Assessment of Genetic Variability and Selection of Superior Genotypes for Future Rice Breeding Programs: A Comprehensive Study on Yield-Related Traits and Multi-Trait GenotypeIdeotypes Distance Index (MGIDI)

Rice, a vital staple for over half the global population, provides one-fifth of calorie consumption. Our study aimed to assess genetic variability among 187 rice genotypes and identify superior ones using the Multi-trait genotype-ideotypes distance index (MGIDI) for future breeding programs. Evaluations took place from November 2020 to June 2021 at the Bangladesh Rice Research Institute, Barishal using an Augmented block design. ANOVA revealed significant differences between genotypes in all traits, indicating considerable variability. Heritability and genetic advance suggested the influence of additive gene action, allowing direct selection for improvement. Notably, the highest variability was observed in filled grain number per panicle (34.63% PCV, 28.46% GCV) and panicle number per hill (18.29% PCV, 15.38% GCV). Grain yield exhibited positive correlations with plant height, flowering time, growth duration, filled grain per panicle, fertility, and thousand-grain weight. Principal component analysis revealed that the first five components contributed over 80% of the total variation, with fertility, tiller number per hill, maturity time, panicle number, and flowering time having the most significant contributions. Genotype NGR 1170-1 exhibited the highest contribution to overall diversity, followed by NGR 783-1, NGR 756-1, NGR126-1, NGR 821-1, NGR 338-1, NGR 914-1, NGR 1087-1, NGR 817-1, and NGR 988-1. The genotypes with the greatest quality divergence were NGR 554-1, NGR 769-1, NGR 325-1, NGR 1369-1, NGR 336-1, NGR 462-1, NGR 710-1, BRRI dhan92, NGR 1165-1, and NGR 7721. Hierarchical cluster analysis grouped the 187 genotypes into three clusters, with Cluster I containing the highest number of genotypes (105), followed by Cluster III (56) and Cluster II (26). Employing the MGIDI index with a 15% selection intensity, we identified 28 superior genotypes (G3, G10, G17, G66, G98, G110, G113, G120, G124, G125, G127, G131, G135, G136, G137, G138, G141, G146, G154, G157, G159, G162, G165, G169, G172, G184, G186, G187, and G187). These selected genotypes require further testing for variety release and future hybridization programs. Overall, our findings indicate sufficient variability for developing improved rice varieties, with the studied traits serving as valuable selection criteria. Keywords: Principal Component Analysis (PCA), Cluster Analysis, Heritability, Genetic Advance, Rice.