RT Journal Article SR Electronic T1 Impact of Prebloom and Fruit Set Basal Leaf Removal on the Flavonol and Anthocyanin Composition of Tempranillo Grapes JF American Journal of Enology and Viticulture JO Am. J. Enol. Vitic. FD American Society for Enology and Viticulture SP 367 OP 376 DO 10.5344/ajev.2012.11116 VO 63 IS 3 A1 María P. Diago A1 Belén Ayestarán A1 Zenaida Guadalupe A1 Stefano Poni A1 Javier Tardáguila YR 2012 UL http://www.ajevonline.org/content/63/3/367.abstract AB The influence of timing and method of basal defoliation on the profile and content of anthocyanins and flavonols in Tempranillo grapes was investigated. Basal leaf removal was manually and mechanically performed at two phenological stages, prebloom and fruit set. Phenolic composition was determined in grape extracts by HPLC-UV-Vis and 13 anthocyanin and flavonol compounds were identified and quantified. Regardless of the timing and method of defoliation, basal leaf removal led to more ripened fruit in terms of higher soluble solids and reduced acidity and favored the accumulation of flavonols and anthocyanins, which was related to the increase in total leaf area per yield observed in defoliated vines. For anthocyanins, there was a significant relationship between their concentrations and the larger relative skin mass observed in berries of defoliated vines. In general, the enhancement in flavonols and anthocyanins observed in berries from basal-defoliated vines tended to be greater when defoliation was conducted mechanically; yet overall, no evident differences between prebloom and fruit-set defoliation were found.