Heat tolerant races of mulberry silkworm (Bombyx mori L.) in Nepal.

Thapa, R. B. and N. P. Ghimire. 2007. IAAS Research Advances Vol. 2. Institute of Agriculture and Animal Sciences, Rampur, Chitwan, Nepal. pp. 85-88.

Keywords: Silkworm strains, heat treatment, cocoon yield, market value

Fifth instar larvae of six different silkworm strains (J₁₂ x C₁₂; N₁₀₇ x  N_111; N₁₀₇ x N₁₁₂; N₁₀₈ x N₁₁₂; Shogetsu; and N₁₀₉ x N₁₁₂) reared on Kanva-2 variety with four replicates (50 larvae in each replication) were exposed to 40 ⁰C temperature for seven hrs in BOD chamber after 48 hrs of feeding in the fifth instar. The results confirmed the superiority of J₁₂ x C₁₂ strain for yield and price of cocoon with a difference of 18% and 17% with its nearest competitor, N₁₀₉ x N₁₁₂  (30.41 kg cocoon/box; Rs.4980.07/box) strain, respectively.