Rootstock and Scion Effects on the Seasonal Distribution of Dry Weight and Carbohydrates in Young Apple Trees

Carbohydrates were measured in young apple ( Malus domestica Borkh.) trees throughout the period of 28 Mar. 1983 to 16 Apr. 1984. Two rootstocks, M.9 (full dwarf) and MMIII (vigorous) and 2 scion cultivars, ‘Redchief and ‘Northern Spy’ were used in the 4 possible combinations. Trees were separated into 5 classes of vegetative tissue and analyzed for starch, sorbitol, and soluble sugars. Dry weights also were measured. Trees of MMIII had a greater dry weight in the above and below ground portions than trees on M.9. Carbohydrate contents followed a similar pattern. ‘Northern Spy’ scions had greater dry weight and carbohydrate content in the above ground portion than ‘Redchief. ‘Redchief had greater dry weight and carbohydrate content in the below ground portion than ‘Northern Spy’. Above ground starch content and below ground sorbitol and soluble sugar content did not follow this pattern.