Genetic diversity in round gourd [Praecitrullus fistulosus (Stocks) Pangalo] accessions introduced from USDA for various qualitative and quantitative traits

摘要

Assessment of genetic variability in available germplasm, identification of genetically diverse genotypes for developing F, hybrids, and to generate further variability are prerequisites for any crop improvement program. Here, 15 accessions, including5 released varieties, of round gourd were used to estimate genetic variability for 6 qualitative and 9 quantitative traits. Most accessions had round, shining, and light green fruits. Degree of secondary lobing of leaf blade was the most diverse qualitative trait. The 15 accessions were grouped into four clusters, of which two were solitary. Cluster II had eight accessions, followed by cluster I with five accessions. The grouping pattern revealed that geographical diversity might or might not be correlated with genetic diversity. The principal component analysis indicated that the first three components accounted for 85.73% of the total variation, with principal component 1 (PC1) accounting for 37.21%, PC2 for 36.35%, and PC3 for 12.16% of the total variation. Of nine traits studied, early yield contributed 55.24% toward genetic divergence, followed by vine length (21.90%) and number of primary branches per vine (14.29%). The highest broad-sense heritabil-ity (95.60%) and genetic advance (123.06%) were recorded by early yield followed by vine length and number of primary branches. Crossing between genotypes belonging to clusters I, III, and IV with those belonging to cluster II, and between clusters I and III has been advocated to develop F, hybrids, and to search for transgressive segregants with new combinations of genes to bring necessary improvement in the crop.