Genetic divergence in onion (allium cep a l.) genotypes for seed yield and its component characters

Abstract

Abstract : Thirty one onion genotypes being maintained at Bangabandhu Sheikh Mujibur Rahman Agricultural University, Gazipur were evaluated for their genetic diversity with regard to seed yield and its components. The genotypes were grouped into five clusters, based on Mahalanobis D2 statistics. Geographical and genetic diversity were observed to be unrelated, as genotypes from diverse geographical regions were placed in the same cluster, while genotypes from the same centre were grouped into different clusters. Characters like plant height (cm), number of umbels per plant, 100- seed weight (g) and seed yield per plant (g) contributed considerably to the total divergence. The intra-cluster distances were smaller than inter-cluster distances which indicates that genotypes within in the cluster were less diverse. Maximum inter-cluster distance was observed between clusters I and cluster II, followed by II and V indicating wide genetic divergence between the genotypes of these clusters. The lowest inter-cluster distance was observed between clusters I and V suggesting a close relationship among the genotypes of these two clusters. Thus, crossing between the genotypes of cluster I and II would produce high heterotic progeny and may produce new recombinants with desired traits.