Integration of Cryopreservation and Tissue Culture for Germplasm Conservation and Propagation of Rosa pomifera ‘Karpatia’

Abstract

Cryopreservation is an useful technique for long-term conservation that requires minimal space and maintenance. Germplasm protection of Rosa is important to preserve genetic diversity, to store material for breeding and to expand new research. This study was conducted to develop a droplet vitrification cryopreservation and micropropagation of Rosa pomifera cv. ‘Karpatia’, whose large hypanthia are characterized by remarkable pro-health properties. Culture in vitro was stabilized and shoot tips collected from dormant buds served as initial explants. The multiplication of shoots was carried out on MS medium containing benzyladenine. For the droplet vitrification cryopreservation, shoot tips from in vitro cultures were used: small with exposed meristem, and large with a meristem covered with leaves, as well as shoot tips from in situ plants, which were collected in winter. Treatment time with plant vitrification solution (PVS2) was also tested (10-30 minutes). From in vitro culture, 32-41% small explants with exposed meristem survived, but they regenerated at a very low level. The best cryostorage results were obtained for shoot tips from dormant buds and a 20-minute PVS2 treatment: the survival was 84% and regeneration 72%. During the post-freezing regeneration multiplication index was 2.4 shoots per one multiplication cycle, after cryopreservation and in the control. On half MS medium without growth regulators, 97-99% of shoots rooted, and all rooted plants have adapted to ex vitro conditions and were planted into the soil. Biometric analyses during shoot multiplication, rooting and acclimatization stages did not reveal any changes compared to the non-cryopreserved samples.