Adaptive responses and diversity pattern in watermelon

Abstract

Genetic variation and genetic divergence among 48 watermelon inbreds of diverse geographical sources was studied using Mahalanobis's D2 approach. The results indicated that high heritability coupled with high genetic advance were observed for yield/plot, number of nodes, days to female flowers appeared and number of fruits/plot. Selection based on yield and its attributes may be effective in watermelon breeding programme. Under D2 cononical analysis, all inbreds fell in 10 different clusters of different sizes. Further study revealed genetic divergence and geographic distribution were not necessarily related. The Fusarium wilt resistant inbreds fell in well-separated clusters. Such types of diverse inbreds will be helpful in producing transgressive segregants with resistant gene. Of the 13 characters, only yield/plot, days to female flowers appeared and TSS contributed 46.63% towards total divergence, whereas number of fruits/plot, number of branches/node at which female flowers appeared have contributed 26.35% towards total divergence. Further, it is suggested that selection pressure can be exercised in identifying inbreds possessing these attributes from well- separated clusters to formulate a sound watermelon breeding programme to develop improved varieties/hybrids possessing resistance Fusarium wilt.