Genetic control of virulence of Pyrenophora teres drechs, the causative agent of net blotch in barley

The genetic control of virulence was studied in four isolates of the fungus Pyrenophora teres f. teres, originating from various geographic regions in experiments with nine barley accessions, possessing known resistance genes. Experiments were performed with the ascospore progeny of two crosses. The results of segregation for virulence in the progeny of direct crosses were confirmed by analysis of backcrosses and sib crosses. One to four genes for avirulence toward various barley genotypes were found in the isolates under study. It is suggested that dominant suppressor genes are involved in the genetic control of avirulence toward four barley genotypes.