Assessment of concentrations of iron and zinc and bioavailable iron in grains of early-maturing tropical maize varieties.

Twenty elite early-maturing (75-90 days) tropical maize varieties grown in three diverse agroecologies in West Africa were evaluated to identify varieties with high kernel-Fe and -Zn and bioavailable Fe levels. Bioavailable iron was assessed using an in vitro digestion/Caco-2 cell model. Significant (P < 0.001) varietal differences were observed in mean kernel-Fe and -Zn levels. The ranges were 15.5-19.1 mg kg(-)(1) for Fe and 16.5-20.5 mg kg(-)(1) for Zn. Genetic component accounted for 34% of the total variation in kernel-Zn and for 11% of the variation in kernel-Fe levels. Mean bioavailable Fe in varieties ranged between 4% below and 49% above the reference control variety. A significant negative relationship was detected between kernel-P concentration and bioavailable Fe (R = -0.36; P < 0.004; n = 60). Two varieties, ACR90POOL16-DT and ACR86TZESR-W, were identified as the most promising for further evaluation to determine their efficacy as improved sources of iron in target populations.