The aim of this thesis was to investigate and compare the effects of grapevine defoliation on the physicochemical and sensory quality parameters of grapes based on a review of relevant scientific and professional literature. A descriptive and critical review of the scientific literature was conducted. In the context of ongoing climate change, recommendations regarding defoliation as an ampelotechnical practice are undergoing significant change. Whereas the primary objective of defoliation was traditionally to increase solar radiation exposure within the grape cluster zone, its purpose and effects may vary considerably depending on the timing and intensity of defoliation, grapevine cultivar, and site-specific climatic and growing conditions. The literature review demonstrated that both grapevine cultivar and climatic conditions have a major influence on the optimal timing of defoliation. The thesis focuses particularly on research findings concerning grapevine defoliation in Switzerland, Croatia, Greece, and Australia. The results indicate that defoliation is an important ampelotechnical practice that allows grape growers to directly modify the microclimate of the grape cluster zone. However, its overall effectiveness is not universal, and is highly dependent on the timing and intensity of its application, as well as on the specific characteristics of the grapevine cultivar and growing site. Consequently, defoliation represents an important vineyard management practice that requires careful consideration and appropriate adjustment to prevailing climatic conditions, cultivar characteristics, and site-specific conditions.
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