Articles
ROOT PRUNING FOR GROWTH CONTROL IN APPLE TREES
Root pruning at dormant or full bloom stages reduced trunk cross-sectional area, shoot length, leaf size and fruit size and increased yield efficiency.
Root pruning at June drop and preharvest stages had no effect on shoot growth or leaf size, but increased preharvest fruit drop.
Mature ‘Melrose’/M.26 apple trees were annually root pruned at full bloom on 2 sides at either 80 or 60 cm from the trunk and to a depth of either 25 or 30 cm.
Root pruning at 60 cm distance reduced shoot growth and leaf size more than at 80 cm and both treatments reduced shoot length, shoot leaf size, trunk cross-sectional area, fruit size and fruit drop.
Yield was not affected by root pruning thus, yield efficiency was increased.
All root pruning treatments increased light penetration of the leaf canopy, increasing spur quality, fruit color and fruit soluble solids.
There were no differences between pruning at 25 cm or 50 cm depth.
Mature ‘Golden Delicious’/M.9 apple trees were annually root pruned on two sides at 50 cm distance and deblossomed at full bloom in all possible treatment combinations.
Root pruning reduced trunk cross-sectional area and shoot growth of cropping trees by 44%, and that of deblossomed trees by 14%. Root regeneration was slight on cropping trees while root pruned plus deblossomed trees had abundant root regeneration.