MANDATED VIDALIA ONION VARIETY TRIALS; HOW WELL HAS IT WORKED?

George Boyhan*, William M. Randle, Anna V. Resurreccion, Reid L. Torrance, Ronald H. Blackley Jr., M. Jefferson Cook, Heath Paradice, C. Randell Hill, and J. Thad Paulk

University of Georgia, Department of Horticulture, East Georgia Extension Center, PO Box 8112, GSU, Statesboro, GA 30460. Email: gboyhan@uga.edu

Beginning in 2001 the Georgia Department of Agriculture mandated testing of new and existing Vidalia onion varieties under the supervision of the University of Georgia. This was prompted by the introduction of early maturing Japanese overwintering varieties, which were perceived to be more pungent than traditional varieties grown in the Vidalia district. The testing primarily focused on flavor and pungency (pyruvate analysis) to determine suitability as a Vidalia onion variety. Our testing compared varieties to an industry standard, initially variety Granex 33, which was later switched to ‘Savannah Sweet’. In almost all flavor and pungency tests differences were detected among the varieties, however, since the chosen standard variety usually fell within the middle of the tested range there never was any consistent rejection of a variety. If a different statistical approach had been used it would have been possible to reject several varieties over the course of testing. Using multiple comparison with the best (MCB), a modification of Dunnett’s test where the best performing variety for a particular test becomes the standard, several varieties would have been excluded, but not all of the early Japanese overwintering types. Finally, in 2004 two varieties WI-609 and WI-3115, Japanese overwintering types, were removed from the list due to poor performance in grower fields. Misshaped and soft bulbs with ‘WI-609’ resulting substantial losses prompted the removal of these varieties. In addition, several new Japanese overwintering varieties that would have otherwise qualified were not recommended for inclusion.

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