Yam (Dioscorea spp., Dioscoreaceae) is the preferred alternative to cassava since the large, starchy tubers of cultivated species are usually free of toxic substances. Yam is a staple crop particularly in West Africa which provides over 90% of world production. However, due to the labor-intensive cultivation of the perennial herbaceous vines and its climatic requirements (humid tropics), yam production is less than 20% of cassava production.