Identification of duplicate collections in the mulberry (Marus spp.) germplasm usingRAPD analysis

Abstract

Mulberry (Morus spp.) is the only source of food for the domesticated silkworm; Bombyx mar; L. Large numbers of mulberry germplasm have been conserved in the field gene banks, many of which are suspected to be duplicates. PCR based markers like RAPDs are neutral to environmental effects and can be efficiently utilized along with passport and morphological data for identification of duplicate collection in a gene bank. A close examination of passport and morphological data became a basis for identification of four suspected group of duplicates along with a closely related genotype of suspected duplicate Group I. Two sets of true duplicates (Mysore Local and V-I) were used as controls. A total of 31 random primers were used for PCR amplification, generating 357 markers of which, 228 (63.9%) were polymorphic. The DNA marker profiles of true duplicates were identical demonstrating the reliability of the technique. The closely related genotype RFS-135 was discriminated from the suspected duplicate Group I (Anantha and RFS-175) with a similarity of 94.4%. Group I, II, and IV were unambiguously confirmed duplicate sets and clustered at 100% similarity within the group. But the suspected duplicate collection in the Group III comprising of Kousen and Xuan-10 were discriminated by 12 primers and 16 markers. The result obtained from the study predicted a minimum requirement of 100 markers or 9 primers for detection of at least one difference for discrimination of closely related collections.