Assessment of Genetic Variability, Heritability and Genetic Advance for Yield and Nutritional Traits in Rice (Oryza sativa L.) Genotypes

Abstract

The present study was conducted during Kharif, 2024 at ICAR-Indian Institute of Rice Research (IIRR), Hyderabad, to assess genetic variability, heritability, and genetic advance for yield and nutritional traits in sixty rice (Oryza sativa L.) genotypes, comprising 52 advanced breeding lines, three restorers and five checks for yield and nutritional comparison. The experiment was laid out in an alpha lattice design with three replications. Analysis of variance revealed highly significant differences among genotypes for all 14 studied traits, indicating ample genetic variability, which is essential for effective selection and genetic improvement. The phenotypic coefficient of variation (PCV) was slightly higher than the genotypic coefficient of variation (GCV) across all traits, highlighting minor environmental influence. Notably, for days to 50% flowering (DFF), 1000 grain weight (TGW), and single plant yield (SPY), the PCV and GCV values were nearly identical, suggesting that these traits are predominantly governed by genetic factors and are less influenced by the environment. High GCV was recorded for number of unfilled grains per panicle (41.99%), single plant yield (22.55%), number of filled grains per panicle (22.25%), 1000 grain weight (19.91%), indicating high genetic variability. Moderate GCV was observed for plant height, productive tillers, panicle length, zinc content in brown and polished rice, and protein content of brown rice, whereas low GCV was noted for days to 50% flowering and spikelet fertility, Iron content of brown rice and polished rice. Traits such as single plant yield, 1000-grain weight, filled grains per panicle, unfilled grains per panicle, plant height, and zinc content (both in polished and brown rice) exhibited both high heritability and high genetic advance as percent of mean, reflecting the predominance of additive gene action and indicating that simple selection methods will be highly effective for improving these traits in the advanced breeding lines. The study concludes that substantial genetic improvement can be achieved by selecting superior genotypes for both yield enhancement and nutritional biofortification in rice breeding programmes.