Genetic Variability, Heritability and Genetic Advance for Yield, Milling and Grain Quality Traits in Rice (Oryza sativa L.) Accessions

Genetic variability and the extent to which phenotypic variation is heritable are important considerations in rice improvement. Forty-eight rice genotypes comprising 44 accessions and four checks were evaluated during kharif 2018 in a randomised block design with two replications. Twenty-three yield, milling and grain-quality traits were assessed to estimate genotypic and phenotypic coefficients of variation, broad-sense heritability and genetic advance as a percentage of the mean. Analysis of variance indicated significant differences among genotypes for 22 of the 23 traits, whereas harvest index was non-significant. Phenotypic coefficients of variation exceeded the corresponding genotypic coefficients for all traits. Gel consistency recorded the highest GCV and PCV values, at 40.26% and 40.30%, respectively, and also showed the highest broad-sense heritability of 99.82% with a genetic advance of 82.85% of the mean. High heritability together with high genetic advance was also observed for plant height, 100-seed weight, milling percentage, head rice recovery, several brown-rice and kernel dimensions, cooked rice length and cooked rice L/B ratio. Grain yield per plant, filled grains per panicle and biological yield per plant showed moderate heritability accompanied by high genetic advance. In contrast, effective tillers per plant and harvest index exhibited low heritability. The results demonstrate substantial variability among the evaluated rice genotypes and identify several yield and grain-quality traits with potential value for selection in subsequent breeding evaluations. Traits combining high heritability with high genetic advance, particularly gel consistency, head rice recovery, milling percentage and grain dimensions, can be prioritised for direct selection in rice quality breeding programmes, although confirmation across seasons and locations is required.