Improve virus detection techniques and to update quarantine measures of fragaria and rubus in respect to germplasm importation and movement

The U.S. Department of Agriculture's Animal and Plant Health Inspection Service (APHIS) awarded a $205,355 Cooperative Agreement to the University of California, Davis, effective September 1, 2025, through August 31, 2026, under the Plant and Animal Disease, Pest Control, and Animal Care program (CFDA 10.025). The award supports research to improve virus detection techniques and update quarantine measures for strawberry (Fragaria) and blackberry/raspberry (Rubus) germplasm importation and movement. UC Davis will compare traditional graft indexing protocols with modern diagnostic methods, including reverse transcription quantitative polymerase chain reaction (RT-qPCR) and high-throughput sequencing (HTS), to identify more reliable viral disease screening approaches for berry germplasm.

The primary deliverables include optimized virus detection protocols and regulatory recommendations for disease testing and quarantine timeframes applicable to strawberry, blackberry, and raspberry germplasm imports. By validating superior diagnostic methods, this project will enable earlier germplasm availability following controlled importation, accelerate the release of disease-free germplasm to breeders and stakeholders, and shorten breeding cycles for cultivar development. A subaward to Oregon State University will support student participation in the research activities.

Current protocols for berry germplasm report require graft indexing to screen for viruses, but this process can be unreliable compared to modern diagnostic methods. The objectives of this research are: 1) compare graft indexing of fragaria to RT-qpcr and high throughput sequencing detection (HTS) methods for viral diseases, 2) compare graft indexing of rubus to RT-PCR and HTS methods for viral diseases, and 3)optimize and update virus detection protocols and provide recommendations to regulatory agencies on disease testing and quarantine time for fragaria and rubus. This project will deliver improved diagnostic protocols for strawberry, blackberry, and raspberry germplasm imports. Earlier germplasm availability after controlled importation and releasing germplasm quicker to breeders and stakeholders will shorten the breeding cycle and enhance cultivar development, as well as facilitating the production of disease-free germplasm. A subaward with oregon state university will support a student conducting part of the work.