Crop Reports
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CROP REPORTS or multiplier onions (A. cepa) and shallots. By far, most of the cultivated onions fall into the Common Onion Group, noted for producing a single bulb per plant. Onions are also classed by their response to day length. Short-day on- ions require a relatively short day length Crop to trigger bulbing. In the Vidalia onion growing region, bulbing begins at day lengths slightly over 11 h. In compari- son, intermediate-day and long-day Reports onions bulb at day lengths that exceed 13 and 14 h, respectively (Brewster, 1994); however, the exact day length required for bulb initiation may vary from season to season and from field to field within sea- consistent as expected for extending sons, because several other factors includ- Vidalia Onions— onion shelf life. In addition, some grow- ing, temperature, leaf area, variety, and Sweet Onion ers have expressed concern over some intercepted light significantly affect the new varieties being too hot to be called process. Within the short-day varieties Production in Vidalia onions. Other varieties have in- grown in the Vidalia region, differential creased problems with late season dis- bulbing responses result in onions being Southeastern eases. Vidalia onions, however, remain harvested from the beginning of April to one of the bright spots in American the beginning of May in most years. Even Georgia agriculture by providing good returns though factors other than day length influ- for the producers. Although somewhat ence bulb development, classifying onion 1 uncertain, the Vidalia onion’s future varieties according to day length response George E. Boyhan and remains promising. For the industry to is important to seed companies and grow- Reid L. Torrance2 continue to prosper issues concerning, ers because it indicates varietal adaptation increased competition, production prob- to specific regions of production. The lems including variety selection, and use USDA National Agricultural Statistics ADDITIONAL INDEX WORDS. Allium cepa, of CA storage have to be addressed. Service uses the classification of spring spring nonstorage onions, short-day Vidalia onions are also referred to nonstorage, summer nonstorage, and onions, dry-bulb onions, Granex, as yellow onions, salad onions, green summer storage onions to report onion Grano, Bermuda onions, and dry bulb onions. In order to statistics (USDA, 2000). This roughly be a Vidalia onion they must be a yellow coincides with the short-day, interme- outheastern Georgia is ideal for Granex type. Salad and green onions diate-day, and long-day classes. sweet onion (Allium cepa) pro refers to immature onions. They are The short-day onions grown in S duction. This region is noted for comparable to scallions, however they southeastern Georgia bulb relatively its mild winters, low sulfur soils, and tend to be longer in total length with early, usually during late February or abundant water supply. Vidalia onions larger leaves and an expanded bulb, early March as the day length increases. with their national reputation for mild- about 1 inch (2.5 cm). For this reason, seeds of such varieties ness have dramatically increased in avail- The objective of this article is to are sown in the fall when days are get- ability in the last 10 to 12 years. Several highlight the Vidalia onion industry, ting shorter. This will enable seedlings factors have contributed to this increase and to describe its past, present and to emerge and develop sufficient leaf including; national name recognition, future with respect to production prac- area before bulbing is initiated in the regulatory control of the Vidalia name, tices, issues of concern, and marketing. spring. Short-day onions planted in the ideal region of production, Marketing spring would begin to bulb almost im- Order 955 (USDA, 1989), and the Classification mediately resulting in very poor yields. adoption of controlled atmosphere (CA) Onions are monocots and mem- Origin and variety storage. These factors have resulted in a bers of the Alliacae family, which in- 3-fold increase in production since 1989 cludes garlic (A. cepa), leek (A. development (USDA, 2001). ampeloprasum), japanese bunching on- Onions have been known to be in The growth of the Vidalia onion ion (A. fistulosum), shallots (A. cepa), cultivation for at least 5000 years. They industry has not been without challenge chives (A. schoenoprasum), elephant are native to the Eurasia region of Tur- or controversy. Wide fluctuations in garlic (A. ampeloprasum), and a few key, Afghanistan, Iran, Pakistan, and performance from one year to the next ornamental types (Brewster, 1994). into northeastern China and Mongolia have caused CA storage not to be as Onions can be organized into two (Brewster, 1994). Wild alliums are typi- broad groups, the Common Onion cally found in open arid regions with 1University of Georgia, Dept. of Horticulture, East Group and the Aggregatum Group cool climates. Georgia Extension Center, P.O. Box 8112, GSU, Statesboro, GA 30460. (Brewster, 1994). The Aggregatum Considered a cool-season crop, 2Tattnall County Cooperative Extension Service, P.O. Group is noted for producing clusters of onions have been adapted to a wide Box 580, Reidsville, GA 30453. bulbs. The two main entries are potato geographic area through selection for 196 G April–June 2002 12(2) CropRpt 196 2/27/02, 9:50 AM States were ‘Valencia’, which came from ers considered these varieties to be too Spain and ‘White Bermuda’, which came pungent to market as Vidalia onions. from Italy via Bermuda (Goldman and The elevated pungency levels were es- Havey, 1998). These early populations pecially troublesome because these vari- were the foundation for short-day on- eties would be the first onions offered to ions in New Mexico, Texas, and Geor- the public in the spring. Many have gia. ‘Valencia’ was ultimately the source suggested that it is not the pungency, for ‘Texas Early Grano 951C’, which but rather bitter off-flavors, that are the was one of the parents for the hybrid problem with the Japanese varieties. ‘Granex YB986’. A selection of ‘Excel’, Concerns related to the flavor of became the other parent in the ‘Granex’ these early Japanese overwintering vari- hybrid (Goldman and Havey, 1998). eties prompted the Georgia Depart- The ‘Granex’ name is conjoined from ment of Agriculture in 1997 to restrict the names ‘Grano’ and ‘Excel’. This Vidalia onion varieties to 12 varieties Fig. 1. Granex onion pedigree. hybrid became the basis for the Vidalia (Table 1). These varieties were: Sweet onion industry (Fig. 1). Vidalia, Granex 33, Savannah Sweet, bulbing response to day length. Onions Variety development has contrib- Pegasus, Granex F1, Sweet Success, have been adapted to most regions of uted to the release of several varieties Dessex, Southern Belle, Southern the world from the most northern ar- adapted to the Vidalia onion growing Honey, Rio Bravo, Mr. Max, and Ado- able climes to the tropics. region. One of the most popular early nis. In 1999, this issue was again brought The biennial nature of onions poses varieties, Granex 33, is still grown today. to the fore and three varieties: Sugar challenges to plant breeders. In addi- The industry’s success, over the past de- Queen, Spring Express, and Sweet Dixie tion, breeding efforts must be specific to cade, has fostered the release of several new were identified by the Georgia Depart- particular regions according to day varieties. Currently about 50% of the ment of Agriculture as unacceptable length requirements. Selection of new acreage is planted to ‘Sweet Vidalia’, and were not allowed to be grown. In varieties is therefore time consuming which is an early to midseason onion. addition, rules were adopted that man- and difficult. The process can be accel- In the mid-1990s, a new type of dated the University of Georgia was to erated with seed-to-seed production, onion was introduced to the Vidalia make variety recommendations to the which forces the plant to produce seed onion industry. These Japanese over- Georgia Department of Agriculture based in the same season it is sown. This can be wintering onions had two important on variety trial including pyruvate analyses troublesome because ease of seedstem advantages over the traditional varieties. and taste panel evaluations (Georgia De- formation (bolting) is considered unde- They were 2 weeks earlier than previous partment of Agriculture, 2001). sirable in the bulb crop. On the other varieties and they had very good foliar In 2000, the Georgia Department hand, because bulb quality and yield are disease resistance. However, many grow- of Agriculture attempted to expand the of utmost importance in the breeding process, and seedstems are considered Table 1. List of current and proposed Vidalia onion varieties. objectionable, selection for bolting re- sistance often results in plants with poor Variety Source Season seed producing ability. Adonisz Harris Moran The 20th century has seen the de- Cyclops (XP 6995) Asgrow Late velopment of modern plant breeding Dessexz Sunseeds techniques, which have resulted in DPS 1032y,x D. Palmer Midseason tremendous advancements in yield and Granex 33 Asgrow Midseason quality of onions. The discovery of male Mr. Maxz Sunseed sterility in onions in 1925 led to a method Pegasus Asgrow Late y,x of creating F1 hybrid onions (Goldman PS 7092 Petoseed Midseason and Havey, 1998). Male-sterile plants can Rio Bravoz Sunseeds be interplanted with pollenizer plants re- Savannah Sweet Petoseed Midseason sulting in large-scale production of F1 seed Southern Belle D. Palmer Midseason precluding the need for controlled hand Southern Honey D. Palmer Midseason pollinations. F1 hybrids have advantages Sunseeds Improved Granex F1 Sunseeds Midseason over open-pollinated varieties in that supe- Sweet Advantage (1058)y D. Palmer Early rior varieties can be developed more quickly Sweet Melissa (Sunex 1519) Sunseeds Midseason and they exhibit heterosis or hybrid vigor Sweet Melody Sunseeds Midseason (Simmonds, 1979).