IMPLEMENTING CRYOTECHNIQUES FOR PLANT GERMPLASM: STORING SEEDS, EMBRYONIC AXES, POLLEN AND DORMANT BUDS
National Cryogenebank at National Bureau of Plant Genetic Resources (NBPGR), New Delhi, India developed, over a span of 26 years, species-specific cryoprotocols using seeds, embryos, embryonic axes and pollen of difficult-to-store species belonging to non-orthodox seed species and dormant buds of temperate fruits and nuts. Cryopreservation protocols were standardized primarily for tropical species of horticultural, plantation, agroforestry and industrial importance. Desiccation-freezing, vitrification and encapsulation-dehydration and classical techniques of step-wise slow freezing were applied to range of germplasm resulting in base collection of several indigenous species representing wide genetic diversity. More than 6000 accessions of difficult-to-store non-orthodox seed species, 3200 accessions of orthodox seeds, 387 accessions of buds and 404 accessions of pollen have so far been cryostored. The intermediate and recalcitrant seeds and dormant buds were investigated for their morphological and physiological parameters especially for desiccation and freezing tolerance. For more than 250 accessions of 48 species tested, original viability of explants was found to be retained for various periods, maximum being 25 years of cryostorage. Degree to which low temperature prolonged life span depends on how seeds are handled before cryostorage. High survival and healthy plantlets have been obtained from species with intermediate seed storage behaviour and dormant buds of Morus species. Improvement in recovery and regrowth was achieved by manipulating maturity stage of explant, duration and rate of desiccation and freezing and also by improving recovery media. Efforts are continued to conserve sizable variability of additional indigenous and exotic species.
Chaudhury, R. and Malik, S.K. (2014). IMPLEMENTING CRYOTECHNIQUES FOR PLANT GERMPLASM: STORING SEEDS, EMBRYONIC AXES, POLLEN AND DORMANT BUDS. Acta Hortic. 1039, 273-280
germplasm storage, techniques, pollen, seed, vegetative