Performance of ten apple orchard systems: Ten-year summary of the 1990 NC-140 systems trial

Ten orchard systems, composed of three training systems and several rootstocks, were compared with two cultivars at nine locations for ten years. The training systems were slender spindle (SS) with 2,460 trees/ha, vertical axis (VA) with 1,561 trees/ha, and central leader (CL) with 1,111 trees/ha. Trunk cross-sectional area (TCA) tended to be related to tree density. TCA was greatest for CL trees, smallest for SS trees and intermediate for VA. Cumulative yields per ha varied greatly with location and cultivar, but the relative performance of orchard systems was fairly consistent across locations and cultivars. CL trees on M.26 or Mark rootstock tended to be least productive, whereas SS trees on M.9, Mark, and B.9 rootstocks were the most productive. VA/M.9 was the most productive of the VA systems and at some locations it was as productive as SS. Plantings at Michigan, New York, and Virginia were more productive than plantings at Illinois, North Carolina, Ontario, and Washington. Relative to other systems, VA/M.9 produced higher yields at the high-productivity locations than at the low-productivity locations.