Levels of nutritionally-important trace elements and macronutrients in edible leaves and grain of 27 nodulated cowpea (Vigna unguiculata L. Walp.) genotypes grown in the Upper West Region of Ghana

Analysis of edible leaves and grain of 27 nodulated cowpea genotypes in 2005 and 2006 revealed differences in mineral density. Cowpea genotype IT82D-889 exhibited high concentrations of P, K, Ca, Mg and S in grain relative to Brown Eye, IT84S-2246 and TVx3236. Fe concentration in cowpea grain ranged from 63 mg/kg in Ngonji to 137 mg/kg in Soronko, while Zn was 44 mg/kg in Ngonji and 65 mg/kg in Vuli-1. Leaf concentrations of Cu, Mn, B and Fe were consistently higher in the genotypes Apagbaala, IT84S-2246, Fahari and IT97K-499-39, while Fe, Cu, B and Zn were lower in TVu11424, Brown Eye, Vuli-1, Soronko and Glenda. Compared with spinach, cowpea leaves had greater levels of Fe (5-fold in magnitude), Mn, P, Ca, K and Mg. Based on these data it is likely that when and where the dietary intake of cowpea leaves is high in Africa, children would suffer less from micronutrient deficiency.