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- Title
Selection and heritability of resistance to Bacillus thuringiensis subsp kurstaki and transgenic cotton in Helicoverpa armigera (Lepidoptera: Noctuidae).
- Authors
Mei-guang Lu; Chang-hui Rui; Jian-zhou Zhao; Gui-liang Jian; Xian-lin Fan; Xi-wu Gao
- Abstract
Compared with an unselected susceptible population, a cotton bollworm, Helicoverpa armigera (Hübner), population selected for 22 generations with transgenic cotton leaves (modified CrylA) in the laboratory developed ll.0-fold resistance to CrylAc (one single-protein product MVPII). Resistance to Bacillus thuringiensis Berliner subsp kurstaki (Btk) was selected for 22 generations with a 5.2-fold increase in LC50. The estimated realized heritabilities (h²) of resistance for transgenic-cotton- and Btkselected populations were 0.1008 and 0.2341, respectively. This reflects the higher phenotypic variation in response to CrylAc in the transgenic-cotton-selected population. This variation may have been caused by differences in protein toxin levels expressed in different growth stages of the transgenic cotton. Because of the different slopes of the probit regression lines between CrylAc and Btk, the estimated realized he cannot be used visually to compare resistance development to CrylAc and Btk in H armigera. Thus, the response quotient (Q) of resistance was also estimated. The Q values of resistance for transgenic-cottonand Btk-selected populations were 0.0763 and 0.0836, respectively. This showed that the rate of resistance development would be similar in both selection populations. This result indicates that the selection of resistance using transgenic cotton is different from that selected using the single toxin. Resistance risk to transgenic cotton and Btk in field populations was assessed assuming different pressures of selection by using the estimated h². Assuming the he of resistance in a field population was half of the estimated he, and the population received prolonged and uniform exposure to transgenic cotton or Btk causing >70% mortality in each generation, we predicted that resistance would increase 10-fold after >23 generations for CrylAc in transgenic cotton-selected-populations and after >21...
- Subjects
HELICOVERPA armigera; COTTON; PEST control; BACILLUS thuringiensis; TRANSGENIC plants
- Publication
Pest Management Science, 2004, Vol 60, Issue 9, p887
- ISSN
1526-498X
- Publication type
Article
- DOI
10.1002/ps.882