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Front. Plant Sci. | doi: 10.3389/fpls.2018.01719

Identification of new sources of resistance to wheat stem rust in Aegilops spp. in the tertiary genepool of wheat

 Pablo D. Olivera1, Matthew Rouse2 and  Yue Jin2*
  • 1Department of Plant Pathology, University of Minnesota, United States
  • 2Cereal Disease Laboratory, Agricultural Research Service, United State Department of Agriculture, United States

Recent stem rust epidemics in eastern Africa and elsewhere demonstrated that wheat stem rust is a re-emerging disease posing a threat to wheat production worldwide. The cultivated wheat gene pool has a narrow genetic base for resistance to virulent races, such as races in the Ug99 race group. Wild relatives of wheat are a tractable source of stem rust resistance genes. Aegilops species in the tertiary genepool have not been exploited to any great extent as a source of stem rust resistance, however. We evaluated 1,422 accessions of Aegilops spp. for resistance to three highly virulent races (TTKSK, TRTTF and TTTTF) of Puccinia graminis f. sp. tritici. Species studied include Ae. biuncialis, Ae. caudata, Ae. comosa, Ae. cylindrica, Ae. geniculata, Ae. neglecta, Ae. peregrina, Ae. triuncialis, and Ae. umbellulata that do not share common genomes with cultivated wheat. High frequencies of resistance were observed as 977 (68.8%), 927 (65.2%), and 850 (59.8%) accessions exhibited low infection types to races TTKSK, TTTTF, and TRTTF, respectively. Association analyses showed strong association for resistance to different races in several Aegilops spp., indicating that for a given species, the resistance genes effective against multiple races. Inheritance studies in selected accessions showed resistance to race TTKSK is simply inherited.

Keywords: Wild wheats, Disease Resistance, Ug99, Genetic resources, Tertiary gene pool

Received: 26 Aug 2018; Accepted: 05 Nov 2018.

Edited by:

István Molnár, Centre for Agricultural Research (MTA), Hungary

Reviewed by:

Hakan Ozkan, Çukurova University, Turkey
Peter M. Dracatos, University of Sydney, Australia  

Copyright: © 2018 Olivera, Rouse and Jin. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: Dr. Yue Jin, Cereal Disease Laboratory, Agricultural Research Service, United State Department of Agriculture, St. Paul, 55108, Minnesota, United States, yue.jin@ars.usda.gov