Socio-economic, agronomic and molecular analysis of yam and cowpea diversity in the Guinea-Sudan transition zone of Benin

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.Management and use of yam and cowpea genetic resources analysed in this thesis are important to realize agricultural development inBenin, 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 methodological 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 se