Role of molecular markers in mulberry with future relevance

Mulberry leaf (Morus alba L.) is an exclusive food source of mulberry silkworm (Bombyx mori L.) producing natural silks, that is the major raw material for the foreign exchange earning sericulture industry. Focused R & D in obtaining increased leaf yields coupled with good quality of mulberry leaf, through the development of variety/genotype could enable us to compete in international silk markets. The analysis of existing genetic diversity of mulberry varieties and their differentiation with unique banding pattern could be carried out using the molecular markers viz., Random amplified polymorphism DNA-RAPD and directed amplification of mini satellite DNA (DAMD) methods, which is of prime importance. The article lays emphasis on the use of DAMD to obtain a robust profiles for the range of diversity among four minisatellite core sequence primers for directed amplification of minisatellite DNA (DAMD), three simple sequence repeat (SSR) motifs as primers for inter simple sequence repeat (ISSR) and 20 arbitrary sequence decamer primers for random amplified polymorphic DNA (RAPD) reactions employed. A comparitive study of ISSRs and SSRs with respect to their informativeness and efficiency in determining the genetic diversity and relationships among mulberry genotypes, realized more than 75% polymorphism among the varieties, utilizing 17 random amplified polymorphic DNA (RAPD) and 11 inter-simple sequence repeat (ISSR) primers. PCR based DNA finger printing could be quite extensively in cross pollinating species like mulberry. The genetic engineering tools have paved way for introduction of desirable genes and promises to revolutionize sericulture Industry. Future relevance would be characterization of germplasm diversity, identification of the ideal markers in Molecular Assisted Selections (MAS), Map-based cloning and Allele mining or Ecotilling. The challenge is to identify and incorporate advantageous alleles in a breeding programme.