Introduction

Genebank Operations

The operation of a genebank is a complex activity which must be carried out in an orderly and efficient way to adequately conserve the genetic resources that it holds in care. In view of the responsibilities involved in curating these resources, the standard of day-to-day work must be careful and precise. There are two major categories of genebanks:

1. Base collections store accessions under adequate conditions for long-term storage. They are not used as a routine source for distribution of germplasm but as a security against loss. Seeds are removed from base collections at infrequent intervals to monitor viability and for regeneration, when seed viability drops or when stocks of an accession are no longer available.
2. Active collections store accessions from which seed samples are drawn for distribution, regeneration and evaluation of plant characteristics. Storage conditions are usually less demanding than those of base collections because seeds are stored for shorter periods (medium-term).

Base and active collections are closely linked. All the accessions stored in base collections should also be available from several active collections. Base and active collections need not be located in the same place, although they often are. Information about the accessions must flow freely between the different genebanks.

Many diverse tasks are involved in conserving germplasm in the best possible way. The major activities and procedures involved are the same for both base and active collections. They are explained in detail in the following Sections:

I. Sample registration
II. Seed cleaning
III. Seed moisture content
IV. Seed drying
V. Seed viability
VI. Seed packaging
VII. Seed storage
VIII. Monitoring accessions
IX. Distribution of germplasm from active collections
X. Regeneration of accessions

General Workplan

When seed samples are received and are entered into the genebank, there is a general scheme which can be followed so that the seeds are processed and entered into the genebank with speed, accuracy and efficiency. The flow chart in Figure 1. shows this general scheme and the preferred order which the procedures should follow. A typical workplan would be:

* Seeds are received at the genebank. They are checked and registered and sent for cleaning.
* The seeds are first checked for insect infestation and purity. If there is no sign of insect damage the seeds can be sent directly for cleaning and drying. If insects are present the seeds should be isolated and sent directly for seed drying using silica gel in separate containers to prevent the spread of insects as outlined in Section II.
* Samples with few seeds will need regeneration to provide sufficient seeds for storage. Regeneration of a sub-sample of the accession should be done as soon as possible, but seeds should be dried and stored temporarily at low temperatures.
* Drying is continued over several days or weeks. When it is predicted that the seed moisture content has reached between 3 - 7%, sub-samples are tested to accurately determine the moisture content using the techniques outlined in Section III.
* Sub-samples are also taken to determine seed viability as explained in Section V after the drying period, so that the results are available before the seeds are packaged. Poor quality seeds will be found at this time and arrangements can be made for a sub-sample of the accession to be regenerated and good quality seeds placed into the genebank. Seeds awaiting regeneration before final storage should also be stored temporarily in good storage conditions, but should not be a part of the genebank distribution list.
* Seeds which are dry are packaged as explained in Section VI.
* The seeds are placed into the seed store and the data recorded in the inventory, together with the data about seed viability when the data becomes available.
* At regular intervals after storage, the seeds are monitored for viability as explained in Section VIII. When the viability has fallen below 85%, the accession should be regenerated and fresh seeds placed in the genebank.
* The seeds are distributed on request from active collections and the data recorded in the appropriate data files as outlined in Section IX.
* When the number of seeds in store falls to a low level, the seeds will need to be regenerated as outlined in Section X.

Figure 1. Preferred sequence of events in a genebank.

General Rules

* Process the seeds as quickly as possible.

Why? Because seeds left around in the open may become infested with insects, will lose viability and can easily become mixed.

* Dry seeds as soon after receipt as possible.

Why? Because drying seeds to low moisture contents will help to improve their storage life even at room temperatures.

* Never place wet seeds in sub-zero temperatures.

Why? Because seeds with moisture contents of approximately 16 to 20 percent or more can show cellular damage during freezing which causes loss of viability.

* Once seeds have been dried, store them in moisture-proof containers.

Why? Because the moisture content of seeds will always equilibrate with the relative humidity of the surrounding air and dried seeds will absorb moisture again, unless properly protected from the air.

* Treat all accessions separately.

Why? Because different accessions of the same species can have different storage characteristics.

* Keep all the data relating to an accession.

Why? Because the more information available about an accession the more useful it is and information which might seem irrelevant may be important in the future.

* Always work in an orderly and accurate way.

Daily Procedures

Some tasks should be done every day to make sure that the genebank runs efficiently. These are:

TASK 1. KEEP A DAILY RECORD OF WORK DONE

1. Record the daily work in a record book or desk diary. This will enable you to check back for the date when samples were received and when they were tested.

2. Use this book to write down the date of any future tasks as a reminder.

TASK 2. KEEP A DAILY RECORD OF THE ENVIRONMENTAL DATA OF THE FACILITY

1. Measure and record the maximum and minimum temperatures in the laboratory, drying room and seed storage room(s) or freezers. Keep these data in either a log book or a data file.

2. Measure and record the relative humidity in the laboratory, drying room and seed storage room(s) at a cool time and at the hottest part of the day.

TASK 3. KEEP COMPREHENSIVE DATA FILES ON THE SEED ACCESSIONS

1. Data files can be in the form of notebooks, filing cards and computer files.

2. Use different files to record the different data types:

Management data files

- to record data concerned with the management of the accessions and the seed store.

Passport data files

- to record passport and collection data.

Characterization and evaluation data files

- to record data collected during the characterization and evaluation of the accessions.

General work plan for your genebank

Outline the general work plan used in your genebank:

	Management data files	- to record data concerned with the management of the accessions and the seed store.
	Passport data files	- to record passport and collection data.
	Characterization and evaluation data files	- to record data collected during the characterization and evaluation of the accessions.