Securing good seed potatoes for Florida

Material Information

Securing good seed potatoes for Florida
Series Title:
Veg. crops MR - Florida Cooperative Extension Service ; 67-4
University of Florida -- Agricultural Extension Service
Place of Publication:
Gainesville, Fla.
Florida Agricultural Extension Service
Publication Date:
Copyright Date:
Physical Description:
3 leaves : ; 28 cm.


Subjects / Keywords:
Potatoes -- Seeds -- Florida ( lcsh )
Commercial production ( jstor )
Tubers ( jstor )
Diseases ( jstor )
government publication (state, provincial, terriorial, dependent) ( marcgt )
non-fiction ( marcgt )


General Note:
Caption title.
Statement of Responsibility:
Florida Agricultural Extension Service.

Record Information

Source Institution:
University of Florida
Holding Location:
University of Florida
Rights Management:
All applicable rights reserved by the source institution and holding location.
Resource Identifier:
434441687 ( OCLC )


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Full Text
)Veg. Crops MR 67-4

Florida Agriculture Extension Service JUL 11 1972

There is no substitute for good quality seed potatoes to h~ jg gOja

high quality potatoes. Most Florida growers buy certified seed, shipped into the

state from northern U. S. and Canada. Growers have from time to time experienced

difficulty in securing certified potatoes in good condition.

Potato seed certification dates back to 1914 when certain standards and require-

ments were recommended for the production of quality potato seed. Since then many

states and Canada have developed potato seed certification programs, designed to

put on the market good seed.

The enforcement of certification standards is the responsibility of the Colleges

of Agriculture, the State Department of Agriculture, or grower's organizations

authorized by the state. These organizations must see that the minimum standards

as agreed upon, are met before the potatoes can be marketed as certified seed.

The production of certified seed depends upon the quality of foundation seed

stock and the manner in which it is grown. Foundation seed is obtained by select-

ing tubers of a variety and growing from one eye, under controlled conditions, a

single plant. If the plant proves to be free of seed-borne diseases the remaining

eyes of the tuber are planted for increase. These disease-free tubers are planted

in units in an isolated area and rogued during the growing season to remove all

diseased, weak, off-type plants or varietal-mixtures. These potatoes are used for

the production of certified seed.

Certified potato seed is grown in the northern states and Canada or at high

altitudes in other states where conditions are favorable for potato production and

less favorable for the development of insects responsible for the spread of many

virus diseases. They are grown under a system of inspection performed by the

certifying agency. The plants are inspected at least twice during the growing

season and the harvested tubers are stored in approved storage and inspected in the

bin. For each inspection a minimum percentage of affected plants or tubers for each

2 -

disease is allowed. The tolerance varies for different diseases and by certifying

states but is usually between 0 to 5 percent.

The maximum tolerances allowed for various diseases and varietal mixtures by

the a~taastB Crop Improvement Association at first and second field inspection

is shown.

International Crop Improvement Association
Minimum Field Standards*

Factors First Inspection 2nd Inspection

Leaf roll 2 percent 1 percent
Mosaic 3 percent 2 percent
Spindle tuber 1- percent 1 percent
Other Viruses 3 percent 2 percent
Total Virus 4 percent 2 percent
Bacterial Ring Rot 0 0
Varietal Mixture 1 percent .5 percent

*Black leg, late and early blight, Fusarium wilt, any other disease
or abnormal condition at discretion of the certifying agency.

Certified seed potatoes meeting the above requirements must be inspected in

the bin just prior to or at time of shipment. This is to determine the presence

and amount of tuber defects and diseases on potato tubers. Example Blackwart,

Ringrot, nematodes, powdery scab, late blight, early blight, Fusarium wilt, corky

ringspot, tuber moth, cuts and bruises. The standards for these defects may vary

between states as they are established by the certifying agency.

Potatoes may be bruised or damaged during harvest and movement into storage.

Under favorable climatic conditions, temperature and humidity, injured potatoes

will heal in 24 to 48 hours by producing a protective layer of corky cells eliminat-

ing future damage. However, below 500 F and above 900 F this healing process takes

place very slowly allowing disease producing organisms to enter, which may complete-

ly spoil the tuber. Thus proper curing conditions following harvest may greatly

affect the quality of the seed. Storage temperature of 400 F and a relative humidity

of 85 percent is recommended to prevent the spread of diseases. The conditions are


not always maintained in storage and especially during shipment from the seed pro-

ducer to the Florida growers. Thus tuber defects and diseases may increase during

this period. Florida growers should purchase certified seed potatoes that meet

U.S. grade standards when received.

It is recommended that certified seed potatoes purchased for planting in

Florida should (1) meet the minimum standards established by the International Crop

Improvement Association. (2) All seed potatoes should conform to U.S. No. 1 grade

standard except for size (tuber size should be printed on tag.). (3) Be free from

serious damage. Tubers should not show more than 1/3 of the area affected by

sunburn and not more than 3 percent of rot from any specific disease, otherwise the

usual tolerances for U.S. No. 1 grade would apply.

The meeting of the standards given during the growing, harvesting, storing and

shipping of certified seed potatoes will insure the arrival in Florida of seed

potatoes of good quality. The maintenance of this quality from time of arrival

until planted will be effected by the storage conditions of the potatoes from time

of arrival until planted.

Should growers be dissatisfied with seed quality from a given area there are

many states meeting the standards of certified seed that are anxious and fully

capable of furnishing quality seed. At least one year of prior notification may be

necessary to assure a supply of certified seed of any specific variety. This is

particularly true if large quantities of seed are desired.