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ARS Home » Plains Area » Fargo, North Dakota » Edward T. Schafer Agricultural Research Center » Cereal Crops Improvement Research » Research » Publications at this Location » Publication #418840
Research Project: Improvement of Disease and Pest Resistance in Barley, Durum, Oat, and Wheat Using Genetics and Genomics

Location: Cereal Crops Improvement Research

Title: Identification of stem rust resistance genes in monogenic lines derived from wheat cultivar Waldron

Author
item Klindworth, Daryl
item SAINI SHARMA, JYOTI - University Of Minnesota
item Faris, Justin
item Friesen, Timothy
item Peters Haugrud, Amanda
item Xu, Steven

Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/14/2025
Publication Date: 2/7/2025
Citation: Klindworth, D.L., Saini Sharma, J., Faris, J.D., Friesen, T.L., Peters Haugrud, A.R., Xu, S.S. 2025. Identification of stem rust resistance genes in monogenic lines derived from wheat cultivar Waldron. Crop Science. https://doi.org/10.1002/csc2.70010.
DOI: https://doi.org/10.1002/csc2.70010

Interpretive Summary: Stem rust is a major pathogen on wheat globally, which can reduce wheat yield in heavy infestations. Although it can be controlled by fungicides, genetic resistance remains the best option as fungicide applications can be missed due to environmental conditions. Previously, a wheat cultivar named ‘Waldron’ from North Dakota State University was found to carry 6 genes conferring resistance to stem rust in North America; however, the location on the Waldron genome of these genes was not identified. Identifying genetic location (chromosome and position) is important for developing resistant lines for farmers to grow and molecular markers for breeders to track these traits. In this study, we successfully identified the chromosome location of four of these genes, with all six genes now mapped and identified. This research demonstrated that the resistance in Waldron can be used to provide genetic resistance to current stem rust populations in North America, helping farmers protect their wheat crop from this damaging pathogen, especially in seasons when fungicide application is not possible.

Technical Abstract: The wheat (Triticum aestivum L.) cultivar Waldron carries at least six genes for resistance to stem rust caused by Puccinia graminis Pers.:Pers. f.sp. tritici Eriks. and Henn. (Pgt). The identity and map location of some of these genes are known, but there is limited knowledge of SrWld1, an important gene that conditions resistance to all North American Pgt races. Our objective was to identify and map additional stem rust resistance genes in Waldron through aneuploid analysis, allelism tests, and linkage with molecular markers. Four lines, WDR-A1, WDR-C2, WDR-D1, and WDR-E4, each carrying a single stem rust resistance gene from Waldron, were crossed to appropriate genetic stocks. Telosomic analysis failed to confirm the previously reported location of SrWDR-C2 to chromosome 7A. Monosomic analysis, allelism tests and multi-pathotype seedling tests indicated that the genes in WDR-A1 and WDR-D1 were Sr18 and Sr9g, respectively. Telosomic analysis, allelism tests, and marker analysis of WDR-E4 indicated that SrWld1 should be reassigned from chromosome 2A to 2BL. When families were tested with races LBBLB, TMLKC, and TPPKC co-segregation of resistance was not observed. This suggests that inheritance of the SrWld1 phenotype was polygenic and that additional studies are needed on the inheritance of SrWld1. When results from this study were combined with previous studies, the stem rust resistance genes in Waldron are identified as Sr9g, Sr11, Sr18, Sr41, SrWld1, and SrWld2.