Studies on Yam Domestication and Farmers' Practices in Benin and Nigeria

Abstract

This paper combines the results of surveys carried out between 1995 and 2001 in Benin and Nigeria on farmers' practices in connection with the domestication of yams (Dioscorea rotundata), which is still an active process in West Africa. In Benin more than 500 yam producers belonging to four major yamproducing ethnic groups (Bariba, Mahi-Fon, Nago and Yom) and nearly 300 farmers in six different states of Nigeria were interviewed. The knowledge of wild yams is still alive even among farmers who have never domesticated yam. In the two countries the techniques described are very similar and the domesticated wild yams belong either to D. abyssinica in the northern part of the studied area (drier savanna zone) or to D. praehensilis in the southern part (humid savanna). The percentage of farmers who are domesticating or have recently domesticated yams varies from 3-14%. The domestication process mainly leads to early maturing cultivars, which are produced in double-harvest systems. The practice of domestication is decreasing, especially in the regions where commercial yam production is well developed.

Does the Domestication of Yam Wild Type Dioscorea praehensilis and Dioscorea abyssinica has a Genetic Basis?

“…This result was in accordance with those reported by Vernier et al (2003) but contrary to those reported by Baco who previously identified three morphotypes (Baco, 2000) in the same cultural area. This variation in the number of domesticable morphotypes reflects the lack of control of the phenomenon of the domestication by a large number of farmers (Baco, 2000;Vernier et al, 2003). Likewise, the domestication could be considered as a subjective phenomenon because what is domesticable for some farmers is not always for others.…”

“…Likewise, the domestication could be considered as a subjective phenomenon because what is domesticable for some farmers is not always for others. (Vernier et al 2003), they were genetically closer to the latter species whose control used is in this study clustered in the same group. Thus, the real genetic nature of non domesticable D. abyssinica deserves to be studied more thoroughly.…”

Changes in the availability and uses of wild yams according to climatic dryness and land-cover in Western Burkina Faso (West Africa): a joint ecological and ethno-botanical approach using GIS and remote-sensing

“…Indeed, conjointly with the exchange of cultivars, farmers always use the domestication of wild yams to mitigate genetic erosion due to the vegetal multiplication of the cultivated yams (Trèche 1996;Dumont and Vernier 2000;Vernier et al 2003;Mignouna and Dansi 2003). Thus, there exists a co-evolution between wild (e.g.…”

Dioscorea

“…This hypothesis was not clear until recently when numerous studies using powerful tools (such as enzymatic and molecular markers; flow cytometry) were carried out to understand the relationship between D. rotundata and wild yams. In addition, social surveys carried out in Benin (Dumont and Vernier 1997) and Nigeria (Vernier et al 2003) showed similar practices of domestication by farmers in these regions. Hildebrand (2003) also reported a similar kind of domestication process in southwestern Ethiopia where several wild yams have been brought under cultivation.…”