Genetic diversity and performance evaluation of long-fruited snake gourd genotypes (Trichosanthes anguina L.) under sodic soil conditions in Tamil Nadu, India

Snake gourd (Trichosanthes anguina L.) is a cucurbitaceous vegetable of economic and nutritional significance, widely cultivated in tropical and subtropical regions. This study evaluated 30 genotypes under sodic soil conditions at Horticultural College and Research Institute for Women, Tiruchirappalli, over 2 seasons (kharif and rabi, 2024–2025) to assess variability for growth, yield, physiological and quality traits. Analysis of variance revealed significant differences among genotypes for all seventeen traits at p≤0.01, indicating the presence of considerable genetic variability. Phenotypic coefficients of variation (PCV) were higher than genotypic coefficients of variation (GCV) for most traits, suggesting that environmental factors contributed to the observed phenotypic expression. However, the relatively small differences between PCV and GCV for several traits indicate that environmental influence was present but moderate and that a considerable proportion of the variability was genetically controlled. High heritability coupled with high genetic advance was observed for fruit yield per plant, single fruit weight, fruit length and number of seeds per fruit, reflecting predominant additive gene action and the potential for improvement through selection. Genotypic correlation analysis showed that fruit yield was positively associated with vine length, number of fruits per plant, single fruit weight, proline content and vitamin C, whereas days to flowering and Na+/K+ ratio were negatively correlated. Principal component analysis (PCA) identified 3 principal components with eigenvalues >1. The 17 traits to 3 major components explaining 83.6 % of the total variability, with PC1 alone contributing 70.7 %, highlighting yield and quality traits as major discriminators among genotypes. Mahalanobis D² cluster analysis grouped genotypes into four clusters, each exhibiting superiority for specific traits. The highest inter-cluster distances were observed between Cluster I & IV and Cluster I & III, indicating substantial genetic divergence, suggesting these clusters as potential parents for heterotic breeding. Genotypes S06, S21, S27, S12, S09, S18 and S16 were identified as superior performers and represent promising parental lines valuable genetic resources for breeding high-yielding, quality-enhanced and sodicity-tolerant snake gourd cultivars.