GENETIC STABILITY ASSESSMENT OF WASABI PLANTS REGENERATED FROM LONG-TERM CRYOPRESERVED SHOOT TIPS USING MORPHOLOGICAL, BIOCHEMICAL AND MOLECULAR ANALYSIS

This study compared the effect of cryopreserved storage duration of wasabi shoot tips, which derived from the same in vitro mother-plant. We compared the survival of shoot tips and the genetic stability of regenerated plants originating from four experimental groups: shoot tips stored in a -150 degrees C deep-freezer for 10 years; shoot tips stored in liquid nitrogen for 2 h; shoot tips treated with PVS2 vitrification solution; and untreated controls. No significant difference in survival was observed between the four experimental groups. Survival ranged between 93 and 100%. Genetic stability of plants regenerated from cryopreserved shoot tips was assessed over a period of 24 months using morphological, biochemical and molecular markers. While glucose, fructose and glutamic acid concentrations differed slightly between experimental groups after 16 months, these differences disappeared after 24 months. No significant differences were noted for the morphological markers studied (petiole length, shoot number and leaf index). No differences were observed in RAPD profiles obtained with the six primers tested.