In parts of South America, vitamin-A deficiency is a serious health problem, especially among children  In one region, agriculturists hope to improve nutrition by encouraging farmers to plant a new variety of sweet potato called SPK004 that is rich in betacarotene, which the body converts into vitamin A
The plan has good chances of success, since sweet potato is a staple of the region' s diet and agriculture, and the varieties currently grown contain little beta-carotene
The currently cultivated varieties of sweet potato contain no important nutrients that SPK004 lacks.