Iron Biofortification of Cereals Grown Under Calcareous Soils: Problems and Solutions

Abstract

Iron (Fe) deficiency is a prevalent nutritional deficiency throughout the world, affecting an estimated 3.7 billion people. Increasing Fe concentration in foodcrops is an important global challenge due to the high incidence of Fe deficiency in human population. Further, cereals grown on calcareous soil are low in Fe contents. High pH, high temperature, low organic matter and poorly managed soil with respect to fertility are the factors which cause low Fe availability to cereal crops in calcareous soil. Iron fertilization in calcareous soil is not effective due to their rapid conversion into unavailable forms and poor mobility of Fe in phloem. Iron-organic compounds in manure are effective in maintaining Fe availability to plants. Fe bioavailability inhibitors such as polyphenols and phytate inhibit iron absorption but it was concluded that their inhibitory effect on iron absorption can be limited by increasing iron content. Ferritin, an iron storage protein, can deposit thousands of iron atoms asnon-toxic form and ferritin iron is bioavailable to humans as ferrous sulphate. Improving both concentration and bioavailability of Fe in cereal grains is, therefore, an important challenge and a high-priority research area. Hence, there is a need for effective strategies to overcome Fe deficiency in cereals and to increase Fe bioavailabilty in cereals grains. Biofortification of food crops with Fe to combat iron deficiency problems in humans, is a cost-effective and sustainable agricultural strategy to alleviate malnutrition. We hypothesized that Fe nutrition management in calcareous soil can increase growth, yield and Fe bioavailability from cereals.