Response of training system planting density and cultivar in pear.

摘要

High-density planting (HDP) in pear is expanding due to the widespread use of quince rootstock able to reduce tree size and induce early bearing. However, HDP introduces high costs so the break-even point occurs 8 to 10 years after planting. The combination of HDP and compact tree architecture is fundamental to achieve success. In 1997, the University of Bologna in Italy, started a trial to compare and evaluate the production and economic aspects of seven types of pear plantations. There were three pear cultivars (Abbe Fetel, Conference and Doyenne du Comice), two quince rootstocks clones (MC and Sydo), and four planting densities, i.e. 7936 (VHDP), 5555 (HDP), 3968 (MDP) and 1984 trees/ha (LDP). The training systems were vertical axis/MC for VHDP, V-shape/MC for MDP and HDP, slender spindle and drapeau/MC for MDP, and slender spindle and drapeau/Sydo for LDP. The most productive results were obtained with Abbe Fetel with the vertical axis/MC (VHDP) and the V-shape at HDP. After seven years, the cumulative production was 32 kg/tree and 47 kg/tree, 257 t/ha and 262 t/ha, respectively. With Conference, the same 2 training systems performed similarly with a cumulative yield of 179 t/ha and 181 t/ha. In Doyenne du Comice, with the vertical axis/MC (VHDP), the accumulated yield was 132 t/ha followed by V-shape/MC for MDP with 120 t/ha. It must be stressed that the investments required by VHDP layouts requires high farm-gate prices for equitable returns to growers. This means that, in Italy, if the farm-gate price is lower than 0.45 Euro/kg, the break-even point is at least 10 years and enterprise is at risk..