Evaluation of Second Generation Bt Cotton Hybrids against Sucking Pests and Bollworms

The field trials were conducted at Cotton Improvement Project, Mahatma Phule Krishi Vidyapeeth, Rahuri during 2009 to 2011 to monitor the population of sucking pests as well as boll damage in commercially released second generation Bt cotton hybrids. The results revealed that second generation transgenic Bt cotton does not afford any protection against sucking pests of cotton and their tolerance or resistance is mainly dependent on the morphological or genetic base. Jassids and thrips population were above ETL both in Bt as well as non-Bt cotton hybrid. More than eight Bt cotton hybrids recorded higher population of sucking pests than non Bt cotton hybrid. The Helicoverpa armigera damage to square and green bolls was completely nil in almost all Bt cotton hybrids whereas non Bt hybrid Phule 492 recorded higher damage of 15.23 per cent and 10.90 per cent, respectively. The incidence of Pectinophora gossypiella on green bolls was also nil in all Bt cotton hybrids; while it was 14.29 per cent in non Bt cotton. In addition, Bt cotton hybrids recorded lower open boll and locule damage compared to non Bt cotton hybrid. The seed cotton yield of Bt cotton hybrids were more than that of non Bt cotton hybrid. This revealed the superiority of second generation Bt cotton hybrids in terms of pest resistance and yield.