DUS-based characterization and diversity analysis of French bean (Phaseolus vulgaris L.) genotypes from the North-Western Himalaya

Abstract

French bean (Phaseolus vulgaris L.) is an important cool-season legume valued for its nutritional richness and contribution to food and nutritional security in the Himalayan region. The North-Western Himalaya harbours diverse indigenous landraces that remain largely unexplored for their distinctness and breeding potential. The present study aimed to characterize and evaluate 45 French bean genotypes collected from different locations of Uttarakhand using distinctness, uniformity and stability (DUS) descriptors and morpho-phenological traits. The experiment was conducted at the ICAR–Central Institute of Temperate Horticulture (CITH), Mukteshwar, under a randomized Block Design in year 2023-2025. Considerable morphological variability was observed among the genotypes for growth habit, leaf, flower and pod traits. Frequency distribution analysis revealed that 82.2% of the genotypes exhibited indeterminate growth habit, while only 13.3 and 4.5% showed determinate and semi-determinate growth habits, respectively. Medium green leaf colour (51.1%), medium leaflet size (55.6%) and persistent to intermediate leaf retention (88.9%) were predominant among the accessions. Principal component analysis generated 19 principal components, of which six components with eigenvalues greater than one explained 67.8% of the total variation. The first two principal components accounted for 31.25% of the variability, with PC1 and PC2 contributing 18.49 and 12.76%, respectively. Traits such as leaf shape, pod curvature, pod shape, pod colour and standard petal colour contributed most to genotype differentiation. The wide dispersion of genotypes in the PCA biplot confirmed substantial genetic diversity and distinctness among the evaluated landraces. The study underscores the importance of systematic characterization of indigenous French bean germplasm for its effective utilization in crop improvement programmes.