SUMMER AND DORMANT PRUNING OF APPLE – A FOUR YEAR SUMMARY

Vigorous ‘Delicious’, ‘Golden Delicious’, and ‘Stayman’ apple trees on Malling Merton 111 rootstocks were summer pruned in mid-August (14 weeks after full bloom) or late in the dormant period (early April). Compared to dormant pruning, summer pruning increased mean shoot length in some years but the 4-year means did not differ between treatments in any of the 3 cultivars.
The increase in trunk circumference was suppressed by summer pruning in ‘Golden Delicious’ but not the other 2 cultivars.
Mean fruit number and weight per tree were not affected by time of pruning over the 4-year period.
In ‘Golden Delicious’ mean fruit weight was smaller on summer pruned trees; in the other cultivars there was no treatment effect.
In all 3 cultivars, summer pruning suppressed the level of soluble solids.
In some cases, summer pruning improved red color development and delayed preharvest drop compared to the dormant pruned controls.
As practiced in this study, summer pruning did not offer any advantage over comparable dormant pruning as a means of tree size control or vigor suppression and there were undesirable as well as desirable effects on the fruit.

International Workshop on Controlling Vigor in Fruit Trees

J.A. Barden, R.P. Marini

https://doi.org/10.17660/ActaHortic.1984.146.30