Variability, heritability, character association, and path coefficient analysis in advanced breeding lines of rice (Oryza sativa L.)

Abstract

Seven advanced breeding lines developed through hybridization breeding program and a popular cultivar were used to study variability, heritability, character association, and path coefficient analysis in rice for grain yield and its related agronomic traits. The results indicated that genotypes differed significantly in terms of grain yield and its related agronomic traits. Pronounced variations were observed for all the traits except for growth duration and harvest index. High genetic variability was observed for number of filled grains per panicle, number of secondary branches per panicle, plant height, spikelet sterility (%), grain yield per hill, number of primary branches per panicle, 1000-grain weight, duration of flowering and maturity, number of tillers per hill, number of panicles per hill, and panicle length. Based on high heritability and high GA and GAPM along with close values between σ2g vs. σ2p and GCV vs. PCV all the traits (except for harvest index, number of primary branches per panicle, days to maturity, and days to flowering) could be selected for improving the grain yield of rice as these traits exhibited less influence of environment. The significant and desirable correlations were observed for number of filled grains per panicle, number of secondary branches per panicle, spikelet sterility (%), days to flowering both at genotypic and phenotypic level. Considering genetic parameters, correlation, and path coefficient analysis, direct selection based on number of filled grains per panicle and spikelet sterility would significantly increase the grain yield of rice. So, direct selection based on these traits would be effective for the improvement of these breeding materials. The residual effect was found 0.1386 which indicated that 86.14% of the variability was accounted for grain yield and yield contributing traits included in the present study. Rest 13.86% variability might be controlled by other yield contributing traits that were not included in the present investigation.