Particle film treatments on 'Assyrtiko' grapevines enhance physiology and grape attributes in Santorini Island

Like many viticultural regions of the Mediterranean region, Santorini is also affected by climate change. These changing climatic conditions pose challenges to adapt the island's traditional viticulture practices to the new climatic conditions of climate change, which will intensify in the future, with the use of short- and longterm solutions with a sustainable manner respecting the tradition and the island's landscape. Viticulture in this region copes with high temperatures, heat waves and drought which affect the maturity process, the technological maturity, as well as the physiology of the grapevine. The aim of this study was to investigate the effects of kaolin and calcium carbonate foliar application on water relations, photosynthesis and berry composition of vines of grape cultivar 'Assyrtiko', trained with the traditional training system 'Kouloura', under drought conditions and vertical shoot positioned training system in Santorini. The effects of foliar application with kaolin and CaCO3 on vines of grape cultivar 'Assyrtiko' were evaluated, focusing on the impact on the vine's physiology attributes, grape quality, and environmental sustainability. Based on the results of the present study, there were statistically significant differences on vine water stress where the foliar application of inert films reduced water stress during the three studied years. Kaolin and CaCO3 increased significantly the photosynthesis and stomatal conductance of the vines in comparison to the control. Furthermore, the foliar application with inert minerals has reduced sunburn and pest damage. The results of the present study confirm that the application of kaolin and CaCO3 constitutes an effective and economical solution for the water saving of the vines in dry conditions, while at the same time, it can improve the physiology of the plant and preserve the qualitative and quantitative attributes of the grapes. The foliar use of inert particle films on Santorini's traditional vineyards could consist a sustainable and effective alternative to mitigate the effects of climate change which have intensified over the last decades in the region.