Analysis of Genetic Variability, Heritability, and Genetic Advance in Rice (Oryza sativa L.)

Abstract

Understanding genetic variability and selection indices are the essentials for the program of rice improvement. This study assessed 80 genetically diverse rice (Oryza sativa L.) genotypes during Kharif 2021 at the Seed Breeding Farm, Department of Plant Breeding and Genetics, JNKVV, Jabalpur, India, arranged in a randomized complete block design with three replications. The significant (p < 0.01) differences were found in all the characters studied, which is an indication of the large genetic diversity in the experimental material. The phenological traits like days to 50% flowering (98.90 days) and days to maturity (125.98 days) showed that the tested genotypes covered the whole range of early to late maturity groups, while plant height had a broad range (67.36 to 149.78 cm). Likewise, considerable variation was recorded for yield‐related characters such as 1000‐grain weight (12.32 to 34.75 g), fertile spikelets per panicle (mean 173.25), and grain yield per plant, thus providing significant scope for selection. The comparison of PCV and GCV gave a hint of moderate to high variability for the majority of the traits, with characters related to spikelets, flag leaf traits, and yield components being the most influenced by the genotypic factors. Heritability in the broad sense was high for the majority of the traits, especially for flag leaf length (97.90%), total spikelets per panicle (97.20%), fertile spikelets per panicle (96.80%), and 1000‐grain weight (93.50%), indicating the dominance of additive gene effects. The genetic advance as a percentage of the mean was the highest for spikelet density (78.71%), total spikelets per panicle (66.05%), fertile spikelets per panicle (67.05%), and sterile spikelets per panicle (65.18%), thus demonstrating strong selection potential. The high heritability together with the high genetic advance for the most important traits such as spikelet density, 1000‐grain weight, and grain yield per plant, supported further the direct selection efficiency. The research has reconfirmed the large genetic variability and has pointed out the traits whose changes depend mainly on the additive gene effects; thus the traits are open for the improvement by simple genotypic selection. The results of this investigation shed light on trait inheritance and selection efficiency to a great extent, thereby they provide a lot of useful guidance in breeding high-yielding rice cultivars adapted to subtropical ecosystems.