PACKAGING OF SEED
It is important to package seed in dry containers for proper storage. For small quantities of seed, these containers may be tin cans, jars, or pots that are glazed on the inside; even reinforced boxes or bags can be suitable. Metal or plastic jerricans, or drums are often used to package large quantities of seed. Regardless of the type of container employed, it should be of standard size and shape, if possible, so that when one is filled with seed of a known purity percentage, the approximate number of seeds it contains can be estimated. Also, containers of standard sizes and shapes are easier to handle.
For subsequent identification, each package of seed, or each aggregation of packages representing a given seed collection, should be labelled. The information recorded for the collection of Prosopis fruit from which the seed was extracted should be repeated(see p.15), plus the following:
|Quantity:||Number of seeds (estimated)|
|Technique of extraction|
|Fumigation:||Date (if undertaken)|
|Method of fumigation, including chemicals|
|Number of seeds per unit weight (estimated)|
Once again, this information should be recorded in a notebook or ledger, with duplicate labels attached outside and placed inside the packaging container.
PACKAGING OF SEED It is important to package seed in dry containers for proper storage. For small quantities of seed, these containers may be tin cans, jars, or pots that are glazed on the
What is meant by seed packaging?
This is the placing of a counted or weighed sample of seeds of an accession into a container which is then hermetically sealed ready for storage.
Why are seeds packaged?
Seeds are packaged to prevent absorption of water from the atmosphere after drying, to keep each accession separate and prevent contamination of the seeds from insects and diseases.
When should seeds be packaged?
The best time to package seeds is directly after the moisture content has been determined and found to be within the required limits for safe storage. Seeds will always show an equilibrium between their moisture content and the relative humidity of the environment and therefore, if possible, seeds should be packaged into containers and hermetically sealed in the drying room or without delay on being removed from it.
How should seeds be packaged?
Different containers and special equipment for sealing are available for the storage of seeds. Storage containers for base collections should be hermetically sealed and moisture-proof. Cans, bottles, and laminated aluminium foil containers are all acceptable for both base and active collections. The techniques used will vary with the type of container and the equipment that your genebank is using. The general steps outlined in this section could be followed.
Moveable racks make the best use of available space and are ideal to store containers in walk-in stores. Small containers or aluminium foil packets can be filed in boxes for ease of locating individual accessions. Coding systems by number or colour are also helpful in exactly locating accessions.
Chest freezers are adequate for the maintenance of small collections. Filing systems have been developed to hold the containers in freezers and allow easy location of material. Some examples of filing systems are shown here.
STEP 1. PREPARE FOR PACKAGING
1. Work in the drying room or, if not possible, expose the seeds to the ambient relative humidity for the shortest possible time.
2. Write on the outside of each container or on an adhesive waterproof label. Also prepare a label for inclusion with the seeds. Record the accession number, date of storage, genus and species if required. Use permanent markers for this.
Notes and Examples
Adhesive labels can be used for the outside of containers, but they must be waterproof and remain adhesive for long periods at low temperatures.
Laminated aluminium foil containers, cans or bottles
Machines for sealing
1. Weigh out or count samples of seeds to fit the containers used in your genebank.
2. Fill the labelled containers with the seeds. Add the label prepared for the inside.
3. Seal immediately, so that the moisture content of the seeds does not increase due to equilibration with ambient relative humidity.
4. Note the weight or number of seeds in each container.
Notes and Examples
It is important that the containers used should be moisture-proof and sealed. The exact sealing technique will depend on the type of containers and sealing methods that are available.
Laminated aluminium foil bags are easy to package, can be cut to size to save space and can be sealed again after use. However, they are difficult to stack and must be made of good quality material and have good seals or leakage may occur.
Cans are rigid and easy to stack and usually will not break open if dropped. However, some types of cans are not resealable and therefore are expensive to use. A standard size can with only a few seeds inside wastes space in the store.
Glass bottles can usually be sealed again and the amount of seed left is visible. However, a standard size will waste space and bottles are easily broken.
Seeds can be packaged in bulk into large containers and/or sub-samples can be packaged separately into smaller containers. Although the initial packaging period is longer, sub-samples can then be removed quickly without having to remove the bulk of the accession from the store.
1. Enter the relevant data about each accession into the data file.
2. The data should include number of containers per accession, number or weight of seeds per container, type of container (if not standard) and the date of packaging.
STEP 4. CHECK THE QUALITY OF THE CONTAINERS
1. After sealing, make a visual examination of each container to make sure that there is no obvious damage and that the seals do not leak.
2. Any containers that are below standard should be replaced immediately.
3. At regular intervals the containers should be checked to see that they remain in good condition. It is suggested that this check should be carried out routinely once a year and that individual containers should also be checked whenever they are removed from the genebank.
4. If containers are found to have been leaking and the relative humidity of the store was not controlled, determine the seed moisture content by using one of the methods described in Section III.
5. If the moisture content has risen, dry the seeds back to the required moisture content level as described in Section IV.
6. Enter the value of the new moisture content into the data files. Make a note that the seeds in that container have been held at increased moisture content for a limited period and dried again.
7. Check the inventory data file for the descriptor ‘date of packaging’ and make a list of any other accessions which were packaged in similar containers on the same day or one day before or after.
8. Check the containers on this list for leaks and poor condition and replace any that are faulty using the methods described above.
9. Remember that any containers removed from the cold store should be allowed to warm to room temperature before opening. This may take several hours especially with large volumes of seeds.
Notes and Examples
If any defective containers are found, it may indicate that containers made or sealed at the same time are also faulty or it may just be one faulty container or seal. Checking those packaged at the same time will show if the problem is widespread.
Summary of seed packaging in your genebank
Fill in this table for your future reference:
Seed packaging What is meant by seed packaging? This is the placing of a counted or weighed sample of seeds of an accession into a container which is then hermetically sealed ready for