BP Singh

Z46R.S. RanaGene Bank Standards(i) Seed sample size: About 3,000 viable seeds in case of selfpollinated crops and twice that number for cross-pollinatedspecies. One third of this samples is sealed in a separate packetand stored alongside the original sample under identicalconditions(at _20DC) for monitoring germinability at regularintervals.(ii) Viability testing: Initial germination tests are carried out ona minimum of 200 seeds drawn randomly from the originalsamples.Acceptable initial germination percentage should be higherthan 90% for most species but lower level$ are acceptable for somevegetables an.d wild forms. .50-100 randomly drawn seeds are used for subsequentviability monitoring tests.(iii) Seed drying : Seeds are dried in seed drying cabinetsoperated at 15 D C and 15% relative humidity uSing, silica gel asdesiccant based on adsorption system and appropriate air flow.(iv) Seed storage conditions : Seeds are dried to 5% moisturecontent and sealed jn laminated aluminium foils. Base collectionsare stored in modules operating at -20°C. Active collections arestored at 40C and 35% relative hUmidity.(v) Regeneration: Undertaken when seed viability falls to 85%of the initial value. '100 plants or more are preferred for thispurpose.Capacity of the Indian N ationa! Gene BankA built-in cold storage vault of 1003m size was obtained fromUK in 1983 to gain experience in medium and long term seedstorage. It comprised two compartments, on.e operating at 4°C andthe other at-20°C. Four more modules were subsequently, ..procured, assembled; installed and made operative maintaining-20°C. Two of them had ,a capacity of lO03m each while the othertwo were larger with a size of 176 3 m each. A long term storagecapacity for OVer 2,00,000 seed samples was thus created, backedfully by diesel generator sets. A sizeable capacity for in vitro. repository and cryopreservation has been developed recently to