UNITED

NATIONS

Distr.

GENERAL

TRADE/WP.7/2000/11/Add.20

12 January 2001

ORIGINAL : ENGLISH AND FRENCH

ECONOMIC COMMISSION FOR EUROPE

COMMITTEE FOR TRADE, INDUSTRY AND

ENTERPRISE DEVELOPMENT

Working Party on Standardization of

Perishable Produce and Quality Development

Fifty-sixth session, Geneva, 6 to 8 November 2000

REPORT OF THE FIFTY-SIXTH SESSION

Addendum 20

Note by the secretariat

This document contains the revised UN/ECE Standard for Seed Potatoes (S-1) as adopted by the Working Party.

GE.01-

UN/ECE STANDARD

concerning the certification and

commercial quality control of

SEED POTATOES

moving in international trade between and to

UN/ECE member countries

INTRODUCTION

In October 1949, the Economic Commission for Europe's Committee on Agricultural Problems established the Working Party on Standardization of Perishable Foodstuffs1 . The Working Party was entrusted with the task of "determining common standards for perishable foodstuffs" and "studying steps to be taken on the international level in order to secure the general adoption of standards and control systems".

The standards have been drawn up within the framework of the Geneva Protocol on Standardization of Fruits and Vegetables, adopted by the Working Party in 1958 and last amended in 1984. They apply to produce moving in international trade and are intended for application at the export control point by the control authorities of the exporting countries.

The standard contained in this document is a revision of the Standard for Seed Potatoes adopted by the Working Party at its thirty-eighth session in 1982. The standard introduced for the first time separate provisions for the marketing of pre-basic seed potatoes. A publishing history of the standard, together with a list of related documents, may be found following the text of the standard.

UN/ECE STANDARD S-1

concerning the certification and

commercial quality control of

SEED POTATOES

moving in international trade between and to

UN/ECE member countries

I.	DEFINITION OF PRODUCE

Seed potatoes are tubers or any other propagation material, other than true seed, of Solanum tuberosum L. which, after regular inspection :

1.	during growth

2.	at sorting

3.	during verification inspection

are certified by an officially approved body as suitable for reproduction.

This standard does not apply to seed potatoes :

1.	intended for trials or scientific purposes

2.	intended for selection work.

These shall, however, always be covered by documentary confirmation of quality by an officially approved body.

II.	PROVISIONS CONCERNING QUALITY

The purpose of the standard is to define the quality requirements of seed potatoes at the export control point, after preparation and packaging.

A.	Minimum requirements

Seed potatoes shall be substantially free from injurious diseases and pests and from any defects likely to impair their quality as seed. They shall be substantially dry outside and, in general, of normal shape for the variety.

These requirements shall be observed in conjunction with the standards and tolerances set out under B. Classification.

Neither growing crops of seed potatoes nor seed potatoes shall be treated with sprout inhibitors.

B.	Classification

Seed potatoes shall be classified according to variety and the standards given below. Their classification shall be subject to official control in the producing country. They shall be placed in one of the three categories defined below :

(i)	Pre-basic Seed

Seed potatoes of generations prior to basic seed as specified in Annex I

(ii)	Basic Seed

Potato tubers which are

(a)	descended directly from Pre-basic Seed or Basic Seed or are produced under special provisions of a national certification scheme.2

(b)	are mainly intended for the production of certified seed potatoes

(c)	meet the minimum requirements given in annexes III, IV and V for basic seed potatoes.

(iii)	Certified seed

Potato tubers which

(a)	are descended directly from Pre-basic, Basic or Certified seed

(b)	are mainly intended for the production of potatoes other than seed potatoes

(c)	meet the minimum requirements given in annexes, III, IV and V for certified seed potatoes.

C.	Subdivision of the categories

Producing countries are free to create within the categories provided for in paragraph B, classes which are subject to specific requirements.

D.	Sampling

Sampling of seed potatoes for certification purposes shall be carried out officially or under official supervision.

E.	National phyto-sanitary provisions

The provisions of this standard do not hinder national legislation provisions justified by reasons of the protection of the health of persons and animals or the protection of crops or industrial or commercial property.

However, each producer country for the marketing of seed potatoes in the whole or any part of its territory, take more vigorous measures than those provided for in annexes III and V against the introduction of certain regulated non- quarantine pests which do not exist there or which seem particularly injurious to the crops in that country or in any part of its territory.

F.	Comparative tests

It is recommended that trials be established by national certifying authorities to ascertain the condition of the seed potatoes certified according to this standard. The guidelines given in annex VII of this standard could be followed.

The results of such trials shall be treated in confidence but on request the results relating to individual consignments may be exchanged between the certifying authorities of the importing and exporting countries concerned.

III.	PROVISIONS CONCERNING SIZING

The minimum size of tubers must be such that they do not pass through a square gauge of 28 mm; for varieties having, on average, a length of at least twice the greatest width, the square gauge must not be less than 25 mm. In the case of tubers which are too large to pass through a square gauge of 35 mm, the difference between the maximum and minimum limits of size should be expressed in multiples of 5.

The maximum variation in size between tubers in a lot must be such that the difference between the dimensions of the two square gauges used does not exceed 20 mm unless the buyer and seller agree to deviate from this requirement.

IV.	PROVISIONS CONCERNING TOLERANCES FOR SIZING

A lot shall not contain more than 3 per cent by weight of tubers smaller than the minimum size indicated nor more than 3 per cent weight for tubers larger than the maximum size indicated.

V.	PROVISIONS CONCERNING PRESENTATION

(i)	Condition of units of presentation

Packages of up to 50 kg or one "hundredweight" (112 lbs avoirdupois) as the case may be, shall be new. Larger units of presentation shall be clean.

(ii)	Closing of units of presentation

Units of presentation shall be closed officially or under official control in such a manner that they cannot be opened without damaging the official sealing device or without leaving evidence of tampering on the official label provided for in section VI (i).

The official system of closing shall comprise either the incorporation into the system of the label mentioned above if it is without a stringhole or in all other cases, by the application of an official seal.

Only the official control service may, in case of need, reclose a package or container.

(iii)	Weight

The packaging unit for bags shall be 50 kg net, but the "hundredweight" may be used in trade with countries using that measure, unless the buyer and seller agree to deviate from these requirements.

(iv)	Nature of contents of units of presentation

Each unit of presentation shall contain tubers of the same variety, category, class, size and origin.

A lot should be sufficiently homogeneous.

VI.	PROVISIONS CONCERNING MARKING

(i)	Official label

Units of presentation shall bear on the outside an official label in accordance with annex VI and which has not been previously used; the label shall be white with a diagonal purple line for pre-basic seed, white for basic seed and blue for certified seed. Reference to the UN/ECE Standard may be included on the label.

(ii)	Official statement

Units of presentation shall have on the inside an official statement of the same colour and showing at least the particulars indicated under 3, 5 and 7 in annex VI. The statement shall be so worded that any confusion with the official label referred to in (i) shall be avoided.

This statement is not necessary when an adhesive label or a label of untearable material is used. The particulars given on the label may be indelibly printed on the unit of presentation in substitution for the official statement provided for above.

(iii)	Re-labelling

If a second check appears necessary, the authority which carried out the second check must be stated on the label, as well as the date of the re-closing. If a new label is necessary, this must show the particulars which appeared on the old label, the date of the re-closing and the authority concerned.

(iv)	Supplier's label

The units of presentation may be accompanied by a special label of the supplier.

(v)	Chemical treatment

The nature of the active substance of any chemical treatment of the seed potatoes shall be indicated on the outside of the unit of presentation, on a tear-resistant or adhesive label being either the official label or a label provided by the supplier, or printed on the unit of presentation. This information may also appear inside the unit of presentation.

Adopted 1961 as European Standard No. 19

Revised: 1994, 1998, 2000

Annex I

PROVISIONS CONCERNING PRE-BASIC SEED

A.	Directly derived from micropropagation

Tissue Culture plantlets or tubers of any size in the first generation directly derived thereof may be marketed under the standard provided the following conditions are complied with :

1.	They have been certified by an officially approved body as suitable for reproduction.

2.	Packages or containers shall be marked in accordance with the provisions concerning marking laid down in Section VI, subject to the following special conditions in respect of the official label:

(i)	the label shall be white with a diagonal purple line;

(ii)	the particular required in respect of the category shall be "PRE-BASIC SEED-TC".

3.	They have been produced in accordance with requirements set out in annex II.

B.	Not directly derived from micropropagation

Seed potatoes of generations prior to basic seed may be marketed under the standard, provided that the following conditions are complied with :

1.	They have been certified by an officially approved body as suitable for reproduction in accordance with at least the provisions concerning quality laid down under Section II for basic seed.

2.	They are placed in packages or containers, in accordance with the provisions concerning presentation laid down under Section V.

3.	Packages or containers shall be marked in accordance with the provisions concerning marking laid down in Section VI, subject to the following special conditions in respect of the official label:

(i)	the label shall be white with a diagonal purple line;

(ii)	the particular required in respect of the category shall be "PRE-BASIC SEED".

Annex II

MINIMUM CONDITIONS TO BE SATISFIED

IN THE PRODUCTION OF PRE-BASIC SEED POTATOES

BY MICROPROPAGATION

1.	The facilities and procedures used must be subject to official approval by the certification authority.

2.	The parent tuber must be true to type for the variety and the initial plantlet(s) free from pathogenic organisms.

3.	The growing medium shall not be contaminated by Globodera rostochiensis (Wall) nor Globodera pallida (Stone).

4.	All reasonable husbandry practices for the prevention or spread of pests and diseases must have been effectively carried out.

5.	The growing crop must have been kept free from Synchytrium endobioticum (Schilb) Prc., potato viruses, bacterial diseases, and from deviations of variety or type.

6.	Diagnostic tests shall be prescribed by the official authority.

7.	The seed potatoes shall be practically free from defects and diseases.

8.	The satisfaction of these conditions shall be established by official inspection and/or testing. Confirmation of varietal purity or trueness to type will be dependent on inspection of the crop derived from this Pre-Basic material.

Annex III

MINIMUM CONDITIONS TO BE SATISFIED BY THE CROP

1.	The field shall not be contaminated by Globodera rostochiensis (Woll) nor Globodera pallida (Stone).

2.	The proportion of growing plants affected by blackleg shall not exceed:

(a)	in crop for the production of pre-basic seed, 0 per cent;

(b)	in crop for the production of basic seed, 1 per cent;

(c)	in crop for the production of certified seed, 2 per cent.

3.	The crop shall be free from:

(a)	Synchytrium endobioticum (Schilb) Perc.

(b)	Clavibacter michiganensis Spp. sepedonicus (Spieck. and Kotth.) Skapt. and Burkh.

4.	Depending on the circumstances and character of potato production in the country, there may be considered:

(a)	Requirements for isolation of the crop;

(b)	Without prejudice to the requirements of Annex V the establishment of tolerances for virus diseases and varietal purity.

5.	The satisfaction of the above-mentioned standards or other conditions shall be established by official inspection and/or testing.

6.	Depending on the circumstances and character of potato production in the country a programme of post-harvest testing for virus diseases may be considered.

Annex IV

MINIMUM QUALITY CONDITIONS FOR LOTS OF SEED POTATOES

A.	Tolerances for defects and disease allowed for seed potato tubers:

1.	Presence of earth and extraneous matter

- pre-basic	1 per cent by weight

- basic and certified	2 per cent by weight

2.	Dry and wet rot, where not caused by Synchytrium endobioticum, Clavibacter michiganensis Spp. sepedonicus (Spieck. and Kotth.) Skapt. and Burkh., Ralstonia solanacearum (E.F. Smith)

E.F. Smith

- pre-basic	0.2 per cent by weight

- basic and certified	l per cent by weight

3.	External defects (e.g. misshapen or damaged tubers)

- pre-basic	3 per cent by weight

- basic and certified	3 per cent by weight

4.	Common scab 3: Tubers affected over a specified per cent of their surface

- pre-basic (> 10% surface cover) 3	5 per cent by weight

- basic and certified (> 33.3% surface cover)	5 per cent by weight

5.	Powdery scab4: Tubers affected over a specified per cent of their surface

- pre-basic TC	0 per cent;

- pre-basic (> 10% surface cover)	1 per cent by weight

- basic and certified (> 10% surface cover)	3 per cent by weight

6.	Rhizoctonia : Tubers affected over a specified per cent of their surface

- pre-basic (> 1% surface cover) 3	1 per cent by weight

- basic and certified (> 10% surface cover)	5 per cent by weight

Total tolerance for items 2 to 5 :	6 per cent by weight

- pre-basic	3 per cent by weight 3

- basic and certified	6 per cent by weight

B.	The seed potatoes shall be free from Globodera rostochiensis (Woll) and Globodera pallida (Stone), Synchytrium endobioticum (Schilb.) Perc., Clavibacter michiganensis Spp. sepedonicus (Spieck. and Kotth.) Skapt. and Burkh., and Ralstonia solanacearum (E.F. Smith) E.F. Smith.

Annex V

MINIMUM CONDITIONS TO BE SATISFIED

BY DIRECT PROGENY OF SEED POTATOES

1.	Pre-basic seed

(a)	The proportion, in direct progeny, of plants not true to the variety and of other varieties should not exceed 0.01 per cent.5

(b)	The proportion, in direct progeny, of plants showing symptoms of mild or severe virus diseases should not exceed 0.1 per cent.5 6

2.	Basic seed

(a)	The proportion, in direct progeny, of plants not true to the variety should not exceed 0.25 per cent. The proportion, in direct progeny, of plants of other varieties should not exceed 0.1 per cent.

(b)	The proportion, in direct progeny, of plants showing symptoms of mild or severe virus disease should not exceed 4 per cent with not more than 2 per cent showing severe virus disease.

3.	Certified seed

(a)	The proportion, in direct progeny, of plants not true to the variety should not exceed 0.5 per cent. The proportion, in direct progeny, of plants of other varieties should not exceed 0.2 per cent.

(b)	The proportion in direct progeny of plants showing symptoms of severe virus disease should not exceed 10 per cent. Mild mosaics merely causing discolouration and no leaf deformation should be ignored.

4.	In assessing the progeny of a variety carrying a chronic virus, account will not be taken of slight symptoms caused by the said virus.

5.	The tolerances allowed under points 1 (b), 2(b), and 3. are applicable only where the virus diseases are caused by viruses already prevalent in countries applying the UN/ECE Standard for Seed Potatoes.

Annex VI

LABEL

A.	Required particulars

1.	Nature of the contents: "Seed potatoes"

2.	The certification authority or its recognized initials

3.	Country and/or region of production

4.	Reference number of the lot, including where appropriate the producer's identification number

5.	Month and year of closing

6.	Variety

7.	Category, and where appropriate, class

8.	Size

9.	Declared net weight

B.	Minimum dimensions

110 X 67 mm.

Annex VII

ORGANIZING THE INSPECTION OF CROPS GROWN FROM

SAMPLE LOTS OF SEED POTATOES

(certified according to the standard)

I.	PURPOSE OF THE INSPECTION

The examination of seed potatoes in crop tests enables the quality (vigour, purity, healthiness, productivity) of home-grown and imported lots put on the market to be checked at random.

II.	ORGANIZATION

1.	Place of sampling

Depending on the mode of transport (road, rail or waterway), the sample should preferably be taken when the lot arrives at its destination.

2.	Organs responsible for the sampling

The sampling shall be done by an official department.

3.	Sampling

(a)	The lot as defined in annex VIII is the unit represented by a sample. If the lot is a large one, the number of samples shall be increased to :

-	One sample per wagon or vehicle, in the case of transport by rail or road;

-	One sample for every 50 tonnes, in the case of transport by ship.

(b)	A sample consists of 110 tubers, taken from different places in the container or from at least 10 sacks.

(c)	The sample shall be placed in a sealed sack; its label shall bear the number of the wagon or the name of the ship, in addition to the information mentioned in annex VI.

4.	Preservation of samples

Samples shall be preserved in a uniform manner in favourable conditions.

5.	Trial fields

(a)	The land must be suitable for potato growing.

(b)	Planting should be done in plots of 100 plants. The plots should be grouped by variety in order to facilitate comparison.

(c)	Manuring must be adapted to the needs of the crop, but moderate; the use of nitrogen during growth should be prohibited.

(d)	The usual cultural care must be conducive to keeping the field clean and the foliage intact.

6.	List of plots

A nomenclature of all the samples planted in the same field with the number of the plot concerned shall be sent to the organs responsible for evaluating them.

7.	Evaluation of the crop inspection

In order to be accurate, the evaluation shall in principle be carried out in two stages, with an interval of 10-15 days between them. Primary virus infections should not be taken into consideration.

Annex VIII

DEFINITIONS OF TERMS APPLICABLE

TO THE STANDARD

The definitions provided herein apply specifically to certified seed potatoes moving into international trade under provisions of this standard and their meaning may therefore differ from their classical meaning.

Incorporation of the terms in this glossary signifies their unique use by countries which have adopted the standard.

Blackleg:

Commonly used name of a bacterial disease of potatoes, generally caused by Erwinia carotovora subsp. atroseptica. Similar symptoms may, however, be caused by E. carotovora subsp. carotovora and E. chrysantemi.

Certification:

An official control procedure which aims at ensuring the production and supply of seed potatoes which satisfy the requirements of this standard.

Certification authority:

Organization or agency designated and empowered by national legislation to administer the certification of seed potatoes.

Consignment:

A quantity of seed potatoes consisting of one or more lots which have been consigned to one commercial party and is covered by one set of documents.

Contaminated field:

A field made subject to regulatory action because of the presence of a designated pathogenic organism in the soil.

Disease:

Any disturbance of a plant caused by pathogenic organisms which interferes with its normal structure, function or economic value.

Field:

A defined area of land used for cultivation of seed potatoes.

Free from:

Not present in numbers or quantities that can be detected by the application of appropriate sampling, inspection and testing procedures.

Homogeneous:

Uniform in composition and appearance.

Inspection:

Visual examination of plants, tubers, units of presentation, equipment or facilities by an authorized person, to determine compliance with regulations.

Lot:

A quantity of seed potatoes bearing the same reference number, which has been prepared for marketing and being of the same variety, category, class, size and origin.

Mild mosaic:

Disease symptom, caused by a virus, characterized by foliage discolouration or mottle and not easily discernible by visual inspection.

Origin:

Officially defined area where a lot of seed potatoes was grown.

Phytosanitary provisions:

Provisions in accordance with the International Plant Protection Convention.

Primary virus infection:

Infection occurring during the current growing season and not arising from the seed tuber.

Quality:

The sum of all characteristics that determine the acceptance of seed potatoes in relation to the specifications of this Standard.

Quality Control:

The control by the certification authorities of all activities encountered in the process of producing and marketing seed potatoes in conformance with the Standard.

Quality pest:

A pest carried by planting material, subject to official regulatory control, but not a quarantine pest.

Quarantine pest:

A pest of potential national economic importance to the country endangered thereby and not yet present there, or present but not widely distributed and being actively controlled.

Regulated non-quarantine pest:

A non-quarantine pest whose presence in plants for planting affects the intended use of these plants with an economically unacceptable impact and which is therefore regulated with the territory of the importing part.

Sampling:

The procedure of drawing at random a number of tubers, plants or parts of plants which may be taken as representative of the lot or the field.

Seed Potatoes:

Tubers which are certified by an official certification authority as meeting specified requirements and being suitable for reproduction.

Severe Mosaic:

Disease symptom caused by a virus, characterized by discolouration and distortion of foliage and easily discernible by visual inspection.

Sprout inhibitor:

Chemical substance, applied either to the plants during the growing season or to the tubers after harvest which suppresses or prevents the normal development of sprouts.

Substantially free:

Not present in numbers or quantities in excess of those that can be expected to result from and be consistent with normal handling and good cultural practices employed in the production and marketing of the commodity.

Testing:

The use of one or more procedures for determining the presence or absence of a pathogenic agent.

Annex IX