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V e g e t a r i a n  N e w s l e t t e r
  
 A Vegetable Crops Extension Publication
    Vegetarian 03-11  grnbullet.gif (839 bytes) November 2003
  
Print Version


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 (Fig. 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-P2O5-K2O were applied in a split application during the season. 


Fig. 1. ‘Ambra’, a yellow-flesh European
 gourmet type potato.

‘Ambra’ produced a marketable yield similiar to 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).

   

Clone


 Total Yield (cwt/A)

Marketable Yield1

Size Distribution by Class (%)2

Size Class Range (%)

  
Specific Gravity

 (cst/A)

% of LaC

 C

B

A1

 A2

A3

A4

 A1-A3

 A2-A3

Ambra

367

268

86

4

4

51

39

2

0

92

41

1.049

LaChipper

433

310

100

10

7

38

15

30

0

83

45

1.065

Yukon Gold

402

278

 90

 9

 7

38

27

 18

 0

84

46

1.073

LSD

91

93

 

ns

8

21

14

14

Ns

15

16

0.004

P Value

0.0001

0.0001

 

0.08

0.01

0.01

0.01

0.01

--

0.01

0.01

0.01

1 Marketable Yield: size classes A1 to A3

2 Size classes: C = .5 to 1.5”, B = 1.5 to 1 7/8”, A1 = 1 7/8 to 2.5”, A2 = 2.5 to 3.25”, A3 = 3.25 to 4”, A4 + >4”

 

Table 2. External and internal tuber defects for 'Ambra' and standard potato selections.

  

Clone

% External Tuber Defects

% Internal Defects2

Growth Cracks

Mis-shapen

Sun-burned

Rotten & Misc.

Total Culls1

 HH

 BR

 CRS

 IHN

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.

 

Table 3. Plant growth and tuber characteristics of 'Ambra' and standard potato selections.

 

Plant Growth Characteristics

Tuber Characteristics1

Clone

% Stand

Early Vigor

Vine Type

Vine Maturity

IFC

SC

ST

TS

ED

APP

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 Fig. 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.

For assistance with sampling your ponds, contact the NFREC Plant Disease Diag. Lab, Quincy at (850)875-7140.


Fig. 1. Bacterial wilt.


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 lb 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 seen.

(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 similar to damage caused by other chloroacetamides herbicides sprayed over the top of tomatoes (Fig. 1). 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 other chloroacetamides herbicides sprayed over the top of tomatoes.

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. Cantliffe
Professor and Chairman

Rafael Munoz-Carpena
Assistant Professor, hydrology

John Duval
Assistant Professor, strawberry

Mark A. Ritenour
Assistant Professor, postharvest

Chad Hutchinson
Assistant Professor, vegetable production

Steven A. Sargent
Professor, postharvest

Elizabeth M. Lamb
Assistant Professor, vegetable production

Eric Simonne
Assistant Professor
and EDITOR, vegetable nutrition

Yuncong Li
Assistant Professor, soils
William M. Stall
Professor, weed science
Donald N. Maynard (retired)
Professor, varieties
James M. Stephens (retired)
Professor, vegetable gardening

Stephen M. Olson
Professor, small farms

Charles S. Vavrina
Professor, transplants
 

James M. White
Associate Professor, organic farming

Related Links
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
UF/IFAS Postharvest

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