Sciaccarellu and climate change: A study of levers limiting berry shriveling during hot and dry vintages

Abstract

In the context of climate change, the increasing frequency and intensity of hot and dry vintages lead to profound modifications in the physiological functioning of the vine and the composition of the grapes. In France, Mediterranean regions, particularly Corsica, are at the forefront of these upheavals. Sciaccarellu, the island’s emblematic black grape variety, is particularly affected: acceleration of ripening, berry shriveling, yield losses, and wine imbalances (high alcohol levels, low acidity, disturbed phenolic maturity) [1].

Consequently, the CRVI has set up an experiment to limit berry shriveling (2020 – 2025). It involves five agronomic levers acting on different processes, notably the regulation of photosynthesis, the reduction of evapotranspiration, and the modification of the microclimate of the fruiting zone. The modalities were evaluated in comparison with a control on a Sciaccarellu plot at the ‘Alzipratu estate (AOP Calvi). They concern late pruning (carried out after budburst), shading nets creating respectively 20% and 50% shade (installed at bunch closure), vegetation management in downward shoot positioning (implemented at bunch closure), severe trimming (carried out at ripening begins) and Kaolin spraying (applied three times at the start of summer).

Under experimental conditions:

• Shading nets allow a significant reduction in water stress, an almost total decrease in berry shriveling and, for the 50% net, a marked slowdown in the Ripening kinetics. However, these effects are accompanied by a slight drop in yields and a decrease in anthocyanin content at maturity [2];
• Downward shoot positioning and Severe trimming show intermediate results with a moderate reduction in berry shriveling and water stress, as well as a delay in ripening of a few days;
• Late pruning induces a clear delay in ripening and a reduction of berry shriveling, but it generates a major decrease in vigor, yield, and assimilable nitrogen content of the berries;
• Kaolin sprays prove to be poorly suited; they do not reduce berry shriveling and lead to an acceleration of the sugar accumulation kinetics.

Ultimately, shading nets offer a credible operational option for the adaptation of Sciaccarellu to climatic constraints. Downward shoot positioning and severe trimming are also effective. However, their implementation involves economic compromises (installation, labor) and may modify the organoleptic profile of the wines [3].

References

[1] van Leeuwen, C., & Destrac-Irvine, A. (2017). Modified grape composition under climate change conditions requires adaptations in the vineyard. OENO One, 51(2), 147–154. https://doi.org/10.20870/oeno-one.2017.51.2.1647

[2] Oliveira, M., Teles, J., Barbosa, P., Olazabal, F., & Queiroz, J. (2014). Shading of the fruit zone to reduce grape yield and quality losses caused by sunburn. OENO One, 48(3), 179–187. https://doi.org/10.20870/oeno-one.2014.48.3.1579

[3] Reta, K., Netzer, Y., Lazarovitch, N., & Fait, A. (2025). Canopy management practices in warm environment vineyards to improve grape yield and quality in a changing climate. A review A vademecum to vine canopy management under the challenge of global warming. Scientia Horticulturae, Volume 341. https://doi.org/10.1016/j.scienta.2025.113998