Evaluation of slender spindle form in young ‘Topaz’ apple orchard

Two growing systems were compared – slender spindle and modified slender spindle, supplemented with or without additional summer pruning. The trial was carried out in orchard of the apple variety ‘Topaz’ in years 2012–2014. The assessed parameters were: trunk cross sectional area (TCSA), crown volume, number of cuts, dry matter weight of pruned wood, cumulative yield, yield efficiency, and relative occurrence of size classes of fruits. The objective was to confirm the hypothesized advantages of modified slender spindle in the period of increasing yields. Based on statistical analysis there was no significant difference among systems in growth measured by TCSA. Increase in crown cubage was the highest on slender spindle with additional summer pruning. The lowest increase of crown cubage was on modified spindle without summer pruning. Number of winter cuts and similarly dry weight was significantly higher on the modified spindle only in 2013. Additional summer pruning influenced both the above-mentioned parameters. There were no significant differences in cumulative yield and yield efficiency between systems. Similarly, the difference in the occurrence of various fruit size classes was not significant. We conclude that study needs to be extended in order to confirm the suggested trends.