Maria Jenderek, Barbara Ambruzs, Greg Holman, Dianne Skogerboe, Elise Staats, Marie Turner, and David Ellis. USDA, ARS, NCGRP, 1111 South Mason St., Fort Collins, CO 80521
Out of 476,049 germpaslm accessions maintained by the USDA, ARS, National Plant Germplasm System, ca. 30,000 are vegetaively-propagated and as such require preservation as non seed propagules. Numerous research reports demonstrated the advantages of long term storage of plant tissues in liquid nitrogen over field only maintained collections. While successful cryopreservation protocols were established for many plant species, the protocols are usually not applicable for the entire collection of a species or genus they were developed, and have to be modified for accessions not responding to the procedure. Currently, the NCGRP maintains over 3,150 vegetatively-propagated accessions in liquid nitrogen or its vapors (Allium sativum, Corylus, Cynodon, Fragaria, Humulus, Ipomoea, Lolium, Malus, Mentha, Prunus, Pyrus, Ribes, and Rubus) as dormant buds or apical shoot tips. Even with these successes, approximately 90% of the vegetative-propagated genetic resources in the NPGS are not backed up under long term storage conditions. Preliminary studies initiated on the cryopreservation of priority species selected by the NPGS curators, include Juglans cinerea, J. regia, Prunus armeniaca, P. dulcis, and Punica granatumum, with an emphasis on using dormant buds over aseptically preserved tissues.