2019 ASHS Annual Conference

Preservation of apricot (Prunus armeniaca L.) is traditionally done in orchards requiring extensive land and labor and risk exposure to stressors. Alternatively, the species might be conserved by pollen or clonally by in vitro culture in slow growth conditions and cryopreservation of shoot tips. In vitro methods are effective; however, they are labor and cost intensive. Experimenting with four apricot cultivars (‘Moorpark’, ‘Patterson’, ‘Tracy’ and ‘Westley’), we were able to successfully modify a dormant bud (DB) technology developed originally for Malus, by using sucrose and antioxidant solutions. In winter harvested twigs were cut into 3.5 cm segments with at least one dormant bud and exposed to different combination of 0.3 and 0.75 M sucrose with vitamin C, L-proline, ABA, cysteine, or a combination of L-proline and ABA, for various times (3 to 16 h) prior to their desiccation (25-27% MC) in subzero (-5^oC) conditions. After desiccation the DBs were slow cooled (-5^oC to -30^oC) and immersed into liquid nitrogen vapor (LNV; -182 to -196^oC). The post LNV viability was tested in a greenhouse under high relative humidity of about 75%. Dormant buds that swell and showed any signs of growth were scored as ‘1’ (alive) versus ‘0’ (dead) with no signs of growth. Overall, the highest percent of post LNV DBs scored as ‘alive’ (60 %) was observed for 0.3 M sucrose (16 h) and 0.75 M (3 h); however, 95% of ‘Tracy’ DBs showed bud swelling when pretreated in this sucrose combination with 0.5 mM vitamin C.