The biochemical analysis of Aspartate aminotransferase and Succinate dehydrogenase in twelve bivoltine silkworm (Bombyx mori L.) genotypes viz. NB4D2, SH6, Meigitsu, CSR4, Sheiki II, Pampore-5, J122, J2M, 14M, JBEL, NJ3 and B38 was done using native-polyacrylamide gel electrophoresis. Considerable amount of polymorphism was shown by both aspartate aminotransferase and succinate dehydrogenase. In all five bands and six isozymic forms were recorded in both the isoenzyme fingerprints.the relative mobility, in case of aspartate aminotransferase, ranged from 0.31 to 0.73 and the intensity score ranged from 3 in B38 to 6 in NB4D2, SH6 and Meigitsu. In succinate dehydrogenase, the relative mobility ranged from 0.41 to 0.78 and the intensity score from 5 in J122, J2M, 14M, JBEL, NJ3 and B38 to 10 in NB4D2. Out of ten bands observed in the two isoenzyme systems, two were monomorphic and eight were polymorphic. Moreover, the isoenzymes showed an appreciable range of relative mobility and activity, thus, suggesting their use as a marker for silkworm characterization. Further, the isoenzymes were found significantly and positively associated with single cocoon weight, single shell weight, cocoon yield/10,000 larvae by number and cocoon yield/ 10,000 larvae by weight. Hence, the enzymes could be utilized in Marker Assisted Selection programmes in silkworm breeding.

Keywords: Aspartate aminotransferase, succinate dehydrogenase, characterization, silkworm