Genetic Divergence Studies in Plus Trees of Pongamia pinnata (Karanj)

Thirty plus trees of Pongamia pinnata (Karanj) were selected and their progeny was tested in the nursery. Substantial variability was recorded in seed morphological and biochemical traits of selected plus trees. Significant variation was observed in progenies for germination percentage, shoot and ischolar_main length, collar diameter and seedling biomass. Heritability and genetic advance as per cent of mean were also moderate to high for 100 seed weight, oil and protein contents, collar diameter, ischolar_main and shoot length indicating the effectiveness in selection for these characters for developing productive trees. Genetic diversity among these plus trees for important seed and seedling traits using Mahalanobis' D² analysis showed grouping of these trees into eight clusters. The clustering pattern indicated that geographical diversity did not have one to one relationship with genetic diversity. Cluster VI was the largest and consisted of seven trees followed by Clusters I and IV with six trees each. Cluster III had only one tree. Intra cluster D² values revealed that cluster VIII was most diverse (5.423) followed by cluster IV (4.131), V (4.081), I (3.915) and cluster II (3.831). Maximum inter-cluster distance was observed between clusters III and VIII (9.922) followed by between cluster V and VIII (7.085), cluster IV and VIII (6.738) and cluster III and V (6.722)). On the basis of high cluster mean and wide genetic distance, the superior plus trees of cluster III (PT- 19) and cluster V (PT- 8, PT-18. PT-24) may be used as potential parents for P. pinnata tree improvement programme.