Desiccation Tolerance in Bare-rooted Apple Trees Prior to Transplanting

Abstract Ten types of apple (Malus domestica L.) trees (six different scions on M.7 rootstock and four ‘Red Delicious’ scions on M.7, MM. 111, MM.106 and seedling rootstocks) were subjected to air drying for periods of 0 to 48 hr with or without 3 months of cold storage at 0°C (32°F). The kinetics of water loss during drying treatment and the transplanting survival and regrowth vigor were recorded. Both the scions and rootstocks influenced the tolerance of apple trees to desiccation stress. Among the plant materials tested, ‘Red Delicious’ on MM. 111 rootstock had the highest level of tolerance to desiccation. Three months of cold storage at 0°C (32°F) resulted in the considerable loss of tissue water, but the grafted trees survived if no further desiccation occurred prior to planting. Only ‘Red Delicious’/MM. 111 tolerated desiccation from the combination of three months of cold storage followed by a 48 hr exposure to air drying, while other scion/rootstock compound systems seldom survived. The analyses ...