Vol. 9, Special Issue 10, Part I (2025)

Summer squash (Cucurbita pepo L), is a significant vegetable crop with significant nutritional, therapeutic and financial importance. Assessing the degree of genetic diversity and population structure among the available genotypes is crucial for successful breeding. Using forty different genotypes arranged in a randomized full block design, the current study was carried out at SKUAST-Kashmir during Kharif 2024. To evaluate genetic diversity and cluster the genotypes, data on morphological, yield and quality variables were examined using Ward's technique and Mahalanobis D2 statistics. Analysis of variance indicated the existence of extensive variability by showing substantial differences across all genotypes. Four clusters were formed from the genotypes using cluster analysis; Cluster II had the most genotypes (17) and the highest fruit yields per plant (4.52 kg) and per hectare (226.64 q). Early flowering and fruiting, a desired feature for creating hybrids that mature early, was displayed by Cluster I. With the highest levels of vitamin C (13.42 mg/100 g), total soluble solids (10.03 °Brix), and crude fiber (2.13%), Cluster III was notable for its quality qualities despite its smaller size. The greatest inter-cluster distance was found between Clusters I and II, indicating that crossings between these genotypes will result in more variety and high heterotic combinations. Breeding efficiency will be improved by choosing parents from genetically distant clusters, particularly those that combine high yield and superior quality features, according to the study. The findings offer a solid basis for creating summer squash cultivars that are early maturing, high yielding and nutritionally enhanced and suited to temperate climates.