Location: Cereal Disease Lab
Project Number: 5062-21220-025-025-S
Project Type: Non-Assistance Cooperative Agreement
Start Date: Sep 1, 2023
End Date: Aug 31, 2025
Objective:
1. Screening wheat breeding germplasm for response to virulent foreign strains of the stem rust pathogen in appropriate biocontainment facilities; 2. Incorporate effective stem rust resistance genes into elite U.S. wheat lines through backcrossing; and 3. Characterizing new stem rust resistance genes including those derived from screening diverse wheat and wheat wild relative germplasm in addition to newly synthesized novel haplotypes of wheat stem rust resistance genes.
Approach:
1. Screen wheat breeding germplasm for response to virulent foreign strains of the stem rust pathogen in biocontainment facilities. Wheat germplasm derived in house and received from collaborators will be assessed at the seedling stage for response to multiple strains of the wheat stem rust fungus in appropriate containment facilities.
2. Incorporate effective stem rust resistance genes into elite U.S. wheat lines through backcrossing. Stem rust resistance genes that have been identified to be broadly effective to virulent, foreign strains of the stem rust pathogen will be prioritized for incorporation into elite U.S. wheat lines. Further, multiple stem rust resistance genes will be combined during backcrossing. Elite U.S. wheat lines will be selected in coordination with collaborating wheat breeders. Fixed lines at the BC4F3 generation will be derived. Lines will be validated for presence of stem rust resistance genes through molecular marker analyses and seedling stem rust assays.
3. Characterize new stem rust resistance genes including those derived from screening diverse wheat and wheat wild relative germplasm in addition to newly synthesized novel haplotypes of wheat stem rust resistance genes. A total of 10 new forms of wheat stem rust resistance genes will be synthesized. The Golden Gate cloning method will be utilized for construct design and assembly. Transgenic plants of the cultivar 'Fielder' will be created for each new resistance form. Evaluation of transgenics with different stem rust pathogen strains will be conducted using stem rust seedling tests. In addition, new stem rust resistance genes will be characterized from previously identified resistance sources through genetic mapping.
