Plasmopara halstedii (Farl.) Berl. & De Toni causing downy mildew of sunflower is responsible for considerable economic losses worldwide. Because P. can be seed-transmitted, monitoring seeds pathogen contamination important the seed trade. The relevance asymptomatic or latent infections as factors disease spread have not been studied by molecular techniques. A marker based on a putative effecto...

Depending on host-pathotype combination, two types of sunflower-Plasmopara halstedii incompatibility reactions have previously been identified. Type I resistance can restrict the growth of the pathogen in the basal region of the hypocotyls, whereas type II cannot, thus allowing the pathogen to reach the cotyledons. In type II resistance, a large portion of the hypocotyls is invaded by the patho...