Genetic Variability and Correlation Analysis for Yield Attributing Traits in Rice (Oryza sativa L.)

Abstract

Aim: To evaluate genetic variability, heritability, genetic advance, and correlation among yield and yield-attributing traits in rice genotypes to identify effective selection criteria for yield improvement. Study Design:  Augmented block design. Place and Duration of Study: Institute of Rice Research, ARI, Rajendranagar, Hyderabad, Telangana, India, during the Kharif season of 2024. Methodology: The study involved 100 rice genotypes and five checks, sown in a nursery bed and transplanted after 25 days with a spacing of 30 cm between rows and 15 cm between plants. Ten agronomic and yield-related traits were evaluated: days to 50% flowering, plant height, panicle length, number of productive tillers per plant, 1000-grain weight, number of grains per panicle, grain yield per plant, kernel length, kernel breadth, and kernel length-to-breadth (L/B) ratio. Observations were recorded from five randomly selected plants per genotype. Statistical analysis was conducted using INDOSTAT software to assess variance, heritability, genetic advance, and phenotypic correlations. Results: Analysis of variance revealed significant variation (P < 0.01) among genotypes for all traits. High heritability (>80%) was observed for days to 50% flowering (86.47%), plant height (93.90%), number of productive tillers per plant (85.24%), 1000-grain weight (94.68%), number of grains per panicle (97.34%), grain yield per plant (90.59%), kernel length (97.73%), kernel breadth (96.14%), and L/B ratio (96.07%), with panicle length showing moderate heritability (73.99%). High genetic advance as a percentage of the mean was recorded for plant height (24.28%), number of productive tillers per plant (32.77%), 1000-grain weight (45.09%), number of grains per panicle (63.42%), grain yield per plant (42.80%), kernel length (22.59%), and kernel breadth (24.02%). Grain yield per plant showed a significant positive phenotypic correlation with the number of grains per panicle (r = 0.1155, P < 0.01) and non-significant positive associations with plant height (r = 0.1116), panicle length (r = 0.0635), number of productive tillers per plant (r = 0.1540), 1000-grain weight (r = 0.1155), kernel length (r = 0.0757), and kernel breadth (r = 0.0921). Conclusion: ANOVA confirmed significant genetic variation among 100 rice genotypes for all traits, supporting selection. Plant height, productive tillers, 1000-grain weight, grain number per panicle, grain yield, and kernel dimensions showed high heritability (>80%) and genetic advance (22.59–63.42%), indicating additive genetic control ideal for direct selection Days to 50% flowering, panicle length, and kernel length-to-breadth ratio had high heritability but moderate genetic advance, suggesting non-additive and environmental effects. Positive correlations with grain yield support indirect selection (Vennelea et al.2021). Variability among traits is useful for further selection in breeding programme.