Facteurs géographiques et sociaux de la diversité des ignames cultivées au Nord Bénin = Geographical and social factors of cultivated yam diversity in northern Benin

This study aimed at contributing to the sustainable management of yam (Dioscorea sp.) diversity. It was carried out in northern Benin on 220 farms and in 8 villages. The main hypothesis considers that varietal diversity is influenced by ethnic diversity and the market. Results show that diversity remains high with 182 landraces observed in the fields. The study underlines the major role of cultivation practices and of socio-cultural determinants that depend on the history of each ethnic group. In relationship to this point, the Bariba, the Nago and the Gando, who have cultivated yams since remotest times, still remain the best social vectors of diversity. Characteristics of villages, such as links with the geographic and social levels, act on the level of diversity. The reduction of diversity brought about by market development is not confirmed. Facing the complexity of diversity determinant factors, the study concludes that the success of an in situ conservation policy will depend on the difficult choice of the area where it is carried out