Article Figures & Data
Figures
- Figure 1
Schematic representation of the three shoot light exposure treatments used in Thompson Seedless vines. B: buffer vines; E: experimental vines.
- Figure 2
Schematic representation of the four shoot light exposure treatments used in Flame Seedless, Chardonnay, and Cabernet Sau-vignon vines. B: buffer vines; E: experimental vines.
- Figure 3
Potential fruitfulness expressed as integrated fruitfulness index (IFI) by cultivar, shoot light exposure level, and node position (treatment means). IFI is the sum of average maximum diameters of all inflorescence primordia (mm) when dissected during dormancy. Standard error bars at 95% confidence.
- Figure 4
Potential fruitfulness of Thompson Seedless expressed as mean inflorescence primordia per node. Values are averages for each node across shoot light exposure treatments. QSI: quantum scalar irradiance.
- Figure 5
Contribution of secondary buds to potential fruitfulness per node by cultivar, shoot light exposure level, and node position (treatment means). Standard error bars at 95% confidence.
- Figure 6
Integrated fruitfulness (as integrated fruitfulness index) response curves to midday quantum scalar irradiance (QSI) for all cultivars. Symbols are averages by light level and node position. Only node positions 5 to 15 are considered in Thompson Seedless. Above-canopy QSI levels were ~2,000 μmol m−2 s−1. Regressions (p < 0.0001 for all): Chardonnay [y = (134.1x)/(93.8+x)+0.0911x]; Cabernet Sauvignon [y = 165.54-(8618.98)/((1+0.44x)1/0.89)]; Flame Seedless [y = (50.94x)/(21.7+x)+0.054x]; Thompson Seedless [y = 58.8-(48.81)/((1+0.0001x)1/0.021)].
- Figure 7
Potential fruitfulness expressed as percent bud fruitfulness by cultivar, shoot light exposure level, and node position (treatment means). Standard error bars at 95% confidence.
- Figure 8
Potential fruitfulness (as integrated fruitfulness index) response curves of Flame Seedless to midday quantum scalar irradiance (QSI). Open circles represent data from individual buds (mean of eight dates for each bud). Closed circles are averages by node and light exposure treatment as reference (from Figure 6). Correlation coefficient and linear regression parameters are for data represented by open circles. Measured above-canopy QSI levels were ~2,000 μmol m−2 s−1.
- Figure 9
(A) Potential fruitfulness (as integrated fruitfulness index) responses of individual Chardonnay buds to diurnal quantum scalar irradiance (QSI). Each linear regression plot represents eight buds from a single vine and each vine one of the four shoot light exposure treatments. Diurnal QSI was recorded with photodiodes attached next to buds (in nodes 2 or 3) and aligned with their axes. (B) Potential fruitfulness responses of Chardonnay vines to diurnal QSI. Each point represents the fruitfulness and diurnal QSI mean of all buds on each of the six vines in Figure (9a). Corresponding vine number is indicated inside each open circle.
- Figure 10
Potential fruitfulness (as integrated fruitfulness index) in relation to internode diameter. Values are averages by light exposure treatment. Data are from internode 3 in Flame Seedless, Cabernet Sauvignon, and Chardonnay, and internodes 5 to 15 in Thompson Seedless.
- Figure 11
Effect of light and temperature on bud fruitfulness of Thomp-son Seedless and Flame Seedless under growth chamber conditions (16-hr daylight, 25°C, 60% relative humidity). Mean separations by cultivar using Tukey’s method (p > 0.05). QSI: quantum scalar irradiance.
- Figure 12
Photosynthetic active radiation (PAR) intercepted by individual fruitful and unfruitful buds of Thompson Seedless vines growing under controlled conditions (14-hr days, 25°C, and 60% relative humidity). Values were averaged by light exposure treatment. PAR was measured when leaves were fully expanded. Mean separations by light exposure level using Tukey’s method (p > 0.05). Buds with one or more inflorescence primordia were considered as fruitful.
Tables
- Table 1
Vine spacing and trellis configuration of cultivars used in the study.
Spacing (m) Vine head Foliage wire Cross arm Cultivar (vine x row) height (m) height (m)a length (m) aFour foliage wires were evenly spaced on cross arms and served as support for the experimental shoots and the overhead canes used as natural shade in the low and medium-low shoot light exposure treatments. Thompson Seedless 2.4 x 3.6 1.50 1.80 1.0 Flame Seedless 2.4 x 3.6 1.05 1.52 1.0 Cabernet Sauvignon 1.8 x 3.0 1.37 1.62 0.6 Chardonnay 1.8 x 3.0 1.37 1.62 0.6 - Table 2
Effect of shoot light exposure level on potential (P) and observed (O) bud fruitfulness.a
Thompson Seedlessb Flame Seedless Cabernet Sauvignon Chardonnay Exposure P***c O*** O/P P*** O** O/P P** Ons O/P P** Ons O/P aInflorescence primordia per node for P and inflorescences per node for O. bMeans for nodes 5 to 15 in Thompson Seedless and nodes 1 to 3 in the other cultivars. cLight exposure treatment effects: *, **, ***, and ns indicate significance at p > 0.05, 0.01, 0.001, and not significant, respectively. High 1.79 1.59 0.89 2.61 1.97 0.76 3.56 1.40 0.39 3.22 2.03 0.63 Medium-high 1.42 1.27 0.89 1.44 1.42 0.98 3.20 1.62 0.51 3.03 1.84 0.61 Medium-low 1.14 1.12 0.98 2.14 1.4 0.65 2.54 2.00 0.79 Low 0.77 0.83 1.07 0.95 0.78 0.82 1.89 1.32 0.70 2.40 1.71 0.71 - Table 3
Effect of shoot light exposure level on relative inflorescence dry weight per node.
Thompson Flame Cabernet Exposure Seedless***a,b Seedless** Sauvignon* Chardonnay* aMeans for nodes 5 to 15 in Thompson Seedless and nodes 1 to 3 in the other cultivars. Highest mean weight within cultivar considered as 100%, weights taken ~3 weeks after budbreak. bLight exposure treatment effects: *, **, and *** indicate significance at p > 0.05, 0.01, and 0.001, respectively. cStandard error at 95% confidence in parenthesis. High 100 (4.7)c 99.2 (5.4) 100 (7.0) 100 (8.5) Medium-high 71.0 (3.5) 100 (8.0) 92.6 (5.4) 74.7 (10.2) Medium-low 70.7 (9.2) 77.2 (3.7) 39.9 (7.6) Low 34.3 (3.3) 47.0 (7.6) 69.1 (8.8) 59.4 (7.3) - Table 4
Correlation coefficients of percent fruitfulness or integrated fruitfulness index with observed fruitfulness under four light levels.
High Medium-high Medium-low Low Measure of potential fruitfulness %FFa IFIb %FF IFI %FF IFI %FF IFI a%FF: percent fruitfulness (% buds with one or more cluster primordia). bIFI: integrated fruitfulness index (sum of diameters of all primordia in mm). Thompson Seedless 0.87 0.76 0.96 0.98 0.80 0.80 Flame Seedless 0.87 0.84 0.97 0.91 0.91 0.84 0.92 0.91 Cabernet Sauvignon 0.80 0.80 0.99 0.89 1.00 0.96 0.93 0.99 Chardonnay 0.88 0.96 0.98 0.87 0.95 0.75 0.90 0.82 Means 0.86 0.84 0.98 0.91 0.95 0.85 0.89 0.88
Vol 56 Issue 4
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