Effect of grain colour on iron and zinc density in pearl millet

Pearl millet (Pennisetum glaucum (L.) R. Br.) is a climate resilient crop with higher nutrition and serve as staple food for several million populations in semi-arid regions of India and Africa. To utilize the nutritional variability of this crop, biofortification research has been initiated to combat micronutrient malnutrition, chiefly iron (Fe) and zinc (Zn) deficiency. Large variability for grain Fe and Zn density has been reported in pearl millet and mostly the high-Fe lines had relatively dark grey grain colour. Therefore, this study was designed to investigate the effect of grain colour on grain Fe and Zn density in pearl millet. Two dark grey lines were crossed with five white grain colour lines to produce 10 hybrids. These hybrids were evaluated along with their parental lines for Fe and Zn density in two seasons. Highly significant Fe density differences observed for both parents and hybrids while significant Zn density differences observed only for hybrids. The significant genotype × environment (G × E) interaction observed for Fe and Zn density in hybrid trial. Interestingly, grain colour× environment variance was not significant for both micronutrients. Results indicate both micronutrients were not differed from white to grey grain lots among hybrids (70-103 mg kg-1 Fe density and 64-80 mg kg-1Zn density), implying the genetic improvement of grain Fe and Zn density in pearl millet is highly feasible without compromising the grain colour preference of the farmers and consumers. Further, highly positive and significant correlation between these two micronutrient density irrespective of the grain colour recommended increase in Zn density as an associated trait while breeding for high Fe density in pearl millet