Rare virulences of barley powdery mildew found in aerial populations in the Czech Republic from 2009 to 2014

Abstract

In breeding plants for resistance to disease pathogens major genes are often used. They mostly confer a resistance, which can be overcome by a corresponding pathogen virulence specific to the resistance conferred by that gene. Therefore, monitoring of new virulences in the pathogen population is an integral part of both the study of resistance and practical breeding. The aim of this paper is to present the detection of rare virulences that have been found in aerial populations of Blumeria graminis f.sp. hordei collected in the Czech Republic during the last six years. In total, 822 random isolates originating from cultivated spring and winter barley fields were evaluated on 37 differential varieties and 12 isolates carrying rare virulences were found. At least four virulences to resistances in Laverda, Psaknon, Venezia and SJ048311 were novel. In contrast, four rare isolates avirulent to the resistance Ha were also found. No isolate avirulent to resistances Ra, HH (a8) and Lo was detected. Monitoring of new virulences allows the selection of resistant donors for breeding new varieties and the identification of new resistances.