Genetic structure and dispersal of pear psylla (Cacopsylla pyri L.) populations

摘要

The electrophoretic analysis of eight polymorphic enzyme loci in one Italian and 14 French psylla populations showed no significant differences between the genotype frequencies and the Hardy-Weinberg equilibrium. Gene differentiation was low (Fst = 0.0111) and gene flow was high (Nm = 22.3). Populations from western France presented higher gene differentiation than those from eastern France. Separately studying two genes coding for esterases revealed a high level of structuring. Each locus was independent and characterized by a null allele and an expressed allele with the same mobility. The geographical distribution of each locus and the existence of confluence zones suggest that the exchanges between sub-populations preferentially occur via the north and the south of the Massif Central. The possible involvement of esterase genes in resistance to insecticides is discussed in relation with their known role of detoxification. (C) Elsevier, Paris. [References: 18]