Statewide Crop Load Project: A Researcher-Industry Partnership to Understand the Yield-Quality Relationship in Cool Climate Pinot noir and Chardonnay Production

The Statewide Crop Load project was conducted in 13 vineyard sites in 2016, including 12 Pinot noir vineyards and 1 Chardonnay vineyard. Results of the Pinot noir vineyards are reported here for data obtained as of this reporting and data are still pending from the Chardonnay vineyard. Yields during 2016 were down from 2014 and 2015, the highest yielding years of the project and were similar to yields obtained in 2013. Average yield across all crop thinning treatments and sites was 0.85 lb/ft in 2016 compared to the 5-year mean of 0.89 lb/ft. Heat units (GDD50) in 2016 were also lower than in 2014 and 2015, but harvest was earlier than the past four years with all harvest completed by the end of September. Fruit composition data indicates advanced ripening with total soluble solids ranging from 24.3 – 25.6°Brix for 2016. Analysis of fruit composition data across all sites in 2016 revealed that vineyard site, not crop level, led to differences in fruit composition. Treatment effects were tested within each vineyard site, and results show that the majority of sites (82{aed9a53339cdfc54d53cc0c4af03c96668ab007d9c364a7466e3349a91bf0a23}) had some treatment effect on fruit composition; however, the effects varied by site. No one fruit composition parameter was affected by crop level at all sites, and the most common differences found by treatment were for pH, titratable adidity, tartaric acid, and tannin in 2016. However, this effect was found at approximately one-third of vineyard sites. Furthermore, few crop level effects were found for anthocyanin content in 2016 while 15-28{aed9a53339cdfc54d53cc0c4af03c96668ab007d9c364a7466e3349a91bf0a23} of sites from 2013-2015 had higher anthocyanin with lower crop levels. Further data analysis of vine growth, fruit composition and wine sensory is underway. Sensory evaluation has been expanded to include new in-house wine evaluation methods that were developed in 2016 for implementation in 2017. To capture industry-collaborator observations from the study to be used to enhance data interpretation and to develop yield management metrics, survey and interview tools were developed in 2016 and will be conducted in 2017. Updates on this project will be provided in future grant reports and outreach to the industry.

Interactive Effects of Mechanical Canopy Management and Reduced Deficit Irrigation on Shiraz Grapevines

Canopy architecture, yield components, fruit composition and vigor of Syrah were measured in response to the following treatments over three years. Four crop load levels were imposed by dormant pruning to 22, two node spurs (HP) with no further manipulation, and mechanically box-pruning others to 10 cm hedges and mechanically thinning the canopy to a density of five (CLL); and seven count shoots/30 cm of row (CLM); or mechanically box-pruning to a 10 cm hedge with no shoot thinning (CLH). Control vines were irrigated to 70{aed9a53339cdfc54d53cc0c4af03c96668ab007d9c364a7466e3349a91bf0a23} of ETo from fruit set until harvest (RDIC). Other vines received 70{aed9a53339cdfc54d53cc0c4af03c96668ab007d9c364a7466e3349a91bf0a23} of full vine ETo until veraison, and 50{aed9a53339cdfc54d53cc0c4af03c96668ab007d9c364a7466e3349a91bf0a23} of ETo (RDIL) thereafter or vines received 50{aed9a53339cdfc54d53cc0c4af03c96668ab007d9c364a7466e3349a91bf0a23} of ETo between fruit set and veraison (RDIE) and 70{aed9a53339cdfc54d53cc0c4af03c96668ab007d9c364a7466e3349a91bf0a23} thereafter. Mechanical shoot thinning (CLM) removed 25{aed9a53339cdfc54d53cc0c4af03c96668ab007d9c364a7466e3349a91bf0a23} of the total shoots exposing 70,600 shoots?ha-1 with a distance of 4.6 cm between count shoots on the cordon. This translated to four leaf layers and 12.6 m2 of leaf area. The combination of the CLM and RDIE decreased berry weight at harvest by 12{aed9a53339cdfc54d53cc0c4af03c96668ab007d9c364a7466e3349a91bf0a23} without decreasing yield compared to HP resulting in 21.5 tons?ha-1 yield. To achieve vine balance with a crop load of 9.9 kg of yield/kg of pruning weight and a leaf area to fruit ratio of 0.75 m2?kg-1, a combination of CLM and RDIE was needed. The study identified a canopy management method that can be used in combination with RDI that reduces input costs through mechanization, enhances berry composition with a vine balance that provides sustainable production.

Effect of Pruning Mechanization on Vine Performance and Fruit Composition of Chardonnay Grapevines Under Warm Climate Conditions in the San Joaquin Valley of California

Experiments conducted so far revealed that most of the parameters of yield components and fruit composition are significantly affected by pruning mechanization. Number of nodes retained and shoots was comparable for mechanical pruning and minimal pruning while hand pruned vines had fewer nodes and shoots. Light penetrating into the fruiting zone was greater in minimally pruned vines, compared to hand or mechanical pruned vines. Number of clusters and yield were higher in minimally pruned vines than that in hand or mechanically pruned vines. Clusters were smallest in minimal pruned vines and largest in hand pruned vines while mechanical pruning produced medium cluster size. Maturity was delayed by 9 days in mechanical pruning and by 34 days in minimal pruning, compared to hand pruning. Brix and pH of harvested fruit were also different among the treatments. Juice pH was much higher and TA was much lower in minimally pruned vines when Brix was comparable. Full bloom petiole N, P, and Mn were affected by pruning mechanization. Higher content of N, P, and Mn was found in hand pruned vines than that in mechanically or minimally pruned vines. Minimally pruned vines had higher Mn content which was comparable to hand pruning. Other mineral nutrients were not affected by pruning mechanization.

PDF: Effect of Pruning Mechanization on Vine Performance and Fruit Composition of Chardonnay Grapevines Under Warm Climate Conditions in the San Joaquin Valley of California

Converting 4 Varieties of Mature Winegrapes to Mechanical Pruning

During the first funded year, the project went as outlined in the grant proposal time line. The pruning treatments were imposed as described at all five sites. At harvest time gross and net yields were taken. Bunch counts and berry counts were recorded. Samples were pulled and sent via courier to Canandaigua Wine Company were they were analyzed for sugar, acid and color. The winery did not report any problems with any of the loads sent in. One thing we noticed without taking data was the virtual elimination of bunch rot in the Chenin blanc, Zinfandel, and Chardonnay in both mechanical pruning treatments.

During the spring all of the varieties had to be trimmed to eliminate canes and fruit that were hanging below the cordon and low enough to not be easily harvested mechanically. Chenin blanc on both mechanical pruning systems required the most fruit to be removed. This is due to its low growth habit.

PDF: Converting 4 Varieties of Mature Winegrapes to Mechanical Pruning

Converting 4 Varieties of Mature Winegrapes to Mechanical Pruning

During the first funded year, the project went as outlined in the grant proposal time line. The pruning treatments were imposed as described at all five sites. At harvest time gross and net yields were taken. Bunch counts and berry counts were recorded. Samples were pulled and sent via courier to Canandaigua Wine Company were they were analyzed for sugar, acid and color. The winery did not report any problems with any of the loads sent in. One thing we noticed without taking data was the virtual elimination of bunch rot in the Chenin blanc, Zinfandel, and Chardonnay in both mechanical pruning treatments. During the spring all of the varieties had to be trimmed to eliminate canes and fruit that were hanging below the cordon and low enough to not be easily harvested mechanically. Chenin blanc on both mechanical pruning systems required the most fruit to be removed. This is due to its low growth habit.

Evaluation of Mechanical Thinning to Improve Composition of Wines from

The effect of different levels of mechanical thinning on growth, yield, fruit composition, and wine quahty of Cabernet Sauvignon grapevines was studied. Minimally and machine pruned vines were examined and compared against a bilateral cordon, spur-pruned control. Thinning treatments were performed on mechanically pruned vines using: 1) a mechanical harvester equipped with bo-peep rods set at two head speeds (220 and 250 rpm) and 2) the Morris-Oldridge (M-O) thinner with bo-peep rods set at two speeds (400 and 600 rpm). Thinning treatments were also performed on minimally pruned vines using a harvester equipped with bo-peep rods set at 400 rpm and the M-0 thinner with bo-peep rods set at 600 rpm. Additionally, a mechanically pruned, non-thinned treatment and a minimally pruned, non-thinned treatment were studied. Significant differences in yield, fruit composition, and wine quality were observed. The minimally pruned vines thinned with the M-0 thinner produced a yield of 10.8 tons per acre and was the only treatment with a yield that was not different from the hand pruned control (11.5 tons per acre). The machine pruned vines thinned with the harvester set at 220 rpm (8.4 tons per acre) and the M-0 thinner at 400 rpm (8.5 tons per acre) and 600 rpm (7.7 tons per acre) compared favorably to the control. Large canopy size was problematic for the harvester treatments on the mechanically and minimally pruned vines resulting in reduced yield. The minimally pruned vines thinned with the M-0 thinner set at 600 rpm produced berries with soluble solids equal to the hand pruned control and pH that was lower than the control or vines thinned with the mechanical harvester. All treatments thinned with the M-0 thinner produced wine with a greater color density than all other treatments.

Evaluation of Mechanical Thinning to Improve Composition of Wines from Minimally Pruned and Machine Pruned Vineyards

The effect of different levels of mechanical thinning on growth, yield, fruit composition and wine quality of Cabernet Sauvignon grapevines was studied. Minimally and machine pruned vines were examined and compared against a bilateral cordon, spur-pruned control. Thinning treatments were performed on minimally pruned vines using a mechanical harvester equipped with bo-peep rods set at two head speeds. The moderate thinning treatment was achieved by a striker speed of 150 RPM and the severe thinning treatment by a speed of 200 RPM. Mechanically pruned vines were included in the experiment but were determined to not require crop thinning during the initial season of this study. Additionally, a minimally pruned, non-thinned treatment was studied. Wines were made from the four treatments and were evaluated for composition. Significant differences in growth and yield parameters were observed, however few significant differences were evident among treatments for fruit composition and wine quality. The preliminary results obtained through this study confirm that mechanical thinning may be used as a practical tool to control vineyard crop size. It should be noted that the timing and level at which the thinning practice is performed is of great importance to its effectiveness. Results obtained in 1996 suggest that minimal and machine pruning can produce fruit and wines that do not differ in composition from traditionally trained vines.