Genetic Parameters Governing Yield Traits in Rice under Drought Stress: Implications for Selection and Improvement

The present study was undertaken to estimate the nature and magnitude of genetic variability parameters for nine quantitative traits, including days to fifty per cent flowering, plant height, number of productive tillers, panicle length, number of grains per panicle, grain length, grain breadth, thousand grain weight and grain yield per plant. The field screening of 120 rice genotypes for drought tolerance was conducted using a randomized block design (RBD) with three replications. The experiment was carried out in a drought field at Koothapadi village, Dharmapuri district (Drought-E1), while another low-lying field in the same village served as the irrigated control (Normal-E2). The study was conducted during the Navara seasons of December to April in 2020-21 (Season 1) and 2021-22 (Season 2). The analysis of variance revealed a significant difference among the 120 rice genotypes for all nine traits studied under drought stress conditions, indicating the existence of high genetic variability among the selected rice genotypes for the characteristics under study. The genetic variability parameters revealed that the phenotypic coefficient of variation (PCV) was slightly higher than the genotypic coefficient of variation (GCV) for all traits studied. High values for GCV and PCV coupled with high heritability and genetic advance per cent as mean for all the studied traits under drought stress conditions, indicate that heritability is most likely due to additive gene effects and the selection of a foresaid characters in drought stress conditions that are found to be highly effective.