title: Allele frequency of resistance to Bacillus thuringiensis Cry1ab corn in Louisiana populations of sugarcane borer (Lepidoptera: Crambidae).
abstract: Transgenic Bacillus thuringiensis (Bt) corn, Zea mays L., has been widely used to manage a corn borer complex in the mid-southern region of the United States. The sugarcane borer, Diatraea saccharalis (F.) (Lepidoptera: Crambidae), has become a dominant cornstalk boring species in some areas of this region, especially in Louisiana. Therefore, management of sugarcane borer resistance to Bt corn is critical to ensure the long-term sustainability of Bt corn for the region. This study screened 280 two-parent family-lines of sugarcane borer from four geographical populations in Louisiana during 2005 to determine whether Bt resistance allele frequency in sugarcane borer is sufficiently low to meet the rare resistance assumption of the current "high dose/refuge" resistance management strategy for Bt corn. These sugarcane borer family-lines were examined for Bt resistance by using novel F2 screening procedures. No major Bt resistance alleles were detected in these four populations. The estimated frequency of major Bt resistance alleles was < 0.0027, with a 95% probability and a detection power of 94%. The estimated minor resistance allele frequency was 0.0063, with a 95% CI of 0.0025-0.0117. During a previous study, a major Bt resistance allele was detected in one individual from 213 family-lines of another Louisiana population of sugarcane borer. Combining these data with the current screen, the frequency of major Bt resistance alleles across the five populations was 0.001, with a 95% credibility interval of 0.0001-0.0028 and a detection power of 95%. Major Bt resistance allele frequencies in Louisiana sugarcane borer populations seem to be low, and they should support the rare resistance allele requirement of the high dose/refuge strategy.
authors.affiliation: Department of Entomology, Louisiana State University Agricultural Center, Baton Rouge, LA 70803, USA. fhuang@agcenter.lsu.edu
authors.forename: Fangneng
authors.initials: F
authors.lastname: Huang
authors.forename: B Rogers
authors.initials: BR
authors.lastname: Leonard
authors.forename: Steven H
authors.initials: SH
authors.lastname: Moore
authors.forename: Donald R
authors.initials: DR
authors.lastname: Cook
authors.forename: Jack
authors.initials: J
authors.lastname: Baldwin
authors.forename: Kelly V
authors.initials: KV
authors.lastname: Tindall
authors.forename: Donna R
authors.initials: DR
authors.lastname: Lee
mesh_terms: D000483:Alleles; D000818:Animals; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000235:genetics* / Q000494:pharmacology*; D004731:Endotoxins / Q000235:genetics* / Q000494:pharmacology*; D006460:Hemolysin Proteins / Q000235:genetics* / Q000494:pharmacology*; D007305:Insecticide Resistance / Q000235:genetics*; D008145:Louisiana; D009036:Moths / Q000187:drug effects* / Q000235:genetics*; D030821:Plants, Genetically Modified; D003313:Zea mays / Q000235:genetics*
chemical_list: D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D004731:Endotoxins; D006460:Hemolysin Proteins; C030956:insecticidal crystal protein, Bacillus Thuringiensis