CRYOCONSERVATION METHODS FOR VEGETATIVELY PROPAGATED CROPS (REVIEW)
This article presents a review of cryopreservation methods used to create cryocollections of plant genetic resources. The application of cryopreservation methods for the long-term conservation of the vegetatively propagated crops started relatively recently. About 60 years ago, the first methods of programmable (slow) freezing of plant objects were developed. The modern methods include such fast freezing techniques as encapsulation-dehydration, vitrification, encapsulation-vitrification, droplet-method, and droplet-vitrification. These methods are used for cryopreservation of accessions from the field genbanks and samples from in vitro collections. The review considers the main factors determining the viability and regeneration rates of explants after freezing-rewarming. The greatest impact on the efficiency of post-cryogenic explants recovery is provided by such factors as the method of the initial microplants pre-treatment, explant and cryoprotectant type, duration of the explant treatment with cryoprotectants, the composition of the nutrient medium for the post-cryogenic recovery, and the accession genotypic characteristics. The review discusses the rules for the collections formation and cryobanking development. The data on the largest cry-ocollections of cultivated plant species are presented.