Impact of Cluster Thinning on Wine Grape Yield and Fruit Composition: A Review and Meta-Analysis

Table 4

Impact of cluster thinning severity on dependent variables.

Parameter	25% (±10%)^b		45% (±10%)		65% (±10%)		value (trt)^c
	CN^b	CT	CN	CT	CN	CT
Production parameters
Yield (kg/vine)		3.61 ± 0.258	4.83 ± 0.329	3.14 ± 0.264	4.87 ± 0.492	2.81 ± 0.362	<0.001
Leaf area/yield (cm^2/g)	14.4 ± 1.44	18.6 ± 2.41	16.6 ± 1.54	26.4 ± 2.60	16.1 ± 2.60	26.1 ± 4.35	<0.001
Berry weight (g)	1.58 ± 0.059	1.61 ± 0.071	1.54 ± 0.040	1.56 ± 0.041	1.30 ± 0.095	1.39 ± 0.144	0.298
Fruit composition parameters
Total soluble solids (°Brix)	21.6 ± 0.420	21.8 ± 0.411	22.4 ± 0.234	23.2 ± 0.206	21.8 ± 0.484	21.5 ± 0.530	0.026
pH	3.31 ± 0.043	3.37 ± 0.049	3.46 ± 0.027	3.53 ± 0.028	3.47 ± 0.035	3.49 ± 0.037	0.035
Titratable acidity (g/L)	7.92 ± 0.467	7.71 ± 0.479	6.34 ± 0.277	6.18 ± 0.268	7.83 ± 0.611	8.00 ± 0.532	0.341
Total anthocyanins (mg/kg) FW berry	1456 ± 68.9	1712 ± 151	1109 ± 127	1236 ± 146	—	—	0.184

^aData are expressed as means ± standard error. Bold values highlight significant difference () between CN and CT treatments within each severity (25%, 45%, and 65%) using an independent-samples t-test. ^bCN, untreated control; CT, cluster thinning. ^cComparison between CN and CT treatments using data from all time points ().