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United States Department of Agriculture

Agricultural Research Service


Location: Cereal Crops Research

2008 Annual Report

1a. Objectives (from AD-416)
Identify novel sources of resistance to Fusarium head blight (FHB), Stagonospora nodorum blotch (SNB), tan spot (TS), stem rust (SR) and Hessian fly (HF) among accessions of the primary gene pool of wheat. Develop and characterize synthetic hexaploid wheat lines, genetic stocks, and mapping populations useful for the genetic analysis of resistance to FHB, SNB, TS, SR, and HF. Identify novel QTL associated with resistance to FHB, SNB, TS, and end-use quality in tetraploid and/or hexaploid mapping populations. Isolate genes associated with host-pathogen interactions involving host-selective toxins produced by the SNB and TS pathogens. Conduct genomic analysis and fine mapping of genomic regions harboring genes conferring sensitivity to host-selective toxins and for Hessian fly resistance, and develop markers suitable for marker-assisted selection. Introgress genes/QTL for resistance to FHB, SNB, and TS into adapted germplasm using marker-assisted selection. Develop small grains germplasm and varieties with improved disease resistance and end-use quality using high-throughput genotyping and marker-assisted selection.

1b. Approach (from AD-416)
Survey tetraploid relatives of wheat for resistance to FHB, SNB, TS, SR, and HF. Develop synthetic hexaploid lines, near-isogenic lines, and mapping populations using conventional techniques. Develop genetic linkage maps in the segregating mapping populations using molecular markers and identify genomic regions harboring QTL associated with resistance or improved quality. Use QTL analysis to determine the chromosomal locations of genes governing resistance and quality traits. Target genomic regions harboring disease resistance loci, sensitivity to host-selective toxins, and Hessian fly resistance with PCR-based markers to identify markers suitable for marker-assisted selection. Isolate the Tsn1 gene using positional cloning techniques. Develop a high-resolution map of the H26 gene for genomic analysis and positional cloning. Develop improved germplasm through the use of conventional and marker-assisted selection. Release enhanced germplasm to wheat breeders and deposit germplasm stocks in the National Germplasm System. Utilize high-throughput marker platforms for genotyping lines for the small grains breeding community, and develop new high-throughput markers for important agronomic traits.

3. Progress Report
This is a new project initiated in April 2008 for which milestones will be initiated in FY2009. See the former CRIS project 5442-21000-030-00D for FY2008 milestones. We have initiated the screening of tetraploid accessions for reaction to SNB, TS, and FHB. We have initiated the development of hexaploid and tetraploid mapping populations for the molecular mapping of genes associated with resistance to FHB, TS, SNB, SR, and HF, and crosses to develop lines nearly isogenic for S. nodorum host-selective toxin sensitivity genes have been made. We have begun to validate Tsn1 candidate genes and conduct saturation mapping of the HF resistance gene H26. The introgression of genes/QTL for resistance to FHB, SNB, and TS into adapted germplasm is in process, and the high-throughput genotyping of regional breeding materials to conduct marker-assisted selection for varietal improvement is ongoing. These activities align with NP301 Component 2: Crop Informatics, Genomics, and Genetic Analyses, Problem Statement 2C Genetic Analyses and Mapping of Important Traits.

4. Accomplishments
1. This is a new project initiated in April 2008. See the progress report for the previous CRIS project 5442-21000-030-00D for recent accomplishments related to this project.

5. Significant Activities that Support Special Target Populations

Last Modified: 07/25/2017
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