Intra-plot, and intra-plant variability in a vineyard of Catarratto Lucido (Vitis vinifera L.) in Sicily

Dipartimento Scienze Agrarie Alimentari e Forestali (SAAF), Università degli studi di Palermo

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Abstract

Understanding intra-plot to intra-plantvariability is essential for optimizing grape maturity monitoring, harvest time, and sampling protocols. This study investigates the importance of intra-plant variability in grapevine sampling and evaluates whether it should be integrated into protocols to enhance accuracy and improve vineyard management. The study was conducted in a commercial vineyard in the Alcamo PDO area, Sicily, using 24 Catarratto Lucido vines. These vines were categorized into high-vigor (HV) and low-vigor (LV) groups based on Normalized Difference Vegetation Index (NDVI) analysis. Intra-plant variability was assessed for key grape characteristics, including Total Soluble Solids (TSS), pH, acidity, and bunch weight, across different spur, node, and bunch positions. Overall, node position significantly reduced bunch acidity (β=−0.310; p=0.0382), spur position negatively impacted TSS (β=−0.78; p=0.0317), and bunch weight was significantly higher on basal bunches (A) than apical ones (B)(β=−65.642; p<0.0001). Conversely, no significant positional effects were identified in LV vines. Our findings indicate limited intra-plant variability, but these observations require confirmation through multi-year studies including climatic and physiological parameters.