Cryopreservation of in vitro grown Torenia using the cryo-plate vitrification method

Torenia is a popular summer bedding plant that belongs to the family Linderniaceae. Recently, the number of vegetatively propagated cultivars has increased. Cryopreservation is one of the most reliable techniques to keep mother plants for a long time. Therefore, the aim of this study is to optimize the conditions for the cryo-plate vitrification method for Torenia. In this study, an in vitro culture of Torenia was used and the explants size, the duration and the temperature of the pre-culture, exposure time to PVS2 and mother plant age genotype differences were investigated. Regrowth varied from 0 to 80% depending on the temperature conditions and genotypes. For the Torenia hybrid 'Summer Wave Blue', the highest regrowth of 80% was obtained when small explants (0.2 mm) taken from 2- to 8-week-old mother plants were pre-cultured at 10°C for 2 d on 0.3 M sucrose MS medium and treated to PVS2 at room temperature for 10 min prior to LN. Other Torenia species showed lower regrowth than the hybrid.