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 rootsto cks, were compared with two cultivars at nine locations for ten years. The training systems were slender spindle (SS) with 2,460 trees/ha, vertical ax is (VA) with 1,561 trees/ha, and central leader (CL) with 1,111 trees/ha. T runk cross-sectional area (TCA) tended to be related to tree density. TCA w as greatest for CL trees, smallest for SS trees and intermediate for VA. Cu mulative yields per ha varied greatly with location and cultivar, but the r elative performance of orchard systems was fairly consistent across locatio ns and cultivars. CL trees on M.26 or Mark rootstock tended to be least pro ductive, whereas SS trees on M.9, Mark, and B.9 rootstocks were the most pr oductive. VA/M.9 was the most productive of the VA systems and at some loca tions it was as productive as SS. Plantings at Michigan, New York, and Virg inia were more productive than plantings at Illinois, North Carolina, Ontar io, and Washington. Relative to other systems, VA/M.9 produced higher yield s at the high-productivity locations than at the low-productivity locations .