Issue link: http://read.uberflip.com/i/775473
50 POTATO GROWER | FEBRUARY 2017 Diggin' In Diggin' In Diggin' In Diggin' In Diggin' In Diggin' In SEED | By Alan Westra, Idaho Crop Improvement Association & Kasia Kinzer, University of Idaho Interpreting post-harvest test results What It All Means Seed certification is a quality control program that consists of a number of components intended to ensure that specified quality standards are met. One of the more important of these components is post-harvest testing. Post-harvest testing may consist of an off-season grow-out in the field or greenhouse, laboratory testing, or some combination of these. The vast majority of Idaho seed lots are post-harvest tested in a winter grow-out conducted in Waialua, Hawaii. This grow-out consists of a visual assessment of grower-submitted samples for potato leaf roll virus and a laboratory test of harvested leaves for potato virus Y (PVY). Smaller, early-generation seed lots are usually retained for lab testing by the Idaho Crop Improvement Association's (ICIA) seed certification laboratory. The results of the post-harvest test are reported to the seed grower as a percentage based on the number of plants observed or tested. While the process of post-harvest testing and the reporting of results is relatively straightforward, we do occasionally receive questions about why reported post-harvest test results differ from what is observed in the field the following season. This has been a particular issue with PVY levels observed in some seed lots. Why does this occur? Idaho post-harvest test plots in Waialua, Hawaii, in December 2016