Race identification of Plasmopara halstedii isolates extracted from infected ragweed plants

In 2011 in the Krasnodar region were discovered the ragweed plants ( Ambrosia artemisiifolia L.) with signs of downy mildew infection. The isolates of disease agent were pathogenic for sunflower. Race identification by means of the international test-kit of differentiating sunflower lines showed race 330 that affects sunflower. The analysis of 6 DNA SNP-loci confirmed the identity of ragweed isolates with sunflower isolates of race 330. It testifies that race 330 of Plasmopara halstedii can be preserved and resumed on ragweed when changing the crops of cultivated sunflower from susceptible to resistant. The isolates of Albugo tragopogonis extracted simultaneously with P. halstedii were not pathogenic for sunflower seedlings.