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ARS Home » Midwest Area » Ames, Iowa » Corn Insects and Crop Genetics Research » Research » Research Project #428999

Research Project: Risks from Field-Evolved Resistance to Bt Corn by Western Rootworm

Location: Corn Insects and Crop Genetics Research

Project Number: 5030-22000-018-05-N
Project Type: Non-Funded Cooperative Agreement

Start Date: Sep 1, 2015
End Date: Sep 30, 2018

Objective:
To develop and validate single nucleotide polymorphism (SNP) markers, and use the resulting genetic marker data to determine genome regions involved in the inheritance of Bt toxin resistance traits in the western corn rootworm.

Approach:
A series of pedigrees will be established by the single-pair mating of individuals from a field-collected strain of western corn rootworm that show increased survival on corn plants that express the Cry3Bb1 Bt toxin with susceptible individuals. The resulting F1 individuals will be intermated, and the F2 larvae will be phenotyped for their level of Cry3Bb1 resistance using seedling bioassays. DNA will be extracted from Western corn rootworm larvae from each pedigree, and then genotyped using single nucleotide polymorphism (SNP) markers generated by single base extension (SBE) and genotype-by-sequencing (GBS) approaches. The co-segregation between SNP markers and inheritance of high levels of Cry3Bb1 resistance traits will be determined using statistical methods, and the regions of the Western corn rootworm genome involved in the Bt toxin resistance will be identified. By comparison to a draft whole genome assembly currently available from an external collaborator, the genes within the identified genome regions may also be identified. These results will improve the knowledge regarding the evolution of Bt toxin resistance in field populations, and may lead to recommendations that delay the onset of resistance.