As this article is explored, basic facts on germplasm conservation, the need for conservation, its benefits, and the obstacles limiting effective utilisation of germplasm will be discussed.
It is important to appreciate that conservation is a process that involves adequate planning, controlled exploitation, judicious use, and efficient management of resources to ensure their availability for present and future use.
As the human population increases, there is increasing demand on available resources. Conservation of germplasm ensures the continuity of wild species on which biotechnology depends.
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Meaning of Germplasm Conservation in Agriculture
This refers to the conscious storage of genetic materials under standardised conditions by regulated agencies for safekeeping and, most importantly, to avoid loss by extinction.
This is achieved through technological innovations and approaches that ensure conformity with original conditions even in artificial environments.
Biotechnological approaches have been extensively employed in the process, as research continues to accommodate new bio-materials.
The conservation of germplasm in genebanks in the form of seeds requires that the integrity of the conserved material be maintained to the highest standard over prolonged periods.
For this to be achieved, it is necessary to set standards based on current scientific knowledge and available technologies for the proper handling and storage of seeds in gene banks, ensuring their conservation over the longest possible time without frequent, costly regeneration.
Standards for routine gene bank operations and quality assurance must be followed. Several pre- and post-harvest factors such as crop management, seed production environment, maturity, harvest and cleaning, and drying practices influence initial seed quality and its subsequent longevity.
Maintaining seed quality in the accessions of a large collection requires careful planning and adherence to standard protocols during seed production and storage. Ex situ seed storage is the most convenient and widely used method of conservation.
Types of Germplasm Conservation Methods
1. Active Collection: Refers to collections kept for medium-term conservation, which are immediately available for distribution for utilisation and multiplication.
Active collections are kept under conditions that ensure accession viability remains above 65% for 10–20 years. Different combinations of storage temperature and moisture content can provide this longevity (IPGRI 1996).
These are ideally maintained in sufficient quantity to be readily available. The active collections of ICRISAT genebank are stored in standard aluminium cans for all crops and in plastic cans for groundnut at 4°C and 30% relative humidity.
Depending on the crop species, the equilibrium moisture content for these samples ranges between 7% and 10%.
2. Base Collection: Refers to collections kept for long-term conservation solely for ‘posterity’, and are not drawn upon except for viability testing and subsequent regeneration.
The accessions in base collections should be distinct, and in terms of genetic integrity, as close as possible to the originally provided sample.
The base collections of ICRISAT germplasm are maintained at 20°C in vacuum-packed standard aluminium foil pouches at 3%–7% seed moisture content, depending on the crop species and with initial seed viability above 85%.
Base collections ensure long-term viability of materials (more than 50 years) as security to the active collection. The storage conditions maintained for both collections represent preferred standards for international genebanks.
Hamilton et al. (2003) have described considerations for improved conservation and utilisation concepts and strategies.
Need for Germplasm Conservation in Agriculture
The rapid decline in the abundance of wild or local biodiversity necessitates the preservation of genetic material mainly to avoid its disappearance from natural environments. In the high demand for desired varieties, certain wild forms tend to be ignored. Thus, it is observed that:
- The availability of cultivars is increasing
- Their supply is more controlled
- The quality is high
- Their botanical identification is accurate
- Genetic improvements and agronomic manipulation are involved
- Post-harvest quality is good and they are relatively safe (little or no adulteration)
Benefits of Germplasm Conservation in Agriculture
1. Building blocks/gene pool for genetic improvement or enhancement
2. Genes for adaptation and endurance to varying unfavourable biotic and abiotic stresses
3. Contribution to the development of high-yielding varieties
4. Contribution to sound pest and disease management
5. Reduction of dependency on external inputs
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Obstacles to Effective Use of Germplasm in Agriculture
Several obstacles limit the effective utilisation of plant genetic resources. These include:
- The lack of characterisation and evaluation data
- Poor coordination of national policies and weak linkages between national genebanks and germplasm users
- Limited utilisation of plant genetic resources maintained by farmers due to lack of information on their characteristics and limited availability
Although International Research Centres (IRC) and African National Agricultural Research Systems (ANARS) have developed improved varieties, these often do not reach farmers because of lengthy testing requirements, even in countries with similar agro-ecological conditions.
For existing and approved varieties, the lack of national capacity to maintain and provide basic seed promptly hampers effective utilisation. Additional obstacles include:
1. Weak Disaster Management: Disasters such as droughts, floods, and conflicts are increasing, especially in Africa where they often develop into chronic situations leading to food and seed insecurity.
Despite general acceptance of recurring disasters, there is little planning or consultation at national or regional levels. Many African countries lack the capacity to respond effectively and sustainably.
Efforts like food aid, government food imports, and seed relief programs have had minimal impact. The introduction of unsuitable varieties during such disasters often erodes biodiversity and leads to loss of valuable local genetic resources.
2. Inadequate Regional Seed Marketing: Lack of collaboration, consultation, and harmonisation at regional and continental levels regarding the development, movement, and use of high-yielding vegetatively propagated materials and seeds has led to restrictive seed certification and variety release requirements.
These vary by country and, along with excessive phytosanitary and foreign currency regulations, act as non-tariff barriers to seed exchange. Improved coordination and capacity building at national, regional, and continental levels are needed to address these constraints through harmonisation of seed rules and policy improvements.
2. Germplasm Documentation: Documentation is essential for effective genebank management. Characterisation and evaluation data are of limited value if not properly documented and incorporated into accessible information systems. Accurate information enhances better use of germplasm.
Computerised documentation systems enable rapid dissemination of data and help curators manage collections efficiently. Tools like GIS and satellite imagery aid in identifying germplasm with specific traits, monitoring crop changes, or selecting in situ reserve locations.
The Genebank Information Management System (GIMS) of ICRISAT integrates documentation activities and provides information on accessions due for regeneration or viability monitoring.
Vast data collected on chickpea and pigeon pea germplasm have been summarised and presented in catalogues. Details from exploration and collection missions were published as progress reports.
Core collections (10% of the total collection) and mini core collections (1% of the total) of ICRISAT mandate crops were established, with information published in journals for research workers.
A Manual of Genebank Operations and Procedures has also been published to document collection histories and processes.
Germplasm Distribution and Its Impact on Agriculture
Distribution of germplasm and related information is fundamental to ICRISAT’s mission of enhancing crop productivity and food security.
In line with the International Treaty on Plant Genetic Resources for Food and Agriculture (ITPGRFA), germplasm is distributed under the Standard Material Transfer Agreement (SMTA).
The germplasm conserved at ICRISAT genebank has become a vital source of diversity for researchers globally. Between 1975 and 2008, over 692,000 samples of mandate crops and small millets were distributed to users in 144 countries.
These global collections have helped restore national germplasm in countries affected by calamities or civil unrest. For instance, ICRISAT supplied thousands of accessions to countries like Botswana, Cameroon, Ethiopia, Kenya, Nigeria, Somalia, Sri Lanka, and India.
Impact of Germplasm Supply on Agricultural Development
In addition to restoring native germplasm, ICRISAT genebank has facilitated the testing and release of several accessions directly as cultivars in various countries.
A total of 66 germplasm accessions conserved in the genebank have been released as cultivars in 44 countries, contributing significantly to food security.
Many other distributed germplasm accessions have also served as foundational genetic material for crop improvement programs worldwide.
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