RT Journal Article SR Electronic T1 Effects of Cluster Thinning and Preflowering Leaf Removal on Growth and Grape Composition in cv. Sangiovese JF American Journal of Enology and Viticulture JO Am. J. Enol. Vitic. FD American Society for Enology and Viticulture SP 325 OP 332 DO 10.5344/ajev.2012.11118 VO 63 IS 3 A1 Matteo Gatti A1 Fabio Bernizzoni A1 Silvia Civardi A1 Stefano Poni YR 2012 UL http://www.ajevonline.org/content/63/3/325.abstract AB Crop-regulation techniques applied as preflowering defoliation (D), early cluster thinning at preflowering (ECT), and cluster thinning at lag-phase of berry growth (LCT) were tested over three seasons on high-yielding Vitis vinifera L. Sangiovese and compared to non-defoliated, unthinned control vines. Treatment severity consisted of removing primary leaves and any laterals developed from nodes 1 to 6 in D and of thinning 50% of clusters chosen from among distal clusters or those inserted on weak shoots in ECT and LCT plots. Although yield per vine was not as reduced in D (−32%) as in ECT and LCT treatments (−45%) as compared to the control, D vines also had largely improved sugar and total anthocyanin concentrations and the highest total phenolics. Yield components were also markedly affected by treatments: D vines had smaller clusters and berries, leading to improved cluster looseness and to higher relative skin and seed growth. While all crop-regulating treatments led to an increase in the final leaf-to-fruit ratio, parameters of technological maturity were essentially uncoupled, as equally high Brix levels corresponded to the highest titratable acidity in D and, conversely, to lowest titratable acidity and highest pH in ECT and LCT. Overall results showed that different final yield-grape composition patterns can be reached depending on the technique used for crop regulation as a primary consequence of a diversified degree of compensation triggered on single-yield components.