Studies on path analysis in rice

Analysis of variance revealed differences among the genotypes for all the characters, which indicates that wide spectrum of variation among the genotypes. Phenotypic and genotypic coefficient of variation were high (more than 25%) exhibited for panicle length, number of grains per panicle, biological yield per plant and harvest index, indicating that scope of importance with respect to these traits through selection. High heritability coupled with high genetic advance expressed as per cent of mean were observed for days to maturity, plant height, number of productive tillers per plant, panicle length, biological yield per plant, harvest index and grain yield per plant, indicated that additive gene action and selection may be effective for these characters. Grain yield per plant showed positive and significant stable correlation with biological yield per plant, number of productive tillers per plant, test weight, plant height and number of grains per panicle at genotypic and phenotypic level indicated that by improving these traits the yield can be improved in rice. Biological yield per plant displayed high order of direct effect on grain yield per plant followed by number of grains per panicle and harvest index at both phenotypic and genotypic levels. The high indirect contribution of days to 50% panicle emergence via days to 50% flowering, number of productive tillers per plant and test weight; Days to 50% flowering through panicle length; Days to maturity via test weight; Plant height through number of grains per panicle; Number of productive tillers per plant via days to 50% flowering and plant height; Biological yield per plant through harvest index and test weight via days to 50% flowering were responsible for their positive association with grain yield suggested that these traits may play an important role in improvement of grain yield in rice.