Abstract
Background and Aims Postveraison limitation of canopy photosynthesis delays grape berry ripening and reduces sugar accumulation, thus lowering the alcohol content of the subsequent wines. This study was designed to evaluate whether similar results could be obtained by defoliation apical to the bunch zone using a leaf-plucking machine when berry sugar content was approximately 16–17°Brix. Methods and Results In 2011 and 2012, defoliation treatments were applied postveraison to cv. Sangiovese vines (D) on either side of each row using a mechanical leaf remover, and these D vines were compared to a nondefoliated control (C). The machine removed 35% of the leaves on the vine and created a 50-cm vertical window without leaves above the bunch area, but retained a few leaves at the canopy apex (about 0.50 m2/vine). In both years, leaf removal reduced the rate of berry sugar accumulation and led to a 1.2 lower harvest °Brix and consequently, a lower wine alcohol (−0.6%) content in D relative to that of C vines. In 2012, sugar content of D vines, monitored in a group of vines that was not harvested, had recovered to that of C vines 2 weeks after harvest. The concentration of total phenolic compounds in the grapes, the chemical and chromatic characteristics of the wines and the replenishment of soluble sugars, starch and total nitrogen in the canes and roots were similar in the D and C vines. Conclusion To achieve an effective delay in sugar accumulation in the berries, leaves should be removed at 16–17°Brix, and at least 30–35% of vine leaf area should be removed. Significance of the Study Mechanical removal of leaves postveraison above the bunch zone of Sangiovese can be an easy and economically viable technique for delaying sugar accumulation in the berries and for limiting the alcohol content of wines with no negative impact on desirable composition of either berries or wines.
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Claims 12
Claim · model-written summary
Mechanical leaf removal removed 35% of Sangiovese vine leaves.
- Taxon
- Sangiovese (Vitis vinifera L.) grapevines
Vitis viniferat0 - Outcome
- leaves on the vinee0
- Value
- 35%e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The machine removed 35% of the leaves on the vine and created a 50-cm vertical window without leaves above the bunch area”
t0“Sangiovese (Vitis vinifera L.) grapevines”
Claim · model-written summary
Mechanical leaf removal created a 50-cm window above the bunch area.
- Taxon
- Sangiovese (Vitis vinifera L.) grapevinesVitis viniferat0
- Outcome
- vertical window without leavese0
- Value
- 50-cme0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The machine removed 35% of the leaves on the vine and created a 50-cm vertical window without leaves above the bunch area”
t0“Sangiovese (Vitis vinifera L.) grapevines”
Claim · model-written summary
Leaf removal reduced berry sugar accumulation rate in both years.
- Taxon
- Sangiovese (Vitis vinifera L.) grapevinesVitis viniferat0
- Treatment
- leaf removale0
- Outcome
- rate of berry sugar accumulatione0
- Direction
- reducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In both years, leaf removal reduced the rate of berry sugar accumulation”
t0“Sangiovese (Vitis vinifera L.) grapevines”
Claim · model-written summary
Leaf removal lowered harvest Brix by 1.2 relative to controls.
- Taxon
- Sangiovese (Vitis vinifera L.) grapevinesVitis viniferat0
- Treatment
- De0
- Outcome
- harvest °Brixe0
- Direction
- lowere0
- Value
- 1.2e0
- Comparator
- C vinese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“led to a 1.2 lower harvest °Brix and consequently, a lower wine alcohol (−0.6%) content in D relative to that of C vines.”
t0“Sangiovese (Vitis vinifera L.) grapevines”
Claim · model-written summary
Leaf removal lowered wine alcohol content by 0.6% relative to controls.
- Taxon
- Sangiovese (Vitis vinifera L.) grapevinesVitis viniferat0
- Treatment
- De0
- Outcome
- wine alcohole0
- Direction
- lowere0
- Value
- −0.6%e0
- Comparator
- C vinese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“led to a 1.2 lower harvest °Brix and consequently, a lower wine alcohol (−0.6%) content in D relative to that of C vines.”
t0“Sangiovese (Vitis vinifera L.) grapevines”
Claim · model-written summary
Sugar content in unharvested defoliated vines recovered to control levels two weeks after harvest.
- Taxon
- Sangiovese (Vitis vinifera L.) grapevinesVitis viniferat0
- Treatment
- D vinese0
- Outcome
- sugar contente0
- Direction
- recoverede0
- Qualifier
- 2 weeks after harveste0
- Comparator
- C vinese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In 2012, sugar content of D vines, monitored in a group of vines that was not harvested, had recovered to that of C vines 2 weeks after harvest.”
t0“Sangiovese (Vitis vinifera L.) grapevines”
Claim · model-written summary
Grape total phenolic concentration was similar between defoliated and control vines.
- Taxon
- Sangiovese (Vitis vinifera L.) grapevinesVitis viniferat0
- Treatment
- De0
- Outcome
- concentration of total phenolic compounds in the grapese0
- Direction
- similare0
- Comparator
- C vinese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The concentration of total phenolic compounds in the grapes, the chemical and chromatic characteristics of the wines and the replenishment of soluble sugars, starch and total nitrogen in the canes and roots were similar in the D and C vines.”
t0“Sangiovese (Vitis vinifera L.) grapevines”
Claim · model-written summary
Wine chemical and chromatic characteristics were similar between groups.
- Taxon
- Sangiovese (Vitis vinifera L.) grapevinesVitis viniferat0
- Treatment
- De0
- Outcome
- chemical and chromatic characteristics of the winese0
- Direction
- similare0
- Comparator
- C vinese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The concentration of total phenolic compounds in the grapes, the chemical and chromatic characteristics of the wines and the replenishment of soluble sugars, starch and total nitrogen in the canes and roots were similar in the D and C vines.”
t0“Sangiovese (Vitis vinifera L.) grapevines”
Claim · model-written summary
Cane and root soluble sugar, starch and nitrogen replenishment was similar between groups.
- Taxon
- Sangiovese (Vitis vinifera L.) grapevinesVitis viniferat0
- Treatment
- De0
- Outcome
- replenishment of soluble sugars, starch and total nitrogen in the canes and rootse0
- Direction
- similare0
- Comparator
- C vinese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The concentration of total phenolic compounds in the grapes, the chemical and chromatic characteristics of the wines and the replenishment of soluble sugars, starch and total nitrogen in the canes and roots were similar in the D and C vines.”
t0“Sangiovese (Vitis vinifera L.) grapevines”
Claim · model-written summary
Authors recommend removing leaves at 16–17°Brix for an effective delay in berry sugar accumulation.
- Taxon
- Sangiovese (Vitis vinifera L.) grapevinesVitis viniferat0
- Outcome
- leaves should be removed at 16–17°Brixe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“To achieve an effective delay in sugar accumulation in the berries, leaves should be removed at 16–17°Brix”
t0“Sangiovese (Vitis vinifera L.) grapevines”
Claim · model-written summary
Authors recommend removing at least 30–35% of vine leaf area.
- Taxon
- Sangiovese (Vitis vinifera L.) grapevinesVitis viniferat0
- Outcome
- at least 30–35% of vine leaf area should be removede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“at least 30–35% of vine leaf area should be removed.”
t0“Sangiovese (Vitis vinifera L.) grapevines”
Claim · model-written summary
Mechanical postveraison leaf removal was judged an easy and economically viable technique for delaying berry sugar accumulation and limiting wine alcohol.
Verbatim
e0“Mechanical removal of leaves postveraison above the bunch zone of Sangiovese can be an easy and economically viable technique for delaying sugar accumulation in the berries and for limiting the alcohol content of wines with no negative impact on desirable composition of either berries or wines.”
The same questions in other papers
pruning · molecular: metabolites · Vitis vinifera (wine grape)Results differ
36 papers in the same direction as this paper · 15 in the opposite direction
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