Genetic divergence in soybean [Glycine max (L.) Merrill.]

Divergence analysis among sixty one soybean (Glycine max (L.) Merrill.) genotypes collected from different geographic sources was carried out using Mahalanobis's D2 statistic. The genotypes were grouped into eleven different clusters. The maximum inter-cluster distance was found between clusters II and IX (D=150.36) followed by that between clusters II and XI (D=129.64), II and VIII (D=124.78), X and XI (D=117.46), IV and IX (D=101.49) and IV and XI (D=100.02) indicated that these groups of genotypes were highly divergent from each other. The genotypes in above clusters revealed substantial difference in the means for important yield contributing characters suggesting that the genotypes belonging to cluster II (J659), cluster IX (PK-986), cluster XI (PK-926) and cluster VIII (NRC-2-R) should be selected as parents in hybridization programme for improvement in soybean. The most important trait causing maximum genetic divergence was the number of cluster per plant (33.61) followed by plant height (23.28) and oil content (10.27). These three characters contributed 67.16% of the total diversity in the material studied. Hence, it is advisable to select divergent parents based on these three characters and attempt crossing between them so as to achieve a broad spectrum of favourable genetic variability for yield improvement in soybean.