Genetic divergence analysis in rose (Rosa x hybrida) using morphological markers

In the present investigation 32 genotypes of rose (Rosa x hybrida) were evaluated to assess the nature and magnitude of genetic diversity. The genetic divergence of the genotypes was studied by using Mahalanobis D² analysis. According to D² values, the entire germplasm comprising of 32 genotypes was classified into seven distinct clusters. The larger clusters i.e. cluster I, II and V composed of seven genotypes while cluster III, IV, VI and VII have five, two, three and one genotypes respectively. The cluster means revealed the best cluster for various growth and flowering traits depending upon the aim of breeding, hence the potential lines can be selected from different clusters as parents in a hybridization programme. The divergence at inter and intra cluster level revealed the highest inter cluster distance between V and VII (D=7.863) whereas the lowest was found between II and VI (D=2.885). Cluster VII had the minimum intra cluster distance (D=0.250) while cluster III had the maximum intra cluster distance (D=2.889). The diversity observed within and between the clusters can be utilized in breeding of rose varieties/hybrids for desirable traits. Thus, genetic divergence can also be used as an indirect parameter in selecting parents to produce heterotic high yielding progenies.