Influence of intrinsic soil factors on genotype-by-environment interactions governing micronutrient content of milled rice grains

Abstract

Rice as the major staple food of the world although is high in calories but deficient in essential micronutrients. This deficiency can be tackled by biofortification of rice grains with enhanced micronutrient content. Field experiments were carried out across three locations involving 17 genotypes, with the objective of assessing the genotype environment interaction for native soil micronutrient assimilation in rice kernels and the influence of intrinsic soil variables on micronutrient content in rice grains. Contents of Fe, Zn, Cu and Mn in the milled kernels were found to vary significantly among genotypes and locations. There was significant genotype-by-environment interaction (GEI) for all the nutrients. Further, it was found that soil pH and soil available P had significant influence towards grain Fe content. Soil Zn availability and the electrical conductivity of the soil solution were found closely associated with grain Zn content. The two factors that regulated Cu and Mn content of rice grains were soil organic carbon content and soil Cu availability. The factorial regression (FR) approach to assess the role of significant intrinsic soil factor (s) on enrichment of specific micronutrient in the milled rice kernels showed differential genotype responses that ultimately determined grain micronutrient accumulation in each genotype. These determinants enabled prediction of genotypes suited to different environments. In certain cases, further examination of environmental co-factors is advocated to bring out a comprehensive picture of the micronutrient assimilation in milled rice grains.