title: Frequency of Bt resistance alleles in Helicoverpa armigera in the Xinjiang cotton-planting region of China.
abstract: Helicoverpa armigera Hübner (Lepidoptera: Noctuidae) is a key insect pest of cotton in Xinjiang cotton-planting region of northwest China. In this region, cotton is grown on average ≈ 1.65 million ha (1.53 ≈ 1.80 million ha) annually in largely monoculture agricultural landscapes, similarly to cropping systems in the United States or Australia. Under such cropping regimes, naturally occurring refuges (with non-Bt crops) may be insufficient to prevent H. armigera resistance development to Bt toxins. Therefore, we assessed frequency of alleles conferring resistance to Cry1Ac toxin of F(1) and F(2) offspring of H. armigera isofemale lines from two distinct localities in the region during 2005-2009. More specifically, a total of 224 isofemale lines was collected from Korla County (≈ 70% Bt cotton adoption) and 402 lines from Shache County (≈ 5% Bt cotton planting). Subsequent offspring was screened on Cry1Ac artificial diet. From 2005 to 2009, resistance gene frequency in Korla fluctuated between 0.0000 and 0.0040, while being 0.0000-0.0008 in individuals collected from Shache, and there were no significant increases in both counties from 2005 to 2009. Relative average development rates (RADRs) of larvae in F(1) tests showed significant increases from Korla, but not in Shache. RADR of F(1) larvae is significantly correlated with RADR of F(2) offspring, indicating genetic variation in response to toxin in field H. armigera population. Although the occurrence of Cry1Ac resistance alleles was low in Xinjiang cotton-planting region of China, particular attention should be given to H. armigera resistance development in Korla County.
authors.affiliation: State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, PR China.
authors.forename: Guoping
authors.initials: G
authors.lastname: Li
authors.forename: Hongqiang
authors.initials: H
authors.lastname: Feng
authors.forename: Yulin
authors.initials: Y
authors.lastname: Gao
authors.forename: Kris A G
authors.initials: KA
authors.lastname: Wyckhuys
authors.forename: Kongming
authors.initials: K
authors.lastname: Wu
mesh_terms: D000483:Alleles; D000818:Animals; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000378:metabolism*; D002681:China; D004731:Endotoxins / Q000378:metabolism*; D005260:Female; D003368:Gossypium / Q000378:metabolism; D006460:Hemolysin Proteins / Q000378:metabolism*; D007305:Insecticide Resistance; D007814:Larva / Q000187:drug effects / Q000235:genetics / Q000254:growth & development; D009036:Moths / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development; D010572:Pest Control, Biological; D030821:Plants, Genetically Modified / Q000378:metabolism
chemical_list: D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D004731:Endotoxins; D006460:Hemolysin Proteins; C030956:insecticidal crystal protein, Bacillus Thuringiensis