title: Changes of inheritance mode and fitness in Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) along with its resistance evolution to Cry1Ac toxin.
abstract: The changes of inheritance mode and fitness of resistance in Helicoverpa armigera (Hübner) along with its resistance evolution to Cry1Ac toxin were evaluated in the laboratory. The resistance levels reached 170.0-, 209.6- and 2893.3-fold, on selection of the field population in the 16th (BtR-F(16)), 34th (BtR-F(34)) and 87th (BtR-F(87)) generation with artificial diet containing Cry1Ac toxin, respectively. As the resistance levels increased, more larvae feeding on the Bt cotton expressing Cry1Ac toxin survived. Most larvae of BtR-F(87) could develop to the 5th instar and about 3% individuals reached the adult stage. The inheritance of Cry1Ac resistance trait at three resistant levels was autosomal and incompletely recessive, but the degree of dominance decreased as the resistance increased. The resistance was primarily monogenic in BtR-F(16) strain, but polygenic as resistance increased. The relative fitness of H. armigera, measured as a ratio of R(0) (the net replacement rate) of resistant strain divided by R(0) of the susceptible strain, decreased with an increase of the resistance levels, with ratios of 0.79, 0.64 and 0.59 in their respective BtR-F(16), BtR-F(34) and BtR-F(87) strains.
authors.affiliation: State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100094, China.
authors.forename: Ge-Mei
authors.initials: GM
authors.lastname: Liang
authors.forename: Kong-Ming
authors.initials: KM
authors.lastname: Wu
authors.forename: Hong-Kun
authors.initials: HK
authors.lastname: Yu
authors.forename: Ke-Ke
authors.initials: KK
authors.lastname: Li
authors.forename: Xue
authors.initials: X
authors.lastname: Feng
authors.forename: Yu-Yuan
authors.initials: YY
authors.lastname: Guo
mesh_terms: D000818:Animals; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000494:pharmacology*; D001427:Bacterial Toxins / Q000494:pharmacology*; D004731:Endotoxins / Q000494:pharmacology*; D019143:Evolution, Molecular; D006460:Hemolysin Proteins / Q000494:pharmacology*; D007305:Insecticide Resistance / Q000235:genetics* / Q000502:physiology; D007814:Larva / Q000187:drug effects; D007915:Lepidoptera / Q000187:drug effects* / Q000235:genetics* / Q000502:physiology; D010572:Pest Control, Biological
chemical_list: D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D004731:Endotoxins; D006460:Hemolysin Proteins; C030956:insecticidal crystal protein, Bacillus Thuringiensis