Introduction

The viticulture of Santorini Island, in the Cyclades, is unique and has contributed to the remarkable breakthrough of Santorini’s wine into the global quality wine market. The wine industry is a leading economic activity for the island, with significant value added in terms of GDP, investments and revenues. Closely related to tourism, wine is linked to Santorini’s brand name as one of the top world destinations. Hence Santorini remains one of the few places in Europe where traditional viticulture is still practised. Local varieties trained with the traditional ‘Kouloura’ and ‘Kladeftiko’ training systems (Figure 1) have been cultivated for thousands of years on the island producing worldwide recognised high-quality PDO wines. The literature on these local varieties and traditional training systems is scarce. Investigations into how these unique training systems adapt viticulture to the specific climatic conditions of the island are important because they inform their possible use as alternative training systems in similar environments to adapt to climate change.

Winegrapes are one of the world's most valuable horticultural crops (Alston and Sambucci, 2019), and viticulture is facing massive challenges due to climate change, such as increased extreme precipitation events (i.e., drought and heavy rainfall), more frequent heatwaves and less frequent extreme cold temperatures and cold waves (Jones and Goodrich, 2008; Tomasi et al., 2011; Xyrafis et al., 2022; Jones et al., 2022). Among the chief concerns are that a combination of increased temperatures and decreased rainfall will increase the frequency and/or severity of droughts (IPCC., 2022). High temperatures, in combination with decreased precipitation, can cause complete yield loss depending on the phenological stage (Venios et al., 2020). Even if the yield is not affected, these conditions can lead to early technological maturation of the grape with significant sugar increases and negative impacts on wine quality (acidity, aroma, colour) (Costa et al., 2016).

Adaptation measures must be planned and applied to maintain the sustainability of vineyards (Metzger and Rounsevell, 2011), and several adaptions have been reported for use in viticulture (Koundouras et al., 2008; Duchêne et al., 2012; Brillante et al., 2016; Petoumenou et al., 2017; Fraga and Santos, 2018; Biniari et al., 2023). These include a blend of strategies such as using more suitable clones/rootstocks/varieties, decreasing planting densities and/or changing training systems (Naulleau et al., 2021). In particular, new training systems and different planting densities could provide complementary solutions to mitigate the effects of high temperature, radiation and water deficits. These cultural adaptations to drought may lead to yield reductions and a shift in wine aromatic profiles (Deloire et al., 2022).

Changing training systems is particularly interesting because it has the potential of adapting the production system without changing the variety grown and, in some cases, without the need to replant and restructure the entire vineyard. A thorough training system assessment requires knowledge of vine photosynthesis, sugar and acid metabolism, micrometeorology and many other fields (Reynolds and Heuvel, 2009). Over the last decades, the main objectives of relevant experiments on training systems focused primarily on increasing the photosynthetic efficiency of the canopy by increasing the leaf area and increasing the light exposure of the grapes (Carbonneau and Casteran, 1987). However, in the context of climate change, training systems are being reconsidered with opposite objectives: on the one hand, decreasing the water demand by reducing the leaf area while maintaining an adequate sugar content in the berries and, on the other hand, leaving the grapes in the shade as much as possible (Favero et al., 2010; Duchêne et al., 2014).

The vine training system determines the light interception and bunch sun exposure, thus completing berry ripening. Palliotti et al. (2014) identified adapted training systems allowing for an optimal bunch microclimate under future climatic conditions. However, it is difficult to state which training system best adapts to drought. Over centuries, wine growers in the Mediterranean basin have developed a training system which is particularly resistant to drought and high temperatures: the so-called Mediterranean goblet or bush vine. This training system makes it possible to dry-farm vines in extremely dry environments, down to a mere 350 mm of rainfall/year (Deloire, 2012; van Leeuwen et al., 2019a). We note that there is currently a lack of comparisons of the water use efficiency of different training systems, including traditional forms like goblet systems (Medrano et al., 2015, Salvi et al., 2017). In Central Europe, under relatively cool climates, pruning systems such as semi-minimal pruning are promoted as an adaptation to climate change, as they present higher yields with lower alcohol than vertical-shoot positioning systems (Clingeleffer, 2010; Molitor et al., 2019). However, the large water requirements of such systems would not be adapted to rainfed systems in semi-arid climates.

Santorini island (36.3932° N, 25.4615° E) is an active volcanic complex in the Cyclades (Greece), with an area of 76.19 km², of which today 1100 ha is covered with cultivated vineyards. Santorini has a Mediterranean climate composed of high temperatures (an average of 3 days during summer with max temperatures of >35 °C was observed for the 2009–2019 period), heatwaves (which often occurred during summer) and long drought periods. These climate challenges affect yield, berry development and composition and the associated wine aromatic profiles, and are intensifying due to climate change in the Mediterranean region (Fraga et al., 2017; Alba et al., 2021; Xyrafis et al., 2022). Recent studies reveal that in both Santorini (Greece) and in the Hérault region (South France), there is a similar increase in the annual mean temperature of 0.06 °C (Laget et al., 2008; Xyrafis et al., 2022). Regarding the annual precipitation of the island, an amount of 316 mm (average from 1974 through 2019) has been observed, which is even lower than in arid regions of Extremadura (Southwest Spain) and Pafos (Cyprus), where the precipitation varies from 380 to 700 mm (García-Martín et al., 2022).

Own-rooted and phylloxera-free vines have been cultivated on the volcanic soil of Santorini for thousands of years. All this time, vines have been cultivated using two traditional training systems, the ‘Κouloura' and the ‘Κladeftiko' (Figure 1), which are well-adapted to the specific climatic conditions of the island. (Xyrafis et al., 2021).

Figure 1. Illustration of the traditional training systems of Santorini (‘Kladeftiko’ and ‘Kouloura’) and the VSP.

Save View full size Expand inline Collapse inline

The objective of this study was to compare the physiological and agronomic response of Assyrtiko grapevines to the traditional training systems ‘Kouloura’ and VSP training system over two growing seasons and to establish the factors influencing the performance of each system in the semi-arid conditions of Santorini Island as an alternative training system to adapt viticulture in other warm, dry wine regions.

Material and methods

Results

2. Vine water status

Figure 2. Water potential: Ψpredawn and Ψleaf (MPa) at three growth stages (bunch closure, veraison and harvest) of KLR and VSP training systems for 2020 and 2021. The values are averages ± SD. Averages followed by * are different p < 0.05, Tukey’s HSD, n = 5.

Save View full size Expand inline Collapse inline

There were significant differences in vine water status between the two training systems depending on the developmental stage, and globally KLR always maintained a less stressed water status (i.e., less negative Ψ). In 2020, VSP Ψ_predawn was significantly more negative than KLR (~0.1 MPa difference), and at harvest, VSP also had more negative Ψ_predawn than KLR, although the differences were not statistically significant. In 2021, during harvest, VSP again exhibited more negative Ψ_predawn than KLR (~0.1 MPa difference), while differences were not significant during bunch closure and veraison. In 2020, no significant differences in midday Ψ_leaf were observed at bunch closure, while at veraison and harvest, VSP was significantly more negative (~0.2 MPa difference) than KLR (Figure 2). In 2021, during harvest, VSP again exhibited more negative midday Ψ_leaf (~0.15 MPa difference) (Figure 2). Although KLR also maintained slightly less negative Ψ_leaf during bunch closure and veraison in 2021, these differences were not statistically significant.

3. Photosynthesis and gas exchange

Figure 3. Leaf assimilation rate (Pn, μmol m-2 s-1), leaf stomatal conductance (gs, mol m-2 s-1) and the leaf transpiration (E, mmol H2O m-2 s-1) of KLR and VSP at three growth stages (bunch closure, veraison and harvest) during the 2020 and the 2021 season. The values are averages ± SD. Averages followed by * are different p < 0.05, Tukey’s HSD, n = 5.

Save View full size Expand inline Collapse inline

Leaf assimilation rate, leaf stomatal conductance and leaf transpiration presented significant differences at the three growth stages (bunch closure, veraison and harvest) during the 2020 and 2021 seasons (Figure 3). Specifically, photosynthesis during veraison in both years was significantly higher in the KRL training system (~8 μmol m^-2 s^-1 difference in 2020 and ~4 μmol m^-2 s^-1 difference in 2021). At bunch closure and harvest, there were no significant differences. Regarding the stomatal conductance, in 2020, at veraison and harvest, the VSP stomatal conductance decreased and presented lower values than KLR (~0.07 mol m^-2 s^-1 difference). During bunch closure, there were no significant differences. Similarly, in 2021, during veraison, the VSP had lower stomatal conductance than KLR (~0.08 mol m^-2 s^-1 difference). At bunch closure and harvest, no significant differences were found. Correspondingly, leaf transpiration values were higher in KLR during veraison in both years (~1.2 mmol H₂O m^-2 s^-1). At bunch closure stage in 2021, VSP was higher than KLR (~2 mmol H₂O m^-2 s^-1). No significant differences were observed at harvest for both training systems in 2021. No significant differences have been mentioned regarding water use efficiency between KLR and VSP training systems for both studied years (data not shown).

4. Microclimate and heatwave responses

Table 3. Leaf and grape temperature during the harvest period at midday in 2021. The values are averages ± SD. Averages followed by * are different p < 0.05, Tukey’s HSD, n = 10.

View popup Expand inline Collapse inline

Organ measured	Temperature (°C)		Significance
	KLR	VSP
Leaf	33.5 ± 1.8	33.9 ± 3.2	n.s.
Random grapes	32.6 ± 0.2	34.3 ± 0.6	*
Sun-exposed side of grapes	35.3 ± 1	36.7 ± 1.2	*
Shaded side of grapes	31.4 ± 0.4	30.8 ± 0.3	n.s.
During heatwave-sun exposed side of grapes	40.1 ± 0.5	39.4 ± 0.3	n.s
During heatwave-shaded side of grapes	32 ± 0.3	31.3 ±0.1	n.s

There were significant differences in microclimate temperature between the two training systems at harvest. Table 3 presents measured temperatures of grapes and leaves at midday for both training systems during the harvest period and heatwave days in 2021. Leaf temperatures presented similar values with no significant difference. At midday, during harvest, the sun-exposed side of VSP grapes showed significantly higher temperatures than KLR. The shaded grapes of both training systems were not significantly different. During the heatwave, temperatures reached 40 °C for KLR sun-exposed side with no significant difference from VSP. Though there was a clear separation of temperatures between shaded and sun-exposed sides at midday and during the heatwave.

Figure 4. Open-air temperature and temperature under the canopy of KLR and VSP training systems from veraison until harvest for three periods (morning, midday and night) for the two studied years, 2021 and 2020. The values are averages ± SD. Averages followed by different letters are different p < 0.05 Tukey’s HSD, n = 32.

Save View full size Expand inline Collapse inline

Figure 4 shows the temperature and humidity evolution during the open-air day and temperature under the canopy of KLR and VSP training systems for the period from veraison until harvest. In 2020 (Figure 4, left), during the morning, temperatures for both training systems were significantly lower (~28 °C) in comparison to open-air (~31 °C). At midday, temperatures for both training systems are significantly lower (~33 °C) than open-air temperatures (~38 °C). At night, KLR and VSP had significantly higher values (~26 °C) than open-air. In 2021 (Figure 4, right), during the morning, KLR presented significantly lower temperatures in comparison to open-air and VSP but with no significant difference. During midday, the temperatures increased, reaching values around 35 °C, while open-air, VSP and KLR exhibited similar values. At night, the VSP training system had the lowest temperatures (25 °C), and KLR had the highest temperatures (27 °C) during this period.

Regarding humidity, in 2021, during the morning, KLR had significantly higher humidity (~66 %) from open-air and VSP, and VSP presented the lowest values (~55 %). At midday, KLR showed markedly higher humidity (~56 %) than VSP (46 %). At night, there were no significant differences in humidity between the training systems.

Figure 5. Temperature and humidity evolution under the canopy of KLR and VSP training systems during a heatwave in 2021 at harvest. The values are averages ± SD. Averages followed by different letters are different p < 0.05, Tukey’s HSD, n = 5.

Save View full size Expand inline Collapse inline

During the heatwave of 2021, there were clear differences in fruit damage between the two training systems, where KLR exhibited 19 % damaged fruit while VSP reached 32 % (data not shown). During the heatwave, there were significant differences in the temperature and humidity evolution under the canopy between the KLR and VSP training systems and compared to the open-air temperature and humidity. Regarding temperature (Figure 5, above), the VSP training system exhibited lower values (~25 °C) than KLR and open-air temperature at night. During the morning, no differences were observed between the training systems and open-air temperatures. From 11:00 through 15:00, when temperatures were at their maximum, the open-air temperature reached values around 42 °C. For the same period, VSP and KLR showed markedly lower values (~38.5 °C and 37 °C, respectively) than open-air temperature, while the KLR presented the lowest values. From 16:00 to 24:00, no differences were observed. No differences in humidity were observed during the night and early morning (Figure 5 below). From 11:00 until 15:00, KLR presented significantly higher humidity (47 %) than VSP (~32 %). Similar differences were found from 16:00 until 20:00, although they were not significant.

Discussion

In this work, we analyse the traditional training system (‘Kouloura’) and vine density of Santorini while comparing it with the globally used VSP training system. We found significant differences in vine water status between the two training systems depending on the developmental stage, and globally, KLR always maintained a less-stressed water status (i.e., less negative Ψ). In our study, the KLR system produced the largest exposed canopy surface area while net mean photosynthesis during veraison on fully exposed leaves was 30 % higher. KLR maintained a more beneficial microclimate, especially during heatwaves, with lower leaf, grape and under canopy temperatures during days and time periods with high temperatures than open-air and the VSP training system.

Conclusion

The traditional ‘Kouloura’ training system used in Santorini proved to be well-adapted to the extreme climatic conditions of the island. Hence, our results validated that the empirical use of ‘Kouloura’ persisted through time and became part of the authenticity of the landscape/terroirs of this wine region. This work details the physiological mechanisms by which this traditional training system enhances performance. Learning from traditional viticulture systems such as the one described in this study could be significant in improving global vineyard sustainability because it can highlight mechanisms that have created drought-resilient systems in the past. Our research inspires further comparative analysis of other traditional training systems and vine densities in wine-growing regions that are currently arid and those that will become so in the future.

Acknowledgements

The authors wish to thank Domaine Sigalas for allowing the use of their vineyards for this research.

References

• Alba, V., Gentilesco, G., & Tarricone, L. (2021). Climate change in a typical Apulian region for table grape production: spatialisation of bioclimatic indices, classification and Future Scenarios. OENO One, 55(3), 317–336. https://doi.org/10.20870/oeno-one.2021.55.3.4733
• Alston, J. M., & Sambucci, O. (2019). Grapes in the World Economy. In: D. Cantu & M. A. Walker (Eds.), The Grape Genome (pp. 1–24). Springer, Cham. https://doi.org/10.1007/978-3-030-18601-2_1
• Archer, E., & Strauss, H. C. (1989). The effect of plant spacing on the water status of soil and grapevines. South African Journal of Enology and Viticulture. 10, 49-58. https://doi.org/10.21548/10-2-2286
• Archer, E., & Strauss, H.C. (1990). The effect of vine spacing on some physiology aspects of Vitis vinifera L. (cv. Pinot noir). South African Journal of Enology and Viticulture. 11:76-87. https://doi.org/10.21548/11-2-2272
• Baeza, P., & Ruiz, C. & Cuevas, E., Sotés, V. & Lissarrague, J.R. (2005). Ecophysiological and agronomic response of Tempranillo grapevines to four training systems. American Journal of Enology and Viticulture. 56. 129-138. https://doi.org/10.5344/ajev.2005.56.2.129
• Beauchet, S., Rouault, A., Thiollet-Scholtus, M., Renouf, M., Jourjon, F., & Renaud-Gentié, C. (2019). Inter-annual variability in the environmental performance of viticulture technical management routes - a case study in the Middle Loire Valley (France). International Journal of Life Cycle Assessment 24(2), 253-265. https://doi.10.1007/s11367-018-1516-y
• Biniari, K., Athanasopoulou, E., Daskalakis, I., Xyrafis, E. G., Bouza, D., & Stavrakaki, M. (2023). Effect of foliar applications on the qualitative and quantitative characters of cv. Assyrtiko and cv. Mavrotragano in the island of Santorini, under vineyard conditions. In BIO Web of Conferences (Vol. 56, p. 01008). EDP Sciences. https://doi.org/10.1051/bioconf/20235601008
• Brillante, L., Belfiore, N., Gaiotti, F., Lovat, L., Sansone, L., Poni, S., & Tomasi, D. (2016). Comparing kaolin and pinolene to improve sustainable grapevine production during drought. PLoS One, 11(6), e0156631. https://doi.org/10.1371/journal.pone.0156631
• Carbonneau, A., & Casteran, P. (1987). Optimization of vine performance by the lyre training system. In Proceedings of the Sixth Australian Wine Industry Technical Conference. T. Lee (Ed.), pp. 194-204. Australian Industrial Publishers, Adelaide
• Clingeleffer, P. R. (2010). Plant Management Research : Status and what it can offer to address challenges and Limitations. Australian Journal of Grape and Wine Research, 16, 25 32. https://doi.org/10.1111/j.1755-0238.2009.00075.x
• Costa, M., Vaz, M., Escalona, J., Egipto, R., Lopes, C., Medrano, H. and Chaves, M. (2016) Modern viticulture in southern Europe: vulnerabilities and strategies for adaptation to water scarcity. Agricultural Water Management 164, 5–18. https://doi.org/10.1016/j.agwat.2015.08.021
• Drappier, J., Thibon, C., Rabot, A., & Geny-Denis, L. (2019). Relationship between wine composition and temperature: Impact on Bordeaux wine typicity in the context of global warming—Review. Critical Reviews in Food Science and Nutrition, 59(1), 14–30. https://doi.org/10.1080/10408398.2017.1355776
• Deloire, A. (2012). A few thoughts on grapevine training systems. Wineland Mag, 274, 82-86.
• Deloire, A., Rogiers, S., & Baeza Trujillo, P. (2022). What could be the architectural forms of future vines adapted to climate change: a new challenge! Let’s discuss the Gobelet (Bush Vine). IVES Technical Reviews, Vine and Wine. https://doi.org/10.20870/ives-tr.2022.5384
• Duchêne, E., Butterlin, G., Dumas, V., & Merdinoglu, D. (2012). Towards the adaptation of grapevine varieties to climate change: QTLs and candidate genes for developmental stages. Theoretical and Applied Genetics, 124(4), 623-635. https://doi.org/10.1007/s00122-011-1734-1
• Duchêne, E., Huard, F., & Pieri, P. (2014). Grapevine and climate change: what adaptations of plant material and training systems should we anticipate. Journal International des Sciences de la Vigne et du Vin, 3, 61-69.
• Favero, A. C., Amorim, D. A. D., Mota, R. V. D., Souza, C. R. D., & Regina, M. D. A. (2010). Physiological responses and production of 'Syrah'vines as a function of training systems. Scientia Agricola, 67, 267-273. https://doi.org/10.1590/S0103-90162010000300003
• Fraga, H., García de Cortázar Atauri, I., Malheiro, A. C., Moutinho-Pereira, J., & Santos, J. A. (2017). Viticulture in Portugal: A review of recent trends and climate change projections. OENO One, 51(2), 61–69. https://doi.org/10.20870/oeno-one.2017.51.2.1621
• Fraga, H., Santos, J. A. (2018). Vineyard mulching as a climate change adaptation measure: Future simulations for Alentejo, Portugal. Agricultural systems, 164, 107-115. https://doi.org/10.1016/j.agsy.2018.04.006
• Garcia-Tejera, O., Bonada, M., Petrie, P. R., Nieto, H., Bellvert, J., & Sadras, V. O. (2023). Viticulture adaptation to global warming: Modelling gas exchange, water status and leaf temperature to probe for practices manipulating water supply, canopy reflectance and radiation load. Agricultural and Forest Meteorology, 331, 109351.
• García-Martín, A., Aguirado, C., Paniagua, L. L., Alberdi, V., Moral, F. J., & Rebollo, F. J. (2022). Spatial Analysis of Aridity during Grapevine Growth Stages in Extremadura (Southwest Spain). Land, 11(12), 2125. https://doi.org/10.3390/land11122125
• Greer, D. H., & Weedon, M. M. (2013). The impact of high temperatures on Vitis vinifera cv. Semillon grapevine performance and berry ripening. Frontiers in plant science, 4, 491. https://doi.org/10.3389/fpls.2013.00491
• IPCC., Sixth Assessment Report: Climate change. (2022). Impacts, adaptation and vulnerability. Pörtner, H. O., Roberts, D. C., Adams, H., Adler, C., Aldunce, P., Ali, E., ... & Birkmann, J. (2022), 37-118.
• Jackson, D. I., & Lombard, P. B. (1993). Environmental and management practices affecting grape composition and wine quality-a review. American journal of enology and viticulture, 44(4), 409-430. https://doi.org/10.5344/ajev.1993.44.4.409
• Jones, G.V., & Goodrich, G.B. (2008). Influence of climate variability on wine regions in the western USA and on wine quality in the Napa Valley. Climate Research, 35, 241-254. https://doi.org/10.3354/cr00708
• Jones, G. V., Edwards, E. J., Bonada, M., Sadras, V. O., Krstic, M. P., & Herderich, M. J. (2022). Climate change and its consequences for viticulture. In Managing Wine Quality (pp. 727-778). Woodhead Publishing. ISBN 9780081020678. https://doi.org/10.1016/B978-0-08-102067-8.00015-4
• Koundouras, S., Tsialtas, I. T., Zioziou, E., Nikolaou, N. (2008). Rootstock effects on the adaptive strategies of grapevine (Vitis vinifera L. cv. Cabernet–Sauvignon) under contrasting water status: leaf physiological and structural responses. Agriculture, ecosystems & environment, 128(1-2), 86-96. https://doi.org/10.1016/j.agee.2008.05.006
• Kriedemann, P., & Smart, R. (1971). Effects of irradiance, temperature, and leaf water potential on photosynthesis of vine leaves. Photosynthetica, 5(5), 6–15.
• Laget, F., Tondut, J.-L., Deloire, A., & Kelly, M. T. (2008). Climate trends in a specific Mediterranean viticultural area between 1950 and 2006. OENO One, 42(3), 113–123. https://doi.org/10.20870/oeno-one.2008.42.3.817
• Medrano, H., Tomás, M., Martorell, S., Escalona, J., Pou, A., Fuentes, S., Flexas, J., & Bota, J. (2015). Improving water use efficiency of vineyards in semi-arid regions. A review. Agronomy for Sustainable Development, 35(2), 499 517. https://doi.org/10.1007/s13593-014-0280-z
• Metzger, M.J., Rounsevell, M. (2011). A need for planned adaptation to climate change in the wine industry PERSPECTIVE. Environmental Research Letters. 6. 031001. doi:10.1088/1748-9326/6/3/031001
• Mira de Orduña, R. (2010). Climate change associated effects on grape and wine quality and production. Food Research International, 43(7), 1844–1855. https://doi.org/10.1016/j.foodres.2010.05.001
• Molitor, D., Schultz, M., Mannes, R., Pallez-Barthel, M., Hoffmann, L., & Beyer, M. (2019). Semi-Minimal Pruned Hedge : a potential climate change adaptation strategy in viticulture. Agronomy, 9(4), 173. https://doi.org/10.3390/agronomy9040173
• Naulleau, A., Gary, C., Prévot, L., & Hossard, L. (2021). Evaluating Strategies for Adaptation to Climate Change in Grapevine Production-A Systematic Review. Frontiers in plant science, 11, 607859. https://doi.org/10.3389/fpls.2020.607859
• Palliotti, A., Tombesi, S., Silvestroni, O., Lanari, V., Gatti, M., & Poni, S. (2014). Changes in vineyard establishment and canopy management urged by earlier climate-related grape ripening: A review. Scientia Horticulturae, 178, 43-54. https://doi.org/10.1016/j.scienta.2014.07.039
• Petoumenou, D., Xyrafis, E., Dimakis, I., &Battista, F. (2017). Application of a Specific Inactivated Dry Yeast to Muscat Hamburg cultivar in a Mediterranean Climate: Effects on Vine Performance and Grape Quality. Conference: 8th International Table Grape Symposium, Foggia, Italy, 2017.
• Reynolds, A. & Heuvel, J. (2009). Influence of Grapevine Training Systems on Vine Growth and Fruit Composition: A Review. American Journal of Enology and Viticulture. 60. 251-268. 10.5344/ajev.2009.60.3.251. https://doi.org/10.5344/ajev.2009.60.3.251
• Salvi, L., Cataldo, E., & Mattii, G. B. (2017). Grapevine quality characteristics as affected by the training system. Acta Horticulturae, (1188), 113-120. https://doi.org/10.17660/ActaHortic.2017.1188.15
• Smart, R. E., Robinson, J. B., Due, G. R., & Brien, C. J. (1985). Canopy microclimate modification for the cultivar Shiraz. I. Definition of canopy microclimate. Vitis.
• Spayd, S. E., Tarara, J. M., Mee, D. L., & Ferguson, J. C. (2002). Separation of Sunlight and Temperature Effects on the Composition of Vitis vinifera cv. Merlot Berries. American Journal of Enology and Viticulture, 53(3), 171–182. https://doi.org/10.5344/ajev.2002.53.3.171
• Stavrakaki, M., Biniari, K., Daskalakis, I., & Bouza, D. (2018). Polyphenol content and antioxidant capacity of the skin extracts of berries from seven biotypes of the Greek grapevine cultivar Korinthiaki Staphis'(Vitis vinifera'L.). Australian Journal of Crop Science, 12(12), 1927-1936. https://doi.org/10.21475/ajcs.18.12.12.p1261
• Tomasi, D., Jones, G. V., Giust, M., Lovat, L., & Gaiotti, F. (2011). Grapevine Phenology and Climate Change: Relationships and Trends in the Veneto Region of Italy for 1964–2009. American Journal of Enology and Viticulture, 62(3), 329-339. https://doi.org/10.5344/ajev.2011.10108
• van Leeuwen, C. van, Barbe, J.-C., Darriet, P., Geffroy, O., Gomès, E., Guillaumie, S., Helwi, P., Laboyrie, J., Lytra, G., Menn, N. L., Marchand, S., Picard, M., Pons, A., Schüttler, A., & Thibon, C. (2020). Recent advancements in understanding the terroir effect on aromas in grapes and wines. OENO One, 54(4), 985–1006. https://doi.org/10.20870/oeno-one.2020.54.4.3983
• van Leeuwen, Destrac-Irvine, Dubernet, Duchêne, Gowdy, Marguerit, Pieri, et al. (2019a). An Update on the Impact of Climate Change in Viticulture and Potential Adaptations. Agronomy, 9(9), 514. MDPI AG. Retrieved from http://dx.doi.org/10.3390/agronomy9090514
• van Leeuwen, C., Pieri, P., Gowdy, M., Ollat, N., & Roby, J.-P. (2019b). Reduced density is an environmental friendly and cost effective solution to increase resilience to drought in vineyards in a context of climate change. OENO One, 53(2), 129–146. https://doi.org/10.20870/oeno-one.2019.53.2.2420
• Van Zyl, J.L., & Van Huyssteen, L. (1980). Comparative studies on wine grapes on different trellising systems. 1. Consumptive water use. South African Journal of Enology and Viticulture. 1:7-14. https://doi.org/10.21548/1-1-2409
• Venios, X., Korkas, E., Nisiotou, A., Banilas, G. (2020) Grapevine Responses to Heat Stress and Global Warming. Plants (Basel). 11;9(12):1754. doi: 10.3390/plants9121754. https://doi.org/10.3390/plants9121754
• Williams, L. E., & Araujo, F. J. (2002). Correlations among predawn leaf, midday leaf, and midday stem water potential and their correlations with other measures of soil and plant water status in Vitis vinifera. Journal of the American Society for Horticultural Science, 127(3), 448-454. https://doi.org/10.21273/JASHS.127.3.448
• Wu, J., Drappier, J., Hilbert, G., Guillaumie, S., Dai, Z., Geny, L., Delrot, S., Darriet, P., Thibon, C., & Pieri, P. (2019). The effects of a moderate grape temperature increase on berry secondary metabolites. OENO One, 53(2), 321–333. https://doi.org/10.20870/oeno-one.2019.53.2.2434
• Xyrafis, E. G., Deloire, A., Petoumenou, D., Paraskevopoulos, I., & Biniari, K. (2021). The unique and extreme vineyards of Santorini Island (Cyclades): Original language of the article: English. IVES Technical Reviews, vine and wine. https://doi.org/10.20870/IVES-TR.2021.4848
• Xyrafis, E. G., Fraga, H., Nakas, C. T., & Koundouras, S. (2022). A study on the effects of climate change on viticulture on Santorini Island. OENO One, 56(1), 259-273. https://doi.org/10.20870/oeno-one.2022.56.1.4843