Combining xylogenesis and modelling to identify environmental drivers of wood formation in ‘Greco’ grapevine in a Mediterranean vineyard

Climate change poses a significant threat to viticulture, especially in Mediterranean regions, highlighting the need for a deeper understanding of grapevine physiological responses to environmental stressors. Wood formation records environmental signals, yet it remains largely unstudied in woody horticultural crop species. This study provides the first detailed analysis of xylogenesis in Vitis vinifera L. ‘Greco’ and proposes a novel modelling approach to interpret data and identify the main environmental drivers in wood formation. Cambial activity and xylem cell production were monitored in vines cultivated in a rainfed vineyard in Southern Italy throughout the 2022 growing season. Vines were subjected to different soil management strategies: cover cropping (C), natural grassing (N) and tillage (T). A Multivariable Fractional Polynomial (MFP) model was employed to identify environmental factors associated with the different phases of xylogenesis, identified and quantified through microscopy and digital image analysis: cambial cells (CC), post-cambial enlarging cells (PC), cells in secondary wall thickening (SW) and mature cells (MT). Our results revealed a bimodal pattern of cambial activity across all treatments, with vines under tillage showing the widest final growth-ring width. The MFP model revealed that distinct environmental factors are associated with the different phases of xylogenesis. The number of CC was explained by solar radiation. The width of the PC zone was co-driven by solar radiation (53%), humidity (27%), and soil moisture (20%). The SW phase was predominantly and negatively influenced by wind speed (86%). Finally, the MT phase was mainly related to solar radiation (64%) and soil temperature (28%). This study indicates that combining xylogenesis with a modelling approach helps the identification of possible environmental drivers in wood formation in grapevine. These findings highlight the high sensitivity of grapevine to specific micro-environmental variables and can aid in developing the potential of dendro-agronomy as a powerful diagnostic tool for assessing climate impacts in woody crops.