Method of preservation is divided according to the type of germplasm: seed ornon-seed(clonal materials).
Storage of seeds:
According to storage tolerance of the seeds to low temperature and dry environment, seeds are further divided into storable (orthodox) and non-storable(recalcitrant) types.
These include small-seeded grain crops and vegetables. They can be stored for a long time under low-temperature and low-humidity environment and are separately stored in long, medium and short-term storerooms in accordance to the purpose of storage.
a.Long-term storage: With storage conditions of -18¡Ó2¢J and 30¡Ó3% RH, long-term RH, long-term preservation is provided mainly for the comprehensive base collection. Careful collection. Careful identification and selection precedes before storage. About 240,000 accessions will be stored. Stored materials will not be used for exchange; they are only preserved for regenerating fresh seed and periodically examined for seed viability level.The purpose of this storage is for the perpetuation of the seed stocks. Life expectancy of seed preserved in long-term storage at this Center will last from 30 to 50 years.
2. Recalcitrant type:
Those classified as non-storable or recalcitrant type of seed, which can not be stored under low temperature and low humidity conditions, are certain vegetables, cocoa, logan and lichee as well as those seeds that are large nd fleshy. Such seeds may be stored in low temperature ranges (0-10¢J) for short periods such as 1-5 years.
Conservation of clonal( vegetatively reproduced ) materials:
¡@¡@Preservation of clonal materials is attained by:
¡@¡@3.cryopreservation in liquid nitrogen.
Preservation of plant tissues in vitro
Tissue culture for many clonal materials in artifical media are more space-saving of intensively managed than field plantings. Tissue culture also ensures virus-free condition in germplasm exchange.
Bulbs, tubers and rhizome of certain crops can be stored at 0-15¢J under high humidity for several months or up to one year. It is also a type of short-term storage.
Embryos, tissues and pollen grains can be stored for long periods, in liquid nitrogen (-196¢J). But its practice use is yet to be developed as crops require different cooling and thawing treatments and have different viability level.
Germplasm materials such as fruit trees, potatoes and grasses are grown in nurseries field for conservation. So far TARI has maintained field nurseries at different elevations above sea level, totalling seven conservatory gardens. One nursery at TARI is used for quarantine and isolation reproduction purpose.
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