Genetic variability among different Italian populations of the aphid Myzus persicae

Aphids life cycle includes cyclical or obligate parthenogenesis, therefore low genetic variation is expected in these insects. Genetic diversity in crop pest aphids such as Myzus persicae, is also influenced by the extensive use of insecticides which favoured the selection of few resistant strains. In the present work, 18 M. persicae populations collected in different Italian regions, were studied by RAPD-PCR (Random Amplified Polymorphic DNA) to assess genetic variability among populations. Twelve different random primers, selected out of 24 previously investigated, were employed for genomic DNA amplification. A total of 150 fragments from the aphid M. persicae populations, and 31 fragments in two outgroups were identified. An UPGMA cluster analysis based on Nei and Li’s genetic distance revealed that the M. persicae populations could be divided into two groups: aphids from Central and Southern Italy were generally located in the same cluster, while aphids from Northern Italy were more often located in the other. The presence of a positive correlation between genetic and geographical distance suggests that at least a portion of the interpopulation polymorphism evidenced could be caused by restricted gene flow.