Table 1.

Chemical and colorimetric properties of wine samples from ‘Cabernet Sauvignon’ grapevines subjected to different photoselective shade film treatments in a vineyard in Oakville, CA, USA in two growing seasons (2020 and 2021).

	2020							2021					Y	Y x S
Wine color parameters	C0	D1	D3	D4	D5	p-value	C0	D1	D3	D4	D5	p-value
CI	12.8 a ±0.2c	15.1±0.9 ab	14.4±0.2bc	16.2±0.3 a	14.1±0.7bc	*	15.3±0.2 b	15.4±0.1 b	15.7±0.0 b	16.6±0.5a	15.7±0.1 b	*	***	.
hue	0.62±0.00a	0.61±0.00a	0.59±0.00b	0.63±0.01 a	0.61±0.01a	*	0.61±0.01	0.62±0.01	0.63±0.01	0.63±0.01	0.63±0.01	ns	**	*
% Polymeric anthocyanins	37.5±0.8b	38.2±0.6ab	37.0±0.6 b	41.5±1.0 a	36.2±2.0 b	.	27.9±0.4 b	28.8±0.7 ab	30.2± 0.6b	29.3± 0.3 a	29.4±0.3 b	.	***	*
TPI (AU)	47.1±1.2b	54.8± 2.9a	48.2± 0.9 b	55.1± 2.0 a	50.9±0.3ab	*	55.8± 2.6 b	64.2±1.3 ab	64.9±5.1 ab	74.4± 3.9 a	63.7±3.2 ab	*	***	ns
Chemical characteristics
Alcohol content (%)	14.7±0.09c	15.2±0.05ab	15.2±0.03b	15.4±0.10 a	15.1±0.05b	***	15.3± 0.01	15.2 ± 0.07	15.3 ± 0.13	15.5 ± 0.17	15.3 ± 0.17	ns	**	.
Residual sugar (g/L)	0.19±0.02b	0.30±0.02a	0.26±0.01a	0.27±0.02a	0.26±0.00a	*	0.07±0.02	0.05±0.00	0.05±0.01	0.06±0.01	0.05±0.01	ns	***	**
pH	3.66±0.01a	3.64± 0.01a	3.61±0.01b	3.66±0.00a	3.66±0.00a	***	3.65±0.02c	3.69±0.01b	3.72±0.01b	3.76±0.01a	3.75±0.00 a	***	***	***
Titratable acidity (g/L)	5.45±0.04b	5.43±0.08b	5.65±0.07a	5.49±0.03ab	5.41±0.01b	.	6.12±0.01a	5.97±0.01bc	6.06±0.05ab	5.85±0.06c	6.08±0.06ab	**	***	*

^aValues represent means ± (n = 3) separated by Duncan’s new multiple range post-hoc text at (α = 0.05). Means separated by different letters are significantly different within each year. AU : absorbance units, CI: Color intensity, TPI: total polyphenol index. Significance or non-significance for shade treatment, year (Y) and interactions between year and shade treatment (Y*S) are indicated by: ‘ns’= not significant; ‘.’ p≤0.1; ‘*’ p≤0.05; ‘**’ p≤ 0.01; ‘***’ p≤0.001.