Impact of Cluster Thinning on Wine Grape Yield and Fruit Composition: A Review and Meta-Analysis
Table 3
Listing of dependent production and fruit composition parameters, as well as the total number of observations (n) and percentage of significant observations for each parameter by severity of cluster thinning application.
Acronym
Parameter
Alteration by CT
Low (∼25%)
Moderate (∼45%)
High (∼65%)
n sign. (% sign.)b
n
n sign. (% sign.)
n
n sign. (% sign.)
Production parameters
Yield
Yield (kg/vine)
Increased
41
0 (0%)
94
0 (0%)
19
0 (0%)
Decreased
26 (63.4%)
83 (88.3%)
16 (84.2%)
LA:Y
Leaf-area/yield (cm2/g)
Increased
4
2 (50.0%)
26
22 (84.6%)
2
1 (50.0%)
Decreased
0 (0%)
0 (0%)
0 (0%)
BW
Berry weight (g)
Increased
18
1 (5.55%)
85
17 (20.0%)
7
2 (28.6%)
Decreased
1 (5.55%)
4 (4.71%)
0 (0.00%)
Fruit composition parameters
TSS
Total soluble solids (°Brix)
Increased
32
6 (18.8%)
103
47 (45.6%)
15
0 (0.00%)
Decreased
5 (15.6%)
1 (1.00%)
3 (20.0%)
pH
pH
Increased
28
8 (28.6%)
89
30 (33.7%)
15
1 (6.67%)
Decreased
1 (3.57%)
2 (2.25%)
0 (0.00%)
TA
Titratable acidity (g/L)
Increased
28
1 (3.57%)
89
7 (7.87%)
15
0 (32.1%)
Decreased
7 (25.0%)
22 (24.7%)
1 (6.67%)
ANT1
Total anthocyanins (mg/100 g) berry FW
Increased
6
2 (33.3%)
39
20 (51.3%)
0
n.a
Decreased
0 (0%)
1 (2.56%)
n.a
ANT2
Total anthocyanins (mg/L)
Increased
5
0 (0%)
28
11 (0%)
1
0 (0%)
Decreased
0 (0%)
0 (0%)
0 (0%)
PHE1
Total phenolics (mg/100 g) skin FW
Increased
1
1 (100%)
14
6 (42.9%)
0
n.a
Decreased
0 (0%)
0 (0%)
n.a
PHE2
Total phenolics (mg/L)
Increased
0
n.a
8
6 (75.0%)
0
n.a
Decreased
n.a
0 (0%)
n.a
aNumber of observations compared between CN and CT at either low, moderate, or high severity levels. bNumber of observations where CT was significantly larger or smaller () than CN using statistical analysis provided in individual studies.
