Studies on gene action and combining ability for yield and its component traits in rice (Oryza sativa L.) by using diallel mating design

Abstract

The present investigation was carried out at the Technology Park of Sardar Vallabh bhai Patel University of Agriculture and Technology, Meerut, during Kharif 2019 and 2020 with 55 genotypes (10 parents + 45 crosses) in Randomized Block Design with three replications. The Data were recorded for fourteen characters, viz. days to 50% flowering, days to maturity, plant height, panicle length, spikelet‟s per panicle, grains per panicle, 1000-grain weight, biological yield per plant, harvest-index, gel consistency, hulling percentage, L/B ratio, kernel length after cooking and grain yield per plant. The analysis of variance for the treatments revealed that all genotypes had highly significant differences in yield and quality traits. The mean sum of squares due to general combining ability was highly significant for all traits under study, while the mean squares due to specific combining ability were observed to be highly significant for all the characters, excluding days to maturity, plant height, L/B ratio and kernel length after cooking. The GCA/SCA ratio variance was less than unity for days to maturity, panicle length, grains per panicle, 1000 grain weight, biological yield, harvest index, hulling percentage and grain yield per plant. The significant GCA effects for parents Vallabh Basmati 23, Pant Basmati 2, and Pusa Basmati 1718 were found to be good general combiners and the best significant SCA effects cross Vallabh Basmati 23 × Pusa Basmati 1121, Pusa Basmati 1637 × Pusa Basmati 1718, and Pusa Basmati 1509 × Vallabh Basmati 24 were found to be good specific combiners for grain yield per plant. The additive component of genetic variation estimates was highly significant for all traits, except for the grain yield per plant. Out of forty-five, twenty-one crosses over better parent and twenty-eight over mid parent were observed with highly significant heterosis for the grain yield per plant character. The mean sum of squares due to treatment was highly significant for all fourteen characteristics. The difference between estimates of phenotypic or genotypic coefficient of variation was smaller. The result indicates that F1s possessed high heritability for traits like grain yield per plant, biological yield per plant, harvest index, spikelet‟s per panicle, kernel length after cooking, 1000 grain weight, panicle length, grains per panicle, hulling percentage, days to maturity, and L/B ratio. High genetic advance as percent of mean was recorded for gel consistency, whereas moderate genetic advance for harvest index, grain yield per plant, days to 50% flowering, biological yield per plant, spikelet‟s per panicle, and 1000 grain weight. The grain yield per plant of genotypic and phenotypic correlation coefficient showed a positive and highly significant correlation association with harvest-index, panicle length, 1000-grain weight, spikelet‟s per panicle, and gel consistency. In the path analysis at the genotypic and phenotypic level, harvest-index, biological yield per plant, days to 50% flowering, kernel length after cooking and panicle length exerted the highest positive direct effect on grain yield per plant. From the foregoing study, it can be concluded that the parents, i.e., Vallabh basmati 23, Pant basmati 2, and Pusa basmati 1718, could be utilized as a parents in the hybridization programme for rice improvement. A significant association between two or more characters aids plant breeders in their selection process.