Physiological responses in genetically modified cotton and its isohybrid attacked by Aphis gossypii Glover (Hemiptera: Aphididae)

In Brazil, genetically modified cotton is increasing in most cultivated areas to manage insects, mainly Lepidoptera. Pests associated with cotton crops are diverse. Aphis gossypii Glover, 1877 (Hemiptera: Aphididae), one of the most important cotton pests, sucks photoassimilates from the phloem sap causing mold growth and damage to plant tissues. The interactions between Bt plants and non-target organisms and the impact of A. gossypii damage on these plants need further studies. Therefore, the objective was to evaluate the physiological stress caused by A. gossypii on Bt cotton and its isohybrid (same genetic background but not transgenic). The Bt cotton (Cotton Event 281-24-236/3006-210-23) and the isohybrid of this plant were planted in pots in a completely randomized design, as the treatments, with 30 replications in a greenhouse. The chlorophyll fluorescence parameters of the plants were evaluated by using a fluorometer. Regression models were adjusted for Bt cotton and the isohybrid, and the differences between treatments were evaluated through the model identity test. The photosynthetic parameters of Bt cotton and its isohybrid infested by this insect were similar.