Evaluation of cultivated and wild barley for resistance to pathotypes ofPuccinia hordei with wide virulence

An isolate ofPuccinia hordei (ND89-3) originally collected in Morocco is virulent on most barley genotypes reported to possess resistance, except cultivar Estate (CI 3410), which possesses theRph3 gene and exhibits a low to intermediate level of resistance (infection type 12). Isolate ND89-3 possesses one of the widest virulence spectrums reported forP. hordei. Accessions ofHordeum vulgare (1,997 in total) andH. spontaneum (885 in total), mostly originating from the Mediterranean region and parts of North Africa, were evaluated with isolate ND89-3 at the seedling stage to identify new sources of leaf rust resistance. Fifty-eight accessions ofH. vulgare, and 222 accessions ofH. spontaneum exhibited low infection types to this isolate. Further evaluations of these resistant accessions with isolates ofP. hordei virulent forRph3,Rph7, andRph12 suggested that most of the resistantH. vulgare accessions possess theRph3 gene. Data suggested additional sources of effective resistance inH. vulgare are rather limited. FiveH. vulgare accessions and 167H. spontaneum accessions were identified as possible sources of new genes for leaf rust resistance. These accessions likely possess resistance genes that are different fromRph1 toRph12, or gene combinations thereof based on their reaction to four leaf rust isolates. Utilization of these accessions in barley breeding will broaden the germplasm resources available for genetic control ofP. hordei. North Dakota Agricultural Experiment Station Journal Series No. 2123. The U.S. Government right to retain a non-exclusive, royalty free licence in and to any copyright is acknowledged.