Veena Gupta
Division of Germplasm Conservation, ICAR-National Bureau of Plant Genetic Resources, New Delhi -110012
E-mail: [email protected]
Plant genetic resources are one of tremendous practical significance for supporting life on earth to generating wealth of nations and therefore conserving these resources is a mean of safeguarding the life exploited by agriculture industry, forestry and aquaculture to supply food, feed medicines, fibre, fuel and many industrial products. Conservation ensures that future generations will benefit from these genetic resources. The basic objective of plant genetic resources conservation is the protection of genetic diversity at intra-specific and inter- specific levels to ensure the future adaptability of cultivars and wild populations, to preserve data and traits that ensure sustainable agriculture; to promote the use of genetic resources in commerce and biotechnology; to conserve diversity for cultural reasons.
The Genebanks -a part of ex-situ conservation strategy, are under increasing scrutiny as in- situ strategies are now gaining more importance mainly due to climatic changes. Therefore, there is an urgent need for precaution in terms of effectiveness and economy in genebank operations with respect to species diversity and responsibilities when it comes to connect it with farming community. The design and management of genebanks must be done keeping in view the conditions, availability of human and financial resources, and the low-cost methodologies available in the country concerned.
The National Genebank at NBPGR has the mandate to
▪ Undertake and promote long-term conservation of plant genetic resources in genebank and assist in the in situ conservation efforts.
▪ Act as the repository of notified /released varieties/cultivars, parental lines of released hybrids, genetic stocks, as also regional repository of duplicate collections of specific crops as a part of the global system.
▪ Monitoring and maintenance of the extant collections, facilitating the organization of regeneration programme.
▪ Complimenting the activities of National Active Germplasm Sites (NAGS) to ensure availability of exotic and indigenous germplasm through periodic seed increase for evaluation, utilization and conservation.
▪ Developing and operating a database and information network system on PGR.
▪ Conducting research related to medium and long-term conservation of germplasm.
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▪ Support/assist in human resource development by organizing short/medium-term training courses on PGR conservation activities at national, regional and international levels.
Genebank activities
The major activities at any genebank involves
i. Acquisition of germplasm-either through explorations or by introduction/exchange with other institutions within country or outside
ii. Processing of the received germplasm for conservation involving seed health/
quarantine testing, viability testing and moisture estimation and its storage in genebank
iii. Allotment of National Identity once the germplasm is qualified for conservation at genebank.
iv. Regular monitoring of the conserved germplasm in storage and regeneration whenever/ wherever required.
v. Distribution of the germplasm to the users
vi. Value addition to conserved germplasm through characterization/ preliminary evaluation, if not available for effective utilization
vii. Documentation of the passport information of the conserved germplasm Conservation procedures
The principles governing conservation procedures are maintenance of viability, vigour and genetic integrity of the germplasm. Desiccation tolerant seeds which maintain high viability under storage at low temperatures are called as orthodox seeds and at National Genebank seeds of all agri-horticultural crops are conserved at -18°C to -20°C. Seed viability and vigour is controlled by genetic, biochemical and physiological characteristics but to a large extent influenced by storage temperature and humidity. Thus at NGB seed lots with initial high viability (above 85%), free of diseases, pest or pathogen are conserved to minimize the loss of vigour and viability during storage. Thus the various procedures adopted for successful conservation of any germplasm are:
i. Testing of initial moisture content as soon as the germplasm is received (using ISTA 2005 guidelines).
ii. Drying of the received germplasm in controlled conditions (drying rooms/cabinets maintained at 15°C and 15% RH)
iii. Seed viability testing using ISTA prescribed optimum conditions for various crops iv. If there is a occurrence of dormancy then evincing dormancy breaking protocols
v. Packaging and vacuum sealing the samples in trilayer aluminum foil pouches
vi. Documentation and labeling of the packets and then assigning location in LTS module vii. Monitoring of the conserved germplasm (for ten years in most of the crops except
oilseeds where after 5-6 years the monitoring is done)
Page | 72 viii. Regeneration of germplasm, in case of loss of viability or less seed quantity but
frequency of regeneration is kept minimum to avoid risks of genetic shift, drift and contamination which are compounded with each regeneration cycle (upto a maximum of two or three cycles)
Standards for germplasm processing Standards for seed storage
• Type of collections: Depending upon the objectives and storage period the collections are classified as
• Active Collection: These are stored for medium period of 2-10 years. They are being regularly used for research and distribution to bonafied users.
• Base Collections: These are conserved for long duration, 15 years or more for safety and posterity. They are to be used only in emergency, such as loss of an accession, for regeneration of active collections and to support other complementary conservation activities.
Seed storage conditions
• For Base Collections- -20°C with seed moisture 3-7%; the standards should not be relaxed
• For Active Collections- Conditions that can maintain seed viability above 65 per cent for 10-20 years. However, decrease in seed moisture content is cost effective than temperature.
Storage modules
• Short Term: Temperature 15-20°C, and 30-40 per cent RH for seed processing.
• Medium Term: Temperature 0-10°C and 25-30 per cent RH. Adequate to maintain seed viability for 2-10 years, suitable for active collections.
• Long-Term: Temperature -20°C and no control of RH. Adequate to maintain seed viability for 10-50 years, suitable for base collections. The seeds are kept in hermetically sealed containers with around 3-5% seed moisture.
Seed drying procedures
• Seeds should be dried soon on receipt to avoid further deterioration
• Avoid damage for seed during drying
• Lower the seed moisture for prolonging longevity using dhimmified chambers (using desiccant for drying at 10-25°C and 10-15 per cent RH.
Page | 73 Seed cleaning and health
The seed to be stored should be free from weeds, pest and diseases. Crop specific knowledge is preferred. Germplasm received at National Genebank is subjected to visual and microscopic examination to remove weed seeds, soil particles, broken parts of flower, debris or any inert material before sending to quarantine examination for any seed borne pathogens and pests.
Storage containers
Containers should be moisture proof and amenable to hermetic sealing. Test to ensure non- exchange of moisture. The containers available are:
• Plastic containers
• Aluminum containers
• Multi-layered pouches of polyethylene, Aluminum etc.
Accession size
In base collections minimum size should be sufficient to meet the requirement of one regeneration cycle and test of viability. 2000 viable seeds for homogenous crops and 4000 seeds for heterogeneous crops (it may be decreased for difficult to multiply crops). In active collection, as large quantity as possible to avoid frequent regeneration.
Monitoring of seed viability
• Seed accessions are monitored in genebanks to adjudge the minimum acceptable limits of germination (65-85%)
• Assessed by means of a germination test
• A minimum of 100-200 seeds are used for germination test at the start of seed storage.
• Period between viability monitoring vary among species and storage conditions. For base collection 10 years or as required, for active collections 5 years
• For viability monitoring randomly drawn 50-100 seeds are used
• Well equipped laboratory and laboratory equipment’s for viability tests, in some cases specialized equipment’s, such as X-ray machine etc. are required
• Based on situation, seedlings raised during germination testing be used for regeneration of an accession
Regeneration standards
Regeneration standards are needed to ensure the seed viability does not fall below acceptable limits.
• Seeds for base collection should be pathogen free and of highest possible quality.
Regeneration should be undertaken when viability falls (85±10%)
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• Plant 100 or more seeds for regeneration to avoid large losses of alleles
• Seeds used for regeneration should be genetically as close as possible to the original sample
Standards for information management
Data as complete as possible both on base and active collections along with standards descriptor as prepared by IPGRI and International centers (Passport information proforma for breeding lines/variety- Annexure 1):
• Passport
• Management
• Characterization
• Evaluation
• Mode of reproduction
Standards for germplasm exchange
While supplying the seeds to bonafied user it is recommended that
• Seeds be supplied in suitable containers
• Adequate information should accompany for effective use
• Seed lot should have high viability level
• Quarantine regulations are strictly followed
• Should accompany MTA as per national requirement Genebank personnel and training
Trained staff with regular updating of skill is essential.
Standards for maintenance of modules
• A voltage stabilizer to protect from fluctuations in electric supply
• A built-in electrical control panel providing complete operation information
• Indicator lights to display operating condition
• Spares: compressor unit, thermostat, fan motor, expansion valves, compressor contractor overload relays, and fuses etc. should always be kept for immediate replacement.
Standards for safety and security of modules
Every effort must be made to ensure utmost safety of equipments. Following need attention:
• Uninterrupted power supply
• Fire precautions
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• Security
• Refrigeration standards and equipment used should be as per DSSF
• Construction and installation-following guidance given by DSSF
• Safety of personnel: protective clothing, etc.
PASSPORT INFORMATION PROFORMA FOR BREEDING LINES/VARIETY GERMPLASM CONSERVATION DIVISION
ICAR-National Bureau of Plant Genetic Resources New Delhi
Supply/co-operating institute:
Date:
Developer:
Collaborating Institute: Name of Scientist(s) and Address:-
Conserved at: ICAR-NBPGR, Pusa campus, New Delhi
S.
No
Crop Bot.
Name Crop- group
Country of Origin
Donor institute
Other ID
Pedigree Source Bio- Status
state Novelty/ Unique features
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