Acta Univ. Agric. Silvic. Mendelianae Brun. 2026, 74(1-2), 11-17 | DOI: 10.11118/actaun.2026.001

Thinning Strategies for the Possible Robotization of Columnar Apple Orchards

Luděk Laňar1, Klára Scháňková1, Lukáš Nývlt1
Department of Technology, Research and Breeding Institute of Pomology Holovousy Ltd., Holovousy 129, 508 01 Holovousy, Czech Republic

Columnar apple varieties, which have a genetically determined slender growth pattern, are seen as a possible solution for simplifying and unifying the structure of orchard canopies. This makes them well-suited for the upcoming robotization. However, columnar varieties usually have very strong tendency to alternate bearing. We investigated the possible thinning strategies for columnar apples to avoid this tendency, maintain high production, and facilitate future robotization. Several treatments were designed in young orchard of the columnar apple variety 'Redspring'/M26. Three different main strategies that could be partly or fully carried out by robots were tested. First, we only removed flower clusters. Second, flower clusters removal was combined with subsequent fruitlet thinning leaving only the king fruit. The third strategy involved removing flower clusters, followed by removing fruitlets to reach the target crop load. In all strategies, the thinning level was set at 2, 3, or 4 units per 10 cm of central axis height. The results indicate that all strategies leading to a crop load 2-2.5 fruits per 10 cm of central axis height seems ideal for maintaining high, quality, and stable production. A strategy that thins to 2 units of flower clusters per 10 cm height without reducing fruitlets could be used as a first step in the robotic management of the crop load of columnar apples.

Keywords: crop load, fruit tree, alternation, flower cluster, robotic management, Malus sp., return bloom, yield

Received: July 7, 2025; Revised: December 12, 2025; Accepted: January 2, 2026; Published: May 1, 2026  Show citation

ACS AIP APA ASA Harvard Chicago Chicago Notes IEEE ISO690 MLA NLM Turabian Vancouver
Laňar, L., Scháňková, K., & Nývlt, L. (2026). Thinning Strategies for the Possible Robotization of Columnar Apple Orchards. Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis, 74(1-2), 11-17. doi: 10.11118/actaun.2026.001
Share...
Download citation
  • BibTeX (.bib)
  • Bookends (.ris)
  • EasyBib (.ris)
  • EndNote (.enw)
  • EndNote 8 (.xml)
  • ISI WoS (.isi)
  • Medlars (.medlars)
  • Mendeley (.ris)
  • MODS (.xml)
  • Papers (.ris)
  • RefWorks (.txt)
  • RefManager (.ris)
  • RIS (.ris)
  • MS Word (.xml)
  • Zotero (.ris)
    • Open full article

    References

    1. BABA, T., MORIYA, Y., SAKAMOTI, D., HANADA, T., IWANAMI, H. 2020. A Case Study on Crop Load to Avoid Alternate Bearing in Columnar Apples. Horticultural Research. 19(3), 285-292. https://doi.org/10.2503/hrj.19.285 Go to original source...
    2. BLAŽEK, J., KŘELINOVÁ, J. 2011. Tree growth and some other characteristics of new columnar apple cultivars bred in Holovousy, Czech Republic. Horticultural Science. 38(1), 11-20. https://doi.org/10.17221/23/2010-hortsci Go to original source...
    3. HOBLYN, T. N., GRUBB, N. H., PAINTER, A. C., WATES, B. L. 1936. Studies in Biennial Bearing.-I. Journal of Pomology and Horticultural Science. 14(1), 39-76. https://doi.org/10.1080/03683621.1937.11513464 Go to original source...
    4. IWANAMI, H., MORIYA-TANAKA, Y., HONDA, C., HANADA, T., WADA, M. 2019. Apple thinning strategy based on a model predicting flower-bud formation. Scientia Horticulturae. 256, 108529. https://doi.org/10.1016/j.scienta.2019.05.056 Go to original source...
    5. KARKEE, M. 2024. Robotics for tree fruit orchards. Acta Horticulturae. 1395, 359-368. https://doi.org/10.17660/ActaHortic.2024.1395.47 Go to original source...
    6. LAŇAR, L., SCHÁŇKOVÁ, K., NÝVLT, L. 2024. Different crop load management on columnar apple trees: first year results. Acta Horticulturae. 1395, 283-288. https://doi.org/10.17660/ActaHortic.2024.1395.37 Go to original source...
    7. LESPINASSE, Y. 1992. Breeding apple tree: aims and methods. In: Proceedings of the Joint Conference of the EAPR Breeding and Varietal Assessment Section and the EUCARPIA Potato Section. Landerneau, France, 12-17 January 1992. Landerneau, France: I.N.R.A., pp. 103-110. https://eurekamag.com/research/002/313/002313646.php
    8. MARYŠKA, L., PLECITÁ, L., ZELENÝ, L. 2026. Critical traits in the selection of columnar apple genotypes suitable for the future orchard automation. Unpublished, under reviews.
    9. R CORE TEAM. 2025. R: a language and environment for statistical computing [software]. [2025-06-07]. Vienna: R Foundation for Statistical Computing. http://www.R-project.org/
    10. ROBINSON, T. L., FRANCESCATTO, P., LORDAN, J. 2021. Advances in precision crop load management of apple. Acta Horticulturae. 1314, 133-138. https://doi.org/10.17660/ActaHortic.2021.1314.18 Go to original source...
    11. TUSTIN, D. S., VAN HOOIJDONK, B. M., BREEN, K. C. 2018. The Planar Cordon - new planting systems concepts to improve light utilisation and physiological function to increase apple orchard yield potential. Acta Horticulturae. 1228, 1-12. https://doi.org/10.17660/actahortic.2018.1228.1 Go to original source...
    12. VÁVRA, R., BLAŽEK, J., VEJL, P., JONÁŠ, M. 2017. Evaluation of biennial bearing of apple genotypes with columnar tree growth habit. Acta Horticulturae. 1172, 395-398. https://doi.org/10.17660/ActaHortic.2017.1172.75 Go to original source...
    13. VÁVRA, R., VEJL, P., BLAŽEK, J. 2021. Tree architecture of columnar apple tree genotypes. Acta Horticulturae. 1314, 337-344. https://doi.org/10.17660/ActaHortic.2021.1314.42 Go to original source...
    14. VERCAMMEN, J., GOMAND, A., SIONGERS, V., BYLEMANS, D. 2016. Fruit set of 'Jonagold': a small dose of gibberellins or Regalis. Acta Horticulturae. 1139, 431-438. https://doi.org/10.17660/actahortic.2016.1139.75 Go to original source...
    15. VERMA, P., SHARMA, S., SHARMA, N. C., CHAUHAN, N. 2023. Review on crop load management in apple (Malus x domestica Borkh.). The Journal of Horticultural Science and Biotechnology. 98(3), 299-321. https://doi.org/10.1080/14620316.2022.2149425 Go to original source...
    16. ZHANG, Q., KARKEE, M., TABB, A. 2019. The use of agricultural robots in orchard management. In: The use of agricultural robots in orchard management. Cambridge: Burleigh Dodds Science Publishing Limited, pp. 187-214. http://dx.doi.org/10.19103/AS.2019.0056.14 Go to original source...
    17. ZELENÝ, L., 2025. Growth of columnar varieties. Personal communication. [2025-06-17].

    This is an open access article distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY NC ND 4.0), which permits non-comercial use, distribution, and reproduction in any medium, provided the original publication is properly cited. No use, distribution or reproduction is permitted which does not comply with these terms.


    Return to the content