Genetic variability, association and multivariate analysis for yield parameters in cold tolerant rice (Oryza sativa L.) genotypes

Genetic variability in germplasm lines imparts basic knowledge on the genetic properties of a population upon which principle breeding methods are constituted for further crop improvement. The relative contribution of variability pertaining to crop species also aids in handling selected donors with high yielding capacity. In this study, 38 cold tolerant rice genotypes were evaluated for four seasons (Kharif, mid-Kharif, late-Kharif and Rabi) during the year 2020–21 in a Randomized Block Design at College farm, PJTSAU, Rajendranagar, Hyderabad to study the genetic variability, association, path analysis and genetic diversity studies for yield and its related traits. ANOVA revealed significant differences for all the traits with high genotypic and phenotypic coefficient of variance for panicle exertion (27.79%, 42.31%) and grain yield per plant (23.11%, 33.87%). High heritability along with high genetic advance as per cent of mean was noticed for plant height (83%, 32.94%), along with high variability as depicted by box plots and heatmap suggesting a direct selection for this trait. The correlation and path analysis identified plant height (0.411, 0.113), days to 50% flowering (0.233, 0.038), panicle length (0.404, 0.173), tillers per plant (0.278, 0.230), spikelet fertility (0.346, 0.203), filled grains per panicle (0.505, 0.304) and test weight (0.032, 0.012) to be having a direct positive effect on grain yield, indicating an overall enhancement in grain yield with the selection of these traits. Among the four seasons evaluated, mid-Kharif was observed to be congenial for improving of most of the traits including grain yield. Since clustering pattern coupled with genetic diversity analysis gives a scope for developing diverse genetic base, D2 analysis along with Principal component analysis were performed which identified diverse genotypes like K116, K429, HPR-2336 and VL DHAN with high cluster means for grain yield per plant (19.37 g) that might be utilized as good combiners in future breeding programmes. © 2022, The Author(s) under exclusive licence to Society for Plant Research.