| Abstrakt: |
Background: During field surveillance in Gujarat, India, in 2009, scientists found that pink bollworm was surviving in the first generation of Bollgard cotton, which contains a single protein. This survival was observed in four districts of Gujarat. From 2012 to 2014, surveys revealed that pink bollworm larvae had higher survival rates on Bollgard II cotton in Amreli and Bhavnagar districts. In 2016, a pink bollworm outbreak in Maharashtra caused significant losses in cotton production, leading to damage, yield losses, and increased management costs in several regions. The objective of the present study was to determine the reaction of Pectinophora gossypiellato Cry1Ac and Cry2Ab toxins. Results: Neonates of P. gossypiellacollected from six distinct locations in Vidarbha were subjected to seven different concentrations of Cry1Ac. The highest LC50value was recorded in the population collection of Yavatmal (1.362 μg/ml diet) but the lowest LC50value of 0.600 μg/ml diet in Buldana population. The highest MIC50value was recorded in the population collected from Yavatmal (0.743 μg/ml diet) and the lowest MIC50value of 0.413 μg/ml diet in the Buldana population (0.431 μg/ml diet). The highest IC50value was recorded in the population collected from Yavatmal (0.303 μg/ml diet) but the lowest IC50value of 0.127 μg/ml diet in the Buldana population. Neonates of P. gossypiellacollected from six different locations in Vidarbha were exposed to seven different concentrations (9.0, 3.0, 1.0, 0.333, 0.111, 0.037 and 0.012 for Cry1Ac and 27.0, 9.0, 3.0, 1.0, 0.333, 0.111 and 0.037 μg/ml for Cry2Ab) which revealed that the Yavatmal population had the highest LC50value of 94.294 μg/ml diet and the lowest LC50value was recorded in the Amravati population (42.144 μg/ml diet). The highest MIC50value of 27.258 μg/ml diet was recorded in Buldana population, but the lowest MIC50value was recorded in the Amravati population (12.881 μg/ml diet). The highest IC50value of 3.209 μg/ml diet was observed in Yavatmal population, and the lowest one was recorded in the Amravati population (1.574 μg/ml diet). Conclusions: According to the LC50values, all of the P. gossypiellapopulations in Vidarbha were extremely insensitive and had field-evolved resistance to the Btproteins found in the transgenic cotton varieties of Bollgard II. |
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