Field screening maize germplasm for resistance and tolerance to western corn rootworms (Coleoptera: Chrysomelidae)

Authors: Prischmann, Deirdre; Dashiell, Kenton; Schneider, David; Hibbard, Bruce

Submitted to: Journal of Applied Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/9/2007
Publication Date: 7/1/2007
Citation: Prischmann, D.A., Dashiell, K.E., Schneider, D.J., Hibbard, B.E. 2007. Field screening maize germplasm for resistance and tolerance to western corn rootworms (Coleoptera: Chrysomelidae). Journal of Applied Entomology. 131(6):406-415.

Interpretive Summary: In the hopes of lessening the current reliance on soil insecticides, developing a viable alternative for transgenic corn hybrids, and providing sustainable options for Europe, researchers recently have been developing novel corn lines that exhibit resistance and/or tolerance to corn rootworm larvae. However, genotype by environment interactions can often be large for traits such as insect resistance. Here we report the results of a two-year field experiment in a northern growing region assessing the resistance and tolerance of 14 maize genotypes selected from a southern growing region for varying levels of damage from western corn rootworm larvae, Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae). Maize non-preference, antibiosis, and tolerance to rootworms was evaluated using previously established methods, including: the Iowa 1-6 root damage rating scale, adult rootworm emergence, root size, compensatory root growth ratings, and percent of plant lodging. The resistant transgenic control (DeKalb 46-23) performed the best in terms of resistance (root damage ratings, adult emergence and plant lodging), and was among the top lines with regard to plant tolerance (root weight). Among the experimental lines, CRW8-3 had low root damage ratings, while BS29-18-01 and BS29-07-01 had low adult emergence. Some lines appeared to be tolerant to rootworm damage, as evidenced by large root systems and/or high compensatory root growth ratings, including: NGSDCRW1(S2)C4, CRW8-2, and CRW8-3. In general, root damage ratings paralleled those from trials in Missouri, and thus it seemed that corn line susceptibility to rootworms was similar in these different geographical locations.

Technical Abstract: In the hopes of lessening the current reliance on soil insecticides, developing a viable alternative for transgenic corn hybrids, and providing sustainable options for Europe, researchers recently have been developing novel corn lines that exhibit resistance and/or tolerance to corn rootworm larvae. However, genotype by environment interactions can often be large for traits such as insect resistance. Here we report the results of a two-year field experiment in a northern growing region assessing the resistance and tolerance of 14 maize genotypes selected from a southern growing region for varying levels of damage from western corn rootworm larvae, Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae). Maize non-preference, antibiosis, and tolerance to rootworms was evaluated using previously established methods, including: the Iowa 1-6 root damage rating scale, adult rootworm emergence, root size, compensatory root growth ratings, and percent of plant lodging. The resistant transgenic control (DeKalb 46-23) performed the best in terms of resistance (root damage ratings, adult emergence and plant lodging), and was among the top lines with regard to plant tolerance (root weight). Among the experimental lines, CRW8-3 had low root damage ratings, while BS29-18-01 and BS29-07-01 had low adult emergence. Some lines appeared to be tolerant to rootworm damage, as evidenced by large root systems and/or high compensatory root growth ratings, including: NGSDCRW1(S2)C4, CRW8-2, and CRW8-3. In general, root damage ratings paralleled those from trials in Missouri, and thus it seemed that corn line susceptibility to rootworms was similar in these different geographical locations.