The phenotypic and molecular characterization of some Plasmopara viticola isolates

The objectives of this study were to determine the reactions of 21 grapevine cultivars, which were cultivated in Turkey, to downy mildew agent (Plasmopara viticola (Berk. & Curt) Berl. & de Toni), to define phenotypic and molecular characterizations of the P. viticola isolates collected from different grapevine cultivars. In the study, 21 grapevine cultivars (10 table grape, 1 dried and table grape, 10 vine grape) were first inoculated with the mixture of 91 isolates collected from different cultivars in the vineyards of Tekirdağ Viticulture Research Institute and some different provinces, by using the methods of detached leaves and leaf disc. The cv. Çavuş (Vitis vinifera) and Isabella (V. labrusca) were found as extremely resistant to the pathogen in both methods. To determine phenotypic characterization of the pathogen, each isolate was separately inoculated to the leaf discs of eight cultivars exhibiting different resistance level (extremely resistant, resistant, sensitive and highly sensitive). It was found that there were differences in virulence of the isolates collected from the same cultivars in the same vineyard or those of different provinces and 26 phenotypic groups out of 91 isolates were obtained. In the molecular studies based on three different gene region (Actin a, ß-tubulin and 28S LSU), it was determined that all isolates were genetically similar to each other, but that different haplotypes were present. The pathogen was firstly characterized as phenotypic and molecular for the first time in Turkey.