Genetic variability, heritability and multivariate analysis of 89 rice (Oryza sativa L.) genotypes under sodic soil
Sodic soils, characterised by excessive sodium ion accumulation, significantly hamper rice productivity in major cultivation zones. This study aimed to assess genetic variability, divergence and inheritance parameters among 89 rice (Oryza sativa L.) genotypes under sodic soil conditions to identify promising lines donor lines for breeding programs. The experiment was conducted during kharif 2021 at a single site (ANDUAT, Ayodhya, Uttar Pradesh) using an augmented block design (ABD) with 5 blocks and 13 quantitative traits were recorded. Principal component analysis (PCA) and Mahalanobis D² cluster analysis used to determine genetic divergence and trait contributions to variability. Significant differences were observed among genotypes for all traits, indicating substantial genetic variability. Eight clusters were formed among which cluster II comprised the highest number of genotypes was 16, while Cluster III exhibited the highest inter-cluster distance (3.15), revealing its potential for identifying genetically diverse parental lines. The first 5 principal components showed 62.06 % of the total phenotypic variance, with PC1 (19.36 %) and PC2 (13.18 %) contributing most to total variation. Key traits contributing to this variation included grain yield per plant (GYP), biological yield (BY), plant height (PH), flag leaf area (FLA) and spikelet fertility (SF). The PC1 was primarily associated with the GYP (-0.5721) and biological yield per plant (-0.5187), whereas PC2 was influenced mainly by spikelet fertility (0.4130) and days to maturity (0.4241). Broad-sense heritability was ranged from 3.20 % to 96.63 % across different traits. Biological yield per plant exhibited the highest heritability (96.63 %), followed by grain yield and flag leaf area, which also showed high heritability coupled with high genetic advance as percent of mean, indicating predominant additive gene action and high selection efficiency. Promising genotypes such as WHM-1024 (25.96 g) and WHM-1016 (25.63 g) demonstrated high grain yield, whereas TCN-2080 (84.00), TCN-2066 (90.00) RAU-3074 (90.00), and NDR-2065 (119.00) showed early flowering and maturity. The integration of multivariate and genetic parameter analyses provides a robust basis for selection of genetically diverse parents and key yield-contributing traits for sodicity-tolerant rice breeding programs.