Diversity in rice genotypes under salt affected soil based on multivariate analysis

Diversity of forty four salt tolerant rice genotypes from different geographic regions were assessed using Mahalanobis D2 and principal component analysis (PCA). The D2 statistics grouped the genotypes into 12 distinct clusters. Consisting of 19 genotypes, Cluster I was the largest cluster, followed by Cluster II with nine genotypes. Meanwhile, Clusters III, IV, VI, VII, IX, and XII were mono-genotypic clusters. The maximum intercluster distance was exhibited between Cluster IX and X (144.91), followed by Clusters II and X (131.87), as well as clusters VII and X (126.27). The number of grains per panicle (42.71%), followed by the grain yield per plot (29.81%), was the major contributor to the total divergence. The PCA revealed that axes 1 and 2 accounted for 82.88% and 11.14% of the variance, respectively. The highest contributing variable was the number of grains per panicle in PC1 and the plant height in PC2. The genotypes from more than one place of origin were grouped in one cluster, whereas the genotypes from one state were grouped in more than one cluster. Both D2 and PCA revealed that the morphometric diversity was based on the pedigree and independent of geographical origin. Hybridization among the genotypes which had the maximum inter-cluster distances could produce heterotic combinations and wide variability in segregating generations for many beneficial traits