Iron Biofortification of Maize Grain.

Mineral nutrient deficiencies are a worldwide problem that is directly correlated with poverty and food insecurity. The most common of these is iron deficiency; more than one-third of the world's population suffers from iron deficiency-induced anemia, 80% of which are in developing countries. The consequences of iron deficiency include increased mortality and morbidity rates, diminished cognitive abilities in children, and reduced labor productivity, which in turn stagnates national development. The developed world has made tremendous success in alleviating nutrient deficiencies through dietary diversification, food product fortification, improved public health care, and supplementation. In developing countries, these strategies are often expensive and difficult to sustain. Poverty is the most common cause for dietary deficiency in developing countries, as consumers' dietary choices are limited as regards the quality, quantity, and diversity of foods consumed. The resource-poor typically consume what they grow and are dependent upon a small number of staple crops for the vast majority of their nutrition. Therefore, genetic improvement of staple crops (biofortification) is the most cost effective and sustainable solution to this global health problem. Here we describe an integrated genetic, physiological and biochemical analysis of iron nutrition in maize grain, to discover the genes and compounds that influence grain iron concentration and bioavailability. Multiple quantitative trait loci (QTL) for each trait have been identified and validated via multi-year and/or multi-location testing. QTL for iron bioavailability have been isolated in near isogenic lines, which were provided to collaborators in five states for planting in Summer 2008. Efficacy of these QTL in multi-location trials will be discussed. We will also present the results from poultry feeding experiments that validate iron nutritional quality predictions made from the QTL model and in vitro bioassays for iron nutritional quality. Our results indicate that biofortification of maize grain with iron is an achievable goal.