Location: Small Grains and Potato Germplasm Research
Project Number: 2050-21000-038-023-S
Project Type: Non-Assistance Cooperative Agreement
Start Date: Aug 1, 2024
End Date: Oct 31, 2025
Objective:
This project will identify new sources of genetic resistance to oat stem rust caused by Puccinia graminis f. sp. avenae (Pga) and crown rust caused by Puccinia coronata f.sp. avenae (Pca) in cultivated (Avena sativa) and wild (A. fatua) oat accessions, respectively. Accessions will be selected from the National Small Grains Collection. Selected resistant materials will be utilized in oat breeding programs.
Approach:
The National Small Grains Collection (NSGC) holds over 24,000 accessions classified in the Avena genus, including both cultivated oat and its wild relatives. Of these 10,288 accessions belong to the cultivated species A. sativa, and 1269 accessions belong to the wild species A. fatua. None of the wild accessions are characterized for any of oat diseases, while only 38.6% (3968 accessions) of the cultivated species were evaluated for their reaction to stem rust. Hence, the gene bank contains un-tapped genetic variation within these accessions, which may have the potential to provide oat cultivars with new genetic resistance to oat stem and crown rust diseases. This project will evaluate previously uncharacterized A. sativa (for stem rust) and A. fatua (crown rust) accessions in the NSGC identified by the ARS PI. Resistance to stem rust and crown rust diseases will be scored by the Cooperators under field conditions. Single panicles of accessions identified as resistant to moderately resistant to diseases will be collected by the University Cooperator for crossing. Some of the selected accessions will be crossed with elite but susceptible oat lines. This will allow development of populations that could potentially be used to determine the novelty of the effective genes. In addition, the effective genes carried in the wild or cultivated oat accessions may be transferred to the elite oat lines conferring to them resistance to stem and crown rust diseases. Crossing will be done following the conventional approach as both species are hexaploids without crossing barriers that arises due to ploidy level differences. The University Cooperator will deliver F1 or F2 seed to the ARS PI for population development and genotyping. The ARS PI, ARS Cooperator and University Cooperator will evaluate the resulting populations for disease resistance and agronomic performance under fall-planted and spring-planted growing conditions. The ARS PI and University Cooperator will collaborate in mapping disease resistance genes. Characterization and mapping of stem and crown rust resistance identified in the NSGC will ensure that the resistance deployed into subsequently released germplasm is effective against prevailing races of Pga and Pca.
