Sweetpotato(Ipomoea batatas L.Lam.)ranks fifth among the most important food crops,after rice,wheat,maize and cassava,on a fresh-weight basis in developing countries(Scott and Maldonado,1999).Sweetpotato cultivars have white,yellow,purple or orange flesh,but only orange-fleshed sweetpotato cultivars are the rich sources of(3-carotene,which is the precursor of vitamin A(Failla et al.,2009).Accordingly,the orange-fleshed sweetpotato is the main source of(3-carotene for the people in underdeveloped coun- Sweetpotato (Ipomoea batatas L. Lam.) Ranks fifth among the most important food crops, after rice, wheat, maize and cassava, on a fresh-weight basis in developing countries (Scott and Maldonado, 1999). Sweetpotato cultivars have white, yellow , or orange flesh, but only orange-fleshed sweetpotato cultivars are the rich sources of (3-carotene, which is the precursor of vitamin A (Failla et al., 2009). Accreditedly, the orange-fleshed sweetpotato is the main source of (3-carotene for the people in underdeveloped coun-