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Registration
.jpg) View the full chapter on registration by clicking on the icon above. (0.2 MB) |
Page compiled by: Bioversity International/ILRI, Addis Ababa, Ethiopia (Alexandra Jorge); ILRI, Addis Ababa, Ethiopia (Jean Hanson) including information extracted from: Rao NK, Hanson J, Dulloo ME, Ghosh K, Nowel D and Larinde M. 2006. Manual of seed handling in genebanks. Handbooks for Genebanks No. 8. Bioversity International, Rome, Italy. 147pp.
What is registration
Registration is the first step after acquisition of a sample in any genebank. Collections in genebanks are the genetic base for current and future breeding programmes and a source of safety material for distribution to researchers and other users. It is essential that samples are all properly documented from the moment they enter a genebank, through all subsequent genebank operations.
Registration is the assignment of a unique identification number called an accession number for tracking each seed or plant material sample received by a genebank in order to distinguish it from other samples.
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Registration of samples. (photo: ILRI) |
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Why germplasm should be registered
Registration is carried out in order to allow genebanks to keep accurate records of samples and to produce inventory lists for conservation, distribution, and other aspects of germplasm management.
When it should be done
Registration is done when the sample first enters the genebank. For efficient management and use of the collections, register the samples if they meet the conditions described below.
How it is done
Registration is carried out in several steps.
(click here to see the flow chart for printing purposes)
Step 1: Before registration
Prior to registration, the status of the samples should be verified to ensure that the following minimum conditions are met before acceptance in the genebank:
- Acquisition agreements and permits
The samples should have been acquired from collectors, genebanks or other sources with appropriate material acquisition or material transfer agreements and permits in line with national and international regulations regarding conservation, distribution and use.
- Passport information
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Example of collection accession sheets. Click it to see a bigger picture. (photo: ILRI) |
Samples should be accompanied by adequate passport information especially cultivar name, collector number and pedigree (for genetic stocks and improved material) to ensure that each sample does not already exist in the genebank. The minimum required passport data may include the following:
a) Samples from collecting missions:
- Common crop name and/or genus and species.
- Collecting number.
- Location of collecting site.
- Country of origin.
- Collecting date.
- Phenology.
- Collecting source.
- Number of plants sampled.
b) Samples received as donations:
- Common crop name and/or genus and species.
- Accession name and/or other identification associated with the sample.
- Pedigree information and breeding institute’s details (for breeding lines).
- Phenology.
- Acquisition source.
- Country of origin.
- Donor accession number (if applicable).
- Distinctiveness
New samples should be genetically distinct from any other accessions already registered in the genebank. Two samples may have identical or very similar names and identical grain characteristics, but may be genetically distinct, while samples with very different names may be genetically similar.
Morphological, biochemical and molecular approaches can be used to identify duplicates, depending on the facilities and resources available in the genebank. The following tests can be performed:
a) Morphological:
- The suspected duplicates are grown side by side in the field or in a greenhouse and differences between morphological characteristics such as plant height, flowering time, leaf and flower size, and shape and colour are compared.
- The candidate accession is defined as distinct when it is found to differ significantly in at least one characteristic from existing registered accessions.
- Morphology-based distinctness tests can be similar to the crop-specific set of characteristics that comply with guidelines set by the International Union for the Protection of New Varieties of Plants (UPOV, 1991). If necessary, these characteristics can be assessed over two or three seasons. This may not be practical in landraces with high within-accession variation, however.
- The statistical procedure to assess distinctness is the t-test.
b) Biochemical:
When phenotypic comparison does not provide enough evidence of distinctness, biochemical methods such as electrophoresis of seed (or other plant parts) proteins and isozymes can be used for improving the comparison of morphological traits and to discriminate the samples.
c) Molecular:
DNA markers such as AFLPs, SSRs and SNPs offer powerful discriminating tools and can be successfully applied in checking genetic relatedness between samples, provided that this approach is feasible and cost effective. For more details on molecular methods, see de Vicente and Fulton (2003).
If the samples being compared are confirmed to be duplicates, genebanks are recommended to bulk the seeds or plant material and treat them as one entity. If the sample is identical to an existing accession, maintain it under the original accession number.
- Plant health
Each sample should be accompanied by a phytosanitary certificate and additional declarations as required under the host country’s phytosanitary regulations.
Seed or plant samples should be inspected by visual examination under a stereoscopic microscope. They should be free of pathogens, fungal growth, bacterial and viral infections, and insects.
- Sample quality and quantity
Seeds or plant material should be of the highest quality and in adequate numbers for storage.
--> In general, the percentage germinated should not be below 85% for cultivated species or below 75% for the wild species.
Seed or plant material quantity should be sufficient to conduct at least three regenerations. This will ensure that seeds or plant material are still available for another planting even if the first attempt to regenerate fails.
- What if minimum conditions are not met?
If the sample does not meet the required conditions, assign a temporary number until the sample is ready to receive a permanent registration number. The temporary number should be easily distinguishable from other accession numbers.
a) Agreements and permits:
Contact the collector or donor for the necessary agreements defining the status of samples with regard to conservation and further use.
b) Duplicate accessions:
Confirm duplication and assign the sample as a new seed or plant lot under the original accession number.
c) Missing passport information:
Write to the collector or donor of germplasm to request missing information.
d) Poor seed health:
If seeds contain pathogens or insects, send the sample to a phytopathologist or entomologist for treatment. If it is possible to acquire a replacement sample, immediately incinerate the sample and make a note of the action taken and the justification; request a fresh sample from the donor.
e) Inadequate seed quality and quantity:
Regenerate the sample immediately.
- Restructuring samples
In self-pollinating crops, if a sample comprises of a physical mixture of two or more distinct lines or species, they may be subdivided and maintained as distinct accessions. In this case, subdividing the sample into its components helps in effective maintenance of genetic integrity. Note that subdivision should not be undertaken if variation in the original sample is continuous, as in highly cross-pollinating crops.
If samples are registered without adequate passport data, their identities and biological status will remain unknown, hampering their use. Failure to regenerate samples with low viability or very few seeds or plant material may result in loss of the accession, leaving gaps in inventory.
Step 2: Procedure for registration
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Various types of labels used at the at the USDA genebank (photo: L. Guarino, by kind permission of USDA genebank in Ames, Iowa, USA) |
If the sample meets the minimum conditions described above, it may be accepted for registration and assigned an accession number using the following procedure:
1. Arrange the material in alphabetical order by variety name or in numerical order by collection number, depending on the identification provided.
2. Check all packets against the list accompanying the samples.
3. If no list is provided or seeds or plant material do not correspond to the data, prepare a new list. Check again to confirm that all packets have been included.
4. Check the passport data file to determine the last accession number given.
5. Assign the next ascending accession number to the first sample on the list and consecutive numbers to succeeding samples.
6. Write the accession number clearly on the packet using a permanent marker and on the list of new samples.
7. Enter the details in the passport data files of the genebank’s documentation system. For each accession, record all passport data, original identification data and registration date in the designated fields of the passport data file.
8. If data are missing, leave the field blank and contact the donor to supply the missing data.
Numbering procedures for new genebanks
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Processing samples (photo: Bioversity/ILRI, by kind permission of RDA genebank, National Agrobiodiversity Center, Suwon, Republic of Korea)
Documenting the accessions. Notice the barcoding device (photo: Bioversity/ILRI, by kind permission of RDA genebank, National Agrobiodiversity Center, Suwon, Republic of Korea) |
A genebank numbering system should be simple and practical to use.
1. Consecutive alpha numeric or numeric codes must be used for each new accession acquired. Assigned numbers are usually preceded by an acronym (such as GBK for Genebank of Kenya) to identify each sample with its registered genebank. Additional information such as year of acquisition and crop code should not be incorporated into an accession number. This code must be linked to all subsequent information about this sample: passport data, designation status and taxonomic information.
2. If large collections of germplasm are maintained, separate but sequential accession numbering may be given for each crop. However, this approach is not recommended if the genebank is small or has many crops.
3. Avoid assigning ‘reserved’ numbers for particular crops (for instance, 1 to 500 for maize, 501 to 1000 for cowpea) or for wild species when using a single numbering system.
Documentation
Documenting the information received along with a sample is an important aspect of registration. Information documented at registration consists of passport data providing basic information for identification and general management of individual accessions.
Much of this information is either recorded when the sample is collected or accompanies the sample if it is received from other sources. The use of internationally accepted descriptor lists to document passport information simplifies data exchange between genebanks. The standard Multi-crop Passport Descriptor (MCPD) list developed by FAO and IPGRI is available here.
Information systems
An information management system must be created in each genebank. This database must be searchable by the genabank curators and staff for specific information through a range of queries. The information system must keep a record of genebank operation data, including storage location, stocks, monitoring, health tests and the distribution status. The same system must also manage germplasm orders, shipment related information and genebanks ‘contacts’ information.
Barcoding is a useful tool that can compliment a genebank information system.
References and further reading
Breese EL. 1989. Regeneration and Multiplication of Germplasm Resources in Seed Genebanks: The Scientific Background. 69pp. [online] Available from: http://www2.bioversityinternational.org/publications/Web_version/209/. Date accessed: 08 April 2010.
Engels JMM, Ramanatha Rao R, editors. 1998. Proceedings of a Consultation Meeting 4-7 December 1995, ICRISAT, Hyderabad, India: Regeneration of Seed Crops and Their Wild Relatives. 167pp. Available in English (1.5 MB).
Engels JMM, Visser L, editors. 2003. A guide to effective management of germplasm collections. IPGRI Handbooks for Genebanks No. 6. IPGRI, Rome, Italy. Available in English (1.4 MB) and Spanish (1.5 MB).
FAO/IPGRI. 2001. Multi-Crop Passport Descriptors. FAO and IPGRI, Rome, Italy. Available in English, French and Spanish.
International Union for the Protection of New Plant Varieties (UPOV). 1991. International Convention for the Protection of New Varieties of Plants. UPOV, Geneva. http://www.upov.int.
Rao NK, Hanson J, Dulloo ME, Ghosh K, Nowel D, Larinde M. 2006. Manual of seed handling in genebanks. Handbooks for Genebanks No. 8. Bioversity International, Rome, Italy. Available in English (1.5 MB), Spanish (1.4 MB) and French (1.9 MB).
de Vicente C, Fulton T. 2003. Using molecular marker technology in studies on plant genetic diversity: Learning module Vol 1. IPGRI, Rome, Italy. Available from: http://www.bioversityinternational.org/publications/publications/publication/issue/molecular_marker_learning_modules_vols_1_and_2.html. Date accessed: 24 March 2010.
How registration is done?
| How registration is done? Registration is carried out in several steps Step 1: before registration Prior to registration, the status of the samples should be verified to ensure that the following minimum conditions are met before acceptance in the genebank:
The samples should have been acquired from collectors, genebanks or other sources with appropriate material acquisition or transfer agreements and permits in line with national and international regulations regarding conservation, distribution and use.
Samples should be accompanied by adequate passport information especially cultivar name, collector number and pedigree (for genetic stocks and improved material) to ensure that each sample does not already exist in the genebank. The minimum required passport data may include the following:
New samples should be genetically distinct from any other accessions already registered in the genebank. Two samples may have identical or very similar names and identical grain characteristics but may be genetically distinct, while samples with very different names may be genetically similar.
Each sample should be accompanied by a phytosanitary certificate and additional declarations as required under the host country’s phytosanitary regulations.
Seeds or plant materials should be of the highest quality and in adequate numbers for storage.
If the sample does not meet the required conditions, assign a temporary number until the sample is ready to receive a permanent registration number. The temporary number should be easily distinguishable from other accession numbers.
In self-pollinating crops, if a sample comprises of a physical mixture of two or more distinct lines or species, they may be subdivided and maintained as distinct accessions. In this case, subdividing the sample into its components helps in effective maintenance of genetic integrity. Note that subdivision should not be undertaken if variation in the original sample is continuous, as in highly cross-pollinating crops.If samples are registered without adequate passport data, their identities and biological status will remain unknown, hampering their use. Failure to regenerate samples with low viability or very few seeds or plant materials may result in loss of the accession, leaving gaps in inventory. Step 2: Procedure for registration If the sample meets the minimum conditions described above, it may be accepted for registration and assigned an accession number using the following procedure: 1. Arrange the material in alphabetical order by variety name or in numerical order by collection number, depending on the identification provided. 2. Check all packets against the list accompanying the samples. 3. If no list is provided or seeds or plant materials do not correspond to the data, prepare a new list. Check again to confirm that all packets have been included. 4. Check the passport data file to determine the last accession number given. 5. Assign the next ascending accession number to the first sample on the list and consecutive numbers to succeeding samples. 6. Write the accession number clearly on the packet using a permanent marker and on the list of new samples. 7. Enter the details in the passport data files of the genebank’s documentation system. For each accession, record all passport data, original identification data and registration date in the designated fields of the passport data file. 8. If data are missing, leave the field blank and contact the donor to supply the missing data. |
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| Numbering procedures for new genebanks
A genebank numbering system should be simple and practical to use. 1. Consecutive alpha numeric or numeric codes must be used for each new accession acquired. Assigned numbers are usually preceded by an acronym (such as GBK for Genebank of Kenya) to identify each sample with its registered genebank. Additional information such as year of acquisition and crop code should not be incorporated into an accession number. This code must be linked to all subsequent information about this sample: passport data, designation status and taxonomic information.
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Documentation Documenting the information received along with a sample is an important aspect of registration. Information documented at registration consists of passport data providing basic information for identification and general management of individual accessions. |
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Information systems An information management system must be created in each genebank. This database must be searchable by the genabank curators and staff for specific information through a range of queries. The information system must keep a record of genebank operation data, including storage location, stocks, monitoring, health tests and the distribution status. The same system must also manage germplasm orders, shipment related information and files genebanks ‘contacts’ information. |
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Further reading Engels J.M. and Visser, L. (eds.). 2003. A guide to effective management of germplasm collections. IPGRI Handbook for Genebanks No.6. IPGRI, Rome, Italy. International Union for the Protection of New Plant Varieties (UPOV). 1991. International Convention for the Protection of New Varieties of Plants. UPOV, Geneva. (http://www.upov.int) |
Sample processing
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View the full chapters on sample processing by clicking on the icon above. (0.2 MB) |
Page compiled by: Bioversity International/ILRI, Addis Ababa, Ethiopia (Alexandra Jorge); ILRI, Addis Ababa, Ethiopia (Jean Hanson) including information extracted from: Rao NK, Hanson J, Dulloo ME, Ghosh K, Nowel D and Larinde M. 2006. Manual of seed handling in genebanks. Handbooks for Genebanks No. 8. Bioversity International, Rome, Italy. 147pp.
What is sample processing
The processing of seeds or plant material is the preparation of the samples to be stored. This is directly linked to the method of conservation, i.e. seed cleaning and drying is related to seed conservation while extraction and disinfection of plant material is related to tissue culture or cryopreservation. Therefore, for practical purposes in this presentation this is incorporated within each conservation method.
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Use the arrow to view the slides. (Photos 1,3,4 by ILRI, 2 by ICARDA, 5 by Bioversity) |
Seed processing is usually done in four main steps:
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Contents: |
Seed cleaning is the removal of debris, physical contamination, inert material, damaged and infected seeds and seeds of other species. It is essential to improve the quality of samples and should be done immediately after harvesting or as soon as the material arrives at a genebank, before storage.
Why it should be done
- To reduce the volume of seeds/propagules to be transported and stored (removing extraneous material).
- To improve the purity of the samples (removing damaged seeds/planting material).
- To optimize storage space and reduce genebank costs.
Steps of seed cleaning
Threshing
Seed threshing is the separation of the grains from the straw either by impact, friction or combing action. It can be done manually or with threshing machines.
Cleaning
The first cleaning usually separates seeds from debris, physical contamination and inert material. It can be done manually or with cleaning machines.
Visual inspection
This is important to check and prevent further spread of insect and fungal damage and remove damaged or empty seeds.
Final cleaning
This is when damaged and empty seeds are identified and removed. It is usually done manually.
Purity analysis
Purity is an expression of how ‘clean’ the seed lot is.
ISTA (2005) specifies a pure seed faction to contain:
- Intact seeds of actual species as well as dead, shrivelled, diseased, immature and pre-germinated seeds.
- Achenes and similar fruits, such as samara with or without perianth regardless of whether they contain a true seed, unless it is apparent that none is contained.
- Fractions of broken seeds, achenes, etc. that are more than half of the original size.
Information on actual seed lot composition is important; purity analysis serves as a guideline to determine the necessity of further cleaning. During purity analysis, each ‘pure’ seed fraction from the working sample is separated from the inert matter and other seeds.
- Weigh out a working sample of a given weight (for example 250 g) of the total seed lot randomly using electronic scales.
- Spread the sample on the table and separate out all pure seeds manually with tweezers or remove impurities by blowing, sifting or letting seeds roll down a slanting surface.
- Weigh the ‘pure’ seed fraction and express purity as the percentage weight of pure seed over the total weight of the working sample, as shown below.
Purity (%) = Weight of pure seeds (g) x 100
Total weight of working sample (g)
Documentation of information about seed cleaning
It is important to file all the relevant information about the cleaning process for future reference. The information may be relevant to explain germination test results or contamination in the future.
Seed drying is the reduction of seed moisture content to recommended levels for storage using techniques that are not detrimental to seed viability. It should be done as soon as possible after clean seeds arrive in a genebank, to avoid deterioration and to reduce the moisture content in the seed. High moisture promotes respiration and growth of seed embryos, insects and fungi.
Seed samples are usually kept in paper, mesh or cotton bags in well aerated and cool environments (with low relative humidity) for a few weeks to dry.
Why it should be done
- To dry the seeds to a safe moisture content level to prevent damage, heating and infestation during storage.
Steps of seed drying
- Determine the seed moisture content (this can be omitted if seed amounts are limiting and/or genebank staff have experience on expected seed moisture content at harvest).
- Dry seed in porous containers.
- Determine seed moisture content.
- Document the information about seed drying.
For more detailed information on seed drying see pages 36-49 of the Handbooks for Genebanks No. 8. (Available here).
Seed moisture content determination
Seed moisture content is the amount of water in a seed and is expressed in terms of the weight of water contained in a seed. The moisture content is one of the most important factors that determines the rate at which seeds will deteriorate in genebanks. It is usually carried out with oven-drying methods or with moisture meters.
Why it should be done
- Knowing the seed moisture and storage temperature allows genebanks to accurately predict the potential storage life of each seed sample.
Steps of moisture content determination
Pre-drying
Pre-drying is obligatory if seeds are wet and their moisture content is suspected to be above 17% (10% for soybean and 13% for rice); it should be conducted prior to moisture content determination by oven-drying.
If pre-drying is required, proceed as follows:
- Weigh two sub-samples of 4-5 g of seeds in their containers.
- Pre-dry the samples overnight in a warm, dry place such as a laboratory bench.
- Weigh them again in their containers and determine the loss of weight (loss of moisture) by subtraction.
- Calculate the moisture content on a fresh-weight basis.
Grinding
Some seeds require grinding into smaller particles to have uniform and complete drying. The table below provides a list of species for which grinding is obligatory (ISTA, 2005).
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Arachis hypogaea
Avena spp.
Cicer arietinum
Citrullus lanatus
Fagopyrum esculentum
Glycine max
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Gossypium spp.
Hordeum vulgare
Lathyrus spp.
Lupinus spp.
Oryza sativa
Phaseolus spp.
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Pisum sativum
Secale cereale
Sorghum spp.
Triticum spp.
Vicia spp.
Zea mays
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Moisture content methods
Recommended methods vary with each species. The table below provides the suggested methods of moisture determination for some important crops and forages (ISTA 2005).
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Low-constant temperature oven method (105oC for 16 hours)
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Brassicas
Castor (Ricinus)* Pepper (Capsicum) Cotton (Gossypium)* Eggplant (Solanum) |
Falseflax (Camelina)
Flax (Linum) Groundnut (Arachis)* Onion (Allium) Radish (Raphanus) |
Sesame (Sesamum)
Soyabean (Glycine)* All tree species |
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High-constant temperature oven method (130oC for 1 hour)
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Alfalfa (Medicago)
Asparagus (Asparagus) Barley (Hordeum)* Bean (Phaseolus)* Beet (Beta) Bentgrass (Agrostis) Bermuda grass (Cynodon) Black salsify (Scorzonera) Bluegrass (Poa) Brome (Bromus) Buckwheat (Fagopyrum)* Canarygrass (Phalaris) Caraway (Carum) Carrot (Daucus) Chervil (Anthriscus) Chickory (Cichorium) Chickpea (Cicer)* Clover (Trifolium) |
Cocksfoot (Dactylis)
Cress (Lepidium) Crested dogtail (Cynosurus) Cucumber (Cucumis) Cumin (Cuminum) Dallisgrass (Paspalum) Fescue (Festuca) Foxtail (Alopecurus) Lettuce (Lactuca) Lupin (Lupinus)* Maize (Zea)* Millet (Panicum) Oat (Avena)* Parsley (Petroselinum) Pea (Pisum)* Rhodes grass (Chloris) Rice (Oryza)* |
Rye (Secale)*
Ryegrass (Lolium) Sainfoin (Onobrychis) Serradella (Ornithopus) Sorghum (Sorghum)* Squash (Cucurbita) Sweetclover (Melilotus) Tall oatgrass (Arrhenatherum) Timothy grass (Phleum) Tomato (Lycopersicon) Trefoil (Lotus) Tufted hairgrass (Deschampsia) Velvetgrass (Holcus) Vetch (Vicia)* Watermelon (Citrullus)* Wheat (Triticum)* |
Calculation of moisture content percentage
Calculate the moisture content on a wet-weight basis using the following formula:
Moisture content (%) = W2 - W3 x 100
W2-W1
where,
W1 = weight of container with lid;
W2 = weight of container with lid and sample before drying; and
W3 = weight of container with lid and sample after drying.
Documentation of information about seed moisture content
This is important to file all the relevant information about the seed moisture content for future reference.
For more detailed information on seed moisture content determination see pages 28-35 of the Handbooks for Genebanks No. 8. (Available here).
Seeds are packaged to:
- prevent absorption of water from the atmosphere after drying.
- keep accessions separate and avoid mixing.
- prevent contamination from insects during storage.
For many crop species, keeping seeds at low moisture content improves longevity during storage. Maintain low moisture during packing by:
- Packing seeds in an air-conditioned room where the relative humidty is controlled in tropical humid environments.
- Exposing seeds taken from the drying room to ambient air for the shortest time possible, so that they do not re-absorb water.
Different types of containers are available for packaging; the choice depends on storage conditions and species (size, shape and sharpness). It is important that the packing and labelling material be completely impermeable to water, withstand freezing and is suitable for long-term use. Frequently used containers include glass bottles, aluminium cans, laminated aluminium foil packets and plastic bottles.
Different types of containers have advantages and disadvantages.
- Glass bottles with tight gaskets around sealed lids are moisture proof but can easily break.
- Aluminium cans are difficult to reseal once they have been opened.
- Aluminium foil packets can be resealed and occupy less space than other containers, but seeds with sharp projections can pierce them and moisture can leak in.
- Plastic bottles and aluminium cans with lids are moisture resistant but not moisture proof unless they have a tight rubber seal. They should be used with caution if the relative humidty of the storage room is not controlled.
Correct and clearly written labels are extremely important in germplasm collections to keep track of packets during storage:
- Label packets with a unique identification number, location and any other important information.
- Write clearly and carefully or print computer labels using indelible ink.
- Use labels that are as indestructible as possible with good sticking properties.
- Place labels inside and outside of each packet.
References and further reading
ISTA. 2005. International Rules for Seed Testing. Edition 2005. International Seed Testing Association, Bassersdorf, Switzerland. ISTA homepage available from: www.seedtest.org/en/home.html.
Rao NK, Hanson J, Dulloo ME, Ghosh K, Nowel D, Larinde M. 2006. Manual of seed handling in genebanks. Handbooks for Genebanks No. 8. Bioversity International, Rome, Italy. Available in English (1.5 MB), Spanish (1.4 MB) and French (1.9 MB).
Germplasm testing
View the full chapter on seed quality testing by clicking on the icon above. (0.7 MB) |
Page compiled by: Bioversity International/ILRI, Addis Ababa, Ethiopia (Alexandra Jorge); ILRI, Addis Ababa, Ethiopia (Jean Hanson) including information extracted from: Rao NK, Hanson J, Dulloo ME, Ghosh K, Nowel D and Larinde M. 2006. Manual of seed handling in genebanks. Handbooks for Genebanks No. 8. Bioversity International, Rome, Italy. 147pp.
Proper handling procedures in genebanks are fundamental to the long-term, cost-effective and efficient conservation of plant genetic resources of the same genetic identity as the original collection. It is very important that germplasm stored in genebanks is capable of producing plants after storage when sown in the field. Genetic resources samples must have high viability at the start of storage and maintain it during storage and should have the same genetic makeup as at the time of collection to avoid loss of diversity during storage. Accessions are tested and monitored both at the start and during conservation in order to ensure the quality of the material in the genebank.
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Testing the germination of seeds at the USDA genebank (photo: L. Guarino, by kind permission of USDA genebank in Ames, Iowa, USA) |
What is germplasm testing
The quality testing of seeds or plant material assures that the material to be conserved is in good condition, i.e. it can be grown again (viable) and is free of external contaminants (pests and diseases) and external genes (artificially produced genes). Monitoring of viability during storage allows careful observation the material and ensures that it is not lost through loss of viability or genetic integrity during conservation.
Germplasm is usually tested for
Viability and quantity are also monitored during the storage period.
More Articles...
Subcategories
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main
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Collecting
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- 31
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Acquisition/Registration
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- 2
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Sample processing
- Article Count:
- 1
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Quality testing
What is quality testing?
The quality testing of seeds or plant materials assures that the materials to be conserved are in good conditions, i.e. can be grown again (viable) and are free of external contaminants (pests and diseases) and external genes (artificially produced genes). They are composed by three major aspects:
- Viability testing
- Plant health
- Transgenes.JPG)
The quality of seed can be tested with a germination test
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- 5
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Methods of conservation
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- 2
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Cold storage
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Tissue culture
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Cryopreservation
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- 1
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Molecular
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In field conservation
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Characterization
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Regeneration
What is Regeneration?
Regeneration is the renewal of germplasm accessions by sowing seeds or planting vegetative materials and harvesting the seeds or plant materials which will posses the same characteristics as the original population.
Germplasm regeneration is the most critical operation in genebank management, because it involves risks to the genetic integrity of germplasm accessions due to selection pressures, out-crossing, mechanical mixtures and other factors. The risk of genetic integrity loss is usually high when regenerating genetically heterogeneous germplasm accessions. Germplasm regeneration is also very expensive..JPG)
Regeneration on fields
Why should germplasm be regenerated?
Germplasm is regenerated for the following purposes:
1. To increase the initial seeds or plant materials
In new collections or materials received as donations, the quantity of seeds or plant materials received by the genebank is often insufficient for direct conservation. Seeds or plant materials may also be of poor quality due to low viability or infection. All these materials require regeneration. Newly acquired germplasm of foreign origin may need to be initially regenerated under containment or in an isolation area under the supervision of the national phytosanitary authorities.
2. To replenishing seed stocks or plant materials in active and base collections
Increase seed stocks or plant materials of accessions that have:
- Low viability identified during periodic monitoring;
- Insufficient stocks for distribution or conservation.
Active collections should be regenerated from original seeds or plant materials in a base collection; this is particularly important for out-breeding species. Using seeds from an active collection for up to three regeneration cycles before returning to the original seeds or plant materials (base collection) is also acceptable (FAO/IPGRI 1994).
Base collections should normally be regenerated using the residual seed or plant materials from the same sample.How is it done?
If possible, regenerate germplasm in the ecological region of its origin. Alternatively, seek an environment that does not select some genotypes in preference to others in a population.
If no suitable site is found, seek collaboration with an institute that can provide a suitable site or regenerate in a controlled environment such as a growth room.
Examine the biotic environment in the context of prior information about the plants and past experience - an inappropriate biotic environment can be detrimental to plants, seed or propagation materials quality and the genetic integrity of an accession.Meeting special requirements
There may be special requirements for regeneration of accessions with special traits that breeders and researchers use frequently—such as high-yielding, pest-and disease-resistant accessions and genetic stocks — or if there are insufficient seeds for safety duplication and repatriation.
The following factors when regenerating germplasm accessions must be consider:- Suitability of environment to minimize natural selection;
- Special requirements, if any, to break dormancy and stimulate germination (such as scarification);
- Correct spacing for optimum seed set; and
- Breeding system of the plant and need for controlled pollination or isolation..JPG)
Regeneration in a protected environment
When should it be done?
It should be done when either the quantity and/or the quality of a particular seed or plant material are not sufficient in a genebank.
The regeneration of accessions that have inadequate quality (low viability) should take priority over that of accessions with inadequate numbers of seeds or planting materials.
The regeneration of accessions in base collections should take priority over regenerating those in active collections.
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Dissemination
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Safety duplication
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Information/Documentation
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List of equipment and supplies
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