Screening Wild Oat Accessions from Morocco for Resistance to Puccinia coronata.

Here, we report the screening of 332 new accessions of 11 different wild oat (Avena) species from the United States Department of Agriculture National Small Grains Collection in Aberdeen, ID, for resistance to crown rust disease, caused by Puccinia coronata f. sp. avenae. This collection originated from Morocco and includes Avena agadiriana, A. atlantica, A. barbata, A. damascena, A. eriantha, A. hirtula, A. longiglumis, A. magna, A. murphyi, A. sterilis, and A. wiestii. After screening this collection with a highly diverse population of P. coronata f. sp. avenae, 164 accessions (49%) were rated moderately resistant to resistant in the preliminary screen at the seedling stage and 181 accessions (55%) rated moderately resistant to highly resistant in the adult plant stage. Although none of the accessions showed a highly resistant response consistently in the seedling stage, 20 accessions did display a highly resistant response in the adult plant stage. Both seedling as well as adult plant resistance was found in 150 (45%) of the accessions. Virulence in P. coronata has been reported to all resistance genes currently being used in North American oat cultivars. The new resistance sources presented here are potentially new sources for future breeding. The resistance found in 52 accessions of A. magna and A. murphyi with the AACC genome is especially valuable because these should be relatively easy to transfer into hexaploid A. sativa.