Gemplasm Conservation

Germplasm conservation

Seed conservation has vital role in preservation of genetic variability as it is simple to handle, cost-effective and capable of maintaining genetic stability over long time periods. Hence, a popular and most efficient tool for germplasm conservation at the global level. ICRISAT Genebank ensures continued germplasm availability for crop improvement. The conservation of germplasm in genebanks in the form of seeds requires that the integrity of the material conserved be maintained to the highest standard over prolonged periods of time. A short-term storage, maintained at 18 to 20ºC and 30 to 40% relative humidity, is used to hold seeds while they are dried and prepared for medium- and long-term storage. Five medium-term storage rooms maintained at 4ºC and 30% relative humidity help conserve seed samples for 20 to 25 years as active collection. Four long-term storage units at -20ºC conserve the seeds dried to 5 to 7% moisture content and hermetically sealed in aluminum foil packets for more than 50 years as base collection. Germplasm accessions that do not produce adequate seed for conservation (such as wild species of groundnut and pearl millet), maintained as live plants in a botanical garden and green houses.

Seed moisture content is an important component affecting seed quality and longevity. For long-term conservation in genebanks, seeds are recommended to be dried to 3-7% moisture content. Under all storage conditions, the moisture content of seeds comes to equilibrium with the relative humidity of the surrounding atmosphere. A decrease in seed moisture content coupled with lower storage temperature and relative humidity substantially improves the life span of the seeds. Seed drying is an essential and important operation in handling germplasm seeds for conservation. Orthodox seed lots with any amount of initial moisture can be safely dried to low moisture levels at 15ºC and 15% RH using sorption type drier with secondary refrigeration. The genebank established a walk-in seed drying room following these principles for regularly processing large number of seed samples for long-term conservation and safety-backup at other locations.

Safety-backup

ICRISAT’s genebank is designed to withstand natural disasters. For further safety, the long-term conservation collection is duplicated in other genebanks. Duplicates of a large portion of chickpea germplasm are conserved at the International Center for Agricultural Research in the Dry Areas (ICARDA), Aleppo, Syria; and pearl millet, groundnut and small millets at the ICRISAT Regional Genebank, Niamey, Niger. The Svalbard Global Seed Vault (SGSV) located in the remote Arctic Svalbard Archipelago, Norway, has been established to preserve unique duplicate samples of seeds held in genebanks worldwide. The Seed Vault provides an insurance against the loss of seeds in genebanks, as well as a refuge for seeds in the case of large scale regional or global crisis. ICRISAT genebank has deposited seed samples of 110,818 accessions of its mandate crops and small millets.

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