Submitted to: Entomological Society of America Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 11/20/2002
Publication Date: N/A
Technical Abstract: Currently, insecticides are the only viable control option for corn rootworm management in continuous corn. We have previously identified several sources of native resistance to western corn rootworm larval feeding that were significantly less damaged than previous sources of resistance. In order to improve the resistance, two populations were developed which underwent recurrent selection. One population was developed solely for the western corn rootworm and the other population also incorporated resistance factors to the European corn borer and concurrently was selected for both corn rootworm and corn borer resistance. In the summer of 2002, cycles 0, 1, 2, and 3 from each population were evaluated in a total of eight locations in four Midwestern states. Each location evaluated plant damage. Some of the locations also evaluated root size, root regrowth, adult emergence, larval weight gain, and root weight. Data received from the first six locations indicate that nine of the 10 resistance sources were significantly less damaged than a modern hybrid without insecticide and that three of the lines were not significantly different from an insecticide-treated modern hybrid for corn rootworm feeding damage. Recurrent selection was successful in improving corn rootworm resistance in one population, but resistance was not significantly improved after three cycles of selection when concurrently selecting for corn borer and corn rootworm resistance. We are currently developing markers so that these sources could more easily be incorporated into elite germplasm. When released and combined with elite, high-yielding germplasm, these sources may provide alternatives to insecticides and transgenic approaches.