Characterization of asara tca isolates from Bulgaria with microsatellite markers

. osev1, I. Simeonov2, G. Djakova3, Ts. Hvarleva1*

1Agrobioinstitute, Agricultural Academy, 8 Dragan Tsankov, 1164 Sofia, Bulgaria 2Instiute of iticulture and Enology, Agricultural Academy, 5800 Pleven, Bulgaria 3Institute of Agriculture and Seed Science, Agricultural Academy, 7007 Rousse, Bulgaria

Abstract. The fungus Plasmopara viticola is the causal agent of downy mildew, one of the most severe grapevine diseases. The genetic diversity of this pathogen in Bulgaria has not yet been investigated. In order to assess the polymorphism among P. viticola isolates in Bulgaria six samples collected in different regions of the country were genotyped with 7 SSRs. The genetic polymorphism revealed by the used microsatelite markers allowed discrimination of P. viticola isolates originating from the different areas of Bulgaria. All samples were found to have a unique microsatellite profile. One sample was found to have a multiallelic profile at three out of seven loci and was excluded from the calculation of genetic diversity parameters. The number of alleles per locus varied between 2 and 6 with a mean value of 3.5 alleles per locus. The obtained values of observed heterozygosity ranged from 0.2 to 0.8 with an estimated average value of 0.46±0.13, which is a bit lower than the mean expected heterozygosity – 0.53±0.07. With this study the characterization of population structure of P. viticola pathogen in Bulgaria was initiated.