Phenotypic Divergence in Mulberry (Morus spp.) Germplasm Collections

Abstract

To improve mulberry foliage productivity, identification of suitable genes related to agronomically important traits in the available mulberry germplasm is essential. Twenty-five indigenous mulberry accessions representing five different species of Morus from seven diverse parts of the India were evaluated via principal component analysis (PCA) for 22 aboveground and underground morphometric traits and silkworm cocoon yield during 2002–2005 in the agro-climates of Berhampore, West Bengal, India. Significant differences among germplasm accessions were observed for all 22 traits and cocoon yield. Six principal components were identified, which explained >88% of total variation. Though 18 major variables were included in the principal components, longest shoot length, leaf area, intermodal distance, green and dry leaf weight, lamina length, lamina weight, root volume, and fresh and dry root weight were recognized as important variables that had direct effect on silkworm cocoon yield. These 10 variables appeared to be minimal traits for quick selection of mulberry progenies in breeding programs. Four distinct groups of accessions obtained after a cluster analysis were partly associated with their places of origin. In addition, the study highlighted a number of distinctive morphological characters in many of the accessions studied. The identified 10 minimum morphological descriptors were expected to be highly discriminating, thus they would help in quick characterization of mulberry germplasm. In addition, the distantly related germplasm were identified on the basis of cluster analysis and can be utilized in targeted mulberry improvement programs.