Source: UNIVERSITY OF GEORGIA submitted to NRP
EVALUATION OF ONION CULTIVARS AND CULTURAL PRACTICES SUITABLE FOR SOUTH GEORGIA
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
COMPLETE
Funding Source
HATCH
Reporting Frequency
Annual
Accession No.
0196058
Grant No.
(N/A)
Cumulative Award Amt.
(N/A)
Proposal No.
(N/A)
Multistate No.
(N/A)
Project Start Date
Jun 1, 2003
Project End Date
May 30, 2009
Grant Year
(N/A)
Program Code
[(N/A)]- (N/A)
Recipient Organization
UNIVERSITY OF GEORGIA
200 D.W. BROOKS DR
ATHENS,GA 30602-5016
Performing Department
HORTICULTURE
Non Technical Summary
Sweet onions need to be of suitable quality and high yielding while minimizing inputs. This project will evaluate new varieties as to suitability for sweet onion production as well as new production practices such direct seeding and monitoring fertility to minimize inputs.
Animal Health Component
75%
Research Effort Categories
Basic
(N/A)
Applied
75%
Developmental
25%
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
2041451106075%
2051451106025%
Knowledge Area
204 - Plant Product Quality and Utility (Preharvest); 205 - Plant Management Systems;

Subject Of Investigation
1451 - Onion, garlic, leek, shallot;

Field Of Science
1060 - Biology (whole systems);
Goals / Objectives
1. Evaluate new and existing cultivars for yield, graded yield, disease incidence, seedstems, doubles, controlled atmosphere storability, harvest date, bulb shape and color, pungency, and sugar content. These results will be used in part to determine suitability for addition to the official Vidalia onion cultivar list maintained by the Ga. Dept. of Agriculture. 2. Develop the protocols necessary for direct-seeding short-day onions in southeast Georgia. This will include planting date, cultivar selection, drip irrigation, fertility requirements, seed coating, and planting method. 3. Evaluate fertility requirements for nitrogen, phosphorus, and potassium from transplanting to final harvest. These results will be used to upgrade soil test fertilization recommendations. 4. As a preliminary step, attempt to correlate foliar nitrogen analysis with expressed onion root sap nitrate levels.
Project Methods
Objective 1. Evaluate new and existing cultivars. All cultivar entries will be evaluated in a randomized complete block design (RCBD) with four replications for three years. Seed will be sown in seedbeds in the fall of each year for transplanting at final spacing in November/December. Fertilization will follow soil test recommendations for onions. Onions will be harvested at maturity (April-May) for that cultivar. All cultivars will be evaluated for field yield, graded yield, days to harvest, bulb shape (globe, flat, spindle etc.), pungency (umol pyruvate/g tissue), sugar content (percent soluble solids), bolting, bulb doubling, disease incidence, and controlled atmosphere storability. Objective 2. Develop protocols for direct-seeding onions. Split-plot designs with 2-4 replications will be used to evaluate a variety of parameters affecting direct seeding. A vacuum planter will be used with coated seed to improve singulation. Onion cultivars, planting dates, fertility, and mowing will be evaluated for direct-seeded onions. Data to be collected will include yield, plant stand and spacing, environmental tolerance, and seedstem formation. Objective 3. Rates of nitrogen, phosphorus, and potassium will be evaluated in light of current soil test recommendations. Yields and foliar nutrient status will be evaluated in studies utilizing a RCBD experiment with 4 replications. Foliar nutrient status will be determined by the Soil, Plant, & Water Testing Laboratory at the University of Georgia using standard laboratory techniques. Objective 4. Root sap will be expressed with a root sap press express from onions in objective 3 to assess nitrate levels and will be correlated with foliar nitrogen levels. Onion root nitrate levels will be measured using a Cardy nitrate meter. This may become an easy to use management tool for growers.

Progress 06/01/03 to 05/30/09

Outputs
OUTPUTS: Objective 1: The 2008 variety trial had 68 entries from 12 different seed companies. Eight companies had multiple varieties entered. Data collected included information on yield, graded yield, storability in controlled atmosphere storage, pungency (pyruvate analysis), and sweetness (soluble solids). As in the previous year, a subset of the variety trial that included nine varieties had no fungicide applications during the season. These onions at harvest performed comparably to the main trial, and unlike the previous season were comparable to sprayed onions after 4.5 months in controlled atmosphere storage. Objective 2: Results of the direct seeding short-day onions has been published in a refereed publication. Objective 3: Results of onion fertility evaluations have been published in a refereed publication as well as being incorporated in the updated onion production bulletin. Organic fertilization for transplant production has been published. In addition, organic fertilization work was completed with dry bulb onions and has been submitted for publication. Fertility changes have also been incorporated into the variety trial. Objective 4: Has been dropped. PARTICIPANTS: Not relevant to this project. TARGET AUDIENCES: Information from this Hatch project has been shared with growers, extension personnel, and the public. PROJECT MODIFICATIONS: Not relevant to this project.

Impacts
The short-day variety trial continues to generate new information that growers are keenly interested in. New varieties continue to be introduced to the industry. Seven new varieties were added to the official Georgia Department of Agriculture's list of approved Vidalia onion varieties. There are now 28 varieties on the official list. This is the final report for this project. The principal investigator has been transferred to cover organic and sustainable vegetable production.

Publications

  • Nischwitz, C., G. Boyhan, H. Sanders, S. Mullis, J. Wilson, and R. Gitaitis. 2008. Effect of double-cropping onions behind either pear millet (Pennisetum glaucum) or corn (Zea mays), year 2. Ga. Onion Res.-Ext. Rpt. Publ. No. 3-2008:3-5.
  • Bateman, A., D. MacLean, and G. Boyhan. 2008. Annual report of the Vidalia onion research laboratory University of Georgia - Tifton campus. Ga. Onion Res.-Ext. Rpt. Publ. No. 3-2008:14-17.
  • Boyhan, G., D. MacLean, R. Torrance, M. Dollar, S. Curry, C. Riner, B. McElvany, R. Hill, T. Bateman, and D. Thigpen. 2008. Short-day onion variety trial, 2008. Ga. Onion Res.-Ext. Rpt. Publ. No. 3-2008:18-28.
  • Boyhan, G., D. MacLean, D. Langston, R. Torrance, M. Dollar, S. Curry, C. Riner, B. McElvany, R. Hill, T. Bateman, and D. Thigpen. 2008. Vidalia onion no-spray trial, 2008. Ga. Onion Res.-Ext. Rpt. Publ. No. 3-2008:29-32.
  • Boyhan, G., R. Hill, D. Thigpen. 2008. Evaluation of fertility programs in onion production. Ga. Onion Res.-Ext. Rpt. Publ. No. 3-2008:42-56.
  • Boyhan, G., D. MacLean, T. Batemen, R. Hill, and D. Thigpen. 2008. Preliminary evaluation of storage conditions and varieties' effect on vidalia onion maretability and weight loss. Ga. Onion Res.-Ext. Rpt. Publ. No. 3-2008:57-59.
  • Boyhan, G., R. Hill, and D. Thigpen. 2008. Evaluation of organic fertilizers and preplant timing application on Vidalia onion production. Ga. Onion Res.-Ext. Rpt. Publ. No. 3-2008:60-62.
  • Boyhan, G., A. Caylor, D. Porch, R. Hill, and D. Thigpen. 2008. Onion variety and spacing evaluation in north Alabama, 2007-2008. Ga. Onion Res.-Ext. Rpt. Publ. No. 3-2008:63-69.
  • Boyhan, G., D. MacLean, R. Torrance, M. Dollar, S. Curry, C. Riner, B. McElvany, R. Hill, T. Bateman, and D. Thigpen. 2008. Evaluation of short-day onions after controlled atmosphere storage. Ga. Onion Res.-Ext. Rpt. Publ. No. 3-2008:70-78.
  • Boyhan, G., D. MacLean, D. Langston, R. Torrance, M. Dollar, S. Curry, C. Riner, B. McElvany, R. Hill, T. Bateman, and D. Thigpen. 2008. Evaluation of disease control and short-day onion varieties after controlled atmosphere storage. Ga. Onion Res.-Ext. Rpt. Publ. No. 3-2008:79-81.
  • Boyhan, G., D. Langston, R. Torrance, C. Riner, R. Hill. 2008. Evaluation of cultural practices and varieties' effect on bacterial onion diseases. Ga. Onion Res.-Ext. Rpt. Publ. No. 3-2008:33-36.
  • Boyhan, G. R. Hill, and D. Thigpen. 2008. Evaluation of Surround (kaolin clay) on onions. Ga. Onion Res.-Ext. Rpt. Publ. No. 3-2008:37-41.
  • Boyhan, G.E. 2008. Sulfur, its role in onion production and related alliums, p. 183-196. In: J. Jez (ed.) Sulfur: a missing link between soils, crops, and nutrition. Amer. Soc. of Agron., Crop Sci. Soc. of Amer., Soil Sci. Soc. of Amer. Madison, WI. ISBN: 978-0-89118-168-2.
  • Boyhan, G.E. and C.R. Hill. 2008. Organic fertility sources for the production of short-day organic onion transplants. HortTechnology 18:227-231.
  • Boyhan, G.E., J.C. Diaz-Perez, C. Hopkins, R.L. Torrance, and C.R. Hill. 2008 Direct seeding short-day onions in sou.theastern Georgia. HortTechnology 18:349-355.
  • Boyhan, G., R. Hicks, R. Torrance, M. Dollar, D. Spaid, R. Hill, and R. Walker. 2008. Private-public collaboration in developing an organic Vidalia onion industry. HortScience. 43(3):605 (abstr.).
  • Boyhan, G.E., R.L. Torrance, J. Cook, C. Riner, C.R. Hill. 2008. Sowing date, transplanting date, plant population, and variety effect on transplanted short-day onion production. HortScience. 43(3):616 (abstr.).
  • Gitaitis, R., C. Nischwitz, H. Sanders, G. Boyhan, R. Torrance, and J. Wilson. 2008. Potential management of sour skin by double-cropping onions with pearl millet. Proc. Nat. Allium Res. Conf. p. 12.
  • Boyhan, G., R. Torrance, M. Dollar, S. Curry, C. Riner, R. Hill, T. Bateman, and D. Thigpen. 2008. Vidalia onion variety trial, 2007. Proc. Southeast Reg. Veg. Conf. p. 52-55.
  • Boyhan, G. and R. Torrance 2008. Effect of biostimulants +/- micronutrients, hydroxy-propanoic acid, cytokinins and humic acid as a transplant dip and plant spray on onions. Proc. 35th Annu. Mtg. Plant Growth Regulat. Soc. Amer. p. 28. (Invited speaker).
  • Boyhan, G.E., R.L. Torrance, R.J. Hicks, C. Riner, C.R. Hill. 2008. Organic Vidalia onion production in southeast Georgia. Proc. Nat. Allium Res. Conf. p. 36.
  • MacLean, D., A. Bateman, G. Boyhan, C.R. Hill, and C. Li. 2008. Effect of curing on postharvest quality of Vidalia sweet onion. Proc. Nat. Allium Res. Conf. p. 39.


Progress 01/01/07 to 12/31/07

Outputs
OUTPUTS: Objective 1: The 2007 variety trial had 49 entries from 10 different seed companies. Six companies had more than five varieties. Data collected included information on yield, graded yield, storability in controlled atmosphere storage, number of seedstems (flowering), doubled bulbs number, pungency (pyruvate analysis), and sweetness (soluble solids). A subset of the variety trial that included nine varieties had no fungicide applications during the season. These onions at harvest performed comparably to the main trial, however, after 4.5 months in controlled atmosphere storage the unsprayed onions had weight loss that was double their sprayed counterparts and marketable yields that were only one-third their sprayed counter parts. Objective 2: Results of the direct seeding short-day onions has been published in a refereed publication. Objective 3: Results of onion fertility evaluations have been published in a refereed publication as well as being incorporated in the updated onion production bulletin. Organic fertilization for transplant production has been published. In addition, organic fertilization work continues with dry bulb onions and is expected to be published next year. Fertility changes have also been incorporated into the variety trial. Objective 4: Has been dropped. TARGET AUDIENCES: Information from this Hatch project has been shared with growers, extension personnel, and the public.

Impacts
The short-day variety trial continues to generate new information that growers are keenly interested in. New varieties continue to be introduced to the industry. Seven new varieties were added to the official Georgia Department of Agriculture's list of approved Vidalia onion varieties. There are now 28 varieties on the official list.

Publications

  • Boyhan, G.E., R.L. Torrance, C.R. Hill. 2007. Effects of nitrogen, phosphorus, and potassium rates and fertilizer sources on yield and leaf nutrient status of short-day onions. HortScience. 42:653-660. Boyhan, G.E., J.C. Carlos Diaz-Perez, C. Hopkins, R.L. Torrance, C.R. Hill. 2007. Direct seeding short-day onions in southeastern Georgia. HortTechnology (Accepted for publication). Boyhan, G.E., R.L. Torrance, J. Cook, C. Riner, and C.R. Hill. 2007. Transplanting date, plant population, and variety effect on transplanted short-day onion production. HortTechnology (in review). Boyhan, G.E. and C.R. Hill. 2007. Organic fertility sources for the production of short-day organic onion transplants. HortTechnology. In press. Boyhan, G., R. Torrance, C. Riner, M. Dollar, and R. Hill. 2007. Short-day onion production in southeast Georgia, U.S.A. Proc. Intern. Symposium Edible Alliums. Oct. 29 - Nov. 1, 2007. Abstr. Boyhan, G.E., R. Hicks, R. Torrance, C. Hopkins, C. Riner, and R. Hill. 2007. Organic Vidalia


Progress 01/01/06 to 12/31/06

Outputs
Objective 1: The 2006 variety trial had 42 entries from 11 different companies. Data generated included yield, graded yield, harvest date, number of doubles, number of seedstems, pyruvate, and sugar content. In addition, taste testing was conducted with these varieties. Results from the variety trial will be used in part to make recommendations for new varieties to the Georgia Department of Agriculture. The 2007 trial has 49 entries and should be harvested later this spring. Objective 2: Direct seeding short-day onions in Georgia is a viable alternative to transplanting. Direct seeding reduces input by about 16%. Planting date is the critical factor with onions. They should be direct seeded on Oct. 15 plus or minus about a week. Earlier seeding results in seedstems (flowering) the following spring, which is undesirable. Objective 3: Fertility evaluations have shown that phosphorus and potassium requirement should be half of what soil test recommendation had been. This information has been used to update soil test recommendations in Georgia. In addition, several new products have been tested for onion production. These are slow release nitrogen fertilizers. In one case using a methylated urea and in the other using a urease inhibitor to prevent volatilation. Both have proven to work as well as current practices with the added benefit of being water soluble and slow release increasing grower's options. Evaluation of organic fertilizers is also underway with several commercial fertilizers, poultry litter, and high quality compost. Objective 4: Correlating nitrogen fertility with nitrate testing has not been fruitful after 2 years of evaluation. Other researchers have indicated roots rather than leaf tissue should be used for nitrate testing. There does not appear to be enough sensitivity in the testing to correlate with nitrogen fertility. This objective is therefore being abandoned.

Impacts
Onion yield and quality has improved due to onion variety trials and recommendations. Fertility recommendations have been reduced which should result in lower costs and improved environmental quality. Organic fertilizer evaluations are in their preliminary stage, but show promise for organic onion production. Direct seeding onions also can reduce costs particularly related to labor.

Publications

  • Boyhan, G., B. Boland, R. Hill, and T. Paulk. 2006. Evaluation of non-traditional onion varieties. Spring 2006 Commercial Veg. Var. Trials. Reg. Bull. 17.
  • Boyhan, G., R. Torrance, C. Hopkins, M. Dollar, C. Riner, R. Hill, and T. Paulk. 2006. Vidalia onion variety trial, 2006. Spring 2006 Commercial Veg. Var. Trials. Reg. Bull. 17.
  • Boyhan, G.E., R. Torrance, C. Hopkins, M. Dollar, B. Boland, H. Paradise, C. Riner, R. Hill, T. Paulk. 2006. Onion variety trial results. Prog. & Proc. 2006 Nat. Allium Res. Conf. p. 115-133.
  • Boyhan, G.E., R. Torrance, C. Hopkins, C. Riner, R. Hill, T. Paulk. 2006. New fertilizers offer options for growers. Prog. & Proc. 2006 Nat. Allium Res. Conf. p. 98-110.
  • Boyhan, G.E., R.L. Torrance, and C.R. Hill. 2007. Effects of Nitrogen, phosphorus, and potassium rates and fertilizer sources on yield and leaf nutrient status of short-day onions. HortScience. (accepted for publication).
  • Boyhan, G.E., J.C. Diaz-Perez, C. Hopkins, R. Torrance, and R. Hill. 2007. Direct seeding short-day onions in southeast Georgia. HortTechnology. (submitted for publication).
  • Boyhan, G., R. Torrance, C. Hopkins, C. Riner, R. Hill, and T. Paulk. 2006. Vidalia onion variety trial, 2006. Ga. Onion 2006 Res.-Ext. Rpt. No. 3-2006:1-6.
  • Boyhan, G., B. Boland, R. Hill, and T. Paulk. 2006. Evaluation of non-traditional onion varieties. Ga. Onion 2006 Res.-Ext. Rpt. No. 3-2006:29-32.
  • Boyhan, G., B. Maw, R. Torrance, C. Hopkins, M. Dollar, C. Riner, R. Hill, and T. Paulk. 2006. Vidalia onion variety trial controlled atmosphere and bulb characteristics results, 2005. Ga. Onion 2006 Res.-Ext. Rpt. No. 3-2006:7-10.
  • Boyhan, G., R. Torrance, C. Hopkins, C. Riner, R. Hill, T. Paulk. 2006. Evaluation of fertility programs for Vidalia onions. Ga. Onion 2006 Res.-Ext. Rpt. No. 3-2006:11-17.
  • Boyhan, G., D. Langston, R. Torrance, C. Hopkins, C. Riner, R. Hill, and T. Paulk. 2006. Variety evaluation without fungicides for disease incidence. Ga. Onion 2006 Res.-Ext. Rpt. No. 3-2006:18-20.
  • Boyhan, G., D. Langston, R. Torrance, C. Hopkins, C. Riner, R. Hill, and T. Paulk. 2006. Evaluation of organic fertilizers for Vidalia onion production. Ga. Onion 2006 Res.-Ext. Rpt. No. 3-2006:25-28.
  • Boyhan, G., M. Erickson, X. Jiang, and M. Doyle. 2006. Compost as an aid to fertility & profit (compost function & safety). GFVGA Conference. Savannah, GA. Jan. 5-8, 2006.
  • Boyhan, G.E., R. Torrance, C. Hopkins, C. Riner, R. Hill, T. Paulk. 2006. New fertilizers offer options for growers. 2006 National Allium Res. Conf. College Station, TX. Dec. 7-8, 2006. (poster)
  • Boyhan, G.E., R. Torrance, C. Hopkins, M. Dollar, B. Boland, H. Paradise, C. Riner, R. Hill, T. Paulk. 2006. Onion variety trial results. 2006 National Allium Res. Conf. College Station, TX. Dec. 7-8, 2006. (poster)


Progress 01/01/05 to 12/31/05

Outputs
Objective 1: The largest variety trial to date was completed with 49 entries from 9 different seed companies. Data generated included yield, graded yield, harvest date, number of doubles, number of seedstems, pyruvate, and sugar content. In addition, taste testing was conducted with these varieties. Results from the variety trial with recommended additions were forwarded to the Georgia Department of Agriculture for addition to the official variety trial list. Objective 2: Direct seeding short-day onions in Georgia is a viable alternative to transplanting. Direct seeding reduces input costs particularly related to labor since the onions are hand transplanted. This year's fertility experiment with direct-seeded onions indicates that at least 150 lbs/acre of nitrogen is required. This eliminates all of the fertilizer applied to plantbed onions. Objective 3: Fertility evaluations have shown that phosphorus and potassium requirement should be half of what soil test recommendation had been. This information has been used to update soil test recommendations in Georgia. In addition, several new products have been tested for onion production. These are slow release nitrogen fertilizers. In one case using a methylated urea and in the other using a urease inhibitor to prevent volatilation. Both have proven to work as well as current practices with the added benefit of being water soluble and slow release increasing grower's options. Objective 4: Correlating nitrogen fertility with nitrate testing has not been fruitful after 2 years of evaluation. Other researchers have indicated roots rather than leaf tissue should be used for nitrate testing. There does not appear to be enough sensitivity in the testing to correlate with nitrogen fertility. This objective is therefore being abandoned.

Impacts
Onion yield and quality has improved due to onion variety trials and recommendations. Fertility recommendations have been reduced which should result in lower costs and improved environmental quality. Direct seeding onions also can reduce costs particularly related to labor.

Publications

  • Boyhan, G.E., R.L. Torrance, R.H. Blackley Jr., M.J. Cook, C.R. Hill. 2005. Evaluation of fertility practices for Vidalia onions. Southern Region-ASHS. Little Rock, AR. Feb. 4-7, 2005. (poster)
  • Boyhan, G.E., A.C. Purvis, W.M. Randle, R.L. Torrance, M. J. Cook, G. Hardison, R. H. Blackley, H. Paradice, C.R. Hill, and J.T. Paulk. 2005. Harvest and postharvest quality of short-day onions in variety trials in Georgia, 2000-03. HortTechnology. 15:694-706.
  • Boyhan, G.E., J.C. Diaz-Perez, R.L. Torrance, R.H. Blackley Jr., C.R. Hill. 2005. Direct seeding Vidalia onions. HortScience. 40:885 (abstr.).
  • Boyhan, G.E., R.L. Torrance, R.H. Blackley Jr., M.J. Cook, C.R. Hill. 2005. Evaluation of fertility practices for Vidalia onions. HortScience. 40:885-886 (abstr.).
  • Boyhan, G., R. Torrance, C. Hopkins, R. Hill, T. Paulk. 2005. Vidalia onion variety trial 2004-2005. Ga. Onion 2005 Res.-Ext. Rpt. No. 3-2005:1-8.
  • Boyhan, G., B. Maw, R. Torrance, C. Hopkins, R. Hill, T. Paulk. 2005. Controlled atmosphere storage of variety trial onions, 2003-2004. Ga. Onion 2005 Res.-Ext. Rpt. No. 3-2005:9-10.
  • Boyhan, G., R. Torrance, C. Hopkins,, R. Hill, and T. Paulk. 2005. Fertilization of direct-seeded onions. Ga. Onion 2005 Res.-Ext. Rpt. No. 3-2005:11-12.
  • Boyhan, G., R. Torrance, C. Hopkins, R. Hill, T. Paulk. 2005. Evaluation of onion fertilization. Ga. Onion 2005 Res.-Ext. Rpt. No. 3-2005:13-15.
  • Boyhan, G., B. Maw, R. Torrance, C. Hopkins, R. Hill, T. Paulk. 2005. Evaluation of onion bulb height/width ratios and number of centers 2003-2004. Ga. Onion 2005 Res.-Ext. Rpt. No. 3-2005:16-17.
  • Boyhan, G.E., R.L. Torrance, C. Hopkins, R. Hill, and T. Paulk. 2005. Vidalia onion variety trial. Spring 2005 Commercial Vegetable Variety Trials. Reg. Bull. No. 15:19-22.
  • Sanders, D.C. (ed.), J.M. Kemble, E.J. Sikora, R.L. Hassel, T. Keinath, G. Miller, J.K. Norsworthy, P. Smith, W.T. Kelley, G.E. Boyhan, A.S. Culpepper, D.B. Langston, A.S. Sparks, D.H. Nagel, R.G. Snyder, J.D. Byrd, D. Ingram, M.B. Layton, M.W. Shankle, A. Rankins, R.B. Batts, M.E. Clough, N.G. Creamer, J.M. Davis, W.R. Jester, D.W. Monks, L.M. Reyes, J.R. Schultheis, A. Thornton, G.T. Roberson, K.A. Sorensen, J.F. Walgenbach, D.B. Orr, D.R. Tarpy, C.W. Averre, M.A. Cubeta, K. Ivors, G.J. Homes, K.M. Jennings, F.J. Louws, D.F. Ritchie, C.R. Crozier, G.D. Hoyt, D.N. Maynard, R.S. Mylavarape, H.J. Savoy. 2005. Vegetable Crop Handbook for the Southeastern U.S. NC Veg. Growers Assoc. and The Grower pp 239.
  • Boyhan, G.E., R.L. Torrance, and C.R. Hill. 2005. Effects of nitrogen, phosphorus, and potassium rates and fertilizer sources on yield and leaf nutrient status of short-day onions. HortScience. In review.
  • Boyhan, G.E., J.C. Diaz-Perez, R.L. Torrance, R.H. Blackley Jr., C.R. Hill. 2005. Direct seeding Vidalia onions. Southern Region-ASHS. Little Rock, AR. Feb. 4-7, 2005. (poster)


Progress 01/01/04 to 12/31/04

Outputs
Objective 1: Four years of short-day onion variety trials have been completed and have accepted for publication in HortTechnology. This year there are 45 entries in the variety trial representing the largest number of entries since these trials began. Results from the variety trials continue to be used to recommend varieties for the official list of the Georgia Department of Agriculture. Objective 2: Direct seeding short-day onions in Georgia is a viable alternative to transplanting. Direct seeding reduces input costs particularly related to labor since the onions are hand transplanted. It has been demonstrated that properly calibrated equipment used with pelleted seed can come close to transplanted stands. Direct seeding should be done in mid-October in south Georgia to have sufficient plant development before cold winter weather sets in and late enough to prevent seedstem formation in the spring. Similar amounts of fertilizer required for a transplanted crop can be used for direct seeding eliminating all the fertilizer used to produce transplants. Objective 3: Fertility evaluations have shown that phosphorus and potassium requirement should be half of what soil test recommendation had been. This information has been used to update soil test recommendations in Georgia. Objective 4: Correlating nitrogen fertility with nitrate testing has not been fruitful after 2 years of evaluation. Other researchers have indicated roots rather than leaf tissue should be used for nitrate testing. There does not appear to be enough sensitivity in the testing to correlate with nitrogen fertility. This objective is therefore being abandoned.

Impacts
Onion yield and quality has improved due to onion variety trials and recommendations. Fertility recommendations have been reduced which should result in lower costs and improved environmental quality. Direct seeding onions also can reduce costs particularly related to labor.

Publications

  • Boyhan, G., R. Torrance, R. Blackley, J. Cook, R. Hill, and T. Paulk. 2004. Evaluation of fertility treatments for Vidalia onion production. Ga. Onion 2004 Res.-Ext. Rpt. No. 3-2004:7-12.
  • Boyhan, G., R. Torrance, R. Blackley, J. Cook, R. Hill, and T. Paulk. 2004. Evaluation of fertilization of direct seeded Vidalia onions. Ga. Onion 2004 Res.-Ext. Rpt. No. 3-2004:13-16.
  • Boyhan, G.E., R. Boland, and R. Hill. 2004. Evaluation of Grano onion varieties for southeast Georgia, p. 19-20. In: Spring 2004 Commercial Vegetable Variety Trials Reg. Bull. 13. Auburn Univ. AL.
  • Boyhan, G.E., A.C. Purvis, W.C. Hurst, R.L. Torrance, J.T. Paulk. 2004. Harvest date effect on yield and controlled atmosphere storability of short-day onions. HortScience 39(3):653 (abstr.).
  • Boyhan, G., B. Randle, A. Resurreccion, A. Purvis, R. Torrance, R. Blackley, G. Hardison, H. Paradice, J. Cook, R. Hill, and T. Paulk. 2004. Mandated Vidalia onion variety trials; how well has it worked? HortScience. 39(3):657 (abstr.).
  • Boyhan, G.E., J.C. Diaz-Perez, R.L. Torrance, R.H. Blackley Jr., and C.R. Hill. 2004. Direct seeding Vidalia onions. Proc. 2004 Natl. Allium Res. Conf. p. 29. (abstr.).
  • Boyhan, G.E., R.L. Torrance, R.H. Blackley Jr., M.J. Cook, and C.R. Hill. 2004. Evaluation of fertility practices for Vidalia onions. Proc. 2004 Natl. Allium Res. Conf. p. 31. (abstr.).
  • Boyhan, G.E., W.M. Randle, A.V. Resurreccion, R.L. Torrance, R.H. Blackley Jr. M.J. Cook, H. Paradice, C.R. Hill, and J.T. Paulk. 2004. Mandated Vidalia onion variety trials; how well has it worked? Proc. 2004 Natl. Allium Res. Conf. p. 83. (abstr.).
  • Boyhan, G.E., R. Torrance, G. Hardison, R. Blackley, and C.R. Hill. 2004. Evaluation of onion fertilizer practices and recommendations. Proc. of the 2004 SE Reg. Veg. Conf. p. 99-101.
  • Boyhan, G.E., W.M. Randle, A.V. Resurreccion, R.L. Torrance, R.H. Blackley Jr. M.J. Cook, H. Paradice, C.R. Hill, and J.T. Paulk. 2004. Mandated Vidalia onion variety trials; how well has it worked? Proc. 2004 Natl. Allium Res. Conf. p. 163-170.
  • Boyhan, G., R. Torrance, R. Blackley, J. Cook, R. Hill, and T. Paulk. 2004. Vidalia onion variety trials 2003-2004. Ga. Onion 2004 Res.-Ext. Rpt. No. 3-2004:1-4.
  • Boyhan, G., B. Boland, R. Hill, and T. Paulk. 2004. Evaluation of Grano onion varieties. Ga. Onion 2004 Res.-Ext. Rpt. No. 3-2004:5-6.
  • Boyhan, G.E., R.L. Torrance, R. Blackley, J. Cook, R. Hill, and T. Paulk. 2004. Vidalia onion variety trial in Georgia 2003-2004, p. 21-22. In: Spring 2004 Commercial Vegetable Variety Trials Reg. Bull. 13. Auburn Univ. AL.
  • Boyhan, G.E., A.C. Purvis, W.M. Randle, R.L. Torrance, M.J. Cook, G. Hardison, R.H. Blackley, H. Paradice, C.R. Hill, J.T. Paulk. 2004. Harvest and postharvest quality of short-day onions in variety trials in Georgia 2000-2003. HortTechnology. (accepted for publication)


Progress 01/01/03 to 12/31/03

Outputs
Objective 1: We have completed 4 years of short-day onion cultivar evaluations and plan on publishing the results of these trials in a refereed publication later this year. We have 35 onion cultivars currently under trial. Some of these trial results have been used to make cultivar recommendations to the Ga. Dept. of Agriculture for the Vidalia onion industry. Objective 2: We have continued to evaluate protocols for direct-seeding short-day onions. We have evaluated spacing, seed coating, planting date, and cultivar. Currently we are assessing fertility regimes for direct seeding short-day onions. We hope to have an extension publication available next year on the best methods to direct seed onion in Ga. Objective 3: We have completed fertility evaluations for short-day onions with regard to nitrogen, phosphorus, and potassium requirements. This information has been given to the soil test laboratory to update recommendations for short-day onions. In addition, these results are expected to be published later this year. Objective 4: This is the first year we are examining nitrogen fertility levels and attempting to correlate foliar nitrogen levels with tissue nitrate levels using portable nitrate testers to manage onion fertility.

Impacts
Continued improvement in onion cultivars for quality and yield. Reduce inputs through the use of direct seeding over transplanting and manage nitrogen fertility to maximize yield, while increasing fertilizer use efficiency.

Publications

  • No publications reported this period