Cryopreservation of cold-tender apple germplasm

摘要

Unlike cold-hardy apple germplasm, dormant vegetative buds from cold-tender accessions require stabilization of meristematic tissue to protect against injury during desiccation and cryopreservation. Dormant buds of 6 apple cultivars (Malus sylvestris var. domestica [M. pumila] Cox's Orange Pippin, Einshemer, Golden Delicious, Jonagold, K14 and Mutsu) collected at specific intervals during 1993-95 at Geneva, New York state (USA), were stabilized by encapsulation in 5% alginate, treated with step-wise imbibition of 0.5 to 1.0 M sucrose and 0.2 M raffinose solution, and desiccated with forced air at 0deg C. Sugar-alginate stabilization reduced injury during desiccation, increased cold-hardiness of the 6 cold-tender cultivars frozen to -30deg C and improvedrecovery following cryopreservation of buds collected before optimal cold acclimation was attained. Sucrose tissue levels did not increase following stabilization treatment, but levels of glucose and fructose, and of an unknown disaccharide increased. This procedure used non-toxic cryoprotectants and has potential to expand the scope of dormant bud cryopreservation to include cold-tender apple germplasm.