Desiccation Tolerance of Dormant Buds From Selected Prunus species.

Dormant buds of woody plant species present a convenient material for backing-up of germplasm in liquid nitrogen. Routinely, this type of material is used in long-term preservation of only a few species (e.g. apple and sour cherry). Cryopreservation procedures of dormant buds are species dependent, but in general a tolerance to desiccation (≤30% MC) and slow cooling (to -30⁰C, 1⁰C/hour) is a good indicator of dormant bud ability to survive an exposure to liquid nitrogen. In an attempt to develop long-term preservation procedures for other woody species, we tested desiccation tolerance of dormant buds of three Prunus species (almond, apricot and sweet cherry). Dormant branches were collected from field-grown trees, cut into 35 mm sections containing one dormant bud per stem section and desiccated to 35-40%, 30-35% and 25-30% MC. Bud sections were then rehydrated in moist peat moss and survival was evaluated by grafting. Data indicated that 65-100% of almond and apricot, and >80% of sweet cherry dormant buds survived desiccation to 25-30% MC. Slow cooling survival studies of dormant buds for these species are underway. Development of dependable cryopreservation protocols would increase the number of almond, apricot and sweet cherry accessions being backed up at the National Center for Genetic Resources Preservation in a considerably shorter time than preserving the accessions via tissue culture material.