2013 Annual Report
1a.Objectives (from AD-416):
Produce F3 populations of Northwest-adapted barleys crossed with sources of genes for resistance to the Ug99 stem rust pathogen.
1b.Approach (from AD-416):
Make crosses between Ug99-resistant barley lines and various market types of barley adapted to Pacific Northwest production. The Ug99 resistant lines will be from ICARDA/CIMMYT material previously tested by Brian Steffenson at University of Minnesota, and the locally-adapted lines will include winter barley of malting, food and forage types. Conduct field evaluations of F2 populations for agronomic traits including cold tolerance and resistance to local diseases, then advance to the F3 generation for further testing. The materials resulting from this SCA will be available for further development and testing to select materials that are locally adapted and have resistance to Ug99. This SCA supports research conducted under National Program (NP) Number303, Plant Diseases. The research is conducted as part of ARS research project 5358-22000-035-00D, augmented by the FY2010 Program Increase for Research to Strengthen Grain Disease Research to Reduce World Hunger.
This research supports the national Ug99 barley breeding effort by evaluating Ug99-resistant lines for agronomic adaptation to Pacific NW conditions, and by producing derivative barley populations for further UG99 resistance assessment. This research relates to objective 1C of the in house project, “Identify germplasm and increase seed for wheat and barley lines with resistance to stem rust Ug99”. During the 2012-2013 crossing season, 137 crosses were made to UG99 resistant lines. The resistance is conferred by alleles at the rpg4/rpg5 gene complex. Therefore, in future cycles of selection, a perfect marker for resistance is available. This resistant germplasm was provided by Canadian research institutes and includes 6 spring lines, 4 hull-less (MC0181-11, MC0181-31, SH98076, SH98073) and 2 hulled (TR02272, SB97197). The resistant lines were crossed with material adapted to the Willamette Valley. Of the 137 total crosses, 26 were made to adapted winter malt lines, 27 were made to adapted spring malt lines, 18 were made to F1 malt crosses, 24 were made to adapted winter food lines, 27 were made to adapted spring food lines, and 15 were made to adapted facultative food lines. From the crosses made, 25 were selected to go into doubled haploid production. Eighty F1 crosses were spring planted in head rows for observation and selection. The remaining crosses were kept and will be used for intermating and backcrossing in fall of 2013. In a parallel line of research, Sequenom assays were designed for the rpg4/rpg5 locus and used to survey a range of exotic germplasm. Interestingly, the resistant haplotype was observed in a number of accessions from the Himalayan region. We followed up on this lead and assessed the seedling resistance phenotype of this germplasm, in collaboration with researchers at University of Minnesota. The haplotype was not perfectly correlated with phenotype, suggesting that additional factors are required for resistance.