Performance of ‘Fuji’ Apple Trees on Several Size-Controlling Rootstocks in the 2014 NC-140 Rootstock Trial After Eight Years

Abstract

This study evaluated the performance of ‘Aztec Fuji®’ grafted onto 14 rootstock genotypes and trained to a tall spindle orchard system. Herein we provide results of the 2014 NC 40 coordinated ‘Fuji’ trial, established at seven locations in the United States and Canada, eight years after initiation. The rootstocks tested were Budagovsky10 (B.10); the Cornell-Geneva rootstocks G.11, G.202, G.214, G.30, G.41, G.935, and G.969; and the Vineland rootstocks V.1, V.5, V.6, and V.7. The industry standard Malling rootstocks M.26 EMLA and M.9-T337 were included for comparison. Tree mortality, trunk cross-sectional area (TCA), tree canopy size, amount of rootstock suckering, yield, and number of fruits were recorded annually. All response variables were influenced by location and rootstock and the interaction of these two factors. By year eight, trees could be distinguished into three rather distinct rootstock vigor classes, as measured by TCA of the rootstock means pooled across all locations: those similar to M.9-T337 (G.935, B.10, G.214, G.11, G.41); those similar to M.26 EMLA (G.969, G.30, V.1); and those more vigorous than M.26 EMLA (V.7, V.5, V.6). Overall, G.935 was 6% smaller in TCA than M.9-T337, B.10, G.214, and G.41 were similar in size to M.9-T337, while G.11 was 3% larger than M.9-T337. G.969 and G.30 were 9% and 11% larger in TCA than M.26 EMLA, respectively, while V.1, V.7, V.5, and V.6 were 12%, 27%, 36%, and 39% larger, respectively than M.26 EMLA. Cumulative yield was not closely associated with tree vigor. All rootstocks out performed M.26 EMLA and M.9-T337 except B.10 and G.41. Averaged over all locations, cumulative yield efficiency (CYE) was greatest for G.935 and G.214. Tree mortality was highest on B.10 and M.9-T337, while suckering was high on M.9-T337, G.30, and G.935, as well as the Vineland rootstocks at some locations. As tree vigor, yield and yield efficiency are related to each scion and rootstock combination, it is necessary to evaluate these characteristics across multiple regions and management practices to identify which rootstocks perform consistently. These results will allow apple producers to make more informed decisions concerning rootstock selection for the tall spindle or similar orchard training systems based upon planting locations with similar growing conditions.