Agronomic Biofortification of Crops with Zinc: A Comprehensive Overview
摘要
Zinc, a seminal micronutrient for crops and humans, performs an essential function in growth and development. Cereals are a leading source of staple food supply but are short in grain Zn content. Zinc biofortification of cereals and other food crops is a substantial impediment due to the alkaline/basic nature of soil. Most of the soil under cultivation in the world has low Zn plant availability due to which Zn-biofortified genotypes are not able to perform at their potential. To combat this challenge, various agronomic and microbial approaches have been adopted to enhance the soil Zn-availability and Zn-contents in edible plant parts. This chapter explores different techniques, zinc sources, their efficacy in zinc amelioration, and their impact on the environment and economics. A combination of fertilizer application and foliar spray has proven essential and sustainable for the improvement of zinc grain percentage. Zn-application enhances photosynthetic activity, Zn re-translocation into seeds, and increases the contents of protein, oil, and starch. In addition to this, Zn-biofortification may also regulate either positively or negatively the concentration of other micronutrients, especially Fe, Cu, Mg, P, etc., and improve soil health and economic returns. Plant growth-promoting microorganisms decompose and mineralize organic matter and metamorphose inorganic matter to improve the Zn-availability in soil, mobilization in crop plant parts, and bioavailability in food grains. Moreover, Zn also preserves the soil environment by promoting the growth of beneficial bacteria. Considering adverse soil conditions, and in the scenario of climate change, an integrated approach of combining genetic and agronomic biofortification strategies would be helpful.