SHOOT PRUNING CAN REDUCE COLD HARDINESS OF APPLE ROOTSTOCKS

Two experiments examining the effects of summer and dormant pruning on plant mortality and post-pruning regrowth following controlled freezing tests were evaluated.
In the dormant pruning experiment, three-year-old McIntosh/B.490, Idared/B.490 and ungrafted O.3 rootstocks were pruned 24-48 hours prior to controlled freezing tests.
In the summer pruning experiment, three-year-old McIntosh and Cortland trees grafted to M.26 and O.3 rootstocks were subjected to four levels of summer pruning severity: control (0 g of shoots per trunk diameter, cm), light (30 g/cm), moderate (110 g/cm) and heavy (200 g/cm). In both experiments, no cultivar differences were found.
Dormant pruning did not increase plant mortality but it did significantly reduce shoot, trunk and root regrowth.
Summer pruning increased plant mortality and reduced leaf, trunk and root regrowth especially for the M.26 rootstock.

VIII International Symposium on Canopy, Rootstocks and Environmental Physiology in Orchard Systems

J.-P. Privé

Malus  domestica, cold stress, whole plant regrowth, tree mortality, summer pruning, dormant pruning

https://doi.org/10.17660/ActaHortic.2007.732.7