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Selection for resistance to the Cry3Bb1 protein in a genetically diverse population of non-diapausing Western Corn Rootworm
Citation:
French, B., M. BAGLEY, C. Nielson, AND U. STOLZ. Selection for resistance to the Cry3Bb1 protein in a genetically diverse population of non-diapausing Western Corn Rootworm. Presented at Entomological Society of America, San Diego, CA, December 06 - 08, 2007.
Impact/Purpose:
Specific objectives are to produce a genetic map of the WCR genome and identify the number, distribution and function of genes contributing to Cry3Bb1 resistance, and to evaluate the trajectory of resistance evolution in WCR under controlled conditions and to assess any correlated responses in fitness-related traits. Here we focus on the trajectory of resistance evolution in a genetically diverse population of non-diapausing WCR.
Description:
The western corn rootworm (WCR, Diabrotica virgifera virgifera) is a serious economic pest of corn, and historically has evolved resistance to many chemical insecticides when used to manage their populations. In 2003 the U.S. Environmental Protection Agency (EPA) approved for commercial use transgenic corn against WCR and other corn pest Diabrotica. This transgenic corn produces a crystalline protein derived from the common soil bacterium, Bacillus thuringiensis, that when ingested kills the corn rootworms. However, given the history of resistance evolution by WCR to insecticides, the EPA mandated that farmers using this transgenic corn plant 20% of their corn acreage to a non-transgenic variety that is either adjacent to or within the transgenic field. This 20% refuge is intended to delay resistance evolution in WCR and other pest Diabrotica by ensuring that Cry3Bb1 resistance does not evolve in WCR to economically damaging levels, as this will negate any positive benefits of the biotechnology. The 20% refuge as a resistance management plan is based on models of resistance evolution. These models utilize the best available information on WCR biology and Cry3Bb1 toxicity. However, critical information on the genetic basis of resistance to Cry3Bb1 in WCR is needed in order to improve the accuracy of these models. Data generated from this research will provide fundamental genetic information for WCR, allowing better parameterization of these models and more reliable model results.