Screening cold hardy strawberry seedlings utilizing in vitro technology

The aim of this study was to evaluate screening technology of cold hardy strawberry seedlings in vitro. Strawberry seedlings of cross combinations 'Kent' x 'Nida', 'Kent' x 'Holiday', 'Nida' x 'Holiday' and 'Holiday' x 'Marmolada' were received utilizing the method of embryo isolation. Embryo axes were isolated on the 24(th) day after pollination. The output of seedlings, utilizing in vitro methods is 94-100%. Strawberry seedlings differentiated by cold hardiness when frozen at -11degreesC in vitro. Only not cold injured plants were selected. The amount of not cold injured plants varied from 5.0% ('Holiday' x 'Marmolada') to 13.8% ('Kent' x 'Nida'). The selected plants were proliferated in vitro by forming clones, rooted and planted to clone trials in the crossing year (approximately 200 days after pollination). Close correlation (r=0.78-0.83) was established between cold hardiness in vitro and in vivo, cold hardiness in vitro and winterhardiness in situ. Utilization of cold hardy seedlings screening technology in vitro enables to speed up breeding process 2-4 times, receive 30% higher output of seedlings for screening and to decrease acreage of strawberry trials.