Yam, Tubers Production and Uses Yam refers to a member of the family of Di oscorea ceae which is a staple food, ceremonial crop, and cash/export crop for Nigerians. The family is made up of 6 genera with over 600 species of which few are edible.  The species commonly grown in Nigeria are –             Dioscorea rotundata (white yam)  –             Dioscorea cayenensis (Yellow yam)  –             Chinese yam)  –             Diocorea bulbifera(Aerial yam) It is a monocotyledonous, predominantly dioecious and herbaceous climbing crop grown in the wet to fairly high rainfall areas with a dry season of not more
