Submitted to: Journal of Plant Nutrition
Publication Type: Peer reviewed journal
Publication Acceptance Date: 6/3/2003
Publication Date: 8/1/2003
Citation: OIKEH, S.O., MENKIR, A., MAZIYA-DIXON, B., WELCH, R.M., GLAHN, R.P. 2003. IRON "BIOFORTIFICATION" OF TROPICAL MAIZE TO REDUCE HUMAN IRON DEFFICIENCY IN WEST AFRICA. JOURNAL OF PLANT NUTRITION. 26:2307-2319. Interpretive Summary: Enhancing the nutritional quality of staple food crops via traditional plant breeding methods can produce high-yielding and more nutritious foods. Experts worldwide agree that these agricultural methods are a cost effective and sustainable way to alleviate the high rate of mineral and micronutrient malnutrition in humans of West Africa. With this overall objective, we evaluated forty-nine elite late-maturing corn varieties grown in three diverse agroecologies of West Africa. The goal was to identify varieties with high Fe and Zn levels and with greater Fe bioavailability. Bioavailable iron was assessed using an in vitro digestion/Caco-2 cell model. The results indicate that genetic differences exist in kernel-Fe concentration and Fe bioavailability, but that concentration was not correlated with improved iron bioavailability. These differences are promising for use in biofortification intervention programs, but additional research is necessary to determine if the iron-enriched maize genotypes can be effective in alleviating iron deficiency in humans.
Technical Abstract: Iron deficiency is estimated to affect over one-half the world population. Improving the nutritional quality of staple food crops by the development of genotypes with high bioavailable iron represents a sustainable and cost effective approach to alleviating iron malnutrition. Forty-nine elite late maturing tropical maize Genotypes were grown in a Lattice Design with two replications in three diverse agroecologies in West Africa to identify genotypes with high levels of kernel-Fe. Bioavailable iron of some genotypes selected for high iron concentration in grain and improved agronomic traits was assessed using an in vitro digestion/Caco-2 cell model. Significant differences in kernel-Fe concentration were observed among genotypes (p< 0.001). Kernel-Fe levels ranged from 16.8 to 24.4 mg kg-1 with a mean of 19.7 mg kg-1. Environment did not have a significant effect on kernel-iron levels, but Genotype by environment (G x E) interaction was highly significant. The genetic component accounted for 12% of the total variation in kernel-Fe levels. Kernel-Fe was positively correlated with kernel-Zn (R2=0.51, P<0.0001). Significant differences in iron bioavailability were detected among selected Fe-enriched genotypes grown at one location. Mean bioavailable Fe ranged between 30% below to 88% above the reference control Genotype. No significant correlation was observed between kernel-Fe concentration and bioavailable Fe levels. The results indicate that genetic differences exist in kernel-Fe concentration and Fe bioavailability. These differences may be useful in biofortification intervention programs, but additional research is necessary to determine the efficacy of iron-enriched maize Genotypes in alleviating iron deficiency in humans.