The most widely grown root and tuber crops in Africa are cassava and yam. The two main species of yam, Dioscorea spp., were domesticated independently, D. rotundata in Africa and D. alata in Asia. D. rotundata, the most widely cultivated yam species in Africa is a staple food for over 100 million people . This species has two close wild relatives D. abyssinica and D. praehensilis [11–14]. The three species are diploid and have 20 chromosomes [2n = 40] [14–16]. The African cultivated yam and its closest wild relatives are compulsory out-crossers because they are dioecious. However, D. rotundata is preferentially propagated through vegetative multiplication . Interestingly, the two wild species have distinct ecological distribution: D. abyssinica is found in the wooded savanna areas while D. praehensilis is found in tropical forested areas . The diploid African yam is cultivated in both ecological areas, thereby allowing gene flow between cultivated and the two wild species . Several key phenotypes differentiate cultivated varieties from their wild relatives. Cultivated yams are characterized by larger and less ramified roots than their wild relatives, and some cultivated varieties do not develop inflorescences . Finally, the wild relatives of yam are vines which grow partly in the shade of their tutor tree, while cultivated yams grow in full sunlight. This change of habitat might be associated with major adaptation.