The use of low-vigor rootstocks is now a well-established strategy in modern sweet cherry production, thanks to advantages in terms of planting density, ease of management, and early bearing.
However, in continental climatic contexts characterized by hot, dry summers, such as that of Hungary, limited water availability represents a critical constraint.
A recent study conducted in Érd, in central Hungary, investigated the water relations of young sweet cherry trees of the cultivars ‘Carmen’ and ‘Regina’ grafted onto three dwarfing rootstocks: MaxMa 14, GiSelA 6, and WeiGi 2, during the post-harvest period under conditions of severe water stress.
The aim was to identify physiological differences among plants in response to water stress by measuring midday stem water potential (MSWP), stomatal conductance (gs), and trunk sap flow velocity.
Trees grafted onto MaxMa 14 exhibited the most negative MSWP values, both under water deficit conditions and after irrigation.
Nevertheless, this rootstock showed a highly dynamic stomatal response: stomatal conductance increased markedly following water supply, with changes up to three times greater than those observed in GiSelA 6.
This suggests a strong ability to rapidly modulate transpiration according to soil water availability.
In contrast, GiSelA 6 showed the smallest variations in both stomatal conductance and MSWP, while WeiGi 2 displayed an intermediate behavior, although closer to MaxMa 14 in terms of stomatal responsiveness.
Sap flow analysis, a direct indicator of whole-tree transpiration, provided further insights: the relationship between sap flow and reference evapotranspiration (ET0) followed a saturation-type curve, whose slope parameter increased significantly after irrigation in GiSelA 6 and WeiGi 2, but not in MaxMa 14.
This indicates that, in the former two rootstocks, water transport capacity improves mainly under conditions of low evaporative demand, whereas MaxMa 14 maintains stable hydraulic behavior both during drought and after the restoration of soil moisture.
From a physiological perspective, these results suggest different strategies for coping with water stress: MaxMa 14 appears to adopt a more isohydric behavior, characterized by rapid and pronounced stomatal regulation, whereas GiSelA 6 and WeiGi 2 show more anisohydric traits, maintaining transpiration activity for longer under water deficit.
However, the fact that MaxMa 14 maintains similar sap flow rates under both dry and wet conditions indicates a remarkable capacity to adapt to contrasting water regimes, which are typical of post-harvest orchard management.
The study’s conclusions highlight MaxMa 14 as the rootstock with the greatest physiological plasticity in drought-prone environments such as central Hungary.
It combines a dynamic stomatal response, stable water transport, and a strong capacity to adapt to varying levels of water availability.
WeiGi 2 exhibits intermediate characteristics, while GiSelA 6 appears to be the least tolerant to prolonged water stress.
From an applied standpoint, these findings provide valuable guidance for technicians and growers in selecting rootstocks for areas with limited water resources.
In the context of climate change and increasing water scarcity, identifying rootstocks with a high capacity to adapt to water stress is crucial to ensure greater economic and environmental sustainability of intensive sweet cherry production.
Source: Mohay, P., & Lakatos, T. (2025). Impact of Severe Drought Stress on Water Relations of Young Cherry Trees Grafted onto Growth-Reducing Rootstocks. Horticulturae, 11(9), 997. https://doi.org/10.3390/horticulturae11090997
Image source: Stefano Lugli
Andrea Giovannini
PhD in Agricultural, Environmental and Food Science and Technology - Arboriculture and Fruitculture, University of Bologna, IT
15 May 2026
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