Cryopreservation of apple (Malus spp.) winter buds

Abstract

One of the practical approaches for long-term conservation of apple garmplasm is the storage of winter buds in liquid nitrogen. The dormant buds were cryopreserved using two-step freezing method. On dehydration at -20°C, moisture content (MC%) of buds ranged from 37 to 47% after 28 days. On silica gel, the MC% was in the range of 24 and 34% after 4 h desiccation. The cryopreserved buds were rewarmed and patch budded and grafted on the rootstocks in the field. Accessions desiccated on silica gel showed post-thaw recovery. The cryopreserved buds on patch-budding showed 0-10% recovery, while buds on grafting showed higher (up to 25%) regeneration. No natural acclimation at sub-zero temperature can be one reason for low post-thaw recovery across the accessions growing in Indian fields. Winter dormant buds of 35 accessions of Malus spp. were cryobanked.