Genotypic Variability of Iron and Zinc in Sweetpotato

Abstract

Sweetpotato [Ipomœa batatas (L.) Lam.] is a major subsistence crop in southern Africa, where iron and zinc deficiency in humans is an important health problem. A cultivar of sweetpotato that is suited for subsistence farming in this region and that is high in iron and zinc could be an important means of combatting these deficiencies. As part of a program of the HarvestPlus program, under the auspices of the International Potato Center (CIP) to develop such a cultivar, we are working to identify the high and low range of iron and zinc in sweetpotato cultivars grown throughout the world by testing a number of cultivars for these nutrients. Subsidiary objects include determining the heritability of iron and zinc levels and surveying the variability in the levels of these nutrients from root to root on the same plant, from plant to plant of the same cultivar, from the proximal to the distal end of a given root, and from cambium to cortex. For the roughly 80 cultivars in the genotypic variability study, results showed a three-fold difference between the high- and low-yielding cultivars on a fresh weight basis and a two-fold difference on a dry weight basis, for both iron and zinc.