New Zealand Journal of Crop and Horticultural Science abstracts

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Pruning strategies for restructuring top-dominant
central leader `Granny Smith' apple trees

I . J. WARRINGTON

The Horticulture and Food Research
Institute of New Zealand
Batchelar Research Centre
Private Bag 11 030
Palmerston North, New Zealand

C. J. STANLEY
J. F. JULIAN

The Horticulture and Food Research
Institute of New Zealand
Riwaka Research Centre
R D 3, Motueka, New Zealand

D. S. TUSTIN
P. M. HIRST
W. CASHMORE

The Horticulture and Food Research
Institute of New Zealand
Hawkes Bay Research Centre
Private Bag 1401
Havelock North, New Zealand

Abstract  Eighteen-year-old, top-dominant central leader trees of `Granny Smith' apple (Malus domestica Borkh.) were restructured during the 1987 and 1988 dormant seasons into either palmette central leader (initially) or pyramid central leader forms. In the palmette form, pruning was restricted to the total removal of the uppermost east- and west-facing fruiting scaffolds in 1987, and the shortening of all middle scaffolds and the upper north-facing scaffold in 1988. In the pyramid form, major scaffold limbs were subjectively removed or shortened to re-establish the desired pyramid shape over the two dormant seasons. Both forms were also renewal pruned annually to totally remove pendant fruiting laterals and spur-bearing wood over 4 years old. In addition, unmodified top-dominant trees that were either renewal pruned or containment pruned (primarily heading cuts) were maintained for comparison with the restructuring treatments. The restructuring treatments resulted in improved light penetration to the lower and inner canopy regions, improved spur quality, and in a greater proportion (50% cf. 30%) of the fruit being borne in the lower half of the tree. Cumulative yield over the 3 years of study was not reduced in the restructured trees in comparison with the containment-pruned top-dominant trees and was reduced by only 20% in comparison with the renewal-pruned top-dominant trees. Mean fruit size in both the upper and lower tree regions was not altered by the restructuring treatments. Renewal pruning alone compared with containment pruning resulted in a total yield gain of 28% and an 8% increase of mean fruit size in the lower canopy but did not lead to a redistribution of fruit within the tree. Major upper canopy restructuring combined with annual renewal pruning, therefore, achieved the greatest gains in both yield, and fruit size along with improved fruit distribution within the tree.

Keywords  fruit yield; fruit size; light transmission; Malus domestica; spur quality

New Zealand Journal of Crop and Horticultural Science, 1995, Vol. 23: 315-322

0114-0671/95/2303-0315 $2.50/0 (c) The Royal Society of New Zealand 1995

PDF file of entire paper: medium quality (645K); (scanned from paper original: notes about this process)

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