SAPO Trust was founded in 2004 and replaced the old SAPO.  Pathology, Quality Control and Registration Department manages plant improvement actions according to the classical plant improvement route i.e.

Nucleus Units
Foundation Units
Mother Units

There are certain requirements with regard to the establishment set out in the scheme to which the units must comply i.e.

    Nucleus unit requirements
    Foundation unit requirements
    Mother unit requirements

These processes are set out in 3 different pathways i.e.

    Flow Diagram: Imports
    Flow Diagram: Breeding Program
    Flow Diagram: Local Selection

The Plant Certification Scheme has 3 major requirements to which plant material has to conform i.e.

    Physical requirements
    Genetic requirements
    Phytosanitary requirements
         1. Stone- and pome fruit
         2. Table- and Dried Grapes

Plant material that SAPO Trust handles and distributes must adhere to these phytosanitary requirements. These requirements, per fruit type, specify for which pests and pathogens the material must be screened. The procedures for these checks and tests are set out in the Standard Operating Procedures for Stone- and Pome Fruit and the Standard Operating Procedures for Grapevines.

The Pathology, Quality Control and Registration Department will help and assist clients in the procurement of import permits for plant material from overseas.  Prior to imports, potential clients must procure the plant material from an overseas source and supply them with an import requirement for the specific material – which it must comply with before importation into South Africa.  This should be done prior to import to ensure that the exporter knows exactly with which conditions the material must comply to.  This ensures the exporter has enough time for the specific plant material to be inspected and tested as required.

The Pathology, Quality Control and Registration Departments apply for a permit from the Department of Agriculture, Directorate Plant Health, Stellenbosch and Pretoria on request from the clients. As soon as the permit is ready, SAPO Trust collects it from the quarantine officials and couriers it to the applicant/supplier overseas. The courier details are then e-mailed to the specific person. As soon as the person receives the permit they should contact their Authorities who consequently supply them with the necessary phytosanitary certificates and documents. They package the plant material and courier it to South Africa as applied.

Importers should understand that the quarantine period for full compliance with the import conditions could be shorter if full compliance could be obtained from the exporting Authorities.

Faster routes for imports exist through exporting tissue culture plants that fully comply with the import requirements.

Establishment, Maintenance also Multiplication of Quarantine Material

SAPO Trust also acts as an agent for clients after the importation of new plant varieties into South Africa.  Once the plant material is received and inspected at the Quarantine Station, SAPO Trust is notified of the condition of such material and also whether the material contained foreign pests/diseases symptoms.

SAPO Trust recently appointed a Quarantine Official at the Quarantine Station to assist in the establishment, maintenance and multiplication of plant material within the quarantine facility.

After the inspections, the plant material is grafted onto suitable rootstock material within Quarantine.  After the establishment and resultant growth of the plant material, it is maintained within the glasshouses and tunnels on the Quarantine Station. Clients can also indicate at an early stage whether they would want their plant material to be multiplied within the secondary quarantine facilities available for such purposes.

The quarantine period that plant material usually spends within the quarantine facility depends upon the phytosanitary status of the material imported. If the material conforms to the SA phytosanitary requirements, it is regarded as low risk material and will spend a shorter time period within primary quarantine. If the material does not conform to the SA phytosanitary requirements, it is considered to be high risk plant material and will spend the full time period of two years within quarantine until all relevant tests are completed.

For SAPO Trust to establish, maintain and multiply plant material within the quarantine facility there are a number of costs involved.  Clients will be invoiced at the end of each year for services rendered.

Nucleus tunnels were established on Fleurbaix in Stellenbosch and conform to the requirements within the Deciduous Plant Certification Scheme as set out in the Standard Operating Procedures for grapevine and the Standard Operating Procedures for Stone- and Pome fruit. These units have insect-proof netting, solid concrete flooring, clean water and restricted entry for personnel. All plants are planted in pots. Grapevine, stone- and pome fruit plants are planted within theire own nucleus facility. Two plants each of stone and pome fruit varieties are established and maintained in the nucleus facility. Four plants of each grapevine variety are established within the nucleus facility. The costs of these actions are depicted in the SAPO Trust pricelist. These costs includes all tests, monitoring inspections, remedies, spray actions, irrigation action and material, growing medium, pots, pruning, hygiene etc.

Plant material from the nucleus source is of very high quality and conforms to a very high phytosanitary status. No entity or vector of pathogens and pests can enter these highly secure units. The material within these units also serves as a supreme backup for material planted outside in open soil at other premises. In a case where outside material become contaminated by pathogens and pests, clean plant material can be obtained from within the nucleus blocks.

Clients will be invoiced at the end of each year for services rendered.

Foundation blocks were established from nucleus plants in the Stellenbosch, Montagu Karoo, Ceres, Wellington and Riviersonderend regions. Certain areas were chosen for certain fruit types to be established, as these areas have conditions which are optimal for the growth of the specific variety. Foundation blocks are usually established within a protected low pathogen risk area on a client’s own premises or within a SAPO Trust foundation facility which has to conform to the requirement as set out in the Plant Certification Scheme. Stone fruit varieties, specifically, are established as far away as possible from older commercial blocks in the vicinity. The reason being the transfer of pollen transmittable viruses by pollinating insects such as bees (see description of these viruses under the diseases unit). These units also have requirements that have to conform to the requirements within the Deciduous Fruit Plant Certification Scheme as set out in the Standard Operating Procedures for Grapevine and the Standard Operating Procedures for Stone- and Pome fruit. Each of the three different fruit types are planted within its own foundation facility. Twenty plants of each stone- and pome fruit variety and fifty of each grapevine variety are established within its own nucleus facility. The costs of these actions are depicted in the SAPO Trust pricelist. These costs include, monitoring, inspections, remedies, spray actions, irrigation action and material, growing medium, pots, pruning, hygiene etc.

Plant material from the foundation source is of very high quality and conforms to a very high phytosanitary status. It would be very difficult for plant material to become infected by diseases and pests in these secure areas. All areas also have restricted entry. The material within these units also serves as a supreme backup for material planted outside within producer’s blocks from which nursery bud wood is usually collected. The reason for the higher number of trees in this case is for backup from mother blocks that become infected. This results in the deletion of that specific mother block and the re-establishing of an uninfected block from the foundation block through a foundation nursery.

In the multiplication process of plant material, the budwood from a foundation unit is taken to a foundation nursery, where the material is multiplied and budded onto certified rootstock varieties. This plant material is a multiplication process for the deliverance of bulked material to be planted within producer’s mother blocks. The plant material from these mother blocks are also tested as specified in the scheme. This plant material is collected in the winter and supplied to nurserymen as certified budwood.

Phytosanitary and genetic inspections by SAPO Trust personnel are done on plants within these premises two to three times per year depending on the ripening dates of the different fruit types. Clients will be invoiced at the end of each year for these services.

These applications are depicted in the SAPO Trust price list (Once plant material is released from the Quarantine Station to SAPO Trust for establishment, these plants are eligible for the application of clones within the register of the DPA. This registration is necessary as plant material can only be certified once a clone application is approved by the DPA.

In order to register a clone hortological descriptions accumulated over one year, locally/overseas, needs to be submitted for the registration of a candidate clone. For a fully registered clone one has to accumulate the necessary hortological descriptions needs to be accumulated over a three year period. A five year period is allowed between the registration of a candidate clone to be upgraded to a full hortological clone.

Clients can apply for clone applications at the QC Technician, SAPO Trust, at any time of the year. The QC Technician will combine the hortological descriptions as supplied, with his own phytosanitary records available. The clone applications will be accepted if the phytosanitary application conforms to the requirements as set out in the Plant Certification Scheme and if all hortological descriptions have been completed.

These clones are then registered within the DPA and an official clone register is supplied to SAPO Trust

The costs involved in these applications are depicted in the SAPO Trust price list. The plant material can consequently be handled as registered within the Plant Improvement Scheme.

The QC Technician also has a list of registrations to comply with in order for the plant material to be taken into the system of the DPA and ultimately to be taken into the Plant Certification Scheme. These are actions to be taken at point specific times in order to ensure that optimal actions are taken to ensure the quality of the resultant plant material. These registrations are depicted on the SAPO Trust price list and will also be listed on the client invoice at the end of every year.

7.1 ELISA test methods

Plant material within the Plant Certification Scheme has to comply with the phytosanitary requirements as requested. This process involves using virus test kits for the testing of viruses as set out in the Scheme. Commercial diagnostic test kits for viruses i.e. ELISA (Enzyme linked immunosorbant assays) tests are used for the detection of these different viruses within the plant material. This specific method entails the trapping of virus particles within plant sap onto specific binding antibodies on the test kit plates. A colour variance within the wells on this plate indicates the presence of the virus concentration. If the colour is intense the virus concentration is high and if the colour is weak, the virus concentration is low.

These test plates can analyze up to 48 samples (in duplicate) simultaneously. Approximately 800 samples can be processed and tested using these test kits per day. SAPO Trust does approximately 10,000 tests per year using this method of detection.

The different ELISA test kits for the different viruses on the different fruit types are described within the Standard Operating Procedure of each fruit type.

ELISA tests are usually performed in autumn and during spring and early summer of each year. Samples are collected according to a standard statistical method of sampling. The material is packed into plastic bags and kept in a cooler until delivered to the laboratory as soon as possible.

These tests are very reliable and are used for diagnostic tests throughout the world.

Clients are invoiced for these ELISA tests during September of every year.

7.2 Polymerase chain reaction (PCR)

Phytosanitary tests for some more damaging organisms like type 3 leaf roll virus, (GLRaV₃ ), apple chlorotic leafspot virus (ACLSV) and the bacterial blight bacterium a more sensitive and sophisticated method, like PCR is used. This technique it is a costly test and large numbers of samples cannot be used. These techniques are used on limited plant material numbers like within the nucleus blocks. This method uses a specific piece of DNA, which is unique to the type of organisms being tested for - it is called a primer. Samples are prepared from plant sap and the DNA within this plant sample is cut into little pieces and multiplied extensively. This multiplication ensures enough genetic material to be used in the test. This plant material with the known primer is loaded onto a gel and an electric current is generated. It is well known for proteins of different sizes to move in a gel in an electric current. Once the run is finished the gel is stained and the protein bands show up as dark stripes. The known sequence is then compared to the other bands on the gel. If the organism in question was present within the plant the bands will compare with the known band.

It is important to screen for these organisms in nucleus plants as they are very damaging for the progeny.

These tests are depicted on the SAPO Trust price list.

7.3 Diagnostic tests

SAPO Trust laboratory also serves its clients/co-operators by doing general and also more specific diagnostic tests for other pests and diseases. Complaints and investigations are followed up by the Pathology unit as soon as reports are received from clients. The Pathologist will then investigate the problem and do the resultant analysis as to the damage caused to the plant material.

The laboratory can do specialized and specific tests on different fruit types for different organisms like viruses, bacteria, fungi, insects and nematodes.

Sometimes plant material is infected by foreign and pathogenic organism like viruses. These viruses can occur in imported plant material or get infested within blocks in South Africa. When this plant material is requested by industry it will first have to be cleaned and made free of the virus/viruses. The owner/agent of the material requests SAPO to eliminate the organism from the plants. These actions are costly and can take from 5-10 years to complete.

The standard process for virus elimination entails a specific heat therapy process to be undergone by the plant material. This heat process on plant material is done in specific chambers designed for this process. The heat process causes viruses not to migrate very high up into the phloem tissue of the plant. The apical meristem, existing of undifferentiated tissue (0,5mm), is removed aseptically and transplanted on to a tissue culture growth medium. These excised undifferentiated cells will know begin to divide and differentiate to form plantlets. These plantlets are further cultivated and hardened off over time (up to two years). Buds from the plants are them budded onto rootstocks in the field for evaluation purposes. Whilst this is in progress the remaining plants are indexed on hardwood indicator plants for the detection of these specific viruses. If these hardwood plants show negative symptoms for this specific virus, it can be deduced that the plant material is free from this virus.

If the evaluation process is successful and the virus free material proves to be better than the infected material, the material will undergo a clonal application and will be incorporated into the Scheme. It is SAPO Trust’s mandate not to supply any virus infected material to the Industry.

Indexing (testing) for the presence of viruses on specific hardwood plant varieties ensures a foolproof method to determine whether material is infected or free form specific viruses. Buds of the variety to be tested and the indicator plant is budded together onto a rootstock. Included into these tests are also positive and negative controls. Once these plants begin to grow the indicator plant will shows the symptoms induced by the specific virus. If the test materials show no symptoms it can be deduced that it is free of that specific virus. Hardwood indexing is costly and time consuming and can take up to three growing seasons to complete. These tests are much more sensitive and reliable than standard ELISA and PCR tests.

SAPO Trust have two different indexing premises for the tests of viruses, one in Stellenbosch and one in Grabouw.

SAPO Trust also exports plant material for clients from secure and tested nucleus and foundation material within SAPO Trust premises. The owner/agent requests the Pathology, Quality Control and Registration Unit to collect material of a specific variety to be exported. The plant material is inspected visually and microscopically for the presence of pathogens and pests. This material is cut during the dormant period in winter and kept in an appropriate cold room. The standard status of the nucleus material in question is known and all tests as specified by the Scheme have been done. The material is then treated with a biocide, a systemic fungicide and a broad spectrum insecticide/miticide. Inspection is done on this material by Quarantine Officials and a phytosanitary certificate issued. The material is wrapped and packed within suitable containers. With this package SAPO Trust also supplies a certificate of compliance that the material was tested and inspected in the nucleus facility for organisms as requested by the Scheme. A suitable courier is contacted which collects the material and transports it to the importer as requested.

The Pathology, Quality Control and Registration Department also supply Eurepgap Certificates at a specified price to specific clients/co-operators when requested. Within this certificate SAPO Trust supplies all information with regard to the origin and the phytosanitary tests conducted