October 2013 Issue of Wines & Vines
Establishing a Noiret Vineyard
Vine training program, spacing and root system impact yield and fruit composition
Noiret is an interspecific red hybrid wine grape that was released by Cornell University in 2006. The original cultivar description (Reisch et al. 2006) describes the growth as semi-upright to semi-trailing and reports that Noiret is smaller than both Concord and GR7 with respect to yield and vine size. However, anecdotal reports from Finger Lakes growers suggest that Noiret vines can be vegetative and unruly. Many growers are interested in planting this cultivar, but there is little research to provide guidance about the appropriate viticultural practices for Noiret. Should the vines be own-rooted or grafted? What training system should be employed? How close or far apart should the vines be spaced? The objective of this field study was to investigate the impact of training system, vine spacing and rootstock on vine growth, yield components, fruit composition and consumer preference for Noiret wines produced from a young vineyard.
Materials and methods
Vineyard site and experimental design. The planting was established in 2007 at the New York State Agricultural Experiment Station in Geneva, N.Y., in a block with deep, well-drained Honeoye fine silt loam. Rows were spaced 9 feet apart and oriented north-south. The experiment was replicated five times. The treatments were training system, as the main plot high-wire cordon (HWC) vs. low cordon with vertical shoot positioning (LVSP), and vine spacing as the sub-plot (6 feet vs. 8 feet), with root system (own-rooted vs. grafted on 101-14 Mgt) randomized among the sub-plots. Panels were 24 feet in length and contained either three or four vines, depending on the vine-spacing treatment. A panel of guard vines was planted at the end of each row, and drip irrigation was installed in the planting. Vine survival was excellent, and all vines were established on the training systems by September 2008. Due to the significantly smaller size of the own-rooted vines, data was collected for grafted vines only in 2009, but for all vines in the experiment in 2010.
Yield components. Fruit from each vine was hand harvested Nov. 4, 2009, and Oct. 22, 2010. Yield per vine was quantified using a hanging scale, and cluster number per vine was recorded. A random sample of 20 clusters per experimental unit was collected at harvest and stored at -40°C until analysis. Vines were pruned during the winter to five nodes per foot of canopy during the spring of 2009 and six nodes per foot of canopy during spring 2010; pruning weights were also collected.
Fruit composition. The 20-cluster sample was thawed at room temperature and crushed by hand. The slurry was pressed through cheese cloth to yield a juice sample. Soluble solids, pH and TA were determined using standard practices.
Winemaking. Field replicates for each grafted treatment (grafted HWC/6’, grafted HWC/8’, grafted LVSP/6’, grafted LVSP/8’) were combined and then separated into two lots for replicated fermentations. Fruit was destemmed, crushed and treated with 50 mg/L sulfur dioxide added as potassium metabisulfite. Diammonium phosphate (DAP) was added at a rate of 1 g/kg, Fermaid K at 0.1 g/L and Goferm at 0.15 g/L in 2009. When yeast-assimilable nitrogen was measured in 2010, all lots were found to have at least 200 mg/L, so no nitrogen supplement was added beyond the GoFerm Protect (0.3 g/L) at yeast rehydration. The must was brought to 20ºC and inoculated with ICV-GRE to 0.27 g/L. Fermentation was performed with skin contact in 114-liter jacketed stainless steel fermentors with automated temperature control.
During the first three days of alcoholic fermentation, the must was warmed slowly from 20ºC to a maximum of 30º-35ºC, after which the temperature was held between 20º and 30ºC. Cap management consisted of manual punch down performed twice daily throughout fermentation. When residual sugar reached <0.5%, as measured by Clinitest tablets, wines were dejuiced, racked into standard 5-gallon glass carboys and inoculated with Alpha to start malolactic fermentation (MLF).
Upon completion of MLF, potassium metabisulfite was added to maintain 40 mg/L free sulfur dioxide. Wines were cold stabilized at 2ºC. In 2009, titratable acidity was adjusted to 6.5 g/L through the addition of potassium carbonate prior to cold stabilization; in 2010, the same acid level was achieved with the addition of tartaric acid post-cold stabilization. The wines were screened for faults by an expert panel prior to bottling in standard 750ml glass bottles closed with screwcaps.
Consumer wine preference. For each vintage, wines produced from the four treatments were compared through preference ranking. Twenty-six sensory panelists were selected from a list of volunteer subjects maintained by the Cornell Enology Extension Lab based on their availability and frequency of red wine consumption; all panelists reported consuming red wine at least once per mont h. As we were not interested in preferences for one vintage over another, wines produced in 2009 and 2010 were evaluated in two separate flights of four wines each; each panelist evaluated both flights during a single session, with a five-minute break between flights. Wines from both vintages were evaluated over two days during late July and early August 2011.
Panelists were seated in sensory booths and presented with 30ml samples of each wine, served at room temperature in 300ml ISO tasting glasses labeled with random three-digit numbers and covered with petri dish lids. Wine serving order was randomized within and across participants. Panelists were asked to smell all the samples prior to indicating aroma preference by ranking wines from one (most favored) to four (least favored). Wines were not ranked for gustatory properties, as research wines are generally unfinished so that viticultural differences among treatments are not masked by cellar practices such as oak exposure or tannin additions, and in our experience unfinished red hybrid wines are generally poorly rated by consumer panels.
Yield components and vine growth. Yield components were minimally impacted by training system or vine spacing in 2009, likely due to vine age; vines had been minimally cropped during their second growing season to encourage vegetative growth, so there was little carryover effect of treatments from the previous growing season. In 2010, vines in the HWC system produced approximately 1.6 tons per acre more fruit than vines growing in the LVSP system by producing bigger (not more) clusters. Yield was 0.6 tons per acre greater in vines spaced at 8 feet compared to those spaced at 6 feet as a result of having larger clusters. Pruning weight was 0.9 pounds per foot lower in the 8-foot treatment, and the crop-load ratio (an indication of vine balance) was greater. Grafted vines produced 0.6 tons per acre more fruit, and the crop-load ratio was higher compared to own-rooted vines.
Fruit composition. Training system and spacing had little impact on fruit composition in either year of the study, but fruit from grafted vines was 0.4 g/L lower in TA compared to own-rooted vines, while root system had no impact on soluble solids or pH (see table on page 92).
Consumer wine preference. Sensory analysis of the wines using a tool called rank sum analysis indicated that wines from the 2009 vintage produced from the HWC/8’ treatment were significantly preferred to wines produced from the LVSP/6’ treatment based on aromatic preference. Wines from the two HWC treatments were ranked first and third preferentially, while wines from the two LVSP treatments ranked second and fourth. Analysis of wines produced in 2010 indicated that the wine from the HWC/6’ treatment was significantly preferred to wine produced from LVSP/6’ and ranked first and fourth, respectively.
In 2010, training system, vine spacing and root system all impacted yield and the crop-load ratio with LVSP, tighter vine spacing (6 feet) and own-roots, all resulting in lower crop-load ratios and lower yields through reduced cluster weights. Vertical shoot positioning has been repeatedly demonstrated to reduce yield as a result of excessive canopy density in other hybrid cultivars unless the canopy is divided with a training system such as Scott Henry.
In this study, yield per foot of canopy increased with greater spacing, which differs from results reported for other hybrids, where increased spacing had limited influence on yield of Chancellor (Reynolds et al. 1995) and reduced yield of Seyval Blanc (Reynolds et al. 2004). However, pruning weight per foot of canopy was considerably lower in those studies compared to the pruning weights reported here for Noiret. This may indicate that vines in this study were considerably more vegetative than those in comparable studies, a suggestion supported by the exceedingly low crop-load ratios reported here (approximately 3-4) compared to those reported for Chancellor (five-year average of 11-16) (Reynolds et al. 1995) and Seyval Blanc (five-year average of 18-22) (Reynolds and Wardle 1994).
Pruning weights in this study suggested that Noiret vines can grow much larger than initially reported in the cultivar description. Yields reported here for HWC were in a similar range as those reported by Reisch et al. (2006). However, yield of LVSP was considerably lower than HWC in 2010. Compared to other hybrid pruning weight data reported in the academic literature, Noiret in this study was larger than every hybrid cultivar other than Corot Noir and Chancellor.
Crop-load ratios in this study were in a similar range to those reported in the cultivar description for a New York planting, but were considerably lower than crop-load ratios reported for Noiret in Vincennes, Ind. (7.5), and West Lafayette, Ind. (6.4), over a six- and 10-year period, respectively (Reisch et al. 2006). Although the cultivar release bulletin suggested that cluster thinning may be helpful in some years, the young vines in this study were overly vegetative and did not produce enough fruit. While there is no specific recommendation for an appropriate crop-load ratio for Noiret—or for hybrids in general—recommendations have ranged from 8 to 12 (Bordelon et al. 2008). Management practices to increase the yield of Noiret need to be pursued.
The significant preference of the panel for the aroma of an HWC wine compared to the aroma of a LVSP wine in both years, combined with the lower yield and crop-load ratio reported for the LVSP in 2010 compared to the HWC, suggests that the preference for the HWC wines may be a function of the higher yield.
We found the LVSP on 6-foot vine spacing to be exceedingly difficult to manage due to the general propensity of Noiret for vegetative growth. The LVSP canopies required multiple hedging passes (minimum of three passes in each growing season), as shoots would grow over the top catch wire and then downward, resulting in complete coverage of the fruiting zone with downward growing shoots. Additionally, the raising of catch wires in the LVSP system generally resulted in unintended but significant leaf removal as the foliage was so dense and confined. Due to the excessive vegetativeness of vines in the 6-foot spacing treatment, every other vine was removed from the 6-foot vine-spacing treatment in the study in early 2011 to investigate the impact of 12-foot vine spacing with this cultivar.
Noiret vineyards planted on fertile soils in regions with ample precipitation can be extremely vigorous with low crop-load ratios. These early results provide the first guidance about choosing a training system and vine spacing for Noiret, and they suggest that the inherent vigor and downward growth habit of the cultivar make it unsuitable for training to a vertically shoot-positioned system during the early years of the vineyard.
Preference testing conducted with wines from this study also supports the suggestion that vertically shoot-positioned systems be avoided, as the consumer wine panel preferred the aroma of an HWC wine to the LVSP/6’ wine in both years of the study. Greater vine spacing should also be considered for Noiret, as in our study vines in the 8-foot spacing treatment had lower pruning weights and greater yields on a per foot of canopy basis.
Justine Vanden Heuvel is an associate professor of viticulture at Cornell University, where she is actively involved in both research and teaching. Her research is focused around improving both the environmental and economic sustainability of wine grape production systems in cool climates.
|E-MAIL THIS ARTICLE|