Location: Small Grains and Potato Germplasm Research
Project Number: 2050-21000-038-030-S
Project Type: Non-Assistance Cooperative Agreement
Start Date: Sep 1, 2026
End Date: Aug 31, 2027
Objective:
This project will identify new sources of adult plant resistance to stem rust caused by Puccinia graminis f. sp. avenae and to map the associated QTL in mapping populations developed from accessions maintained by the National Small Grains Collection
Approach:
The National Small Grains Collection (NSGC) maintains more than 24,000 Avena accessions, representing both cultivated oat and its wild relatives. Among these, 10,288 accessions belong to the cultivated species Avena sativa, while the remainder represent various wild species. To date, none of the wild accessions have been evaluated for resistance to oat diseases, and only 38.6% (3,968 accessions) of the cultivated accessions have been assessed for their response to stem rust. As a result, the NSGC holds substantial untapped genetic diversity that may contain novel sources of resistance to oat stem rust.
This project will evaluate previously uncharacterized NSGC oat accessions identified by the ARS PI as well as previously developed mapping populations. Stem rust resistance will be assessed under field conditions by the University Cooperator. For accessions exhibiting resistant to moderately resistant reactions, the University Cooperator will collect single panicles for further study.
A subset of these resistant accessions will be crossed with elite but susceptible oat lines to develop segregating populations. The ARS PI and University Cooperator will jointly conduct genetic mapping to identify QTL associated with stem rust resistance. This will enable determination of the novelty of the effective resistance genes and facilitate the transfer of those genes into elite germplasm.
Characterizing and mapping resistance present in NSGC accessions will ensure that resistance deployed in future germplasm releases is both effective and durable against prevailing races of Pga.