Barley grass as a source of pathogenic variation in Rhynchosporium secalis

Abstract

The pathogenic variability of 150 isolates of Rhynchospovium secalis collected in southern Australia was examined on 20 biotypes of barley grass (Hordeum lepovinum). The isolates were differentiated into 20 pathotypes on the basis of the reactions of the barley grass. The genetic basis of resistance and susceptibility of barley grass to R. secalis was determined from F2 progeny of crosses among three resistant and two susceptible biotypes of barley grass. The resistance genes identified were all dominant.