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ARS Home » Midwest Area » St. Paul, Minnesota » Cereal Disease Lab » Research » Research Project #429338

Research Project: Understanding Stem Rust Resistance in Barley and Germplasm Enhancement

Location: Cereal Disease Lab

Project Number: 5062-21220-023-07-S
Project Type: Non-Assistance Cooperative Agreement

Start Date: Aug 1, 2015
End Date: Jul 31, 2020

Objective:
The primary goal of this project it to develop agronomically advanced malting cultivars with broad-based stem rust resistance. This will be accomplished by: 1) developing populations from known sources of stem rust resistance identified in Kenya; 2) determining the genetics of resistance in segregating populations; 3) mapping the resistance loci to specific chromosomal regions; 4) identifying closely linked molecular markers for the loci that can be used in marker assisted selection; and 5) select and release new barley germplasm with enhanced resistance.

Approach:
25 different populations with various sources of stem rust resistance in cultivated, landrace, and wild barley accessions have been developed. Eight populations will be advanced for genetic and mapping analysis. These populations will be screened for resistance to Ug99 and its variants in seedling tests by cooperator and as adult plants in Kenya. The recently cloned Rpg5 and rpg4 genes (Brueggeman et al., 2008) have been shown to provide resistance to race Ug99 and two of its variants (Steffenson et al. 2009). A set of resistant parents and susceptible elite breeding lines from the Midwest breeding programs will be assembled and the rpg4 and Rpg5 alleles sequenced to identify SNPs that are diagnostic for the resistance alleles. ARS will develop a set of markers that will be used for marker-assisted selection to quickly deploy this genetic resistance through marker-assisted backcrossing. Resistant parents and newly developed and presumably resistant backcross derived lines will be tested by Cooperator for resistance to Ug99 and in Kenya or Ethiopia. Additional backcrossing and marker screening will be performed. Screening results will be made publicly available. Barley germplasm with enhanced resistance will be evaluated and released to breeding programs to improve regionally adapted cultivars.