Tree Structure and Pruning Response of Six Peach Growth Forms

Abstract

The response of young, nonbearing peach [Prunus persica (L.) Batsch] trees to pruning was studied in six distinct growth forms including semidwarf, spur-type, upright, columnar or pillar, weeping, and standard. Two years after field planting, pillar and upright trees were trained to slender spindle. Semidwarf, spur-type, and standard trees were trained to the open or delayed vase form. Weeping trees were pruned in a manner similar to the Lepage hedge for pear. Branch density before pruning was highest in semidwarf, spur-type, and upright trees and lowest in pillar trees. Standard, semidwarf, and spur-type trees reacted similarly to pruning, but semidwarf trees produced as much wood in the following season as had been pruned off, and produced large numbers of fruiting branches. The small size of semidwarf trees suggested their use for medium-density plantings (MDPs). Pillar trees needed only light pruning. No major cuts were necessary and many fruiting branches were produced even on nonpruned trees. The pillar canopy was 60% thinner and required 50% fewer pruning cuts than the standard canopy and may be particularly suited to high-density plantings (HDPs). The upper canopy of weeping trees grew more than most other forms. They were intermediate in branch density and required an intermediate amount of pruning. Most striking was the unique canopy form of weeping trees, which may be used in developing new training systems. The results of this study suggest that new growth forms have the potential to reduce pruning and training requirements for peach, particularly in MDPs and HDPs. This potential suggests further investigation and exploitation of alternate peach tree growth forms.