Location: Plant Genetics Research
2013 Annual Report
This work is related to sub-objective 1.A of the parent project: “Develop colonies with resistance to Cry34/35Ab1 and test the effectiveness of different refuge types to delay resistance” and contributes to Component 2A of the National Program 304 Action Plan by developing increased knowledge of the biology, ecology, behavior, genetics of pests, and plant traits conferring pest resistance.
Transgenic corn has been highly effective in rootworm management until recently. In fourteen attempts, using all four proteins that are targeted for control of corn rootworm, laboratory selection efforts found resistance to the targeted proteins in just a few generations. Given these laboratory results, it is not surprising that insect resistance has developed over time in the field to the transgenic product planted over the largest land area. It is critical to stay ahead of the curve. ARS scientists in Columbia, MO conducted research aimed at understanding the nature of resistance, cross resistance, and whether or not refuges work in delaying resistance for low-dose rootworm products. This work will serve as an alert to the U.S. corn industry of potential problems. Our cross resistance work will help growers and industry to understand the transgenic options for management.
In both Missouri and Iowa, a non-diapausing strain of western corn rootworm was divided into four strains:.
Simulation studies to optimize the strategy for genome scanning for rotation-resistance in corn rootworm showed that additional genetic markers are needed to supplement the currently available markers to achieve the desired genetic power to detect selection. Specifically, the number of genetic markers should be increased 4- to 10-fold. During the past year, several projects including genome and transcriptome sequencing have generated data that will be mined for additional markers. High-throughput genotyping with a commercially available assay is pending. Consultation with a genotyping service provider indicated that a second type of assay will allow a greater number of marker loci to be analyzed per unit cost. Together, these developments will result in a much richer data set to be generated than was previously anticipated.