International Journal of Horticulture, 2025, Vol.15, No.3, 133-142 http://hortherbpublisher.com/index.php/ijh 135 3.2 Training systems Training systems are designed to shape the grapevine canopy to optimize sunlight exposure and air circulation, which are critical for grape development and disease prevention. Different training systems, such as the Ruakura Twin Two Tier and the Te Kauwhata Three Tier, have been shown to influence canopy architecture and microclimate, thereby affecting yield and fruit composition (Smart et al., 2017). These systems help manage the spatial arrangement of shoots and leaves, reducing shading and promoting uniform ripening of grapes. By adjusting the geometry of the vineyard, training systems can also mitigate the effects of environmental factors, such as temperature and humidity, on grape quality (Pascual et al., 2015). 3.3 Leaf removal practices Leaf removal is a canopy management practice that involves the strategic removal of leaves to improve light exposure and air flow within the canopy. This technique is particularly effective in reducing the incidence of diseases like Botrytis cinerea by decreasing humidity around the fruit clusters (Wang et al., 2019; Mataffo et al., 2023). Leaf removal can be performed at different stages of grape development, such as pre-flowering or pre-veraison, to influence berry composition and ripening (Figure 2) (Gregory et al., 2020; Verdenal et al., 2024). The removal of leaves can also affect the photosynthetic capacity of the vine, which in turn impacts the sugar accumulation and overall quality of the grapes. By carefully managing leaf area, growers can enhance the microclimate of the canopy, leading to improved grape quality and yield. Figure 2 Examples of the hydraulic buffering that occurs at veraison in grapevine (Adopted from Gregory et al., 2020) Image caption: When a vine is subjected to water deficit, pre-veraison berries (i.e. green berries) are sensitive to drought-induced shriveling, and berries that are either undergoing veraison (A, B, reddish-green berries) or post-veraison (C, purple berries) are insensitive. Vines shown are under a very severe water deficit (Ψ stem<−1.5 MPa). Photos courtesy of Markus Keller (Adopted from Gregory et al., 2020) 3.4 Shoot positioning and thinning Shoot positioning and thinning are critical components of canopy management that help control vine vigor and improve the light environment within the canopy. Proper shoot positioning ensures that shoots are evenly distributed and oriented to maximize sunlight interception, which is essential for photosynthesis and fruit development (Wang et al., 2019). Shoot thinning, on the other hand, involves the removal of excess shoots to reduce canopy density and improve air circulation, which can help prevent disease and promote uniform ripening
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