Five-Year Evaluation of Short-Day Onion Varieties

Abstract

Short-day onion (Alliium cepa L.) production is important in many regions with mild winters. Onions are particularly important in southeastern Georgia, where Vidalia onions are produced. These onions represent the vegetable with the greatest farm gate value in the state and variety trials are an important part of University of Georgia research for this industry. Short-day onion variety trials were conducted in southeastern Georgia from 2004 to 2008. Data collected and evaluated included total yield, graded yield, harvest date, number of seed stems, number of doubles, number of onion centers, bulb shape, disease incidence, bulb pungency, and storability in controlled-atmosphere (CA) storage. Not all data were collected in all years. There were between 35 and 68 entries in the trials. Sixteen varieties appeared in all 5 years. Total yields were from ˜23,000 to ˜72,000 kg•ha−1. Marketable yields ranged from 23% to 99% of total yield depending on variety and year. Average marketable yield for the 5 years ranged from 61% to 82%, with the 2006–2007 season having the best average marketable yield. In general, later maturing varieties had lower marketable yields because of bacterial diseases such as sour skin, caused by Burkholderia cepacia Palleroni & Holmes 1981 ex Burhkolder 1950, that developed as temperature increased. Seed stems (flowering) and doubled bulbs differed over years. Both are believed to occur because of a combination of environmental and varietal effects. Average percentage marketable onions, after removal from CA storage, ranged from 48% to 82% depending on year. Botrytis neck rot, caused by Botrytis allii (Munn) Yohalem, was the primary disease affecting marketability post-CA. Onions held for 2 weeks after removal from CA storage under ambient conditions could see a reduction in average marketable onions from 17% to 33% depending on year.