Genetic diversity in Indian snapmelon ('Cucumis melo' var. 'momordica') accessions revealed by ISSR markers

Snapmelon ('Cucumis melo' var. 'momordica') is native to India and many of its accessions have been used as source for disease and insect pest resistance, worldwide. Inter simple sequence repeat (ISSR) markers were used to evaluate intra-specific genetic diversity among twenty-two snapmelon accessions, variable for fruit cracking, peeling patterns, fruit shape, and flesh colour. Of the 32 ISSR markers tested, three produced monomorphic products, nine markers failed to amplify, and rest of the 20 markers produced 127 amplification products, of which 74 (58.38%) were polymorphic. Although the accessions varied greatly in terms of fruit traits, the pair-wise Jaccord's similarity coefficient ranged from 0.59 to 0.88, revealing a narrow diversity in the studied samples owing to dominant nature of the ISSR markers. The dendrogram prepared through unweighted pair group method with arithmetic mean (UPGMA) distinguished two main clusters, cluster I consisting of 8 accessions, while cluster II contained 14 accessions. UPGMA clustering was also supported by principal components analysis (PCA). The first three PCs contributed 21.1, 18.9, and 8.7% of the variation, respectively. The first three PCs contributed for 48.7% variation in the studied accessions. This study could provide useful information for Indian snapmelon germplasm management activities, leading to development of a core collection for use in breeding and conservation programs.