Molecular Marker Analysis on Genetic Variation in Domesticated Silkworm

Among the primers used for ISSR analyses, the primer ISSR2 and ISSR3 generated highest number of fragments. All the primers exhibited 100 per cent polymorphism across 30 silkworm races analysed. The similarity coefficients ranged from 0.33 to 1.00. Of the pairwise combinations, NB7 and Kollegal Jawan showed the lowest similarity index (0.33), whereas the highest similarity index was recorded between C.nichi and P4D3 (1.00), followed by CSR3 and CSR2xCSR4 (0.98). The mean similarity index was 0.68. There was distinct grouping between the multivoltine and bivoltine races when grouped with marker generated by ISSR PCR. The 2D diagram of the PCA analysis of the markers generated by the different ISSR primers helped to visualize the two major clusters which included the multivoltines and bivoltines separately. The grouping of bivoltines in the PCA analysis clearly showed higher similarity among bivoltines as compared to the multivoltines. Superiority over the parents (Pure Mysore and CSR2) with regard to biological parameters was found with F₁.