. (Abstr.) Fribourg, C. E., and J. Nakashima. 1984. An improved latex agglutination test for routine detection of potato viruses. Potato Res. 27: 237-249. Fribourg, C. E., and J. Nakashima. 1984. Characterization of a new potyvirus from potato. Phytopathology 74: 1363-1369. Graza, I., and P. Vander Zaag. 1985. Rapid multiplication of potato (Sola- num spp.) for tuberlet production. Philippine Agric. 68: 287-296. Haverkort, A. 1985. Principe de selection. [Principles of selection.] p. 119-121. La recherche sur les semences bota- niques de la pomme de terre. [Re- search on true potato seed.] p. 123- 127. In Rakotondramanana (ed.), Le ble et la pomme de terre a Madagascar: productions et contraintes [Wheat and potato in Madagascar: production and constraints]. Proceedings of Interna- tional Conference on Wheat and Pota- toes, Antsirabe, Madagascar, September 24-28, 1984. Madagascar: FIF AMA- N OR. 1985. 172 p. Hidalgo, 0. A., and P. Accatino. 1985. 0 Centro Internacional de la Papa e sua contribui9ao para os programas de ba- tata dos paises nao andinos da America Latina. [The International Potato Cen- ter and its contribution to the pota- to research programs in non-Andean Latin America.] Horticultura Brasileira 3 :3-12. Horton, D. E. 1985. The Mantaro Valley Project: some lessons from on-farm re- search in the Andes. FSSP Newsletter 3(3):7-10. Huaman, Z., and D. Midmore. 1985. Tabular descriptions of crops grown in the tropics. Ser. No. 7. Potato (So- lanum tuberosu m L. and Solanum an- digenum Juz . et Buk.). Tech. Memo- randum 85/13 CSIRO, Institute of Biological Resources, Division of Water and Land Resources, Canberra, Austra- lia. 52 p. Huaman, Z., and R. W. Ross. 1985. Up- dated listing of potato species names, abbreviations and taxonomic status. Am. Potato J. 62:629-641. Hunt, G. L. T. 1985. Chap. IV. Tech- nologie apres recolte. [Postharvest tech- nology.] p. 141-155. In Le ble et la pomme de terre a Madagascar. See Haverkort. Jatala, P. 1985. Biological control of nem- atodes. p. 303-308. In An advanced treatise on Meloidogyne. See Canto- Saenz. Jatala, P., J . Franco, A. Gonzillez, and C. M. O'Hara. 1985. Hatching stim- ulation and inhibition of Globodera pallida eggs by enzymatic and exo- pathic toxic compounds of some bio- control fungi. J. Nematol. 17: 501. (Abstr.) Kloos, J. P., and B. B. Fernandez. 1985. An assessment of potato production in Bukidnon, Mindanao. Philippine Agric. 68:275-286. Martin, C. 1985. Verticillium wilt of potato in central Peru. Am. Potato J . 62: 195-199. Mendoza, H. A., and P. Jatala. 1985. Breeding potatoes for resistance to the root-knot nematodes Meloidogyne species. p. 217-224. In An advanced treatise on Meloidogyne. See Canto- Saenz. Moreno, U. 1985. Environmental effects on growth and development of po- tato plants. p. 481-501. In P. H. Li (ed.), Potato physiology. Florida, U.S.: Academic Press. 586 p. Morpurgo, R., R. Y. Antunez, and B. Nacmias. 1985. Response of potato clones to heat stress. Riv. Ortof!oro- frutt. It. 69:365-373. Nganga, S. 1985. Technologie du CIP pour le developpement de la pomme de terre dans le regions tropicales. [ CIP technology for potato development in tropical regions.] p. 115-116. Tech- nique de simple multiplication rapide. [A simple rapid multiplication tech- nique.] p. 117-118. In Le ble et la pomme de terre a Madagascar. See Haverkort . 159 Nganga, S. 1985. The organization and role of CIP regional gerrnplasm distrib- ution center in Kenya for potatoes (Solanum tuberosum ) in the tropics. ActaHort.158:33-39. Niftez, V. (guest ed.). 1985. Household gardens and small-scale food produc- tion. Food Nutr. Bull. 7(3). Niftez, V. 1985. Introduction : household gardens and small-scale food produc- tion . Food Nutr. Bull. 7(3): 1-5. Niftez, V. 1985. Working at half-potential: constructive analysis of home garden programmes in the Lima slums with suggestions for an alternate approach. Food Nutr. Bull. 7(3):6-14. Niftez, V. 1985. Food production for home consumption: nature and func- tion of gardens in household econ- omies. Arch. Latino-Am. Nutr. 35 : 9-21. Ochoa, C. 1985. Kariotaxonomic studies on wild bolivian tuber-bearing Sola- num, Sect. Peto ta [Part II]. Phytologia 57:315-324. O'Hara, C. M., and P. Jatala. 1985. Ultra- structure of Meloidogyne, Globodera and Nacobbus egg shells as related to the activities of biocontrol fungi. J. Nematol. 17: 508. (Abstr.) Otazu, V., M. D. Harrison, G. Caero, M. Coca, and W. M. Brown. 1985. lnci- dencia de Erwinias pectoliticas en cul- tivos y almacenes de papa en Bolivia. [Incidence of pectolictic Erwinias in potato fields and stores in Bolivia.] Fitopatologia 20: 12-16. Pallais, N., P. Malagamba, N. Fong, R. Garcia, and P. Schmiediche. 1985. Pollen selection: a tool for improving true potato seed. p. 153-158. In D. L. Mulcahy et al. (eds.), Biotechnology 160 and ecology of pollen. New York: Springer-Verlag. Potts, A. L., L. Kayitare, and M. J. Potts. 1985. Atlas des varietes de pomme de terre diffusees au Burundi. [Atlas of potato varieties diffused in Burundi.) Burundi: Institut des Sciences Agrono- miques du Burundi (ISABU). 15 p. Potts, M. J. 1985. The role of a country project in agricultural development. Agric. Admin. 20:63-71. Potts, M. J ., and L. Kayitare. 1985. Guide pratique pour la production des se- mences de pomme de terre. [Practical guide for the production of potato seed.) Fiche Technique No. 006. Bu- rundi: Institut des Sciences Agrono- miques du Burundi (ISABU). Raymundo, S. A. 1985. Cropping sys- tems research and root-knot nematode control. p. 277-82. In An advanced treatise on Meloidogyne. See Canto- Saenz. Raymundo, S. A., and J. Alcazar. 1985. Dust with ashes to reduce leafminer fly damage on potatoes. Appropriate Technol. 10: 17. (Abstr.) Raymundo, S. A., and R. Salas. 1985. Integrated control of root-knot nema- tode (Meloidogyne sp.) in potato seed- ling nurseries. Philippine Phytopathol. 21: 14. (Abstr.) Raymundo, S. A., J. Alcazar, and R. Salas. 1985. Comparison of soil solarization and Dazomet for the control of root- knot nematode (Meloidogyne sp.) un- der field conditions. Philippine Phyto- pathol. 21: 14. (Abstr.) Rhoades, R. 1985. Development literature and writers from underdeveloped coun- tries : a comment. Current Anthropol. 26: 98-99. Rhoades, R. 1985. Informal smvey meth- ods for farming systems research. Human Organization 44: 1-7 . Rhoades, R. E. 1985. Farming systems research . Human Organization 44 : 215- 218. Rhoades, R. 1985. The incredible potato. J. Chinese Society Hort. Sci. 31(1) : 6-9. Rhoades, R. , P. Batugal, and R. Booth. 1985. Turning conventional agricul- tural research and development on its head : the farmer-back-to-farmer ap- proach. Extension Bull. of Food and Fertilizer Technology Center (Taipei, Taiwan) 223 :23-37. Rhoades, R. E., R. H. Booth, R. H. Shaw, and R. Werge. 1985. The role of an- thropologists in developing improved technologies. Appropriate Technol. 11:11-13. Rincon, H. 1984. Usuarios de la informa- ci6n. [Users of information.] Ridecab 5(10):19-29. Rincon, H. 1985. Comunicaci6n de la tec- nologia agricola en los niveles inter- nacional, nacional y local. [Commu- nication of agricultural technology at international, national, and local lev- els.] Desarrollo Cooperaci6n No. 3: 17-20. Scott, G. J., and M. G. Costello (eds.). 1985. Comercializaci6n interna de los alirnentos en America Latina: proble- mas, productos y politicas. [Domestic food marketing in Latin America: problems, products, and policies.] Ottawa, Canada: International Devel- opment Research Centre. 253 p. Scurrah, M., and J. Franco. 1985. Breed- ing for resistance to Globodera pallida atCIP. EPPOBull.15 :167-173. Shaw, R. W., and R.H. Booth. 1985. The use of wind in solar dehydration. Ap- propriate Technol. 12: 17-18. Siri, C. 1985. Follow-up: an essential ele- ment in training agricultural workers. p. 155 -160. In Education for agri- culture. Proceedings of 1984 sympo- sium on education for agriculture, Los Banos, Laguna, Philippines, November 12-16, 1984. Philippines : International Rice Research Institute. 204 p. Tafur-Santillan, S., and E. R. French. 1985. Estabilidad de la resistencia en papa a Pseudomonas solanacearum. III Congreso Latinoamericano de Fito- patologia, Santo Domingo, Rep. Domi- nicana, August 19-23, 1985. Fitopato- logia 20: 3 2. (Abstr.) Taja, H., A. Cadorna, D. Suetos, R. Acasio, and P. Vander Zaag. 1984. Potato (Solanum tuberosum L.) tu- ber yield in Cagayan as influenced by planting date, mulching, and location. Philippine Agric. 6 7: 5 5-6 9. Taja, H., and P. Vander Zaag. 1985. Mulching, residue incorporation and fertility : effects on potato (Solanum tuberosum cv Cosima) growth and yield in the lowland tropics. Philip- pine J. Crop. Sci. 10. (Abstr.) Torres, E. M., E. R. French, and C. Martin.' 1985. Differential reaction of potato clones to Pseudomonas solana- cearum at two sites in Peru. Fitopato- logia 20: 1-6. Torres, H., C. Martin, and J. Henfling. 1985. Chemical control of pink rot of potato (Phy tophthora ery throseptica Pethyb.). Am. Potato J. 62:355-361. Uyen, N. V., T. V. Ho, and P. Vander Zaag. 1985. Cabbage (Brassica oleracea var. Capitata) propagation and produc- 161 tion using tissue culture in Vietnam. Phillippine Agric. 6 8: 14 5-15 0. Uyen, N. V., and P. Vander Zaag. 1985. Potato production using tissue culture in Vietnam: the status after four years. Am. Potato J. 62:237-241. Valle Riestra, J. 1 984. The incorporation of nutritional goals into the research design of CIP. p. 57-69. In P. Pinstrup- Andersen et al. (eds.), International agricultural research and human nutri- tion. Washington, D.C.: International Food Policy Research Institute. 3 26 p. Vander Zaag, P., M. Bicamumpaka, and P. Tegera. 1984. The potato in Rwanda. World Crops 36: 156-159. V ander Zaag, P., R. S. Yost, B. Trangmar, K. Hayashi, and R. L. Fox. 1984. An assessment of chemical properties for soils of Rwanda with the use of geosta- tistical techniques. Geoderma 34: 293- 314. 162 Wiersema, S. G., and R. H. Booth. 1985. Influence of growing and storage con- ditions on the subsequent performance of seed tubers under short-day condi- tions. Potato Res. 28: 15-25. Wiersema, S. G., and R. C. Cabello. 1985. Production of seed tubers derived from true potato seed. Am. Potato i. 62 : 449-450. (Abstr.) Wustman, R., R. H. Booth, and R. E. Rhoades. 1985. Possibilities for the application of small-scale potato stor- age techniques in developing countries. Rome, Italy: Food and Agriculture Organization. 48 p. Yamamoto, N. 1985. The ecological com- plementarity of agropastoralism: some comments. p. 85-99. In S. Masuda et al. (eds.), Andean ecology and civiliza- tions. Tokyo: University of To:;yo Press. Research and Consultancy Contracts Thrust I - Maintenance and Utilization of Unexploited Genetic Resources 1. Rothamsted Experimental Station, England - Stability/variability of potato in culture and storage. M. G. K. Jones Thrust II - Production and Distribution of Advanced Breeding Material 2. Cornell University, United States - The utilization of Solanum tuberosum spp. andigena germplasm in potato improvement and adaptation. R . L . Plaisted, H. D. Thurston, W. M. Tingey, R. E. Anderson, B. B. Brodie, M. B. Harrison, and E. E. Ewing 3. North Carolina State University, United States - Breeding and adaptation of cultivated diploid potato species. F. L. Haynes 4. I.V.P. Agricultural University, Netherlands - A breeding program to utilize the wild Solanum species of Mexico. J. G. Th. Hermsen 5. University of Wisconsin, United States - Potato breeding methods with species, haploids, and 2n gametes. S. J. Peloquin 6. Instituto Nacional de Tecnologia Agropecuaria (INTA), Argentina - Program to utilize greater genetic variability in the potato breeding plan. A. Mendiburu 7. Agriculture Canada - A proposal to evaluate modem potato breeding materials and their nutritional values. T. R. Tarn 8. University of Tacna, Peru - Evaluation of sweet potato germplasm for tolerance to certain abiotic stresses under arid conditions. R. Chavez 9. Instituto Nacional de Investigaci6n Agraria (INIPA), Peru - Evaluation of advanced clones from CIP and the national potato program of Peru. D. Untiveros l 0. Potato Research Institute, Poland - Breeding potatoes resistant to the potato leafroll virus (PLRV). E. Kapsa 11. Centro Nacional de Pesquisa de Hortalii;as (CNPH/EMBRAPA), Brazil - Evaluation of potato germplasm (Solanum tuberosum L.) in relation to resistance to Alternaria solani. F. J. B. Reifschneider 12. Aegean Regional Agricultural Research Institute (ARARI), Turkey - Potato germplasm evaluation and multiplication. K. Temiz and B. Comee 163 Thrust III - Bacterial and Fungal Diseases 13. Instituto Colombiano Agropecuario (ICA), Colombia - Evaluating the resistance of potato genetic material to Pseudomonas solanacearum and Phytophthora inf es tans. F. Gomez and J. Llanos 14. Instituto Nacional de Investigaciones Agropecuarias (INIAP), Ecuador - Study and control of potato diseases black rot (Rosellinia sp.) and rust (Puccinia pittieriana) in Ecuador. H. Orellana 15. University of Wisconsin, United States - Fundamental research to develop control measures for bacterial pathogens of the potato. A. Kelman and L. Sequeira 16. Department of Agriculture, Sri Lanka - Development of resistance and control of bacterial wilt for the mid and high elevations of Sri Lanka. M. Velupillai 17. National University of Huanuco, Peru - Development of disease-resistant potato varieties with adaptation to the ecological zones of the Department of Huanuco. E. Torres 18. National Agricultural Laboratories, Kenya - The reaction of selected potato clones to two races of Pseudomonas solanacearum in Kenya. A.H. Ramos Thrust IV - Potato Virus Research 19. Swiss Federal Agricultural Research Station, Switzerland - Development of monoclonal antibodies for potato virus identification. P. Gugerli 20. National Agrarian University-La Molina, Peru - Consultancy on the production of antisera to viruses. C. Fribourg 21. University of the Philippines, Los Bafios (UPLB), Philippines - Integrated control of nematodes and weeds by the use of biological control agents and solarization. R. Davide Thrust V - Integrated Pest Management 22. Foundation for Agricultural Plant Breeding, Netherlands - Resistance breeding against the potato eelworm Globodera rostochiensis. C. A . Huijsman 23. North Carolina State University, United States - Evaluation of potato lines for resistance to the major species and races of root-knot nematodes (Meloidogyne spp.). J. N. Sasser 24. Instituto Nacional de Investigaciones Agropecuarias (INIAP), Ecuador - Evaluation of clones resistant to potato cyst nematode (Globodera spp.) in Ecuador. R. Eguiguren and J. Revelo 25. National Agrarian University-La Molina, Peru - Consultancy on Pratylenchus spp. as important nematode pests of potatoes. M. Canto 164 Thrust VI - Warm Climate Potato Production 26. National Agrarian University-La Molina, Peru - Management of soils, fertilizers and mineral nutrition of the potato under adverse soil and climatic environments. S. Villagarcia 27. National Agrarian University-La Molina, Peru - Training and consultancy research on the effects of soil management and fertilization on flowering, fruit setting, and seed quality of the potato. S. Villagarcia 28. National Agrarian University-La Molina, Peru - Consultancy on efficient use of nutrients by the potato plant. U. Moreno Thrust VII - Cool Climate Potato Production 29. Instituto Colombiano Agropecuario (ICA), Colombia - Consultancy on potato breeding to obtain frost-tolerant clones adapted to Andean countries. N. Estrada Thrust IX - Seed Technology 30. Victoria Department of Agriculture, Australia - Production of pathogen- tested potato germplasm for Southeast Asian and Pacific countries. P. T. Jenkins 31. Instituto Agropecuario (INIA) and University Austral of Chile, Chile - Use of true potato seed in commercial potato production. J. San tos Rojas and J. Banse 32. Instituto de Investigaciones Agropecuarias (INIA), Chile - Production of true potato seed in Chile. A. Cubillos and J. Kalazich. Thrust X - Potatoes in Developing Country Food Systems 33. International Potato Center (CIP), Peru - Consultancy on household gardens in food systems of developing countries. V. Nifiez Support Department 34. National Agrarian University-La Molina, Peru - Consultancy on design, statistics, and computer processing of research experiments. A. Garcia 35. International Potato Center (CIP), Peru - Consultancy on management of sweet potato germplasm. R. del Carpio Regional Research and Training 36. International Agricultural Center, Netherlands - Consultancy for regional research and training. H. P. Beukema 165 Financial Statement COLERIDGE Y A SO C I ADOS R E PRESENTA NTE S O E ARTHUR ANDERSEN & Co. To the Board of Trustees of International Potato Center - CIP: We have examined the balance sheets of INTERNATIONAL POTATO CENTER - CIP, (a non-profit organization established in Peru) as of Dece mber 31, 1985 and 1984, and the related statements of sources, application and changes in unexpended fund balances and changes in financial po s ition for the years then ended. Our examinations were made in accordance with generally accepted auditing standards and, accordingly, included such tests of the accounting records and such other auditing procedures as we considered necessary in the circums tances. In our opinion, the financial statements referred to above present fairly the financial position of International Potato Center - CIP as of December 31, 1985 and 1984, and the sources, application and changes in unexpendend fund balances and the changes in its financial position for the years then ended, in conformity with generally accepted accounting principles applied on a consistent basis. Lima, Peru, February 18, 1986 167 INTERN A TI ON AL POTATO CENTER - CIP BALANCE SHEETS AS OF DECEMBER 31, 1985 AND 1984 (Expressed in U.S. dollars) 1985 1984 ASSETS CURRENT ASSETS: Cash on hand and in banks 1,224,653 336,971 Accounts receivable - Donors 1,429,498 1,209,080 Executives and employees 36,493 14,579 Current portion of loans to executives and employees 104,333 112,846 Other 202,137 143,618 1,772,461 1,480,123 Inventories of laboratory and other supplies 469,613 560,410 Prepaid expenses 102,415 112,082 Total current assets 3,569,142 2,489,586 RESTRICTED FUNDS (Note 3) 400,000 500,000 LONG-TERM LOANS TO EXECUTIVES AND EMPLOYEES (Note 3) 411,792 571,715 FIXED ASSETS (Note 4) 9,271,377 8,484,481 13,652,311 12,045,782 The accompanying notes to the financial statements are an integral part of these balance sheets. 16'8 INTERNATIONAL POTATO CENTER - CIP 1985 1984 LIABILITIES AND FUND BALANCES CURRENT LIABILITIES: Current portion of long-term debt and bank overdrafts 105,558 191,003 Accounts payable and accruals 1,035,118 1,041,876 Grants received in advance 643,992 Other accruals and liabilities 50,225 87,914 Total current liabilities 1,834,893 1,320,793 LONG-TERM DEBT (Note 3) 403,576 553,942 SEVERANCE INDEMNITY LIABILITY , net of advances of 42,039 in 1985 and 39,101in1984 385,512 294,267 FUND BALANCES: Funds invested in fixed assets (Note 5) 9,271,377 8,484,481 Unexpended funds - Working funds 880,000 829,000 Special projects 807,666 465,538 Operations (1,784) 54,465 Cooperative activities 71 ,071 43,296 1,756,953 1,392,299 11,028,330 9,876,780 13,652,311 12,045,782 The accompany ing notes to the financial statements are an integral part o f these balance sheets. 169 INTERNATIONAL POTATO CENTER - CIP STATEMENT OF SOURCES, APPLICATION AND CHANGES IN UNEXPENDED FUND BALANCES FOR THE YEARS ENDED DECEMBER 31, 1985 AND 1984 (Expressed in U.S. dollars) 1985 UNEXPENDED FUND BALANCES, BEGINNING OF YEAR 1,392,299 SOURCES OF FUNDS: Operating grants - Unrestricted 6,100,959 Restricted 3,018,047 9,119,006 Special project grants 1,340,569 Grants for fixed asset additions 627,981 Grants for cooperative activities 274,460 Working fund grants 51,000 Other income, net 303,970 11,716,986 APPLICATION OF FUNDS: Operating costs - Potato research program 2,560,824 Research services 1,263,528 Regional research program and training 2,842,433 Library and information services 408,997 Administrative 1,054,012 Other operating costs 1,344,496 TAC external review 9,474,290 Special projects 998,609 Cooperative activities 246,685 Additions to fixed assets 627,981 Grants returned and other 4,767 11,352,332 UNEXPENDED FUND BALANCES, END OF YEAR 1,756,953 1984 1,923,787 6,032,830 3,094,823 9,127,653 1,132,272 500,000 264,467 43,000 417,200 11,484,592 2,699,505 1,444,271 2,803,375 416,902 1,020,658 1,377,824 (37,356) 9,725, 179 1,175,991 244,571 835,259 35,080 12,016,080 1,392,299 The accompanying notes to the financial statements are an integral part of this statement. 170 INTERNATIONAL POTATO CENTER - CIP STATEMENT OF CHANGES IN FINANCIAL POSITION FOR THE YEARS ENDED DECEMBER 31, 1985 AND 1984 (Expressed in U.S. dollars) FUNDS WE RE PROVIDED BY: Operations - Unexpended fund balances Add (deduct) - Item not requiring use of funds - Provision (credit) for severance indemnities, net of exchange gains of 210, 54 2 in 1985 and 230,666 in 1984 Total funds provided from operations Decrease in restricted funds Decrease in long-term loans to executives and employees Increase in long-term debt Increase in funds invested in fixed assets FUNDS WERE APPLIED TO: Restricted funds Fixed asset acquisitions - Additions Net cost of replacements Decrease in long-term debt Payments and advances of severance indemnities Prior year unexpended fund balances INCREASE (DECREASE) IN WORKING CAPITAL CHANGES IN THE WORKING CAPITAL ACCOUNTS - INCR EASE (DEC REASE): Cash on hands and in banks Accounts receivable Inventories of laboratory and other supplies Prepaid expenses Current portion of long-term debt and bank overdrafts Accounts payable and accruals Grants received in advance Other accruals and liabilities INCREASE (DECREASE) IN WORKING CAPITAL 1985 1, 756,953 101,899 1,858,852 100,000 159,923 786,896 2,905,671 731,994 54,902 150,366 10,654 1,392,299 2,340,215 565,456 887,682 292,338 (90,797) (9,667) 85,445 6,758 (643,992) 37,689 565,456 1984 1,392,299 (47,257) 1,345,042 140,432 553,942 1,148,013 3,187,429 500,000 1,035,259 112,754 37,718 1,923,787 3,609,518 (422,089) (1,147,269) (355,266) (6,597) 65,697 653,415 (130,647) 451,773 46,805 (422,089) Th e accompany ing notes to the financial statements are an integral part of this statement. 171 NOTES TO THE FINANCIAL STATEMENTS AS OF DECEMBER 31, 1985 AND 1984 (Expressed in U.S. dollars) 1. Activities of the CIP The International Potato Center - CIP is a non-profit autonomous scientific organization established in Peru in 1972 through a scientific cooperation agree- ment signed in 1971 (which expires in the year 2000) with the Peruvian govern- ment. The CIP is a member of the group of International Agricultural Research Centers and receives support from the Consultative Group for International Agri- cultural Research. The objective of the CIP is to contribute, through the execution of research pro- grams and training, to the worldwide potato production and development. Besides its headquarters in Lima, Peru, the CIP also has regional offices located in South America, Near and Middle East, Asia, and Africa. In accordance with present legal dispositions the CIP is exempt from income and other taxes. 2. Significant accounting principles and practices 172 a. The CIP's accounting records are maintained in U.S. dollars. Monetary assets and liabilities in other currencies are expressed in U.S. dollars at the year-end exchange rate. Net exchange gains or losses originating during the year are included in the results of each period in the statement of sources, application and changes in unexpended fund balances. b. Grants are recorded as income on the basis of commitments made by the donors. c. Inventories of laboratory and other supplies are stated at average cost . d. Fixed assets are stated at cost. No depreciation is applied to fixed assets. Additions to fixed assets are reported in the statement of sources, application and changes in unexpended fund balances as incurred, and replacement addi- tions are reported as operating costs in such statement. Likewise, such addi- tions and replacements are reported at cost in the funds invested in fixed assets account, in the balance sheets. Fixed assets sold or retired are eliminated from the asset account and from the related fund balances account, and are recorded in contra accounts. Main- tenance, repairs and minor replacements are charged to costs as incurred. e. The severance indemnity liability is recorded under the accrual method for the estimated amount the employees would receive should they retire at the balance sheet date. Certain figures in the financial statements as of December 31, 1984, have been reclassified to make them comparable with those of the current year. 3. Long-term loans to executives and employees and long-term debt The CIP grants loans to its executives for the acquisition of homes and vehicles, financed by a line of credit of US$800,000 from Citibank N.A. -New York. The bank balance outstanding at December 31, 1985, is to be repaid in 54 monthly installments beginning January 1, 1986, and bearing an annual interest based upon New York PRIME rate plus 1-1 /2 °/o on the unpaid principal balance. The bal- ance of loans to executives is repayable under the same conditions, and therefore these loans are made at no direct cost to CIP. The bank loan is guaranteed by a US $400,000 deposit, earning an annual interest rate of approximately 7°/o. The CIP also grants loans to its employees for the acquisition and improvement of homes. A breakdown of loans to executives and employees as of December 31 is as fol- lows (in U.S. dollars): 1985 1984 Current portion 104,333 112,846 Long-term portion 411,792 571,715 516,125 684,561 A breakdown of the outstanding debt as of December 31, follows (in U.S. dollars) : Current portion Long-term portion 4. Fixed assets 1985 86,591 403,576 490,167 1984 96,779 553,942 650,721 This account consists of the following (in U.S. dollars): Buildings and construction in progress Vehicles and aircraft Installations Research equipment Furniture, fixtures and office equipment Site development Farm equipment Communication and other equipment 5. Fund balances As of December 31 1985 1984 2,886,964 1,811,483 1,126,284 1,154,784 965,092 607,532 354,726 364,512 9,271,377 2,786,071 1,761,305 1,079,639 1,015,444 619,954 589,248 318,226 314,594 8,484,481 Funds invested in fixed assets relate to the cost of fixed assets acquired by the CIP for carrying out its·operations. 173 In the event of dissolution of the CIP, all its property, after the liquidation of liabilities, shall be turned over to the Peruvian Ministry of Agriculture. 6. Donation commitments 174 As of December 31, 1985, donations committed by third parties to the CIP, to be applied to special projects from 1986 to 1988, are as follows (in U.S. dollars): Donor 1986 1987 1988 Swiss Development Cooperation and Humanitarian Aid 521, 760 451,000 United Nations Development Programme 230,000 155,500 Belgian Government 150,000 International Development Research Centre - Canada 231,110 55,721 45,322 Federal German Government 42, 750 United States Agency for International Development 70,355 16,651 1,245,975 678,872 45,322 Such amounts are not reflected in the accompanying financial statements. The CGIAR: A Global Agricultural Research System The Consultative Group on International Agricultural Research (CGIAR) was es- tablished in 1971 to bring together countries, public and private institutions, international and regional organizations, and representatives from developing countries in support of a network of international agricultural research centers. The basic objective of this effort is to increase the quantity and improve the quality of food production in developing countries. The research supported by the CGIAR con- centrates on the critical aspects of food pro- duction in developing countries that are not covered adequately by other institutions, but which are of global importance. Currently, the CGIAR network is involved in research on all of the major food crops and farming systems in the major ecological zones of the devel- oping world. The CGIAR consists of approximately 46 donor organizations who meet twice a year to consider program and budget proposals as well as policy issues of the 13 international agri- cultural research institutes supported by the group. The World Bank provides the CGIAR with its chairman and secretariat, while the Food and Agriculture Organization (FAO) of the United Nations provides a separate sec- retariat for the group's Technical Advisory Committee (TAC). The TAC regularly reviews the scientific and technical aspects of all cen- ter programs and advises the CGIAR on needs, priorities, and opportunities for research. Of the thirteen centers, ten have com- modity-oriented programs covering a range of crops and livestock and farming systems that provide three-fourths of the developing world's total food supply. The remaining three centers are concerned with problems of food policy, national agricultural research, and plant genetic resources. CIAT International Center fo r Tropical Agriculture Cali, Co lombia CIMMYT International Maize and Wheat Improvement Center Mexico City, Mexico CIP In ternational Po ta to Center Lima, Peru !CARDA International Center for Agricultural Research in the Dry Areas Aleppo, Syria ICRISAT International Crops Research Institute for the Semi-Arid Tropics Hyderabad, India IITA International Institute of Tropical Agriculture Ibadan, Nigeria ILCA International Livestock Center for Afri ca Addis Ababa, Ethiopia ILRAD International Laboratory for Research on Anim al Diseases Nairobi, Kenya IRR! International Rice Research Institute Manila, Philippines WARDA West Africa Rice Development Association Monrovia, Liberia IBPGR International Board for Plant Genetic Resources Rome, Italy IFPRI International Food Policy Research Institute Washington, D.C., U.S.A. ISNAR International Service for National Agricultural Research The Hague, Netherlands 175 mm~''"'"""",,_ ~ ; ~ 'ff!,, INTERNATIONAL POTATO CENTER ICIPl .,:., ... ~:;-: ..... ISSN 0256-6311