Cryopreservation of mentha piperita l. germplasm and confirmation of genetic stability after cryo-storage

Peppermint is an important aromatic-medicinal plant species and it has valuable essential oil contents such as menthol, linalool and limonene. The main purpose of the current study was to optimize a protocol for cryopreservation of M. piperita local cultivars (G-74, Candarli and Gomec). The secondary aim was to investigate the genetic stability after cryopreservation using ISSR marker system. Three different single step freezing techniques were compared for longterm preservation of these local cultivars and the optimum regeneration percentages were acquired by using the droplet vitrification technique. The PVS2 treatments of this technique showed succesful long-term preservation of M. piperita cultivars with regeneration percentages of 72% to Candarli cultivar (60 min PVS2), 52% to Gomec cultivar (75 min PVS2) and 62.5% to G-74 cultivar (30 min PVS2) respectively. The ISSR PCR results showed that the genetic stability from cryopreserved M. piperita cultivars were high. While genetic stability percentage was similar to 99% for the Candarli cultivar, for the Gomec and G-74 cultivars the genetic fidelity was100%. The shoots that come from the cryopreserved shoot tips showed normal and health rooting, and all of them were also easily adapted to greenhouse conditions.