CRYOPRESERVATION OF ROSA SHOOT TIPS: IMPORTANCE OF PRECULTURE CONDITIONS

The aim of the present study was to investigate the importance of the preculture conditions including the vitrification solution on the survival of Rosa shoot tips cryopreserved using a combined vitrification-droplet procedure. In vitro grown roses (Rosa hybrida L.) cv. “Fairy” and wild roses (Rosa sp.) shoot tips were used for cryopreservation. Preculture was critical for the survival of rose shoot tips after cryopreservation. Among the different tested sugars and sugar alcohols (glucose, sucrose, mannitol and sorbitol) sucrose treatment for 48 h was the most efficient one. From the three vitrification solutions (PVS2, PVS3 and PVS4) tested, PVS2 ensured the highest survival rate. A one step vitrification protocol with PVS2 for 20 minutes was more efficient than a two step protocol that involved treatment of shoot tips with half strength PVS2 solution for 10 minutes after that with full strength PVS2 for an additional 15 minutes. After rapid rewarming and transfer of shoot tips on recovery medium, 66% survival for “Fairy” and 69% for wild roses were obtained. Plants produced from control and cryopreserved shoot tips were phenotypically similar.