Genetic divergence in maize (Zea mays L.)

The genetic divergence among 50 genotypes of maize was estimated by using Mahalanobis D² statistic for 11 characters. The genotypes were grouped into eight clusters. Cluster III was the largest with 20 genotypes followed by cluster I (12 genotypes), cluster II (8 genotypes), cluster IV (4 genotypes), cluster VIII (3 genotypes) and cluster V, VI and VII containing one genotype each. The inter-cluster distances were larger than the intra-cluster distances suggesting wider genetic diversity among the genotypes of different groups. The highest inter-cluster distance was observed between clusters II and VI followed by clusters II and V, clusters II and VII, clusters I and VI, clusters I and VII and clusters IV and VI suggesting more variability in genetic make up of the genotypes included in these clusters. The highest intra-cluster distance was noticed in cluster VIII and lowest in clusters V, VI and VII. The clusters V, VI and VII contained only one genotype and hence, its intra-cluster distance was zero. The cluster VII had highest mean value for grain yield per plant followed by clusters VI and V. Based on the inter-cluster distances genotypes present in clusters I, II, IV, V, VI and VII can be used as parents for hybridization programme to develop potential hybrids.