17th International Symposium GiESCO 2011 - Università degli Studi ...

Corrigenda to Proceedings GiESCO 2011
We apologize for errors that arose during the editing process despite our careful vigilance.
Pag. 488 - fig. 7
Pag. 507 – entire text
ROLE OF LEAF REMOVAL ON GRAPE QUALITY OF SAUVIGNON AND
GRECHETTO CULTIVARS IN UMBRIA
Leonardo VALENTI 1* , Filippo CARLETTI 2 , Fulvio MATTIVI 3 , Isabella GHIGLIENO 1 , Mattia DELL’ORTO 1 ,
Michele BRAVI 1
1 Università degli Studi di Milano, Facoltà di Agraria, Dipartimento di Produzione Vegetale, via Celoria 2, 20133, MILANO, Italy
2 Arnaldo Caprai società agricola s.r.l., Loc. Torre, 06036, Montefalco (PG); Italy
3 Centro ricerca ed innovazione IASMA, Fondazione Edmund Mach, via E. Mach 1, 38010, San Michele all’Adige (TN), Italy
* Corresp. author: Leonardo Valenti, Tel. 0250316562, Fax 0250316553, Email: leonardo.valenti@unimi.it.
Summary
The shading of the productive belt produces clusters with
minor sugar contents and higher acidity. Further it creates
optimal conditions for the establishment of Botrytis cinerea. The
present work aims to analyze the effects of leaf removal on
Sauvignon blanc and Grechetto with three different ways of
defoliation (leaf removal to east, west and total) in addition to the
control test (no defoliation). The study was carried out in the
vineyard “Arnaldo Caprai, Montefalco” (PG) and consisted in
collecting data during the period from 2007 to 2010 (for
Grechetto only in 2007, 2009 and 2010). In the vineyards which
are located on a plain, a spurred cordon system was applied, the
rows were north-south orientated and cover cropping was made
on soil. For each year the main vegetative–productive and
analytical parameters, as well as the polyphenolic content of
grapes, have been observed; for each thesis of 2010 the curves of
technological and polyphenolical ripening were identified, with
the aim to better understand the course of those components,
because they may cause oxidation in wines, above all in the white
ones, leading to browning and aroma losses.
From the years' average resulted that in Grechetto the not-
defoliated vines had the highest average cluster weight with a
medium sugar content, a good level of acidity and the lowest pH.
It could be further seen that in 2010 in Grechetto the notdefoliated
vines recorded the highest quantity of malic acid
together with the west-defoliated ones; from a polyphenolical
mg/kg
3000
2000
1000
0
Cab. Sau. P. Verdot L.
Salamino
Syrah
Extr. skin pfl (mg/kg) 2008 Extr. skin pfl (mg/kg) 2010
Extr. seed pfl (mg/kg) 2008 Eztr. seed pfl (mg/kg) 2010
point of view, west defoliation maintains a constant percentage of
polyphenols in skins during the three years of observation, even
if sometimes the quantities are low. Sauvignon with east
defoliation shows a good sugar and acidity level, maintaining a
medium–low pH; in addition east defoliation leads to a reduced
percentage of polyphenols in skins in 2008 and 2010, whereas the
control test presents in every year medium–low levels of all the
analytical parameters.
INTRODUCTION
Times and effects of leaf removal: generally, this
operation is made between flowering and veraison with the
primary purpose of improving the lighting and the aeration
of grapes (Poni, 2006). In practice, leaf removal can be
also made before vintage, facilitating ripening, improving
plant resistance to pests and accelerating harvesting
(Valenti, 1997); many studies have demonstrated that early
defoliation can lead to a reduction of sugars, an increase of
acidity (Eynard and Dalmasso, 1993) and, further, to a
drop of fruits and a reduction of bud fertility (Candolfi-
Vasconcelos and Koblet, 1990). Some studies (Eberle and
Persano, 2006) have shown that premature loss of leaves
reduces the phenomenon of burns, because the plant is able
to react by growing out new leaves from secondary shoots,
creating a kind of covering, though only partially.
Last update Sept. 9 th 2011