A study of yam domestication practices among smallholders has provided an insight into how farmers exploit wild plant genetic resources so as to adapt them to agriculture. This book describes the domestication operations leading to Dioscorea rotundata yams in Africa. The biodiversity of these yams and of their wild relatives is investigated, and the authors put forward hypotheses to explain the phenotypic changes resulting from smallholder practices. These hypotheses could be possible lines of research for breeders.