Cryopreservation of Prunus cerasus through vitrification and replacement of cold hardening with preculture on medium enriched with sucrose and/or glycerol

Cryopreservation is the only alternative, safe and cost-effective method for long-term storage of plant genetic resources, particularly for stone fruits (Prunus spp.). In this study, an efficient cryopreservation protocol was developed for sour cherry (Prunus cerasus L.). In vitro shoot tips of two varieties (Montmorency and Schattenmorelle) were successfully cryopreserved using the vitrification technique. Our study showed the possibility of replacing the 3-week cold hardening treatment of mother-plants with preculture of apices on medium enriched with sucrose and/or glycerol. The highest recovery percentages after liquid nitrogen exposure were obtained after a cold hardening treatment followed by a 3-day preculture on 0.8 M sucrose medium or by replacing cold hardening with a 7-day preculture on the following media: 0.4 M glycerol or sucrose, 0.4 M sucrose + 0.4 M glycerol or 0.8 M glycerol. Under these conditions, recovery after cryopreservation ranged between 41 and 63%. These results complement the range of Prunus species successfully cryopreserved using in vitro explants. Our protocol, which is simplified in comparison with the original one, since cold hardening of mother-plants in a cold chamber is replaced by pretreatment of apices on medium with high sugar concentration, may facilitate the application of vitrification for cryopreservation of additional Prunus species.

► We applied the vitrification technique for cryopreservation of in vitro shoot tips of two Prunus cerasus varieties.
► We tested the possibility of replacing cold hardening of mother-plants with preculture of shoot tips on medium enriched with sucrose and/or glycerol.
► Optimizing preculture conditions produced recovery percentages of cryopreserved shoot tips similar to those obtained when using cold hardening (ranging between 41 and 63%).