Effects of leader pruning on vine architecture, productivity and fruit quality in kiwifruit (Actinidia deliciosa cv. Hayward)

The effects of two summer pruning strategies on vine architecture, fruit yi eld and quality were compared over three growing seasons. With 'leader prun ing', all vigorous vegetative shoot growth close to the central leader zone was removed continually through the growing season. With 'conventional pru ning', this new shoot growth was left virtually un-pruned over summer with only summer pruning to shorten fruiting laterals in the fruiting zone to th ree to four leaves past the last fruit. Leader pruning resulted in signific ant increases in the ratio of second year wood to first year wood, and in t he number of self-terminating canes per vine. The basal diameter of canes w as significantly reduced in leader pruned vines. Leader pruning was associa ted with an increase in total fruit yield. This increase was a result of in creased fruit size on leader pruned vines, coupled with a small increase in the number of fruits per unit area. The number of winter buds per square m etre did not differ from that of control vines, suggesting that the slight increases in fruit number could be attributed to an increased number of flo wers per winter bud. Changes in vine composition as a result of leader prun ing included a decrease in leaf number, particularly in the upper zone of t he canopy, and these changes were associated with significant changes in fr uit quality, with fruits from the upper zones being larger, and having a hi gher soluble solids content after storage than fruits from lower parts of t he vines in the same treatment. The effects of pruning strategy on vine res ource balance allocation are discussed. (C) 2001 Elsevier Science B.V. All rights reserved.