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ARS Home » Southeast Area » Canal Point, Florida » Sugarcane Field Station » Research » Publications at this Location » Publication #417316
Research Project: Understanding and Incorporating Disease Resistance into New Sugarcane Cultivars

Location: Sugarcane Field Station

Title: QTL mapping of stem rust resistance in a Bill Brown/Gage winter wheat population

Author
item KUMSSA, TADELE - University Of Illinois
item BAENZIGER, P - University Of Nebraska
item Rouse, Matthew
item HUSSAIN, WASEEM - International Rice Research Institute
item BELAMKAR, VIKAS - University Of Nebraska
item WEGULO, STEPHEN - University Of Nebraska
item POLAND, JESSE - King Abdullah University Of Science And Technology

Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/5/2024
Publication Date: 1/5/2025
Citation: Kumssa, T., Baenziger, P.S., Rouse, M.N., Hussain, W., Belamkar, V., Wegulo, S.N., Poland, J. 2025. QTL mapping of stem rust resistance in a Bill Brown/Gage winter wheat population. Crop Science. 65(1).Article e21445. https://doi.org/10.1002/csc2.21445.
DOI: https://doi.org/10.1002/csc2.21445

Interpretive Summary: Stem rust is historically a major disease of wheat in the United States and around the world. Newly emerged strains of this pathogen, such as Ug99, have developed virulence to most deployed stem rust resistance (Sr) genes. Wheat variety 'Gage' possesses resistance to Ug99 and other stem rust pathogen strains that is conferred by more than one Sr gene. To characterize the genetics of stem rust resistance in 'Gage', we used recombinant inbred lines (RILs) developed from the cross of susceptible 'Bill Brown' x 'Gage' and evaluated them for three years for response to six different stem rust pathogen strains. Using molecular markers, we determined the genomic regions that affect stem rust resistance in Gage which identified two QTLs at the seedling stage and one major QTL at the adult stage. We identifed three Sr genes that conferred stem rust resistance in 'Gage' (Sr2, SrTmp, and Sr7) and additional genetic loci that contributed small resistance effects. This study will enable U.S. wheat breeders to develop new varieties with complex genetic resistance, similar to 'Gage', to prevent yield losses caused by new strains of the stem rust fungus. This will help secure the U.S. wheat crop.

Technical Abstract: The wheat (Triticum spp.) stem rust pathogen, Puccinia graminis f. sp. tritici Eriks. and E. Henn. (Pgt), has continued to be a devastating biotic stress in wheat production. Over previous decades, scientists have identified several resistance genes effective against Pgt. However, the ever evolving Pgt and low availability of durable resistance necessitates continuous identification and wise deployment of resistance genes. To elucidate the identity of our previously reported stem rust resistance in hard red winter wheat cultivar ‘Gage’, we used recombinant inbred lines (RILs) developed from the cross of ‘Bill Brown’ x Gage and evaluated them for three years for response to six different stem rust pathogen races individually at the seedling stage in the greenhouse and a mixture of these races in the field. Using molecular markers, we determined the genomic regions that affect stem rust resistance in Gage which identified two QTLs at the seedling stage and one major QTL at the adult stage, giving insight into why Gage has superior stem rust resistance. The seedling stem rust resistance was from SrTmp and likely from an Sr7 allele. Quantitative Trait Loci conferring adult plant resistance in Gage was mainly from Sr2, but molecular analysis suggested additional minor-effect QTL were involved.