Acta Univ. Agric. Silvic. Mendelianae Brun. 2026, 74(1-2), 19-26 | DOI: 10.11118/actaun.2026.002

Performance of 'Gala' apple under chemical thinning or precision crop load management

Tomáš Kiss1, Ivo Ondrášek1, Eliška Zezulová1, Jan Náměstek2, Luděk Laňar2, Tomáš Nečas1
1 Department of Fruit Science, Faculty of Horticulture in Lednice, Mendel University in Brno, Zemědělská 1, 613 00 Brno, Czech Republic
2 Department of Technology, Research and Breeding Institute of Pomology Holovousy Ltd., Holovousy 129, 508 01 Holovousy, Czech Republic

In Europe, the most common measure for crop load management is chemical thinning. Nevertheless, its effect is influenced by many variable factors, thus difficult to control and predict. Precision crop load management is a possible strategy to avoid use of chemical thinning and it provides consistent predictable crop loads. Objective of the research was to test the influence of fruitlet thinning timing on final yield performance when precision quantified crop load management is applied, compare it with chemical thinning, and assess its practical feasibility in current standard spindle orchards. Artificial spur extinction in balloon stage to set 6 flower clusters/cm2 of branch cross sectional area was applied in several treatments which were further hand fruitlet thinned at three different stages: 5 mm, 10-12 mm, or 20 mm of fruitlet diameter. It was variously combined or compared with chemical fruitlet thinning treatments and control. The thinning effect, production parameters and return bloom were assessed. The results obtained in this study did not favour the precision quantified non-chemical crop load management because it is labour demanding and did not outperform standard chemical thinning approach in fruit quality and yield of the Gala variety.

Keywords: crop load, fruit tree, flower cluster, Malus sp., return bloom, yield, quality

Received: November 20, 2025; Revised: January 23, 2026; Accepted: January 28, 2026; Published: May 1, 2026  Show citation

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Kiss, T., Ondrášek, I., Zezulová, E., Náměstek, J., Laňar, L., & Nečas, T. (2026). Performance of 'Gala' apple under chemical thinning or precision crop load management. Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis, 74(1-2), 19-26. doi: 10.11118/actaun.2026.002
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