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Sweet Onion Variety Trial, NFREC - Quincy Spring 2007.
By Dr Steven Olson, Professor, UF/IFAS North Florida Research and Education Center, Quincy, FL
Sweet (short-day) onions are a relatively minor crop in Florida. Production exists as both dry bulbs (mature) and green tops (immature). Limited production exists throughout the state. The biggest deterrent for increased production is from competition from established markets in south Texas and middle Georgia areas (Vidalia). However, the potential exists for expanding production, especially in the areas of local sales and direct marketing.
The objective of this trial was to evaluate the performance of sweet onion varieties under northwest Florida conditions.
The transplants for this trial were produced from field beds at the NFREC, Quincy. Sixteen entries were seeded on 13 Oct 2006. Seed were planted at rate of about 30 seed per ft into rows spaced 12 inches apart. Preplant fertilization of seedbeds was 30-40-40 lbs/A of N-P2O5-K 2O. Dacthal W 75 was applied over the top at 10 lb/A after seeding. Seedbeds were top dressed once with 34 lbs N/A. Entries were transplanted into the production field on 16 Jan 2007. Soil type was an Orangeburg loamy fine sand. Preplant fertilization was 48-96-144 lbs/A of N-P2O5-K 2O. Production scheme was 3 rows spaced 15 inches apart under a 6 ft tractor and in-row spacing was 4 inches (65,340 plants/A). Goal 2XL at 2 pts/A was applied on soil surface before transplanting. Nitrogen was applied twice during the season at 50 lbs N/A each time. One top dressing of 60 lbs/A as KCl was made during the season. Registered pesticides were applied as needed to control pests.
Entries were harvested as they matured, where maturity is defined as when about 50% of the tops of an entry had fallen down naturally. Bulbs were lifted, allowed to dry for a few hours and tops and roots removed. Bulbs were then placed in bushel baskets and dried for 72 hours at 100° F in large drying rooms. After drying time was complete, onions were removed, allowed to cool down and graded. Grading consisted of discarding culls (small onions, splits, off color and decayed) and sizing into medium (1.5-2 inches), large (2-3 inches) and jumbo (>3 inches) categories. Bulbs were then weighed and counted.
Harvest occurred from the period of 26 April to 21 May. Total yields ranged from 1170 50 lb bags/A for ‘Don Victor' to 543 50 lb bags/A for ‘Sweet Caroline' (Table 1). Five other entries produced total yields equal to ‘Don Victor'. Yields were good to excellent in 2007. Growing conditions were good and disease was not a problem. ‘Don Victor' produced the largest bulb at 16.0 oz and ‘Honeybee' produced the smallest at 9.3 oz. Percent marketable bulbs ranged from a low of 43.8 % for ‘Sweet Caroline' to a high of 99.6 % for ‘NUN 1500 ON'. Percent bolting level was very low (<1%) on all entries. Days to harvest from transplanting ranged 100 days for ‘Honeybee' to 126 days for ‘Don Victor', ‘EM 90', ‘Century', and ‘Sweet Caroline'.
Table 1. Sweet onion variety trial results 2007. NFREC-Quincy.
Entry |
Source |
Marketable Yield |
Marketable |
Bulb wt. |
Days to harvest Z |
|
|
|
Jumbo |
Total |
|
|
|
Don Victor |
Nunhems |
1158 aY |
1170 a |
86.5 b-d |
16.0 a |
126 |
NUN 1500 ON |
Nunhems |
1038 ab |
1092 ab |
99.6 a |
13.6 b-d |
113 |
*Granex 33 |
Seminis |
1058 ab |
1070 a-c |
89.3 a-d |
14.5 bc |
118 |
Kalahari |
Nunhems |
1035 ab |
1064 a-c |
95.2 a-c |
13.7 bc |
118 |
Savannah Sweet |
Seminis |
1045 ab |
1064 a-c |
95.8 ab |
13.6 b-d |
122 |
Colina |
Nunhems |
1000 bc |
1045 a-c |
97.5 a |
13.1 cd |
118 |
Sugar Belle |
Shamrock |
955 b-d |
978 b-d |
90.3 a-d |
13.1 |
112 |
Caramelo |
Nunhems |
927 b-d |
939 cd |
83.3 de |
13.6 b-d |
122 |
Honeycomb |
Shamrock |
881 cd |
913 d |
95.6 ab |
11.6 ef |
112 |
Nirvana |
Nunhems |
888 cd |
903 d |
92.6 a-d |
12.0 de |
113 |
Yellow Granex PRR |
Seminis |
856 d |
864 d |
75.7 e |
13.7 bc |
122 |
SSC 1535 |
Shamrock |
719 e |
747 e |
85.4 cd |
10.5 fg |
112 |
Honeybee |
Shamrock |
664 ef |
736 e |
98.9 a |
9.3 g |
100 |
EM 90 |
Harris Moran |
722 e |
728 e |
59.8 f |
15.1 ab |
126 |
Century |
Seminis |
641 ef |
646 ef |
53.1 f |
13.9 bc |
126 |
Sweet Caroline |
Nunhems |
540 f |
543 f |
43.8 g |
13.9 bc |
126 |
Z From Transplanting
Y Mean separation by Duncan 's Multiple Range Test, 5% level.
