Socio-Economic, Agronomic and Molecular Analysis of Yam and Cowpea Diversity in the Guinea-Sudan Transition Zone of Benin

Socio-economic, agronomic and molecular analysis of yam and cowpea diversity in the Guinea-Sudan transition zone of Benin Supervisors: Prof. dr. P. Richards Hoogleraar Technologie en Agrarische Ontwikkeling, Wageningen Universiteit Prof. dr. ir. P.C. Struik Hoogleraar Gewasfysiologie, Wageningen Universiteit Prof. dr. V. Agbo Faculté des Sciences Agronomiques, Université d’Abomey-Calavi, Benin Prof. dr. J. Zoundjihékpon Faculté des Sciences Agronomiques, Université d’Abomey-Calavi, Benin Promotiecommissie: Prof. dr. ir. C. Leeuwis Wageningen Universiteit Prof. dr. ir. A. van Huis Wageningen Universiteit Dr. O.N. Coulibaly International Institute of Tropical Agriculture, Benin Prof. dr. A. Ahanchédé Université d’Abomey-Calavi, Benin Dit onderzoek is uitgevoerd binnen onderzoekschool CERES Research School for Resource Studies for Development. Socio-economic, agronomic and molecular analysis of yam and cowpea diversity in the Guinea-Sudan transition zone of Benin Afio Zannou Proefschrift ter verkrijging van de graad van doctor op gezag van de rector magnificus van Wageningen Universiteit, Prof. dr. M.J. Kropff, in het openbaar te verdedigen op donderdag 19 oktober 2006 des morgens te half twaalf in de ILACI Salle de Conférence, Université d’Abomey-Calavi, Benin Afio Zannou (2006) Socio-economic, agronomic and molecular analysis of yam and cowpea diversity in the Guinea-Sudan transition zone of Benin. Zannou, A. –[S.l.:s.n.]. Ill. PhD thesis, Wageningen University. –With ref. – With summaries in English, French and Dutch. ISBN: 90-8504-435-9 Abstract Zannou, A., 2006. Socio-economic, agronomic and molecular analysis of yam and cowpea diversity in the Guinea-Sudan transition zone of Benin. PhD Thesis Wageningen University, Wageningen, The Netherlands. With summaries in English, French and Dutch, 236 pp. Management and use of yam and cowpea genetic resources analysed in this thesis are important to realize agricultural development in Benin, both on the short and long run. In this thesis the diversity of local varieties of yam and cowpea, often ignored by classical research, is analysed. Different meth- odological approaches, including technography, diagnostic study at village level, and joint farmer- researcher managed experimentation, have been combined with socio-cultural, market and consumer studies. Molecular tools have been used to assess the level of genetic diversity in these two crops. Socio-cultural determinants, market and consumers’ preferences, and the morphological and agronomic characteristics of different varieties of these two crops are all relevant for social acceptability and adaptability, and for the adoption of new varieties by local subsistence farmers. Different yam and cowpea varieties are used for rituals each year. The yield performance varied from one variety to another, and within one variety, from one year to another (or one place to another) depending on variability in agro-climatic conditions. While any successful variety of yam or cowpea should be adapted to stressful agro-climatic or poor soil conditions, it should be also adapted to the often specific needs of the farmer and to his/her socio-cultural environment. Moreover, varieties need to satisfy consumer preferences and market demands. Often, one single variety of yam or cowpea cannot meet all these criteria. Given these multiple purposes and multiple objectives, adequate management of diversity of varieties is essential to farmers, as a strategy to cope with food security and income generation all year round. Prices of different varieties of yam and cowpea on the market reflect the food technological or taste characteristics perceived or recognized by consumers in these varieties. The market provides important information on diversity of varieties and on their characteristics. Based on the morphogenetic and physiological characteristics recognized by farmers as limitations, or as natural constraints in the proper use of seed tubers of different yam varieties, this thesis undertook a participatory technology development programme with farmers to improve the knowledge of both the researcher and the farmers of seed tuber propagation through induced sprouting, and through use of different parts of the tuber as planting materials. The thesis also pays attention to farmers’ own experimentation in developing new yam varieties by domesticating wild yams, and shows that this activity – probably of ancient provenance in Benin – remains effective for farmers excluded by poverty from market participation. The improvement of the performance of these local varieties remains a major future task for researchers and policy-makers in Benin. Two major conclusions can be drawn from this thesis. The first is that both social and natural sciences are necessary contributors to the understanding of diversity in yam and cowpea varieties as managed and maintained by farmers. This diversity is expressed at the molecular level and at farm level, but is also highly relevant on the market and in the socio-cultural life of the farmers. The second conclusion relates to findings concerning the possibility of engaging farmers and researchers in joint study of yam and cowpea diversity, with beneficial practical consequences. Joint experimentation focused on varietal characterization, and the joint participatory technology development, indicated that more effective research results can be obtained when farmers’ perceptions and depth of experience is fully incorporated in research design. In this regard, technography and diagnosis remain continuously reviewed, allowing the incorporation of new ideas or innovations and new stakeholders in the experimentation process. The results assessment with and by farmers remains an essential aspect of judging work in farmer conditions to improve local livelihoods. In particular, the thesis emphasizes that – through domestication of yam – the poor show that they can contribute actively to development of scientific perspectives. These aspects of the Convergence of Sciences as focused upon yam and cowpea varietal management embrace both an inter-disciplinary and trans-disciplinary research perspective. Cooperation and co-knowledge generation with farmers needs follow-up, and a scaling-up to reach other farmers. Specifically, it needs to be incorporated in the curricula of national research training systems. Keywords: Cowpea (Vigna unguiculata (L.) Walp.), yam (Dioscorea spp.), agro-biodiversity, farmer perception, market and consumer preferences, socio-cultural preferences, human and social capitals, genotype by environment interaction, socio-technical knowledge, domestication, inter-(trans)disciplinarity / Beta-gamma science. Acknowledgements My deepest thanks to Professors Paul Richards, Paul Struik, Valentin Agbo, and Jeanne Zoundjihékpon for accepting being my promotors and for their excellent guidance through the whole process of this research and for shaping hybrid ideas related to both social and biological sciences. I express my sincere gratitude to Professors Paul Richards and Paul Struik for playing a very significant and instrumental role and for their constant availability during my stays in Wageningen. I am deeply indebted to Professor Adam Ahanchédé, Drs Rigobert Tossou, Simplice Vodouhè, and Wopke van der Werf, initially members of the supervision team, for all their guidance, advices and discussions. A special thanks to the international coordinator of the Convergence of Sciences (CoS) programme, Professor Arnold van Huis, and the Benin Coordinator, Professor Dansou Kossou, for their constant guidance and for providing facilities for research. I am grateful to the scientific committee of the CoS programme, Professor Niels Röling, Professor Arnold van Huis and Dr. Dominique Hounkonnou for their guidance of the whole process of CoS. Thanks to the members of the Benin Working Group, Dr. Rock Mongbo, Dr. Gualbert Gbèhounou, Dr. Anastase Azontondé, Mr Ramanou Fassassi, Mr René Tokannou, and Mr Yacouba Bouraima, and to the members of the Ghana Working Group for their contribution to this thesis. Thanks to the members of the Ecole Doctorale, Sciences de la Vie, Université d’Abomey-Calavi, for their valuable comments during various presentations of the results of this research. My gratitude to Prof. Ambaliou Sanni, head of the Laboratory of Bio-chemistry and Molecular Biology of the University of Abomey-Calavi for providing me with facilities for laboratory trials. Thanks to Dr. Alexandre Dansi for his advices during the whole research. Particularly, I thank the international secretary of the CoS project, Marthy Boudewijn, for her constant availability and assistance in all administrative issues in Wageningen and between Wageningen University and University of Abomey-Calavi. My gratefulness to the Interdisciplinary Research and Education Fund (INREF) and The Netherlands Directorate General of Development Cooperation (DGIS) for financial support to complete the degree. Thanks to Andrea Looijen, secretary of the Crop and Weed Ecology Group for her help during my last 6 months in Wageningen. Thanks to the Benin CoS secretary and accounting service for their help. Thanks to all persons from Wageningen University, University of Ghana, and University of Abomey-Calavi whose names are not explicitly mentioned for their fruitful discussions and advices. My gratitude to the farmers in my research area for their constant availability and for providing rich information, for accepting setting the principles of co-construction of common knowledge

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