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

Abstract

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 was no 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 parameter becomes the standard, several varieties would have been excluded, but not all of the early Japanese overwintering types. Finally, in 2005 a consumer acceptance study was conducted with 30 consumers evaluating each of 49 varieties resulted in an LSD (5%) with no differences between the top 38 entries, which included several of the Japanese overwinter types. It is becoming clear that concerns over flavor with these early varieties are unfounded.