CRYOPRESERVATION OF MALUS GERMPLASM: RESULTS USING A WINTER VEGETATIVE BUD METHOD

Authors: Towill, Leigh; FORSLINE, P. - GENEVA NY - USDA; Walters, Christina; Waddell, John; LAUFMANN, JULIE - 5402-05-05

Submitted to: Hortscience Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 1/20/2002
Publication Date: 3/20/2002
Citation: TOWILL, L.E., FORSLINE, P., WALTERS, C.T., WADDELL, J.W., LAUFMANN, J. CRYOPRESERVATION OF MALUS GERMPLASM: RESULTS USING A WINTER VEGETATIVE BUD METHOD. XXVIth International Horticultural Congress and Exhibition Program, HORTSCIENCE PROCEEDINGS. Pp. 532. 2002.

Interpretive Summary: The USDA-ARS Malus germplasm collection at Geneva NY is being processed for long-term preservation at the National Seed Storage Laboratory (NSSL), Fort Collins, CO. Scions harvested in mid-winter are sent directly to NSSL where they are cut into nodal sections, desiccated to 30% moisture, cooled at 1 degree C's/hr to ¿30 dagrees C's and held for 24 h before being transferred to the vapor phase over liquid nitrogen (ca. ¿160 degrees C's). Samples are thawed at + 4 degrees C's. At Geneva, samples are rehydrated and viability is measured by budding to seedling rootstock. To date 96% of 1665 Malus accessions tested showed some survival and 91% percent had viabilities of 40% or greater, the level for which we considered an accession successfully cryopreserved. Malus x domestica comprised 65% of the accessions tested and of these 95% had 40% or greater viability. For species other than M. domestica, 83% met this criterion. Some species are very tolerant of the procedure (examples M. robusta and M. pumila) whereas others are sensitive (examples M. angustifolia and M. tschonoskii). Eight lines have been processed each year since 1995; data from this group suggest that mean fall temperature in Geneva NY influences survival. Sixty-four accessions processed in 1988-91 on average have shown no decline over 8 years of storage. A few lines have shown either a slight increase in survival with storage or a slight decline. Lines have been reestablished in the field from this cryopreserved collection to replace trees lost to fireblight. This simple cryopreservation method has been very useful for germplasm management of Malus species.

Technical Abstract: The USDA-ARS Malus germplasm collection at Geneva NY is being processed for long-term preservation at the National Seed Storage Laboratory (NSSL), Fort Collins, CO. Scions harvested in mid-winter are sent directly to NSSL where they are cut into nodal sections, desiccated to 30% moisture, cooled at 1 degree C's/hr to ¿30 dagrees C's and held for 24 h before being transferred to the vapor phase over liquid nitrogen (ca. ¿160 degrees C's). Samples are thawed at + 4 degrees C's. At Geneva, samples are rehydrated and viability is measured by budding to seedling rootstock. To date 96% of 1665 Malus accessions tested showed some survival and 91% percent had viabilities of 40% or greater, the level for which we considered an accession successfully cryopreserved. Malus x domestica comprised 65% of the accessions tested and of these 95% had 40% or greater viability. For species other than M. domestica, 83% met this criterion. Some species are very tolerant of the procedure (examples M. robusta and M. pumila) whereas others are sensitive (examples M. angustifolia and M. tschonoskii). Eight lines have been processed each year since 1995; data from this group suggest that mean fall temperature in Geneva NY influences survival. Sixty-four accessions processed in 1988-91 on average have shown no decline over 8 years of storage. A few lines have shown either a slight increase in survival with storage or a slight decline. Lines have been reestablished in the field from this cryopreserved collection to replace trees lost to fireblight. This simple cryopreservation method has been very useful for germplasm management of Malus species.