Comparative yield performance of Bollgard and Bollgard II cotton under irrigated situation

Bt cotton genotypes under investigation (BG, BG-II) responded similarly for egg population of Helicoverpa armigera (Hübner) with no differential susceptibility. With respect to larval incidence and damage due to H. armigera, Earias vittella (Fabricius), Spodoptera litura (Fabricius) and Pectinophora gossypiella (Saunders) all the second generation Bt cotton genotypes performed better over Bollgard cotton under unprotected condition. Interspecific Bt cotton genotypes were found superior with respect to good opened bolls per plant, bad opened bolls per plant, total number of harvested bolls per plant, seed cotton yield and benefit cost ratio over intraspecific Bt cotton genotypes. Among interspecific Bt cotton genotypes MRC-7918 Bt (BG-II) proved better than the MRC-6918 Bt (BG-I) and with in intraspecific Bt cotton genotypes NCS-145 Bt (BG-I) proved better in all yield contributing factors and benefit cost ratio than NCS-145 Bt (BG-II).