Vol. 12, Issue 3 (2023)

Author(s):
Palvi Sharma, Arti Sharma, Kamlesh Bali and RK Gupta

Abstract:
Growth and development of the silkworm, Bombyx mori L. larvae are strongly influenced by environmental changes such as temperature, humidity etc. The high temperature leads to the poor performance of the bivoltine breeds resulting in poor cocoon characters. The experiment was laid out in completely randomised design with three replications. The larvae of 5^th instar were exposed to three temperature regimes (25±1 ⁰C, 30±1 ⁰C and 35±1 ⁰C). Significant variations in cocoon weight, shell weight and shell ratio were noticed. However, the maximum mean values of cocoon weight (1.80g), shell weight (0.38g) and shell ratio (21.10%) was observed at 25±1 ⁰C whereas the lowest mean values of cocoon weight (0.83g), shell weight (0.06g) and shell ratio (7.21%) was recorded at 35±1 ⁰C. Among the twelve breeds studied, breeds U-3 and U-4 recorded significant results in terms of cocoon characters at high temperatures indicating their capacity for thermo tolerance and thus these breeds can be reared as promising breeds for commercial exploitation under high temperature.