Genetic Variability Studies in Mulberry Silkworm with ISSR Marker

摘要

In investigation was carried out to analyze the diversity in different silkworm races using Inter Simple Sequence Repeat (ISSR) molecular marker for the selection of diverse parents. Among the primers used for ISSR analyses, the primer ISSR2 and ISSR3generated 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 raceswhen 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 groupingof bivoltines in the PCA analysis clearly showed higher similarity among bivoltines as compared to the multivoltines. Since the combining ability of Pure Mysore was reported excellent with bivoltine races for hybridization and also of its high amylase activity, it was selected as donor parent for the F_1 cross. CSR2 was selected as the other parent because of its better quantity and quality parameters. Superiority over the parents with regard to biological parameters was found with F_1 (Pure Mysore x CSR2).