Cryopreservation ofRosa hybridacv. Helmut Schmidt by PVS2 vitrification method usingin vitrofragmented explants (IFEs)

This is the first report on cryopreservation via PVS2 vitrification method on roses using in vitro fragmented explants (IFEs) as the starting material. The aim of this study is to optimize the efficient plant recovery and regeneration system for cryopreservation of Rosa hybrida cv. Helmut Schmidt using IFEs. Some important parameters have been optimized in this study are the effect of ascorbic acid (0.3 mM) examined separately and in combination at all steps in cryopreservation procedure (preculture, loading, unloading and growth recovery), loading type, loading duration, and PVS2 duration. The highest growth recovery of 43.33% was obtained when 3-4 mm size IFEs precultured on 0.25 M sucrose media supplemented with full-strength MS for one (1) day, followed by loading treatment supplemented with 1.5 M glycerol + 0.4 M sucrose + 5% DMSO + 0.3 mM ascorbic acid for 20 minutes, dehydration with PVS2 solution for 30 minutes and then treated with unloading solution supplemented with 1.2 M sucrose + 0.3 mM ascorbic acid for 20 minutes. This finding implies that long-term storage of Rosa Hybrida cv. Helmut Schmidt by PVS2 vitrification method was successful with essential biomolecules.