Population genetics of Chrysomela tremulae: a first step towards management of transgenic Bacillus thuringiensis poplars Populus tremula x .P. tremuloides.
Many strategies have been proposed for delaying the development of insect resistance to Bacillus thuringiensis (Bt). The current paradigm for Bt resistance management is the high dose-refuge strategy. For this strategy to be successful: (i) heterozygotes must be killed in treated areas, (ii) resistant alleles must be rare (frequency < 10-3), and (iii) there must be a high level of gene flow between populations to ensure random mating. We studied gene flow within and between populations with a view to managing the resistance of Chrysomela tremulae (Coleoptera: Chrysomelidae) to new transgenic, highly toxic poplars expressing a synthetic Bt gene. In this study, we assessed the extent of gene flow in C. tremulae within and between 16 sites in France and Belgium, using allozyme markers. We found a high level of genetic variability in C. tremulae, with a mean of 0.206 +/- 0.16. There were no obvious limitations to gene flow between populations of C. tremulae over large geographical distances (several hundreds of kilometres). Nevertheless, a very low level of genetic differentiation was observed between a site located in the south of France and the sampled sites from the Centre region.
Génissel
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A
Unité de Recherches de Lutte Biologique, INRA La Minière, 78 285 Guyancourt, France.
Viard
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F
Bourguet
D
D
D000818:Animals; D001413:Bacillus thuringiensis / Q000235:genetics*; D001517:Coleoptera / Q000235:genetics* / Q000382:microbiology*; D003433:Crosses, Genetic; D005602:France; D005828:Genetics, Population; D005843:Geography; D030821:Plants, Genetically Modified; D019685:Rosales / Q000235:genetics* / Q000382:microbiology*