Responses to ABA and Cold Acclimation Are Genotype Dependent for Cryopreserved Blackberry and Raspberry Meristems

Abstract

The meristems of cold-acclimated cultivars and species of Rubus (blackberry and raspberry) can be successfully cryopreserved through optimization of cryoprotectants, cooling rates, and cold acclimation treatments. Genotypes that do not cold acclimate are difficult to cryopreserve and new methods are needed for this group of plants. The effects of abscisic acid (ABA) (50 μM) and 7-day cold acclimation (CA) treatments on the survival of cryopreserved apical meristems was determined for five Rubus genotypes (Blackberries: Rubus cissoides Cunn. and Rubus hybrid cvs. Hillemeyer and Silvan, and Raspberries: R. parvifolius L., and R. parviflorus Nutt.). ABA alone did not significantly improve the survival of any of the genotypes tested. The combination of ABA and CA significantty improved the survival of R. cissoides, but neither was effective alone. Cold acclimation with or without ABA significantly improved the survival of meristems of 'Hillemeyer,' 'Silvan,' and R. parvifolius L. Survival of R. parviflorus Nutt. meristems was not significantly affected by any of the treatments. In contrast to cytokinin effects in other culture systems, the cytokinin benzyladenine did not significantly affect survival of 'Hillemeyer' and showed no interaction with ABA or CA. Murashige and Skoog-based recovery medium produced higher survival rates than did Anderson's medium for the nine genotypes tested. Overall, genotype played a large role in the survival of cryopreserved Rubus meristems. In this system ABA does not substitute for CA, but in some genotypes may interact with CA to increase survival through a synergistic effect.