UG99 Stem rust (aka TTKSK, African stem rust races in the UG99 lineage)

We are working with colleagues at the USDA-ARS Forage Seed and Cereal Research Unit , Corvallis, OR; ARS, Raleigh, NC; and University of Minnesota - St. Paul, MN to characterize levels of barley seedling and adult plant resistance to stem rust UG99, identify the QTLs/genes responsible for the resistance phenotype, and to deploy resistance alleles in new genetic backgrounds. Thanks to USDA-ARS NACA funding. 

In this project, we are developing UG99-resistant resistant germplasm and by leveraging resources provided by the Barley Stripe Rust NACA, we are also assesing this germplasm for resistance to othe rusts. We are now into our second cycle of doubled haploid resistance allele inrogression and deployment.

Cycle 1

  • Parents

Resistance donors: The donors are spring habit varieties, both hulled (TR02272, SB97197) and hull-less (MC0181-11, MC0181-31, SH98076, SH98073). This germplasm was developed by Drs. Brian Rossnalgel and Aaron Beattie (University of Saskatchewan) and Bill Legge (Agriculture and Agri-food Canada, Manitoba). Seed of each accession, harvested from plants verified for resistance phenotype, was provided by Dr. Brian Steffenson (University of Minnesota).
Adapted germplasm:  The rpg4/Rpg5 donors were crossed with a range of germplasm from the OSU Barley Breeding Program, including winter and spring growth habit; hulled and hull-less; 2-row and 6-row; malting and food types.

  • Doubled haploids

123 doubled haploids were generated from 14 cross combinations among the Cycle 1 parents. All have been genotyped (Illumina 9K) and allele-specific genotyping for Rpg1, rpg4/Rpg5 is in progress. All have been phenotyped for UG99 stem rust at the Steffenson lab (University of Minnesota) and genotyped for stripe and leaf rust via the barley stripe rust NACA in collaboration with the Dubcovsky lab (UC Davis) and the Chen lab (ARS-Pullman). As of September, 2016 17/123 have been selected and characterized for resistance to UG99 stem rust, stripe rust, and leaf rust. Seed of the resistant accessions is available - ordering instructions.

Cycle 2

  • Parents

Resistance donors: The donors are TTKSK resistant selections from Cycle I.
Adapted germplasm:  The Cycle I selections were crossed with winter/facultative malting and multi-use germplasm from the OSU program and accessions from the UC Davis  from the OSU Barley Breeding Program.

  • Doubled haploids

384 doubled haploids were generated. All will be genotyped (Illumina 50K) and allele-specific genotyping for rpg4/Rpg5. All will be phenotyped for TTKSK (seedling) and QCC (adult plant) resistance at the Steffenson lab (University of Minnesota) and genotyped for stripe and leaf rust via the barley stripe rust NACA in collaboration with the Dubcovsky lab (UC Davis) and the Chen lab (ARS-Pullman).