No evidence of superclones in leaf-feeding forms of austrian grape phylloxera ( Daktulosphaira vitifoliae).

The genetic structure of ten grape phylloxera populations, sampled in summer of 2006 and 2007 from four distinct viticultural areas in Austria, Daktulosphaira vitifoliae (Fitch) (Homoptera: Phylloxeridae) was analyzed using six SSR markers ( Dvit1-Dvit6). Leaf-feeding populations were chosen from similar ecological habitats, where susceptible rootstock hosts have overtaken scions in abandoned vineyards and produce grape phylloxera populations. To study population structures and test for dominating genotypes, population genetic measures were performed. The genetic diversity detected within the entire set of 315 genotypes was high, with 223 distinct multilocus genotypes (MLGs). Excess of heterozygotes and significant deviations from Hardy-Weinberg equilibrium in some populations indicated that the major reproduction mode in these populations is asexual but, sexual reproduction also confirmed by the sign. P values. The genetic diversity within populations was higher than between populations, although only three overlapping genotypes could be found. MLGs were rare, indicating that no candidate for superclones were detected in the leaf-feeding populations studied. [ABSTRACT FROM AUTHOR]