Analysis of Genetic Diversity in Rajmah Genotypes from the Barak Valley Zone of Assam, India

A comprehensive examination of genetic diversity is essential for informed decisions in crossing programs. This study focused on 14 diverse germplasm lines of bush/pole type Rajmah (Phaseolus vulgaris), conducted at the Zonal Research Station, Assam Agricultural University, during the rabi seasons of 2020–21 and 2021–22.

The experiment was conducted utilizing a randomized block design (RBD) and comprised three replications The aim was to assess genetic diversity using ANOVA, genetic parameters, Pearson correlation, D² analysis and principal component analysis (PCA).

The results revealed significant differences among the genotypes for all traits measured. The phenotypic coefficient of variation (PCV) was greater than the genotypic coefficient of variation (GCV) across all traits. Key traits like plant height, seed weight per plant and the number of seeds per plant displayed high GCV and heritability, suggesting these should be prioritized in breeding programs. Correlation analysis indicated that seed yield positively correlates with the number of pods per plant, seeds per plant and seed weight, which are critical for selecting high-yield Rajmah genotypes. Cluster analysis categorized the genotypes into six clusters, with Cluster I being the largest. The largest inter-cluster distance was between Clusters IV and VI, indicating potential for heterosis. Principal component analysis highlighted important yield contributors, including days to 50% flowering and average pod weight. Overall, all genotypes exhibited sufficient genetic variability, with genotypes KMJ-R-2019-02, KMJ-R-2019-17 and KMJ- R-2017-08 performing better than the check genotypes in yield-related traits, making them valuable for breeding programs.