Implementing cryogenic storage of clonally propagated plants.

Methodology for plant germplasm cryopreservation was created in the 1970s, expanded in the 1980s, and implemented at the end of the 20th century. Translating experimental techniques into routine cryostorage of a clonal collection requires attention to details beyond those normally required for methods development. Early decisions include the choice of accessions to be stored, number of each accession per storage unit, number of replicates, location of storage, viability testing, record keeping and proper control groups. Emphasis should be placed on selecting a secure storage site and compiling complete records needed for the recovery of plant material. Secure remote storage, duplicate locations, and secure, accurate records are all important in ensuring the safety and usefulness of base collections. Evaluation of cryostored collections should be initiated to determine the longevity of plants and stability of storage conditions. Collections of several clonal genera are now stored in liquid nitrogen and more are in progress worldwide. These base-storage collections of clonal germplasm provide security for safeguarding long-term access to genetic diversity that is vital to food security and to continued improvement of many clonally-propagated agricultural crops.