Biofortification of food crops: a novel strategy for reducing micronutrient malnutrition

Globally, more than two billion people are Fe and Zn deficient. These people are mostly rural poor from developing countries. In the past, food fortification, diet diversification, and nutrient supplementation have been used to address micronutrient malnutrition. Unfortunately, these approaches did not reach malnourished rural population. Thus, biofortification, a biological process of adding micronutrients to food crops, through breeding or agronomic approach has taken place. Varieties, landraces and wild species are explored for their mineral levels and these materials are used in the breeding technique to develop new varieties with increased mineral content. In conventional plant breeding, parent lines with high mineral levels are crossed and back-crossed over several generations to produce plants that have elevated level of the nutrients. Earlier times conventional breeding mainly focused on yield attributes and resistance breeding against any stress e.g. disease. Transgenic approach has made it possible to transfer candidate gene from the same or a different species or organism to the intended crops. Internationally the HarvestPlus programme has taken initiative to address micronutrient malnutrition of rural poor in developing countries through development of staple food crop varieties (rice, wheat, maize, cassava, pearl millet, beans and sweet potato) that rich in Fe, Zn and Vitamin A (β carotene). Not the whole amount of minerals present in plant foods is bioavailable to humans due to presence of antinutritional compounds (e.g. phytate) that interferes with the absorption of the nutrients. Agronomic biofortification provides temporary micronutrient increase through fertilizer application. Nonetheless, in a highly Zn deficient soil the full benefits of growing Zn enriched rice variety would not be achieved. Thus, agronomic biofortification could be complementary to breeding strategy for achieving greater success of breeding efforts for micronutrient enrichment of food crops.