Comparison of Two Training Methods Applied to Apple Trees Trained to Slender Spindle During the First Years After Planting

The research was focused on the comparison of two pruning methods (winter pruning and winter + summer pruning) applied to apple trees trained to a standard and a modified slender spindle. The orchard of 'Topaz' trees, grafted on rootstock M 9, was planted in spring 2011. In the years 2013-2016, trunk cross sectional area (TCSA), crown volume, cumulative yields, yield efficiency, relative proportion of fruit size classes, number of cuts and dry matter of pruned wood were analyzed. The total growth intensity of the trees, measured by TCSA, was similar among the treatments. The trees of modified slender spindle had lower mean crown volume (2.751-2.765 m3) comparing to slender spindle with additional summer pruning (3.355 m3) and proved to better control the tree size. The modified slender spindle brought similar or slightly lower cumulative yields, but significantly higher proportion of good sized fruits (in categories above o 70 mm) comparing to slender spindle. The pruning of modified spindle brings generally higher number of cuts removing a higher amount of woody biomass in comparison to slender spindle, regardless if combined with summer pruning. The additional summer pruning brought no beneficial effect in reduction of growth, fruit production and fruit size of the modified slender spindle.