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ARS Home » Southeast Area » Raleigh, North Carolina » Plant Science Research » Research » Publications at this Location » Publication #356282
Research Project: Genetic Improvement of Small Grains and Characterization of Pathogen Populations

Location: Plant Science Research

Title: Mapping adult plant stem rust resistance in barley accessions Hietpas-5 and GAW-79

Author
item CASE, AUSTIN - University Of Minnesota
item BHAVANI, SRIDHAR - International Maize & Wheat Improvement Center (CIMMYT)
item MACHARIA, GODWIN - Kenya Agricultural And Livestock Research Organization
item PRETORIUS, ZACHARIAS - University Of The Free State
item COETZEE, VICKY - Pannar
item KLOPPERS, FREDERICK - Pannar
item TYAGI, PRIYANKA - North Carolina State University
item Brown-Guedira, Gina
item STEFFENSON, BRIAN - University Of Minnesota

Submitted to: Theoretical and Applied Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/22/2018
Publication Date: 11/2/2018
Citation: Case, A.J., Bhavani, S., Macharia, G., Pretorius, Z., Coetzee, V., Kloppers, F., Tyagi, P., Brown Guedira, G.L., Steffenson, B.J. 2018. Mapping adult plant stem rust resistance in barley accessions Hietpas-5 and GAW-79. Theoretical and Applied Genetics. 131:2245-2266.

Interpretive Summary: Stem rust is a devastating disease of cereal crops worldwide. In North America, the stem rust resistance gene Rpg1 has protected barley from serious losses for more than 60 years; however, widely virulent stem rust races from Africa in the Ug99 group threaten the crop. The accessions Hietpas-5 and GAW-79 both possess moderate-to-high levels of adult plant resistance to stem rust and are the sources of the resistance genes Rpg2 and Rpg3, respectively. To identify genes for stem rust resistance in Hietpas-5 and GAW-79, two biparental populations were developed with Hiproly, a stem rust-susceptible accession. Both populations were phenotyped to the North American stem rust races in St. Paul, Minnesota, and to African Pgt races in Njoro, Kenya. In the Hietpas-5/Hiproly population, a major effect QTL was identified in chromosome 2H, which is proposed as the location for Rpg2. In the GAW-79/Hiproly population, a major effect QTL was identified in chromosome 5H and is the proposed location for Rpg3. These QTLs will enhance the diversity of stem rust resistance in barley improvement programs.

Technical Abstract: Stem rust is a devastating disease of cereal crops worldwide. In barley (Hordeum vulgare ssp. vulgare), the disease is caused by two pathogens: Puccinia graminis f. sp. secalis (Pgs) and Puccinia graminis f. sp. tritici (Pgt). In North America, the stem rust resistance gene Rpg1 has protected barley from serious losses for more than 60 years; however, widely virulent Pgt races from Africa in the Ug99 group threaten the crop. The accessions Hietpas-5 (CIho 7124) and GAW-79 (PI 382313) both possess moderate-to-high levels of adult plant resistance to stem rust and are the sources of the resistance genes Rpg2 and Rpg3, respectively. To identify quantitative trait loci (QTL) for stem rust resistance in Hietpas-5 and GAW-79, two biparental populations were developed with Hiproly (PI 60693), a stem rust-susceptible accession. Both populations were phenotyped to the North American Pgt races of MCCFC, QCCJB, and HKHJC in St. Paul, Minnesota, and to African Pgt races (predominately TTKSK in the Ug99 group) in Njoro, Kenya. In the Hietpas-5/Hiproly population, a major effect QTL was identified in chromosome 2H, which is proposed as the location for Rpg2. In the GAW-79/Hiproly population, a major effect QTL was identified in chromosome 5H and is the proposed location for Rpg3. These QTLs will enhance the diversity of stem rust resistance in barley improvement programs.