Shubham Kumar, Varun Bansal and Shivani
Abstract
Understanding the magnitude and direction of association among yield-contributing traits is central to effective breeding in rice (Oryza sativa L.). In the present investigation, twenty-six diverse rice genotypes were evaluated under a Randomized Block Design with three replications during the Kharif season. Phenotypic (rp) and genotypic (rg) correlation coefficients were estimated between ten agronomic traits and grain yield per plant, and a Heritability-Weighted Genotypic Selection Index (GSI) was constructed by combining broad-sense heritability, genotypic coefficient of variation, and genotypic correlation with grain yield into a unified scoring framework. Results revealed that grains per panicle (rp = 0.862; rg = 0.869), spikelets per panicle (rp = 0.809; rg = 0.815), biological yield per plant (rp = 0.771; rg = 0.785), harvest index (rp = 0.725; rg = 0.739) and test weight (rp = 0.614; rg = 0.625) exhibited highly significant positive phenotypic and genotypic associations with grain yield, identifying these as primary selection criteria. Genotypic correlations were consistently higher in magnitude than their phenotypic counterparts across most trait pairs, indicating that genetic rather than environmental forces largely govern these associations. The constructed GSI effectively differentiated the genotype panel into three performance categories: High (GSI > 0.50), Moderate (0.00â0.50), and Low (GSI < 0.00). NDR-359, IR-64, Amker, KUHUSOI-RI-SAREKU, RRHZ- 2, IR 92960-75-1-3, Pusa Basmati-1, and Sarjoo-52 emerged as superior performers with consistently high GSI scores, making them priority candidates for direct selection or deployment as parents in hybridization programmes. The present study demonstrates that correlation-guided, heritability-weighted selection indices offer a transparent, reproducible, and statistically rigorous method for multi-trait genotype evaluation in rice breeding.