Genetic enhancement of micronutrient content in cereals

Abstract

Cereals provide more than half of global human caloric intake. Though cereals are nutritious, their nutritional density, especially of micronutrients, is far below recommended level in the products we consume. Due to this, over three billion individuals are malnourished globally. About 45 micronutrients (required in μg to mg quantity) including some mineral elements, vitamins, essential amino acids and fatty acids are vital to human body. In addition, antinutrients in food staples, reduced accumulation by plants and low bioavailability of minerals contribute further to micronutrient deficiencies. Vitamin-A, iron and iodine deficiency disorders are the most common. Hence, there is a need to evolve viable strategies of micronutrient enrichment in dietary staples. Of the three major strategies viz., dietary diversification, supplementation and food fortification, agronomic and/or genetic fortification is the cost effective and sustainable way to address the problem of malnutrition. Considering the severity of malnutrition, the HarvestPlus initiated genetic biofortification program of staple food crops focusing on most limiting nutrients viz., iron, zinc, and vitamin A. Most of the HarvestPlus biofortified varieties are bred through conventional breeding. However, MAS and transgenics are also used to biofortify crops in the research programmes other than the HarvestPlus. More than 150 biofortified varieties of 10 crops have been released in 30 countries. More than 20 million people are consuming biofortified crops such as vitamin-A maize, iron pearl millet, zinc rice, zinc wheat, etc. Continuous efforts are needed still to biofortify staples and to encourage adoption further by farmers and consumers. With our present technological competence, multibiofortified staples can be developed by gene stacking. Much work on biofortification is still needed through collaborative and multi-sectoral approaches along with the strong policy support. In future, in addition to deployment of conventionally bred biofortified varieties, transgenic biofortified varieties may be approved and deployed.