Fuente: ISHS (International Society for Horticultural Science) Post date: Wednesday 3 September 2025
Author:
ISHS Secretariat

A key limitation of current phenological models is their reliance solely on natural chill accumulation, without accounting for the effects of dormancy breaking agents. These agents, primarily growth regulators, have become increasingly important for managing and synchronizing cherry production, especially in the southern hemisphere and in regions where winters are becoming too mild to meet chilling requirements naturally. To address this gap, we analyzed temperature data, bloom observations, and dormancy breaking agent application dates from 23 cherry orchards distributed along a latitudinal gradient in Chile. Based on this dataset, we developed four approaches to incorporate the effects of dormancy breaking agents into the PhenoFlex framework. As expected, our results confirm that assuming endodormancy completion at the time of application leads to systematically early bloom predictions. Approaches that added a fixed or scaled amount of chill did not perform well across the diverse climatic conditions in our dataset. In warmer regions, bloom was predicted too late, while in colder environments, predictions were too early, due to an overly high chill addition as a consequence of applying these dormancy breaking agents. Better results came from a method that compensated for insufficient chill by adjusting chill accumulation levels at the time of applying dormancy breaking agents. This created a balancing effect, where warmer locations with low natural chill received higher amounts of simulated extra chill, and colder sites with sufficient chill received only slight adjustments. Advancing these characteristics could be a promising strategy for improving approaches further. Future studies, with repeated measurements and comparisons between treated and untreated trees, will be crucial to better understand the interaction between dormancy breaking agents and the predictability of bloom dates. This work was conducted at the Pontifical Catholic University of Valparaíso in Chile. The findings contribute to our broader objective of improving phenological forecasts and enhancing the relevance of dormancy metrics, ultimately aiming to strengthen our ability to make robust and applicable predictions for temperate fruit orchards under future climate scenarios.
Julian Nick Bauer won the ISHS Young Minds Award for the best poster presentation at the X International Cherry Symposium in USA in June 2025.
Julian Nick Bauer, INRES – Horticultural Sciences, University of Bonn, Auf dem Hügel 6, 53121 Bonn, Germany, e-mail: jnba@uni-bonn.de
The article is available in Chronica HorticulturaeTags: cherryCategories: Young Minds Award Winners