A starchy, nutrient-rich root vegetable of the genus Dioscorea, the yam thrives in a tropical belt across West Africa, with outliers in the Caribbean and some Asian countries such as Japan.

Other Name(s): yam (but this term more correctly refers to the roots of the tropical species Dioscorea and is distinctly higher in starch and less sweet.) There are two basic types of sweet potato.

Shinsuke Yamanaka, Director and Project Leader-Tropical Crop Genetic Resources, JIRCAS, said the system is to help ...