Rootstock, severity of dormant pruning, and summer pruning influences on peach tree size, yield, and fruit quality

Abstract

Peach trees in British Columbia are pruned heavily during the dormant season with some potentially detrimental effects. Summer pruning has been used to control fruit tree vigor and improve fruit quality. The objective of this study was to reduce tree size, increase yield, and improve fruit color by using a less severe dormant pruning system and summer pruning prior to harvest. Over 4 yr, mature, self-rooted (micropropagated) Fairhaven peach trees and Fairhaven on Siberian C rootstock were subjected to two different dormant pruning regimes, with or without summer pruning. Yield, tree growth, pruning weights (dormant and summer) and fruit quality (size and color) measurements were recorded annually. There were no differences in yields per tree for the two rootstocks or for the summer pruning treatments. The lighter ("long") dormant pruning increased yields but average fruit weight was higher in the heavier ("short") dormant pruning treatment. Summer pruning increased the amount of red color on the fruit but only slightly. Own-rooted trees were larger (tree height and ground area covered) than trees budded on Siberian C. Tree height was also increased by the lighter dormant pruning treatment. The partitioning index was higher for trees on Siberian C rootstock, "long" dormant pruned, or non- summer pruned trees. Key words:Prunus persica, fruit color, fruit size, partitioning index