Cryopreservation of red raspberry cultivars from the VIR in vitro collection using a modified droplet vitrification method

Abstract

The goal of the present study was to analyze the post-cryogenic recovery of 12 red raspberry cultivars from the N.I. Vavilov All-Russian Institute of Plant Genetic Resources in vitro collection. The 1.1–1.8 mm shoot tips of microplants were subjected to cryopreservation using the modified droplet vitrification method. The current modifications to the droplet vitrification protocol included the elimination of the initial pretreatment stage of the microplants, and the use of modified media at the stages of initial micropropagation, explant isolation, and post-cryogenic regeneration. The optimized method reduced the duration of some cryopreservation stages compared to the initial protocol, and reduced the total procedure from 14 to 11 wk. This modified cryopreservation method also demonstrated a relatively high level of post-cryogenic regeneration. Depending on the genotype, the shoot recovery of explants after rewarming varied from 24.2–89.3% and averaged 58.8 ± 5.3%. There was a statistically significant influence of the genotype on the shoot recovery after rewarming. No differences in inter simple sequence repeats and in start codon targeted marker spectra were found between post-cryopreservation microplants and donor in vitro plants from two red raspberry cultivars.