The genetics of Ug99 stem rust resistance in spring wheat variety 'Linkert'

Erena A Edae; Zennah Kosgey; Prabin Bajgain; Kimani C Ndung'u; Ashenafi Gemechu; Sridhar Bhavani; James A Anderson; Matthew N Rouse

doi:10.3389/fpls.2024.1343148

The genetics of Ug99 stem rust resistance in spring wheat variety 'Linkert'

Front Plant Sci. 2024 Mar 7:15:1343148. doi: 10.3389/fpls.2024.1343148. eCollection 2024.

Authors

Erena A Edae¹, Zennah Kosgey², Prabin Bajgain³, Kimani C Ndung'u², Ashenafi Gemechu⁴, Sridhar Bhavani⁵, James A Anderson³, Matthew N Rouse^{1

6}

Affiliations

¹ Department of Plant Pathology, University of Minnesota, Saint Paul, MN, United States.
² Kenya Agricultural and Livestock Research Organization (KALRO), Food Crops Research Centre, Njoro, Kenya.
³ Department of Agronomy and Plant Genetics, University of Minnesota, Saint Paul, MN, United States.
⁴ Ethiopian Institute of Agriculture, Debre Zeit Agricultural Research Center, Bishoftu, Ethiopia.
⁵ International Maize and Wheat Improvement Center (CIMMYT), Texcoco, Mexico.
⁶ Cereal Disease Laboratory, United States Department of Agriculture-Agricultural Research Service, Saint Paul, MN, United States.

Abstract

Wheat stem rust caused by Puccinia graminis f. sp. tritici (Pgt) threatens wheat production worldwide. The objective of this study was to characterize wheat stem rust resistance in 'Linkert', a variety with adult plant resistance effective to emerging wheat stem rust pathogen strain Ug99. Two doubled haploid (DH) populations and one recombinant inbred line (RIL) population were developed with 'Linkert' as a stem rust resistant parent. Hard red spring wheat variety 'Forefront' and genetic stock 'LMPG' were used as stem rust susceptible parents of the DH populations. Breeding line 'MN07098-6' was used as a susceptible parent of the RIL population. Both DH and RIL populations with their parents were evaluated both at the seedling stage and in the field against Pgt races. Genotyping data of the DH populations were generated using the wheat iSelect 90k SNP assay. The RIL population was genotyped by genotyping-by-sequencing. We found QTL consistently associated with wheat stem rust resistance on chromosome 2BS for the Linkert/Forefront DH population and the Linkert/MN07098-6 RIL population both in Ethiopia and Kenya. Additional reliable QTL were detected on chromosomes 5BL (125.91 cM) and 4AL (Sr7a) for the Linkert/LMPG population in Ethiopia and Kenya. Different QTL identified in the populations reflect the importance of examining the genetics of resistance in populations derived from adapted germplasm (Forefront and MN07098-6) in addition to a genetic stock (LMPG). The associated markers in this study could be used to track and select for the identified QTL in wheat breeding programs.

Keywords: 90K iSelect; QTL; disease resistance; stem rust; wheat.

Grants and funding

The author(s) declare financial support was received for the research, authorship, and/or publication of this article. Financial support was obtained from the USDA-ARS National Plant Disease Recovery System.