Effects of tree density, tree shape, and rootstock on 'Bosc' pears
While the adoption of high-density pear orchards during the last decades has resulted in a significant improvement in yield and fruit quality, there is great disparity of opinion on the optimum density or the optimum tree shape. In addition, the lack of precocious Pyrus rootstocks means that full production is often achieved many years after orchard establishment and remains one of the main challenges in pear production. A field trial was planted in 2013 at the New York State Agricultural Experiment Station in Geneva, New York, being part of the NC-140 project. This trial compares 3 systems (Tall Spindle, V-trellis and Bi-Axis) using three spacings (0.9×3.7, 1.4×3.7, 1.8×3.7 m) and three rootstocks (OH×F69, OH×F87 and Pyro2-33) with 'Bosc' as the scion cultivar. Bigger trees were observed for Bi-axis than either Tall Spindle or V-trellis. Tree size was significantly affected by spacing. Smaller trees were observed at 0.9 m, followed by 1.4 m, and the largest trees at 1.8 m. Regarding rootstock, bigger trees were on OH×F69, followed by OH×F87, and then Pyro2-33. Fruit weight was affected by tree spacing and rootstock. The wider the spacing the larger the fruit, whereas the smaller fruits were on OH×F87 and the largest on Pyro2-33. Higher crop load was observed on the TS and V-trellis compared to Bi-axis. OH×F69 rootstock had lower cumulative crop load than either OH×F87 or Pyro2-33. In terms of cumulative yield efficiency, Pyro2-33 had the highest value, followed by OH×F87, and then OH×F69. There was a significant interaction among training system, spacing, and rootstock for cumulative yield. The highest cumulative yields were for Tall Spindle on OH×F87 at 0.9 m (70 t ha‑1), followed by V-trellis on OH×F87 at 0.9 m (67 t ha‑1), and Bi-axis on Pyro2-33 at 0.9 m (62 t ha‑1). The lowest cumulative yields were for TS on OH×F69 at 1.8 m (29 t ha‑1), Bi-axis on OH×F87 at 1.4 m (28 t ha‑1), and V-trellis on Pyro2-33 at 1.8 m (27 t ha‑1).
Lordan, J., Francescatto, P. and Robinson, T. (2021). Effects of tree density, tree shape, and rootstock on 'Bosc' pears. Acta Hortic. 1303, 163-170
crop efficiency, pear, Pyrus communis, vigor, yield, yield efficiency