Apple Cultivation Under Climate Stress: Which varieties can withstand the heat?
Climate change is becoming increasingly noticeable in South Tyrol – with rising temperatures, reduced water availability, and more intense solar radiation. Classic apple varieties are under growing pressure. According to Eurac Research, for example, hail nets can reduce evaporation by around 20%.
Water and temperature: The double challenge
Apples need a lot of water. As temperatures rise, evaporation increases – while water supply decreases due to glacial retreat. This is an escalating problem, especially in South Tyrol. For growers, this means choosing varieties that are as tolerant as possible to drought and heat stress.
What makes a variety more heat-tolerant?
• Lower chill hour requirements: Varieties that require fewer cold hours in winter are less sensitive to mild winters and unstable weather patterns.
• Earlier or more flexible blooming: Allows trees to avoid late frosts and peak heat periods – a key trait in volatile climate zones.
• Robust physiological traits: Varieties with thick or waxy skin are better protected against sunburn and heat damage – a factor of both genetics and agronomy.
The classics under heat pressure: Golden, Gala & Co
Golden Delicious
This traditional variety remains widely cultivated – especially in South Tyrol. It’s adaptable, but under intense heat, it shows increased susceptibility to sunburn and bruising. It performs better in higher altitudes, while facing more challenges in lower, hotter areas.
Red Delicious
More heat-tolerant than Golden, though prone to fruit blemishes when water is scarce. Its thick skin provides sun protection, but its low disease resistance is a disadvantage under heat stress.
Gala / Royal Gala
One of the most important apple varieties in Europe. It ripens early, partly avoiding late summer heat – a clear advantage. However, Gala produces smaller fruits under drought and is sensitive to sunburn. There is a trend toward climate-adapted Gala clones like Galaxy or Schniga® Schnico Red.
Innovative strategies for improved heat protection
Monitoring & Technology
South Tyrolean initiatives such as MONALISA or EUFRUIT (between Laimburg, EURAC, and UniBZ) collect and analyze orchard data to manage irrigation and microclimates more precisely.
Agrivoltaics
In southern France, photovoltaic panels have been tested above apple orchards: with about 50–55% variable shading, yields may decrease slightly, but long-term climate conditions for the trees improve. An interesting path to reduce heat via partial shading.
Looking ahead: Adaptation and breeding as the future
Late Blooming Gene
Researchers in Michigan are studying the wild apple Malus coronaria, which blooms later – helping avoid both late frosts and extreme heat. These genes could be key in developing new varieties.
Climate Change as an Opportunity?
Some studies suggest that previously unsuitable regions – such as parts of Norway – may become viable for apple growing. Even in traditional regions like South Tyrol, varietal selection will need to be reassessed.
Conclusion: Diversity and adaptation are key in a changing climate
Climate change presents apple cultivation in South Tyrol and across Europe with new challenges – rising temperatures, water scarcity, and stronger solar radiation. Classic varieties like Golden Delicious, Gala, or Red Delicious are under increasing pressure, yet still show potential depending on location and care.
Apple growing can remain viable if heat-tolerant varieties are promoted, modern technologies like monitoring, shading systems, or agrivoltaics are adopted, and new breeding approaches based on genetic diversity are implemented. Adaptation starts now – with the right balance of tradition, innovation, and climate strategy.
Sources:
https://www.eurac.edu/en/magazine/apples-with-sunburn?.com
https://www.researchgate.net/publication/46221680_Overcoming_adverse_effects_of_hailnets_on_fruit_quality_and_microclimate_in_an_apple_orchard
