Journal of Entomological Research

Effectiveness of transgenic Bacillus thuringiensis Berliner (Bt) cotton varieties, NCEH 6 (Fusion Bt: cry1Ac + cry1Ab), JK 1947 (cry1Ac Modified), NCS 913 (cry1Ac) and rCH 134 (cry1Ac) on mortality of Helicoverpa armigera was evaluated using commercially available #AP003 CrBs, Envirologix, UsA to measure and profile the expression level of Cry proteins in these Bt cotton hybrids. Mortality of H. armigera was more on dual toxin as compare to modified cry1Ac and alone cry1Ac genotypes. the fusion of cry1Ab to transgenic cotton containing cry1Ac significantly increased efficacy against H. armigera. similarly, the amount of Cry1Ac protein was the maximum in dual cotton genotypes through out the season. Maximum mortality was observed on leaves, squares of hybrid NCEH 6 at 90 days old plant followed by 120 and 150 days old plants. However in case of bolls maximum mortality was observed on 120 days old plant. A significant positive correlation between mortality and Cry1Ac protein in leaves (0.962), squares (0.974) and bolls (0.972) was observed.