Preliminary results of cryopreservation of Malus germplasm from the Gene bank collection of the Institute of Fruit Breeding Dresden

摘要

Cryopreservation using winter vegetative buds was successfully applied to the Malus collection maintained at the Institute of Fruit Breeding in Dresden-Pillnitz, Germany. In the first experimental year, three different apple cultivars (Malus x domestica Borkh.) and various accessions of the European crab apple Malus sylvestris were studied. The dehydration time at -5 degrees C to reach about 30% of moisture content for the winter buds varied between two and 10 days. Following a two-step freezing (prefreezing at 1 degrees C/hr to -30 degrees C and maintenance at -30 degrees C for 24 hr) and cryopreservation for five months, chip-budding was performed after a 15-day rehydration period at VC. Up to 77% of buds of the cultivar Idared survived and 27% of Golden Delicious. The cultivar Lord Lambourne and Malus sylvestris showed a very low percentage or no bud recovery. In the second experimental year, five apple cultivars and five accessions of different Malus species originating from different continents were tested using the -5 degrees C cold dehydration or a salt dehydration with NaCl or alternatively KNO3 and different time for scions sampling during December to February. Successful recovery was only observed for scion pieces collected in January using a cold dehydration.