Genetic Variability Assessment in Selected Genotypes of Radish (Raphanus sativus L) Using Morphological Markers

Abstract

A field experiment was conducted at the farm of the Department of Genetics and Plant Breeding, Bangabandhu Sheikh Mujibur Rahman Agricultural University, Gazipur, Bangladesh, using 21 parental genotype to evaluate their genetic diversity with regard to fifteen root yield related characters viz,. plant height (cm), average leaf length (cm), largest leaf length (cm), root length (cm), leaf sheath length (cm), leaf blade length (cm), largest leaf breadth (cm), no. of leaf/plant, total leaf wt per plant (gm), fresh leaf wt per plant (gm), plant weight (gm), root weight per plant (gm), root diameter (mm), dry weight of leaf (gm) and dry weight of root (gm). The genotypes were grouped into four 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 root weight per plant (gm) and root diameter (mm) 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 II and cluster III followed by II and IV indicating wide genetic divergence between the genotypes of these two clusters. The lowest inter-cluster distance was observed between clusters III and IV suggesting a close relationship among the genotypes of these two clusters. Thus, crossing between the genotypes of cluster II and III would produce high heterotic progeny and may produce new recombinants with desired traits. The differences between genotypic coefficient of variation (GCV) and the phenotypic coefficient of variation (PCV) were low for all the characters indicated a low environmental influence over genetic factors on the characters. The GCV and PCV were generally high for Fresh leaf wt per plant (gm) and plant weight (gm).High heritability coupled with high genetic advance was observed for leaf blade length (cm), fresh leaf wt per plant (gm) and plant weight (gm).