Evaluation of resistance to Blumeria graminis (DC.) f. sp. avenae, in Avena murphyi and A. magna genotypes

Powdery mildew is one of the main factors reducing oat yield quality and quantity. New sources of resistance are needed in many breeding programs. The most effective sources of resistance to fungal diseases in cereals have often been found in lower-ploidy species. Thus, tetraploid species could be valuable source of resistance to powdery mildew. The aim of the present study was to identify resistance among tetraploid genotypes that could be used in breeding programmes to increase the level of resistance to powdery mildew in oat. Sixty two Avena magna and 17 A. murphyi accessions were tested and all showed high level of resistance to oat powdery mildew. None of the accessions were completely susceptible to the tested pathogen isolates. Twelve A. magna and six A. murphyi accessions were resistant to all five isolates of the powdery mildew pathogen tested. The rest of the accessions showed a resistant or an intermediate response. The results of the present study show that there are several unexplored resistance sources among A. magna and A. murphyi. Because of the genomic similarity of tetraploid species to hexaploid oats the introduction of the new resistance sources in cultivated oats is promising.