Harvest and postharvest quality in short-day onions in variety trials in Georgia, 2000-03

Short-day onion (Allium cepa) variety trials were conducted in southeastern Georgia from 2000-03. Data collected and evaluated included total yield, graded yield, harvest date, number of seedstems, number of doubles, number of onion centers, bulb shape, disease incidence, bulb pungency, and storability in controlled atmosphere (CA) storage. Fifty-eight varieties were evaluated in the trials with 10 varieties appearing in all 4 years. Twenty-nine varieties appeared only once in the trials. Eight varieties had jumbo yields (greater than or equal to 3-inch diameter) that were not significantly different from the greatest jumbo yielding variety in 2 of the 4 years of testing and included 'Century', 'EX 19013', 'Georgia Boy', 'Mr. Buck', 'Sapelo Sweet', 'Savannah Sweet', 'Sweet Vidalia', and 'WI-609'. Early season varieties were strongly daylength dependent with foliar lodging occuring early and uniformly. Late season varieties were more prone to bacterial infection particularly if postharvest heat curing was employed. Although significant differences between varieties for seedstems (flower formation) and bulb doubling occurred almost every year, environmental conditions were an important part of their development. Five varieties had seedstems in 2 of the 3 years seedstems were prevalent that did not differ from the greatest number of seedstems for that year and included 'Cyclops', 'Georgia Boy', 'Mr. Buck', 'Pegasus', and 'SSC 6372 F1'. 'Sapelo Sweet' and 'Sweet Advantage' had more than 5% bulb doubling in 3 years of the trials. Pungency as measured by pyruvate analysis ranged from 1.1 to 5.4 micromol.g(-1) fresh weight (FW) over the 4 years of trials. There were nine varieties that were, for 2 years or more, among the greatest in percent marketable onions after 4.5 months of CA storage: 'Georgia Boy', 'Granex 1035', 'Granex 33', 'Ohoopee Sweet', 'Sapelo Sweet', 'Savannah Sweet', 'Sweet Melissa', 'Sweet Melody', and 'SRO 1000'.