Frequency of powdery mildew resistances in winter barley cultivars tested in domestic variety trials

Abstract

In 2006–2010, resistance to the powdery mildew pathogen was studied in 225 winter barley cultivars of which 86 two-rowed and 139 six-rowed. The examined set included 59 cultivars tested in the official variety trials and 166 cultivars in variety trials conducted by domestic breeding stations in that period. Thirteen known resistances were identified (Ar, Bw, Dr2, Ha, HH, IM9, La, Ly, Ra, Ru, Sp, St and We). No resistance was found in one cultivar only. The most frequent resistance was Ra detected in 114 cultivars (= 50.7%). The resistance Bw was found in 54 cultivars (24.0%). Resistances typical for spring barley cultivars (Ly, Sp, Ru and We) were also frequent (4.0% to 23.6%). Unknown resistances were found in 20 cultivars, in nine of which they were effective to all used pathotypes of the pathogen. Thirty-six cultivars (16.0%) exhibited heterogeneity in the examined trait, i.e. they were mostly composed of lines with different resistances. Research on cultivars possessing unknown resistances continues.