Tree size and performance were summarized for five-year-old apple trees, with a range of vigor, in several cultivars on several size-controlling rootstocks. Trunk cross-sectional area (TCSA) of trees on EMLA 9 was 86% greater than those on M 9, while trees on EMLA 27 had a 48% smaller TCSA than M 9. The percentage of flowering was greatest on trees on M 9 compared to EMLA 9 and 27; greatest on Clark (C) 54 compared to C 6 and C 43; and least on seedling compared to MM 111, MM 106, and M 7. Trees on EMLA 9 and M 9 had high-yield efficiency (cumulative yield/TCSA), whereas those on EMLA 27 were less yield-efficient. Trees on seedling stock were less efficient than those on MM 111, MM 106, and M 7. Smallest trees based on TCSA were noted for both ‘Oregon Spur Delicious’/EMLA 27 and ‘Starkrimson’/C 54, whereas the largest trees were ‘Starking Delicious’/Merton 793.
Received for publication 9 Apr. 1985. Oregon Agricultural Experiment Station Technical Paper no. 7494. The cost of publishing this paper was defrayed in part by the payment of page charges. Under postal regulations, this paper therefore must be hereby marked advertisement solely to indicate this fact.