Insect resistance and risk assessment studies in advance lines of Bt cotton harboring Cry1Ac and Cry2A genes.

摘要

Advance generations of different transgenic lines of locally approved cotton cultivar CIM-482 expressing two insecticidal genes (Cry1Ac and Cry2A) were confirmed for the integration and expression of insectidal genes, evaluated for the resistance against cotton boll worms especially american boll worm (Heliothis armerigera) under field condition for three consecutive years. Homozygous lines showing high insect resistance, morphological and agronomic characteristics were selected, risk assessment studies of these transgenic lines were also undertaken. Laboratory biotoxicity assays were performed to calculate the mortality %age of Heliothis larvae as a result of expression of insecticidal genes. Most of the transgenic lines showed up to 70-100% resistance against targeted insect pests. After artificial infestation of targeted insects, transgenic lines showed significant resistance levels. Data were recorded in terms of boll damage percentage. Morphological and yield data analysis were recorded. All the characters were stably inherited in advance generations. Experiments conducted to evaluated potential risk of transgenic lines on non target insects and soil organisms showed that these lines have no significant effect on non target insects (insects belonging to orders other than Lepidoptera). No any evidence of transgene flow was found from crop to soil organisms.