Impact of Cluster Thinning on Wine Grape Yield and Fruit Composition: A Review and Meta-Analysis
Table 1
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 timing of cluster thinning application.
Acronym
Parameter
Alteration by CT
Bloom (B)
Pea-size (PS)
Lag phase (LP)
Veraison (V)
n sign. (% sign.)b
n
n sign. (% sign.)
n
n sign. (% sign.)
n
n sign. (% sign.)
Production parameters
Yield
Yield (kg/vine)
Increased
40
0 (0%)
120
2 (1.67%)
32
0 (0%)
96
0 (0%)
Decreased
23 (57.5%)
81 (67.5%)
24 (75.0%)
70 (72.9%)
LA:Y
Leaf-area/yield (cm2/g)
Increased
5
3 (60.0%)
13
7 (53.8%)
15
11 (73.3%)
27
19 (70.4%)
Decreased
0 (0%)
0 (0%)
0 (0%)
0 (0%)
BW
Berry weight (g)
Increased
37
14 (37.8%)
78
19 (24.4%)
25
4 (16.0%)
69
7 (10.1%)
Decreased
0 (0%)
1 (1.28%)
2 (8.00%)
6 (8.70%)
Fruit composition parameters
TSS
Total soluble solids (°Brix)
Increased
48
24 (50.0%)
109
54 (49.5%)
40
23 (57.5%)
99
42 (42.4%)
Decreased
1 (2.10%)
19 (17.4%)
1 (2.50%)
2 (2.00%)
pH
pH
Increased
30
10 (33.3%)
80
38 (47.5%)
37
18 (48.6%)
76
28 (36.8%)
Decreased
1 (3.33%)
8 (10.0%)
1 (2.70%)
3 (3.95%)
TA
Titratable acidity (g/L)
Increased
31
0 (0%)
42
0 (0%)
45
0 (0%)
81
0 (0%)
Decreased
11 (35.5%)
16 (38.1%)
12 (26.6%)
26 (32.1%)
ANT1
Total anthocyanins (mg/100 g) berry FW
Increased
11
3 (27.3%)
31
14 (45.2%)
16
10 (62.5%)
27
12 (44.4%)
Decreased
0 (0%)
0 (0%)
0 (0%)
0 (0%)
ANT2
Total anthocyanins (mg/L)
Increased
3
1 (33.3%)
10
5 (50.0%)
4
0 (0%)
26
16 (61.5%)
Decreased
0 (0%)
0 (0%)
0 (0%)
0 (0%)
PHE1
Total phenolics (mg/100 g) skin FW
Increased
1
1 (100%)
3
2 (66.7%)
4
2 (50.0%)
4
2 (50%)
Decreased
0 (0%)
0 (0%)
0 (0%)
0 (0%)
PHE2
Total phenolics (mg/L)
Increased
7
5 (71.4%)
4
4 (100%)
4
3 (75.0%)
18
8 (44.4%)
Decreased
0 (0%)
0 (0%)
0 (0%)
0 (0%)
aNumber of observations compared between CN and CT at either B, PS, LP, or V. bNumber of observations where CT was significantly larger or smaller () than CN using statistical analysis provided in individual studies.
