Submitted to: CryoLetters
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 7, 2004
Publication Date: December 1, 2004
Citation: Towill L.E., P.L. Forsline, C. Walters, J.W. Waddell and J. Laufmann. 2004. Cryopreservation of Malus germplasm using a winter vegetative bud method: results from 1915 accessions. CryoLetters 25:323-334. Interpretive Summary: The long-term storage of germplasm under cryogenic conditions enhances preservation efforts. We have processed 1915 accessions of Malus representing 48 species using a winter vegetative bud method for cryopreservation. We have identified those species that are tolerant, moderately tolerant, moderately sensitive and sensitive. Overall the method has been successful with 91% of the lines tested having viabilities after cryo-exposure of 40% or greater. Genotypic differences in survival were apparent and the success varied from year to year.
Technical Abstract: Cryopreservation using a winter vegetative bud method is being applied to the Malus collection maintained in the field at the USDA-ARS Plant Genetic Resources Unit, Geneva, NY. Winter hardy materials are sent to the USDA-ARS National Center for Genetic Resources Preservation (NCGRP), Fort Collins, CO, for processing. To date 1915 accessions have been tested. The NCGRP minimum standard for cryopreservation is 40% viable buds, as determined by grafting. For M.x domestica 95% of the accessions tested have been cryopreserved. For species other than M.x domestica, 83% have met the criterion. As an internal control, eight lines were collected, cryopreserved and recovered through grafting each year. Data from this set showed an effect of year and cultivar on survival. There was no strong relationship between viability after cryopreservation and phylogeny. For North American species success after cryopreservation was related to geographical origin.