Abstract

                                A study was undertaken to ascertain the variability in digestive amylase activity in different mulberry silkworm races. PA12 recorded the highest larval and cocoon weight (1.52 g and 0.68 g) in a pool of multivoltines tested and CSR2 recorded the highest (3.08 g and 2.49 g) among bivoltines tested. Among multivoltines, Nistari (1722.5 μg) and CB5 (1648.8 μg) recorded higher amylase activity and Tamil Nadu White recorded the least. Among bivoltines, the amylase activity was significantly higher in PAM101 (184.03μg) and NB4D2 (180.42μg). CSR19, CC1, NB7 and CSR18 were on par and showed low digestive amylase activity. Amylase activity in digestive juice was about 10 to 15 fold higher in multivoltines than bivoltines. Positive significant correlation (P=0.01) was recorded between digestive amylase activity and effective rate of rearing (0.812). Negative correlation was recorded between amylase activity, and biological and yield related traits of silkworm, Bombyx mori L.

Key words : Digestive amylase, Bombyx mori, multivoltine, bivoltine, ERR.