‘홍로’/M.9 사과나무의 세장방추형에서 수고가 투광율, 투약율, 수체 생육 및 과실품질에 미치는 영향

This study was carried out to determine the effect of tree height on light transmission, spray penetration, tree growthperformance, fruit quality attributes, and labor productivity in the slender-spindle system of ‘Hongro’/M.9 apple trees. Withincreasing tree height, the light penetration into the internal parts of the canopy decreased, especially in the lower canopy. Leaf area index (LAI) increased with increasing tree height, thereby leading to a reduction in the extent of spray penetrationinto the interior of the canopy. With increasing tree height, shoot growth was more vigorous but produced slender shoots inthe upper canopy compared to the lower canopy. Although the soluble solid content and coloration of fruit decreased, therewas no difference in fruit firmness and acidity. In addition, the number of final fruit set increased, although the productionof large fruit (> 305 g) decreased. The increase in tree height also significantly increased the labor required for practices suchas thinning of flowers and fruits, pruning, and harvesting. Nevertheless, this problem of increased in labor input in taller treeswould was eased by use of a mechanical lift. Utilizing a lift for thinning the flowers of trees 4.5 m in height saved 14.6 minper tree, compared to the use of ladder. Therefore, it is highly considerable that in order to enhance light transmission andfruit coloration, light conditions should be improved in the internal tree canopy of slender-spindle systems.