Molecular distinction amongst varieties of mulberry using RAPD and DAMD profiles

Mulberry trees are the most important host for rearing mulberry silkworms in sericulture. Improved varieties of mulberry tree have been developed through traditional breeding procedures. Not much work, however, has been carried out on the molecular characterization of these varieties. Random Amplified Polymorphic DNA (RAPD) and Directed Amplification of Minisatellite DNA (DAMD) methods based on Polymerase Chain Reaction are important tools to analyze genetic diversity of mulberries. These have been used to determine variation amongst nine varieties of Morus spp. maintained at Banthra Research Station of National Botanical Research Institute, Lucknow.

The varieties were analyzed using 23 arbitrary sequence decamer primers for RAPD, and 3 minisatellite core sequence primers for DAMD reactions. The RAPD and DAMD band data, (a total of 200 bands), were used to determine the pair wise distances according to Jaccard's algorithm. From these distance values Neighbour Joining (NJ) analyses were carried out separately for the RAPD and the DAMD data. The triploid varieties were found to be most similar to each other using RAPD analysis, while the varieties S13 and S34 were more similar using DAMD analysis. Nearly 85% of the RAPD bands and 91% of the DAMD bands were polymorphic across the nine varieties.

The mulberry varieties could be distinguished by their RAPD and DAMD profiles. As many as five RAPD primers and one DAMD primer generated profiles that can together differentiate all the nine varieties in terms of unique bands.