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A VEGETABLE CROPS EXTENSION PUBLICATION
VEGETARIAN 03-11 NOVEMBER 2003
AMBRA, AN EXCEPTIONAL POTATO VARIETY FOR FLORIDA
A cooperative variety evaluation project was conducted by the University of Florida and HZPC America's Corp. (http://www.hzpc.ca) in
2003 at the PSREU-Hastings. A goal of this trial was to evaluate the production characteristics of early generation clones and advanced
varieties from HZPC in Florida. Many of HZPC's European lines have unique quality characteristics that could broaden the definition of
"new" Florida potato beyond the standard Red LaSoda!
One promising variety evaluated was 'Ambra', a yellow-flesh European gourmet type potato (Fi). 1). Because of limited seed supplies,
'Ambra' was grown from mini-tubers. 'LaChipper' and 'Yukon Gold', two local standards, were grown from standard seed pieces. Potatoes
were planted on 30 January, 2003. Plants were vine killed and tubers harvested 14 May and 2 June, 2003. A total of 230-43-197 lb/A of
N-P205-K20 were applied in a split application during the season.
Fig. 1. "Ambra'. a yellow-flesh European
gourmel lype polalo.
'Ambra' produced a marketable yield similiarto that of 'Yukon Gold' (Table 1) with similar low incidence of external and internal defects
(Table 2). Although the stand and early vigor of 'Ambra' was reduced because the selection was grown from mini-tubers, the overall
appearance was better than both 'LaChipper' and 'Yukon Gold' (Table 3). Variety evaluation trials will be conducted on several grower
farms in the 2004 season.
For complete production details and a list of all varieties and clones tested, visit http://potato.ifas.ufl.edu and click on '2003 Florida Chip
and Fresh Potato Variety Trial Report'.
Table 1 Production statistics for'Ambra' and standard potato selections (harvested 123 DAP)
Marketable Yieldl Size Distribution by Class (%)2
(cst/A) % of
C B Al A2 A3 A4 Al-
ns 8 21 14 14 Ns 15
008 001 001 001 001 001
1 Marketable Yield size classes Al to A3
2 Size classes C= 5to 5", B= 1 5to 7/8", Al =1 7/8to 2 5" A2 = 2 5to 3 25", A3= 3 25to 4", A4+ >4
Table 3. Plant growth and tuber characteristics of 'Ambra' and standard potato selections.
Plant Growth Characteristics
% Early Vine Vine
Stand Vigor Type Maturity
IFC SC ST TS
Ambra 79 4.0 8 2.0 2.5 7.0 7.5 4.0 7.5 7.5
LaChipper 96 7.0 6-9 1.0 1.5 8.0 8.0 2.5 5.0 6.5
Yukon Gold 92 5.3 8 1.3 4.5 7.0 7.5 3.0 5.5 5.5
Early Vigor (40 DAP): 4 plants 2 to 4"; 5 plants 4 to 6"; 7 plants 8 to 10"
Vine Type (full flower): 6 spreading with good canopy; 8 upright with fair canopy; 9 upright with good canopy
Vine Maturity (vine kill, 104 DAP): 3 plants yellow and dying; 1 plants dead
Internal Flesh Color: 1 white, 2 cream, 3 light yellow, 4 medium yellow, 5 dark yellow
Skin Color: 7 buff; 8 white
Skin Texture: 7 moderately smooth; 8 smooth
Tuber Shape: 2 mostly round; 3 round to oblong; 4 mostly oblong
Eye Depth: 5 moderate; 7 smooth, 9 very smooth
Appearance: 5 fair; 7 good; 9 excellent
* 'Ambra' was grown from mini-tubers. 'LaChipper' and 'Yukon Gold' were grown from 2.5 oz seed pieces.
(Hutchinson- Vegetarian 03-11)
BACTERIAL WILT RESEARCH UPDATE
Until recently, research with southern bacterial wilt (Ralstonia solanacearum) has been carried out in the field (Fig. 1 and Fi. 2). However,
since August 2002, researchers at the North Florida Research and Education Center (NFREC) Quincy have been monitoring irrigation
water from surface sources to determine if ponds used for watering tomato plants are actually reproductive environments for spread of this
disease. Several surface irrigation ponds in the north Florida tomato production region have been found to harbor considerable quantities
of the bacterial wilt pathogen during the fall 2002 production season. By November and December 2002, pathogen levels in these ponds
had declined to low and undetectable levels, respectively. However, sampling resumed again in April 2003 and by this past May and
June, Ralstonia spp. was found again in concentrations as high as 1000 bacterial cells/mL of pond water. During a 2-hour irrigation event,
this number grows exponentially in the soil. However, now there are several things known about this problem and recommendations that
can help you make sound decisions for managing the disease on your farm:
1. If you are irrigating from a surface water source, submit a water sample to the Plant Diagnostics Laboratory at the NFREC-Quincy so
that diagnosis of Ralstonia spp. can be made. Take subsamples from approximately 4 areas of your pond that are relatively close to
the banks and send these to the lab.
2. It is known that Solanaceous plants (such as nightshade) in ponds, on pond banks, and in fields are sources of Ralstonia spp., and if
these plants are properly identified and controlled, bacteria levels will drop. Remember that 1 infected plant can put 1 million
bacterial cells back into local water sources!
3. If Ralstonia spp. has a history in your fields (25%+ infection), using cover crops such as rye and oats in the winter, and corn and
sorghum-sudangrass hybrids in the summer will help manage weeds and may break the disease cycle in one or more years.
4. Finally, growers with Ralstonia spp. on their farms should be chlorinating the surface irrigation water so that the concentration of free
chlorine in the drip tubes at the furthest end of each row is 5 parts per million (ppm). Concentrations of chlorine will of course depend
on cleanliness of water and organic matter present in drip lines.
Table 2. External and internal tuber defects for 'Ambra' and standard potato selections.
% External Tuber Defects % Internal Defects2
Growth Mis- Sun- Rotten & Total HH BR CRS IHN
Clone Cracks shapen burned Misc. Cullsl
Ambra 0 0 4 17 20 3 0 0 3
LaChipper 0 5 4 5 14 7 0 0 0
Yukon Gold 0 10 7 0 18 0 0 0 0
LSD 4 12 4 9 15 13 ns ns 11
P Value 0.01 0.01 0.04 0.40 0.01 0.04 0.01
1 Percent of Total Yield. Total culls include the sum of growth cracks, misshapen, sunburned and rotten/misc.
2 Percent tubers; HH hollow heart; BR brown rot; CRS corky ring spot; IHN internal heat necrosis.
For assistance with sampling your ponds, contact the NFREC Plant Disease Diag. Lab, Quincy at (850)875-7140.
I1g. i. bacTenal Will.
Fig. 2. Bacterial wilt vas tissue.
(Josh Mayfield, extension agent & Tim Momol, assistant professor -Vegetarian 03-11)
TRIFLOXYSULFURON (ENVOKE) LABELED ON TOMATOES
Trifloxysulfuron, (Envoke herbicide) has received a label for use as a post-directed spray on transplanted tomatoes. Envoke can be used
as a postemergence-directed spray application in transplanted tomatoes at 0.1/0.15 to 0.2 oz product per acre (0.007-0.014 Ib ai) grown
on plastic mulch. The application should be made prior to fruit set and at least 45 days prior to harvest. A high quality non-ionic surfactant
(NIS) should be added at a rate of 0.25% v/v. The post emergence application will control small weeds species including bristley starbur,
coffee senna, Florida beggarweed, hemp sesbania, lambsquarter, several morningglory species, yellow nutsedge and partial control of
purple nutsedge, many pigweed species, ragweed, sicklepod and several other weeds.
Research in the state has shown that application of Envoke over the top of small tomatoes can temporarily stunt the plants. If the
herbicide is not applied to the growing points, but applied to the lower parts of the plants, no damage has been noted, nor yield loss
(Stall -Vegetarian 03-11)
UPDATE OF PROBLEMS FROM HERBICIDE ROW-MIDDLE APPLICATIONS IN TOMATOES
This fall there have been at least four instances of tomato damage linked to applications of herbicide or herbicide combinations in row
middles. The first thoughts were that it was due to a combination of Dual Magnum and Aim applied to the row middles. Now Aim has been
exonerated and the use of Dual Magnum is being looked at. The damage is similarto damage caused by other chloroacetamides
herbicides sprayed over the top of tomatoes (Fig ). The problem is that this type of damage has not been seen when Dual Magnum has
been applied over the top of tomatoes, nor is it similar to the phyto from pre or ppi applications of Dual Magnum applied at extremely high
rates. The tomatoes do outgrow the initial injury.
Figure 1. Damage caused by olher chloroacelamides
herbicides sprayed over Ihe lop of lomaloes.
One thought is that the damage is caused by volitalization of the herbicide in the row middles. Neither I nor Syngenta research can
duplicate the injury. I have placed tomato plants in pots surrounding pans of Dual Magnum mixes in greenhouses. The solutions have
evaporated, but no damage was noted on any tomato plant. Field applications also have not duplicated the injury. The injury also has not
been seen on a large number of commercial applications using Dual Magnum.
One common factor of all the areas where injury has been seen is that the fields have been very wet. In one instance, a part of the field
that was wet had injury symptoms, but another area of the field that was not as wet (better drained) did not show the injury symptoms. The
rows ran from wet to dry areas so the injury was seen down the row, eliminating application changes.
Syngenta is aware of the problems, and have been trying to establish the cause of the problem. They are not pulling the label for row
middle application, but also are not pushing this type application until the cause of the problem can be identified. I believe that everyone
should be aware of the wet field conditions being linked to the problems and that applications should not be made to wet row middles.
If anyone has other thoughts on this problem, please let me know.
(Stall -Vegetarian 03-11)
Extension Vegetable Crops Specialists
Daniel J. Canlliffe
Professor and Chairman
Assistant Professor. strawberry
Assistant Professor. vegetable production
Elizabeth M. Lamb
Assistant Professor. vegetable production
Assistant Professor. soils
Donald N. Maynard retiredd)
Slephen M. Olson
Professor. small farms
Assistant Professor. hydrology
Mark A. Rilenour
Assistant Professor. postharvesi
Seven A. Sargeni
Assistant Professor and EDITOR. vegetable nutrition
William M. Slall
Professor. weed science
James M. Stephens retiredd)
Professor. vegetable gardening
Charles S. Vavrina
James M. While
Associate Professor. organic farming
University of Florida
Institute of Food and Agricultural Sciences
Horticultural Sciences Department
Florida Cooperative Extension Service
North Florida Research and Education Center Suwannee Valley
Gulf Coast Research and Education Center- Dover
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