South African Seed Potato Certification Scheme

Outline of the South African Seed Potato Certification Scheme

OBJECTIVE

To supply quality seed potatoes to the industry.

The purpose of certification is to certify seed potatoes of which the phyto-sanitary status in respect of diseases and pests falls within predetermined norms and which is true to type.

FOCAL POINTS

The focal points of the Scheme entail:

  1. Certification of seed potatoes that complies with specific quality standards for each generation within the Scheme.
  2. Multiplication of disease-free in vitro material (test tube plants) as starting material.
  3. The production of Generation 0 seed (mini tubers) in accredited greenhouses with zero tolerance for diseases.
  4. Distinct identification of generations 0 to 8.
  5. Dual phasing-out of planting material.
  6. Downgrading of planting material.
  7. Promotion of the use of early generation planting material

GENERATION CONCEPT

The Scheme is based on a generation concept which implies that the number of field multiplications which the seed potatoes have already undergone, is known and for this reason the generation is indicated on the certification label.

PHASING-OUT

The Scheme is based on a dual phasing-out system, which takes the generation and quality class into consideration.

GENERATION

The permissable disease content of seed potatoes increases with consecutive generations and for this reason phasing-out is coupled to the generations.  This entails that the seed potatoes may be multiplied for eight consecutive generations, after which they may not be registered in terms of the Scheme again.

QUALITY CLASSES

Within each generation provision is made for three classes which represent the quality of the seed potatoes in respect of tuber diseases.  These classes are known as Elite, Class 1 and Standard Grade.

Seed potatoes which are certified as Elite and Class 1 of a specific generation may again be used for the production of seed potatoes and specifically for the production of the following generation.  Seed potatoes which are certified as Class 1 may qualify for the Elite class of the following generation.

The second phasing-out phase is implemented if seed potatoes presented for certification have been certified as Standard Grade.  This means that Standard Grade seed potatoes cannot be registered for the further production of seed potatoes.  Quality classes are identified by means of stickers of different colours, namely red for Elite and green for Class 1 on the labels.

The Elite class represents seed potatoes of an exceptionally high standard based on visual inspections, while slightly more tuber diseases may be present in the case of Class 1 seed potatoes.  Standard Grade seed potatoes have to comply with the same standards for all generations and offer the opportunity to make certified seed potatoes of a lower standard available to the ware potato growers.  The buyer is therefore fully informed with regard to the disease status of these seed potatoes.

DOWNGRADING

The Scheme makes provision for downgrading.  This implies that a planting may be downgraded to a following or even a lower generation during field inspections if norms are exceeded.  During tuber inspection seed potatoes presented for certification may not only be placed in one of the three quality classes, but may also be downgraded to an appropriate generation.  Resorting is permissable under certain circumstances.  Exceeding of the virus tolerances for seed potatoes as confirmed by means of laboratory results may also result in downgrading to a following or lower generation.

BENEFITS OF THE SCHEME

  1. The building up of diseases in seed potatoes and the concomitant building up of diseases in soils will be limited.
  2. The planting of early generation planting material wll contribute to greater certainty that minimum seed-borne diseases are present in seed potatoes.
  3. The fact that no uncertified material may be planted on the same field as registered seed potatoes, will combat the infection of plants by viruses and other diseases.

MODUS OPERANDI

The following consecutive processes precede certification:

  1. Registration of the unit 21 days after planting,
  2. At least two field inspections to evaluate the occurrence of diseases and variety purity,
  3. Sampling with a view to test for viruses and bacterial wilt at laboratories,
  4. Tuber inspections for the determination of the phyto-sanitary status in respect of tuber diseases,
  5. Certification of seed potatoes which is confirmed by means of the official certification labels,
  6. Post-control samples are drawn at the time of tuber inspection for the confirmation of the virus content and variety purity.

(Neem asb. kennis dat 'n drukkersfout op die harde kopie van die Afrikaanse weergawe van die Suid-Afrikaanse Aartappelmoersertifiseringskema voorkom in Tabel 4.  'n Regstelling is wel gemaak op die elektroniese weergawe.)

 

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