Characterization of Ethiopian wheat germplasm for resistance to four Puccinia graminis f. sp. tritici races facilitated by single race nurseries

Authors: HUNDIE, BEKELE - Ethiopian Institute Of Agricultural Research; GIRMA, BEDADA - Ethiopian Institute Of Agricultural Research; TADESSE, ZERIHUN - Ethiopian Institute Of Agricultural Research; EDAE, ERENA - University Of Minnesota; OLIVERA, PABLO - University Of Minnesota; ABERA, ENDALE - Ethiopian Institute Of Agricultural Research; BULBULA, WORKU - Ethiopian Institute Of Agricultural Research; ABEYO, BEKELE - International Maize & Wheat Improvement Center (CIMMYT); BADEBO, AYELE - International Maize & Wheat Improvement Center (CIMMYT); CISAR, GORDON - Cornell University; Brown-Guedira, Gina; Gale, Sam; Jin, Yue; Rouse, Matthew

Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/8/2019
Publication Date: 4/11/2019
Citation: Hundie, B., Girma, B., Tadesse, Z., Edae, E., Olivera, P., Abera, E.H., Bulbula, W.D., Abeyo, B., Badebo, A., Cisar, G., Brown Guedira, G.L., Gale, S.W., Jin, Y., Rouse, M.N. 2019. Characterization of Ethiopian wheat germplasm for resistance to four Puccinia graminis f. sp. tritici races facilitated by single race nurseries. Plant Disease. https://doi.org/10.1094/PDIS-07-18-1243-RE.
DOI: https://doi.org/10.1094/PDIS-07-18-1243-RE

Interpretive Summary: Breeding rust resistant wheat varieties is a priority for wheat production. A stem rust epidemic during 2013 to 2014 on previously resistant variety Digalu highlighted the need to determine the effectiveness of wheat lines to multiple races of the stem rust pathogen in Ethiopia. During 2014 and 2015, we evaluated a total of 97 bread wheat and 14 durum wheat genotypes against four stem rust pathogen races at the seedling stage and in single race field nurseries. Resistance genes were postulated using molecular marker assays. Bread wheat lines were resistant to race JRCQC, the race most virulent to durum wheat. Lines with stem rust resistance gene Sr24 possessed the most effective resistance to the four races. Only three lines with adult plant resistance possessed resistance effective to the four races comparable to varieties with Sr24. Though responses of the wheat lines across races were positively correlated, wheat lines were identified that possessed adult plant resistance to race TTKSK, but were relatively susceptible to race TKTTF. This study demonstrated the importance of testing wheat lines for response to multiple races of the stem rust pathogen in order to determine if lines possessed non-race specific resistance. We identified wheat lines that could be utilized in breeding as sources of adult plant resistance for protecting United States wheat against Ug99 and other emerging, virulent stem rust pathogen races.

Technical Abstract: In Ethiopia, breeding rust resistant wheat varieties is a priority for wheat production. A stem rust epidemic during 2013 to 2014 on previously resistant variety Digalu highlighted the need to determine the effectiveness of wheat lines to multiple races of P. graminis f. sp. tritici in Ethiopia. During 2014 and 2015, we evaluated a total of 97 bread wheat and 14 durum wheat genotypes against four P. graminis f. sp. tritici races at the seedling stage and in single race field nurseries. Resistance genes were postulated using molecular marker assays. Bread wheat lines were resistant to race JRCQC, the race most virulent to durum wheat. Lines with stem rust resistance gene Sr24 possessed the most effective resistance to the four races. Only three lines with adult plant resistance possessed resistance effective to the four races comparable to varieties with Sr24. Though responses of the wheat lines across races were positively correlated, wheat lines were identified that possessed adult plant resistance to race TTKSK, but were relatively susceptible to race TKTTF. This study demonstrated the importance of testing wheat lines for response to multiple races of the stem rust pathogen in order to determine if lines possessed non-race specific resistance.