Most certified seed agencies in the US utilize a post-harvest grow out to determine seed lot certification. This robust diagnostic test has eliminated seed lots with high levels of PVY from being certified for many years. However, the logistics of breaking tuber dormancy, shipping and planting PHT tuber samples in Hawaii, inconsistent plant emergence, and delayed PHT results are drawbacks. Direct tuber testing (DTT) could be utilized to eliminate many of the drawbacks associated with the current grow out. Considerations when using DTT includes accuracy of the testing, additional lab equipment and labor, the legal acceptance of this new test, and a lack of quality control data. We will take a close look at how the Colorado Certification Program is currently using DTT to test the dormant variety Canela Russet. We will also explore some challenges with DTT and how different certification programs are addressing this issue.
Andrew Houser, Manager, Colorado Potato Certification Service, Colorado State University