Genetic diversity in traditional genotypes for grain iron, zinc and β-carotene contents reveal potential for breeding micronutrient dense rice

Abstract

Rice is the staple food for half of the world‟s population, however, its edible grain part is deficient in essential micronutrients, especially Fe and Zn. Breeding for micronutrient dense rice demands exploration of available genetic diversity for grain Fe, Zn and β-carotene contents. In this study, we analysed brown and polished grain samples of 26 traditional rice genotypes for Fe and Zn concentration. Fe concentration varied from 13.23 ppm to 45.83 ppm and 1.10 ppm to 36.45 ppm in brown and polished rice, respectively. Whereas, Zn concentration in brown and polished rice ranged from 18.67 ppm to 38.01 ppm and 5.86 ppm to 23.88 ppm, respectively. The landraces had higher Fe and Zn contents than improved varieties and advance uniform lines. Significant positive correlation was present between Fe and Zn concentration in brown (r = 0.694, P < 0.01) and polished rice (r = 0.533, P < 0.01). Fe concentration was greatly reduced by the polishing process than Zn concentration and approved varieties lost less Fe and Zn contents than advance uniform lines. Minimal levels of beta-carotene were detected in rice genotypes indicating need for genetic modifications to enhance pro-vitamin A contents in rice endosperm.