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CHAPTER 4 : GENETIC RESOURCES IN AGRICULTURE (GERMPLASM)
Sunday 11 October 2015 @ 14:48
Germplasm is the living genetic resources such as seeds or tissue that is maintained for the purpose of animal and plant breeding, preservation, and other research uses. These resources may take the form of seed collections stored in seed banks, trees growing in nurseries, animal breeding lines maintained in animal breeding programs or gene banks, etc.Germplasm collections can range from collections of wild species to elite, domesticated breeding lines that have undergone extensive human selection. 2. CONSERVATION IN SEED BANKS A seed bank (also seedbank or seeds bank) stores seeds as a source for planting in case seed reserves elsewhere are destroyed. It is a type of gene bank.The seeds stored may be food crops, or those of rare species to protect biodiversity. The reasons for storing seeds may be varied. In the case of food crops, many useful plants that were developed over centuries are now no longer used for commercial agricultural production and are becoming rare. Storing seeds also guards against catastrophic events like natural disasters, outbreaks of disease, or war. Unlike seed libraries or seed swaps that encourage frequent reuse and sharing of seeds, seed banks are not typically open to the public.
Depending on the species, seeds are dried to a suitably low moisture content according to an appropriate protocol. Typically this will be less than 5%. The seeds then are stored at -18°C or below. Because seed RNA (like our DNA) degrades with time, the seeds need to be periodically replanted and fresh seeds collected for another round of long-term storage.
- Stored specimens have to be regularly replanted when they begin to lose viability.
- Only a limited part of the world's biodiversity is stored.
- It is difficult or impossible to store recalcitrant seeds.
- Seed banks carry a cataloguing and data management burden. The seed banks must document the plant's identity, sampling location, seed quantity, and viability state. Other information, such as farming systems in which the crops were grown, or rotations they formed, should also be available to future farmers.
- Facilities are expensive for Third World countries which contain the most biodiversity.
- Many of the same issues apply to seed banks as with fallout shelters. With regard to its use as an insurance policy against cataclysmic events, it's highly questionable whether a seed bank would be at all usable in staving off starvation and societal collapse in almost any conceivable situation.
- Power would have to be sustained after a cataclysmic event in order to keep the seeds at -18 Celsius, which would be very difficult in an apocalyptic scenario unless linked to an automated power plant that uses solar panels, hydroelectricity, or another source of power that doesn't require resupply.
- In-situ conservation
In-situ conservation of seed-producing plant species is another conservation strategy. In-situ conservation involves the creation of National Parks, National Forests, and National Wildlife Refuges as a way of preserving the natural habitat of the targeted seed-producing organisms. In-situ conservation of agricultural resources is performed on-farm. This also allows the plants to continue to evolve with their environment through natural selection.
- Arboretum
- Seed Library 
A less expensive, community-supported seed library can save local genetic material.
Seeds may be viable for hundreds and even thousands of years. The oldest carbon-14-dated seed that has grown into a viable plant was a Judean date palm seed about 2,000 years old, recovered from excavations at Herod the Great's palace in Israel.
Recently (February 2012), Russian scientists announced they had regenerated a narrow leaf campion (Silene stenophylla) from a 32,000 year old seed. The seed was found in a burrow 124 feet under Siberian permafrost along with 800,000 other seeds. Seed tissue was grown in test tubes until it could be transplanted to soil. This exemplifies the long-term viability of DNA under proper conditions.
There are about 6 million accessions, or samples of a particular population, stored as seeds in about 1,300 genebanks throughout the world as of 2006. This amount represents a small fraction of the world's biodiversity, and many regions of the world have not been fully explored.
- The Millennium Seed Bank housed at the Wellcome Trust Millennium Building (WTMB), located in the grounds of Wakehurst Place in West Sussex, near London, in England, UK. It is the largest seed bank in the world (longterm, at least 100 times bigger than Svalbard Global Seed Vault), providing space for the storage of billions of seed samples in a nuclear bomb proof multi-story underground vault. Its ultimate aim being to store every plant species possible, it reached its first milestone of 10% in 2009, with the next 25% milestone aimed to be reached by 2020. Importantly they also distribute seeds to other key locations around the world, do germination tests on each species every 10 years, and other important research.
- The Svalbard Global Seed Vault has been built inside a sandstone mountain in a man-made tunnel on the frozen Norwegian island of Spitsbergen, which is part of the Svalbard archipelago, about 1,307 kilometres (812 mi) from the North Pole. It is designed to survive catastrophes such as nuclear war and world war. It is operated by the Global Crop Diversity Trust. The area's permafrost will keep the vault below the freezing point of water, and the seeds are protected by 1-metre thick walls of steel-reinforced concrete. There are two airlocks and two blast-proof doors. The vault accepted the first seeds on 26 February 2008.
- The former NSW Seedbank focuses on native Australian flora, especially NSW threatened species. The project was established in 1986 as an integral part of The Australian Botanic Gardens, Mount Annan. The NSW Seedbank hasdcollaborated with the Millennium Seed Bank since 2003. The seed bank has since been replaced as part of a major upgrade by the Australian PlantBank.
- Nikolai Vavilov (1887–1943) was a Russian geneticist and botanist who, through botanic-agronomic expeditions, collected seeds from all over the world. He set up one of the first seed banks, in Leningrad (now St Petersburg), which survived the 28-month Siege of Leningrad in World War II. It is now known as the Vavilov Institute of Plant Industry. Several botanists starved to death rather than eat the collected seeds.
- The BBA (Beej Bachao Andolan — Save the Seeds movement) began in the late 1980s in Uttarakhand, India, led by Vijay Jardhari. Seed banks were created to store native varieties of seeds.
- National Center for Genetic Resources Preservation, Fort Collins, Colorado, United States.
3. CONSERVATION IN PLANT NURSERY
A nursery is a place where plants are propagated and grown to usable size. They include retail nurseries which sell to the general public, wholesale nurseries which sell only to businesses such as other nurseries and to commercial gardeners, and private nurseries which supply the needs of institutions or private estates. Some retail and wholesale nurseries sell by mail.
Although the popular image of a nursery is that of a supplier of garden plants, the range of nursery functions is far wider, and is of vital importance to many branches of agriculture, forestry and conservation biology. Some nurseries specialize in one phase of the process: propagation, growing out, or retail sale; or in one type of plant: e.g., groundcovers, shade plants, or rock garden plants. Some produce bulk stock, whether seedlings or grafted, of particular varieties for purposes such as fruit trees for orchards, or timber trees for forestry. Some produce stock seasonally, ready in springtime for export to colder regions where propagation could not have been started so early, or to regions where seasonal pests prevent profitable growing early in the season.
With the objective of fitting planting stock more ably to withstand stresses after outplanting, various nursery treatments have been attempted or developed and applied to nursery stock. Buse and Day (1989), for instance, studied the effect of conditioning of white spruce and black spruce transplants on their morphology, physiology, and subsequent performance after outplanting. Root pruning, wrenching, and fertilization with potassium at 375 kg/ha were the treatments applied. Root pruning and wrenching modified stock in the nursery by decreasing height, root collar diameter, shoot:root ratio, and bud size, but did not improve survival or growth after planting. Fertilization reduced root growth in black spruce but not of white spruce.
- Hardening off, frost hardiness
Seedlings vary in their susceptibility to injury from frost. Damage can be catastrophic if “unhardenend” seedlings are exposed to frost. Frost hardiness may be defined as the minimum temperature at which a certain percentage of a random seedling population will survive or will sustain a given level of damage (Siminovitch 1963, Timmis and Worrall 1975). The term LT50 (lethal temperature for 50% of a population) is commonly used. Determination of frost hardiness in Ontario is based on electrolyte leakage from mainstem terminal tips 2 cm to 3 cm long in weekly samplings (Colombo and Hickie 1987). The tips are frozen then thawed, immersed in distilled water, the electrical conductivity of which depends on the degree to which cell membranes have been ruptured by freezing releasing electrolyte. A -15 °C frost hardiness level has been used to determine the readiness of container stock to be moved outside from the greenhouse, and -40 °C has been the level determining readiness for frozen storage (Colombo 1997).
In an earlier technique, potted seedlings were placed in a freezer chest and cooled to some level for some specific duration; a few days after removal, seedlings were assessed for damage using various criteria, including odour, general visual appearance, and examination of cambial tissue (Ritchie 1982).
Stock for fall planting must be properly hardened-off. Conifer seedlings are considered to be hardened off when the terminal buds have formed and the stem and root tissues have ceased growth. Other characteristics that in some species indicate dormancy are color and stiffness of the needles, but these are not apparent in white spruce.
4. CONSERVATION IN GENE BANK 
Gene banks are a type of biorepository which preserve genetic material. For plants, this could be by freezing cuttings from the plant, or stocking the seeds (e.g. in a seedbank). For animals, this is the freezing of sperm and eggs in zoological freezers until further need. With corals, fragments are taken which are stored in water tanks under controlled conditions. Plant genetic material in a 'gene bank' is preserved at -196° Celsius in Liquid Nitrogen as mature seed (dry).In plants, it is possible to unfreeze the material and propagate it, however, in animals, a living female is required for artificial insemination. While it is often difficult to use frozen animal sperm and eggs, there are many examples of it being done successfully. In an effort to conserve agricultural biodiversity, gene banks are used to store and conserve the plant genetic resources of major crop plants and their crop wild relatives. There are many gene banks all over the world, with the Svalbard Global Seed Vault being probably the most famous one.
Seed bank
A seedbank preserves dried seeds by storing them at a very low temperature. Spores and pteridophytes are conserved in seed banks, but other seedless plants, such as tubercrops cannot be preserved this way.The largest seed bank in world is the Millennium Seed Bank housed at the Wellcome Trust Millennium Building (WTMB), located in the grounds of Wakehurst Place in West Sussex, near London.
Tissue bank
In this technique buds, protocorm and meristematic cells are conserved through particular light and temperature arrangements in a nutrient medium. This technique is used to preserve seedless plants and plants which reproduce asexually.
Cryobank
In this technique, a seed or embryo is preserved at very low temperatures. It is usually preserved in liquid nitrogen at -196°C. This is helpful for the conservation of species facing extinction.
Pollen bank
This is a method in which pollen grains are stored. We can make plants which are facing extinction in the present world. Using this technique, we can make plants with one set chromosome.
Field gene bank
This is a method of planting plants for the conservation of genes. For this purpose we construct ecosystem artificially. Through this method one can compare the difference among plants of different species and can study it in detail. It needs more land, adequate soil, weather, etc.. Germ plasma of important crops are conserved through this method. 42,000 varieties of rice are conserved in the Central Rice Research Institute in Orissa.
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