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w i n e G R O WIN G 2.5 m x 1.8 m vine spacing. The training system is VSP (vertical shoot positioning) with a bilateral cordon and six two-bud spurs per running meter of cordon. The treatments were randomly located within a greater experimental layout to exclude the natural heterogeneity of the vineyard and consisted of eight panels (four vines per panel) each. To study the impact/role of light and temperature, all leaves and lateral shoots were removed from the fruit zone on the morning side of the canopy to a height of 0.3 to 0.4 m above the cordon. The 100% morning side exposed bunches were compared with a control canopy (100% shaded bunches where no leaves or lateral shoots were removed). Leaf and lateral shoot removal was performed at the phenological stage of berry pea size on Dec. 19, 2011. Stem water potential (ΨSWP) was used to determine vine water status.7 The vines did not experience any water constraint during the growing and ripening period with a mean SWP of Ψ SWP -450 kPa at véraison. Micro-vinification of the two treatments was performed in triplicate in the Stellenbosch University experimental cellar with standardized methods. For the exposed treatment, only exposed bunches were harvested, whereas the complete canopy was harvested for the shaded treatment. Sensory analyses were performed five months after bottling using descriptive analyses. The wines were tasted in triplicate, randomized per taster and presented in black glasses. Aromatic descriptors, generated by the tasting panel during training, were scored on an uncalibrated line scale with the aromatic detection thresholds ranging from "none" to "intense." Merlot The Merlot vineyard is in the Helderberg area, Stellenbosch (33°S; 18°E) in the Western Cape, South Africa. The Merlot vines (clone 348A grafted onto US8-7 rootstock) were planted in 2003. The row direction is east to west with vines spaced 2.4 m x 1.2 m. The trellis system is a VSP on a bilateral cordon with five two-bud spurs per running meter of cordon. Pre-dawn leaf water potential (ΨPD) and stem water potential (ΨSWP) were used to determine vine water status and to manage irrigation, maintaining the vine water status at around -400 to -500 kPa for the ΨPD values.7 To study the effect of light and temperature on the berry IBMP concentration, leaves and lateral shoots were removed Figure 4: Leaf removal as performed on Merlot vines at the phenological stage of berry pea size. Left: The shaded treatment (no leaf and lateral shoot removal). Right: Both sides of fruit zone exposed. This extreme treatment has been done for experimental purposes only. The site, row orientation, and irrigation management made it possible to avoid berry sunburn or berry shriveling. Normally, opening the canopy on one side of the fruit zone is sufficient to achieve lower IBMP concentrations in wine. at the berry pea size phenological stage. All leaves and lateral shoots were removed on both sides of the canopy to the height of the first wire (100% exposed bunches). No leaves or lateral shoots were removed in the shaded treatment (100% shaded bunches) as a control. The grapes were harvested according to the sugar loading model at the fresh and mature fruit stages.6,8 temperature on berry composition due to the cooling effect of the sea breeze.4 The coolest temperature in both treatments was measured at 6 am. The mean hourly temperature over the growing and ripening season for both treatments did not exceed 30.5° C, where 30° C is the upper limit of the temperature threshold for optimal vine functioning. Due to the vineyard location, it was possible to open the canopy without experiencing any sunburn due to the occurrence of the sea breeze (see Figure 5). An increase in wind speed was observed from 10 am onward, reaching a maximum speed between noon and 6 pm. The increase in wind speed resulted in a decrease in the ambient (mesoclimatic) and bunch temperatures, mainly from 1 pm onward (Figure 5). Wind direction measurements (data not shown) confirmed that the wind direction was predominantly from the south (Walker Bay) and from the west RESULTS and PERSPECTIVES Sauvignon Blanc The Sauvignon Blanc vineyard is exposed to the positive effect of the sea breeze, coming from the Atlantic Ocean, on the bunch microclimate. Microclimatic data was collected in the fruit zone, whereas climatic data collected from above the canopy was considered as mesoclimatic data. The sea breeze allowed for the canopy to be opened in the fruit zone, and second to partially separate the effect of light and Treatment Total soluble solids (°Brix) Titratable pH acidity (g/L) Berry fresh mass (g) Sugar per berry (mg) Morning side exposed 24.4 6.53 3.39 1.95 475.81 23.4 7.38 3.31 1.97 460.43 Shaded Table I: Basic Sauvignon Blanc grape berry maturity parameters for shaded and morning side exposed treatments at harvest (3/13/2012). Merlot Sampling dates Harvest °Brix Titrable pH Berry fresh mass Sugar per stages acidity of one berry (g) berry (mg) Expo-both sides 2012/02/10 fresh fruit 23.4 2012/02/20 mature fruit 25.2 5.74 4.94 3.46 3.51 1.58 1.61 370.83 406.23 100% Shaded 2012/02/10 fresh fruit 23.1 2012/02/20 mature fruit 25.0 6.22 4.83 3.40 3.44 1.61 1.61 373.03 402.88 Table II: Basic grape berry maturity parameters for shaded and both sides exposed treatment for grapes harvested at fresh fruit stage (2/10/2012) and mature fruit stage (2/20/2012). pr actica l win ery & vin eya r d JANUARY 20 14 29