Performance of Bt transgenic cotton genotypes in northern transitional zone of Karnataka1

A field experiment was conducted at Main Agricultural Research Station, University of Agricultural Sciences, Dharwad for two consecutive years (2003–04 and 2004–05) to assess the performance of Bt transgenic genotypes. The experiment was laid out in randomized complete block design with eight cotton genotypes (MECH-12 Bt, MECH-162 Bt, MECH-184 Bt, RCH-2 Bt, RCH-20 Bt, RCH-144 Bt, DHH-11 and Sahara) as treatments with three replications. Among the different Bt and non-Bt cotton genotypes, RCH-20 Bt recorded significantly higher seed cotton yield than RCH-144 Bt, MECH-162 Bt, DHH-11 and Sahana. The extent of increase in RCH-20 Bt was 8.36. 13.17, 26.18, 30.79, 48.49, 92.07 and 150.67 per cent over MECH-184 Bt, RCH-2 Bt, MECH-12 Bt, RCH-144 Bt, MECH-162 Bt, DHH-11 and Sahana, respectively. The yield parameters of RCH-20 Bt were superior to other genotypes. The egg load did not differ significantly among the different Bt and non-Bt genotypes. Whereas significantly lower Hellcoverpa larval load was recorded on RCH-20 Bt (0.06/plant) and was on par with MECH-184 Bt (0.07/plant), RCH-2 Bt (0.15/plant), RCH-144 Bt (0.18/plant), MECH-12 Bt (0.24/plant) and MECH-162 Bt (0.28/plant). Significantly higher larval load was noticed on DHH-11 (0.89/plant) and was on par with Sahana (0.67/plant).