Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/29/2013
Publication Date: 12/1/2013
Citation: Szabo, L.J., Carson, M.L. 2013. Screening wild oat accessions from Morocco for resistance to Puccinia coronata. Plant Disease. 97:1544-1548.
Interpretive Summary: Crown rust is the most devastating disease that threatens oat production worldwide. The use of disease resistant varieties is considered to be the most efficient, environmentally friendly and economic solution to battle the disease. Unfortunately there are races or strains of the crown rust pathogen capable of overcoming all the resistance genes present in oat varieties. There is a pressing need for new crown rust resistance genes. Since cultivated oats have been depleted as a source of resistance, the focus has turned to the wild relatives of cultivated oat. Wild species are most often a rich source of diversity and of new resistance genes. In this study we have screened over 300 accessions of wild oat species, originating from Morocco, for resistance to crown rust. This resulted in 124 accessions that were moderately resistant to highly resistant at both the seedling level and the adult plant level to a very diverse mixture of crown rust races. These newly found resistance sources could bring a significant contribution in future resistance breeding in oat. However, it will take the sustained effort of oat geneticists to a get these resistance genes into oat varieties due to the inherent difficulties when crossing wild species with cultivated oat. These resistance genes could have a substantial impact on crop protection and yield stability of oats. This research will be useful for oat breeders, geneticists, and pathologists worldwide.
Technical Abstract: Here we report the screening of 338 new accessions of 11 different wild oat species (Avena) from the USDA Small Grains Collection for resistance to crown rust (Puccinia coronata). Wild oat species were originally collected in Morocco by C. Al Faiz, INRAT Rabat: 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 with a highly diverse bulk of crown rust urediniospores, 212 (64%) accessions were at least rated moderately resistant or higher. Virulence in Puccinia coronata has been reported to all resistance genes currently being used in North American oat cultivars. The new resistance sources presented here will add a very important contribution for future resistance breeding. Because of differences in ploidy levels, and the lack of homology and crossing-over between the genomes of domesticated oat and its wild relatives, transfer of resistance from these sources will require the concerted efforts of oat geneticists.