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July 2018 WINES&VINES 63 WINE EAST GRAPEGROWING sured using midday leaf ψ by pressure bomb. Measurements were made only at designated leaf ψ vines (about 15 per vineyard block), on the same days as SWC measurements, from 1000h to 1400h (ca. solar noon), under full sun. Leaf gs was measured by a hand-held porometer on those vines used for leaf ψ . Fruit from each sentinel vine was harvested, cluster number determined, and fruit weighed. Cane prunings were weighed to determine vine size. A 100-berry sample was taken from each sentinel vine, weighed to determine mean berry weight, and thereafter soluble solids were measured using a refractometer, pH by a pH/ion meter and titratable acidity by autotitrator. Monoterpene aroma compounds [free vola- tile terpenes (FVT) and potentially-volatile terpenes (PVT)] were analyzed on Riesling samples taken from leaf ψ vines based on a distillation method. Cabernet Franc juice sam- ple absorbance was measured using a spectro- photometric method at 420 nm and 520 nm, with color intensity calculated as A 420 +A 520 , and hue as A 420 /A 520 . Total anthocyanins were quantified using the pH shift method, while total phenols were quantified using the Folin- Ciocalteu method. All vines designated for leaf ψ and gs mea- surements were sampled September 2016 to determine grapevine leafroll-associated virus (GLRaV) titer. Total RNAs were isolated from leaf samples using a method recently devel- oped in the Meng lab. Total RNAs were used in reverse transcription using primers specific to GLRaV-2 and 3, followed by amplification through PCR using broad-spectrum primers to identify virus presence. To determine virus titer for comparison and correlation to the UAV and GreenSeeker data, quantitative qPCR was conducted by Power SYBR Green PCR Master Mix and StepOnePlus qPCR (Applied Biosystems). GPS coordinates from vineyard blocks and sentinel vines were imported into a GIS envi- ronment (ArcGIS) and linked to all point data collected from sentinel vines. Spatial interpola- tion techniques (i.e., kriging) applied to these data were used to estimate the value of vine- yard variables at unsampled locations. This permitted further spatial data analyses, includ- ing the integration of these data with the re- mote-sensing datasets. A GreenSeeker unit (Trimble Navigation) mounted on a four-wheel-drive vehicle was used to collect NDVI data on dates close to soil moisture and leaf ψ data collection. An addi- tional reading was collected in mid-September. Data were imported into Farmworks software and spatial maps created. Shapefiles were thereafter imported into the ArcGIS database. GPS coordinates identical to the sentinel vines were identified, and NDVI data corresponding to these coordinates were extracted for statisti- cal analyses. The UAV flights corresponded to the verai- son soil moisture, leaf ψ , and GreenSeeker data collection. Image acquisition was performed using the SenseFly eBee UAV (see Figure 2A) supplied by Air-Tech Solutions, Inverary, ON. The UAV had 30 minutes of endurance, a 9-kg payload, and was equipped with an autopilot system allowing a 1000-m visual range and 5-km radio line of sight. The UAV was flown at both 90 and 120 m elevations in separate flights and a maximum speed of 60 km/h. Two sensors were used for image acquisi- tion. The first operated in the visible and near- infrared portions of the electromagnetic spectrum (EMS) utilizing five spectral bands (blue, green, red, red edge, near-infrared) equipped with an incident light sensor. The second sensor operated in the thermal–infrared (IR) portion of the EMS. It ensured acquisition of imagery in the thermal-IR range covering 750 to 1350 μm. This equipment was comple- mented by a ground receiving station that provided real-time feedback on the position of the aircraft and its imaging. Image acquisition was performed over each ONLINEMARKETINGSYSTEM Wines Vines Analytics Visit winesandvines.com/OMS or call 866.453.9701 to set-up your free demo. Reach Thousands of Winery Decision Makers The Wines & Vines Online Marketing System is designed to help your business: • Increase sales • Generate winery leads • Manage clients and sales territories • Improve marketing effectiveness