Evaluation of New Bivoltine Silk Worm Double Hybrids Tolerant to High Temperature and Muscardine Disease in Eastern Dry zone of Karnataka

Field evaluation of double hybrids of high temperature and muscardine disease tolerant silkworm breeds viz., (B1× B2) × FC1, (B1 x B4) x FC1 and FC2 x (B6 x B8) was carried out in fifteen farmers field, covering Tumakuru and Chikkaballapura districts. The statistical analysis of data was done through Completely Randomised Design with 15 replications of each double hybrid and its control. The results have shown that (B1 x B4) x FC1 double hybrid was superior for ten out of thirteen traits viz. fecundity (587.86 eggs/ dfl), hatching (98.37 %), dead eggs (1.39 %), fifth instar larval weight (47.23 %), effective rate of rearing (97.27 %), cocoon yield by number (8813.43/ 10,000 larvae), cocoon yield by weight (19.77/ 10,000 larvae), single cocoon weight (2.35 g), shell weight (0.46 g) and shell ratio (21.70 %), while (B1x B2) x FC1 for four traits viz. hatching, dead eggs and total larval duration and cocoon yield by weight compared to control commercial double hybrid FC2 × FC1, marking their dual tolerance advantageous to sericulture industry.