Aegilops species are rich sources of resistance to Pgt race TTKSK

Wild relatives are rich sources of genetic diversity for wheat improvement. Our research focuses on characterizing stem rust resistance in Aegilops, a genus whose 23 species are part of the secondary genepool of wheat. In a previous study, we evaluated nine Aegilops species (885 total accessions) from Israel for reaction to Pgt race TTKSK and found the frequency of resistance ranged from 14% for Ae. searsii to 100% for Ae. speltoides. To extend this investigation, we evaluated 231 additional Aegilops accessions from five of the same species, plus 165 accessions from seven uncharacterized species. All of these accessions were collected from countries other than Israel or were of unknown provenance. The frequencies of resistant accessions in Ae. speltoides (94% in this study vs. 100% previously), Ae. bicornis (93% vs. 79%), Ae. geniculata (48% vs. 45%), Ae. peregrina (50% vs. 57%), and Ae. searsii (10% vs. 14%) were very similar to those for the Israel cohort in the previous study with the exception of Ae. bicornis. Of the latter accessions, the highest frequencies of resistance were in Ae. cylindrica (88%) and Ae. columnaris (85%) followed by Ae. binuncialis (37%) and Ae. ventricosa (13%). Accessions resistant to race TTKSK were not found in Ae. crassa, Ae. juvenalis, or Ae. vavilovii. These data show that certain Aegilops species are particularly rich sources of resistance to TTKSK. Yet other species carry no resistance. Research is underway to characterize the genetics of resistance in several select accessions.

Department of Plant Pathology, University of Minnesota, USA
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