Assessment of Genetic Diversity for Grain Iron and Zinc Contents among 123 Rice Germplasm Lines

Abstract

Aims: This study evaluated 123 rice germplasm lines to assess genetic diversity for major biometric and grain iron and grain zinc contents and identify superior donor genotypes for biofortification breeding programmes. Study Design: completely randomized design. Place and Duration of Study: Rice Research Station, Vyttila, Ernakulam, Kerala Agricultural University, between January 2023 to February 2024. Methodology: A completely randomized design experiment was conducted with 123 diverse rice genotypes grown in pot cultures. Major biometric observations including grain yield per plant was taken. Grain samples were analyzed using Atomic Absorption Spectrophotometer for Fe and Zn content, and data were subjected to analysis of variance, correlation analysis, and principal component analysis. Results: Exceptional genetic variation was observed with GIC ranging from 0.00 to 1694.80 ppm (mean 242.79 ppm) and GZC ranging from 0.00 to 159.87 ppm (mean 37.92 ppm). Traditional varieties Chittimuthyalu (1694.80 ppm), Njavara (1471.9 ppm), and Kannukulamban (1318.40 ppm) exhibited the highest iron content, while advanced breeding lines PTB-25 (159.87 ppm), PTB-21 (159.34 ppm), and PTB-18 (151.89 ppm) showed superior zinc accumulation. Genotypes PTB-21 and PTB-41 demonstrated high levels of both micronutrients. Significant positive correlation (r - 0.175, P < 0.01) between GIC and GZC suggests feasibility of simultaneous improvement. Principal component analysis revealed that the first three components explained 59.12% of total variation, with micronutrient traits showing independence from major yield components. Conclusion: The substantial genetic diversity identified in this study, particularly in traditional varieties and released varieties, provides valuable genetic resources for developing biofortified rice varieties. The identified high-performing genotypes represent promising donors for addressing micronutrient malnutrition through conventional and molecular breeding approaches.