Genetic Divergence Studies in Sponge Gourd Genotypes

The presence of genetic diversity and genetic relationships among genotypes is a prerequisite and paramount important for successful sponge gourd breeding programme. Genetic divergence analysis, using Mahalanobis’s D statistic, grouped all the genotypes into six clusters. Cluster III had nine genotypes. The intra-cluster value was maximum in cluster VI and minimum in cluster II. The maximum inter cluster distance average D value was observed between cluster I and cluster IV indicating wide range of genetic diversity between these two clusters. Thus the genetically diverged genotypes could be used as parent in hybridization program for getting desirable segregants. The lowest inter cluster divergence was observed between cluster III and IV. Cluster I showed maximum desirable mean values for node number to anthesis of first pistillate flower, days to anthesis of first staminate flower, days to anthesis of first pistillate flower, days to first fruit harvest, number of fruits per plant and average fruit yield per plant (kg), while cluster VI revealed the highest mean vales for vine length (m), number of nodes per vine, number of primary branches per plant and fruit length (cm). Genotypes much in use of the above mentioned characters both in cluster I and VI would offer a good scope of improvement of the crop through rational selection for hybrid breeding program. The characters like average fruit yield per plant (41.27%) followed by number of fruits per plant and node number to anthesis first staminate flower each (11.38%) contributed maximum to genetic divergence and hence played a major role in improvement of sponge gourd.