Cjps-2019-0291.Pdf

Canadian Journal of Plant Science Spatial variability in Ontario Riesling Vineyards. II. Berry composition Journal: Canadian Journal of Plant Science Manuscript ID CJPS-2019-0291.R1 Manuscript Type:ForArticle Review Only Date Submitted by the 27-Feb-2020 Author: Complete List of Authors: Willwerth, James; Brock University, CCOVI Reynolds, Andrew; Brock University, Terroir, Precision viticulture, Vine water status, Soil moisture, Fruit Keywords: composition Is the invited manuscript for consideration in a Special Not applicable (regular submission) Issue?: https://mc.manuscriptcentral.com/cjps-pubs Page 1 of 35 Canadian Journal of Plant Science Spatial variability in Ontario Riesling Vineyards. II. Berry composition James J. Willwerth and Andrew G. Reynolds 1 Former Graduate Research Assistant, Cool Climate Oenology and Viticulture Institute (CCOVI), Brock University, St. Catharines, ON L2S 3A1. Present address: Senior Viticulturist, Cool Climate Oenology and Viticulture Institute (CCOVI), Brock University, St. Catharines, ON L2S 3A1. 2 Former Professor, and Corresponding author (e-mail: [email protected]). Abstract Spatial variability of berry composition was studied over a 3 year period in 10 Riesling vineyards in the Niagara Peninsula in Ontario. Vineyards were delineated using global positioning systems (GPS) and 75-80 sentinel vines were geo-referenced within a sampling grid for data collection. During 2005 to 2007, vine water status measurements [leaf water potential (ψ)] were collected bi-weekly from a subset of these sentinel vines. Data were collected on soil texture and composition, soil water content (SWC; %), leaf ψ, and fruit composition. These variablesFor were mapped Review using GIS software Only and relationships between them were elucidated. Temporal stability in spatial patterns of soil texture and composition, SWC, leaf ψ, soluble solids (Brix), titratable acidity and monoterpenes were examined. Spatial trends in leaf ψ and/or SWC showed widespread evidence of temporal stability. Fruit composition variables were not as stable over a 3 year period. Spatial trends in Brix were temporally stable in seven vineyards, free volatile terpenes were temporally stable in three vineyards, and potentially volatile terpenes were temporally stable in two vineyards. Consistent leaf ψ zones were identified and these were temporally stable despite different climatic conditions. Furthermore, some soil variables, and particularly vine water status, may contribute significantly to the terroir effect through their effects on vine size and fruit composition. For some vineyards, many viticulture and fruit composition variables were also temporally stable. There was evidence of strong spatial relationships between leaf ψ and fruit composition, suggesting a strong relationship between berry composition and vine water status. Key words: Terroir, precision viticulture, vine water status, soil moisture, fruit composition Introduction The terroir concept can be defined as an interactive ecosystem, in a given place, including climate, soil, and the vine (van Leeuwen 2010; van Leeuwen and Seguin 1994; 2006; van Leeuwen et al. 2004). Soil’s main influence on wine quality seems to be due to its physical properties and its water holding capacity and drainage characteristics (Seguin 1986). Studies of soil physical properties, such as soil texture and its relationship with vine performance have demonstrated that significant variations may exist within single vineyards (Hall et al. 2002). Precision agriculture techniques have been used to study variation in countless studies involving many crops including grapes. Spatial variability in soil, climatic conditions, pests, disease, have been associated with yields and some fruit composition variables (Bramley and Hamilton 2004; Cortell et al. 2005; Hall et al. 2002; Reynolds and Hakimi Rezai 2014a-c). Greenspan and O’Donnell (2001) investigated the spatial variability within two vineyard blocks and some viticultural properties. They were able to distinguish between high and low vine size zones and demonstrated that these “management zones” had significantly different means of yield, soluble solids, and water status. Cortell et al. (2007, 2008) studied a number of yield and fruit quality indices in Oregon Pinot noir vineyards and found that vine size associated with soil and water availability had https://mc.manuscriptcentral.com/cjps-pubs 1 | P a g e Canadian Journal of Plant Science Page 2 of 35 an impact on fruit composition, particularly phenolics. Cabernet Sauvignon vineyards in Coonawarra varied in a number of fruit composition variables and there was some consistency from year to year (Bramley 2005). Intra-annual variation was greater for some berry composition indices such as phenols vs. others such as Brix (Bramley 2005). Many terroir-related studies indicate that water availability and plant water status are the means by which the terroir affects wine style and quality (Hakimi and Reynolds 2010; Koundouras et al. 1999; Ledderhof et al. 2014; Marciniak et al. 2013; Penavayre et al. 1991; Peyrot des Gachons et al. 2005; Seguin 1983). Yet, the impact of site and plant water status on grape/wine composition has not been widely addressed, at least not with important environmental factors and cultural practices kept constant, particularly in New World wine regions. Changes in vine water status can impact vine growth, fruit composition, yield and aroma compounds (Tregoat et al. 2002; van Leeuwen and Seguin 2006; van Leeuwen et al. 2004). Studying within- site variation in soil, vine water status, and fruit composition variables can help elucidate terroir effects while keeping key environmental factors constant. Therefore, precision viticulture techniques including global positioning systems (GPS)For and geographic Review information systems Only (GIS) are being us being utilized to study variation within Ontario vineyards. Little research has been done to see how Niagara’s unique terroir influences wine varietal character. Some studies performed in Ontario indicated that vine size and soil texture were related spatially to fruit composition and sensory characteristics of wines (Hakimi and Reynolds 2010; Ledderhof et al. 2014; Marciniak et al. 2014; Reynolds and Hakimi Rezaei 2014c; Reynolds and de Savigny 2016) but in one case spatial patterns were not temporally consistent (Reynolds et al. 2007). This study attempted to further understand the basis of terroir in Riesling vineyards within sub-appellations of the Niagara Peninsula. The objectives of this study were to demonstrate the influences of soil texture, soil water content, and leaf water potential (ψ) on fruit composition within vineyard blocks and to delineate these terroir effects using geomatic technologies. It was hypothesized that consistent leaf ψ zones would be identified within vineyard blocks, that vine water status would play a major role in fruit composition, while soil type would play a role through its water holding capacity and water supply to the vine. Data on soil texture and composition, soil water content, leaf ѱ, and yield components are included in a companion manuscript (Willwerth and Reynolds 2020). Data describing sensory differences between wines from high and low water status zones in these vineyards are found in Willwerth et al. (2018). Materials and Methods Site selection In April 2005, 10 Riesling vineyard sites were selected throughout the Niagara Peninsula in Ontario (Table S1). These sites were non-irrigated, commercial vineyards and the vineyard blocks had heterogeneous soil types. Each site was also representative of each VQA sub-appellation. Details concerning soil and vineyard characteristics and vineyard management can be found in Table S1. All vineyards were balanced pruned (Jordan et al. 1981) by retaining 20 nodes for each kg of cane prunings prior to each growing season. In each vineyard block, a grid-style sampling pattern was established with a “sentinel vine” at each grid https://mc.manuscriptcentral.com/cjps-pubs 2 | P a g e Page 3 of 35 Canadian Journal of Plant Science intersection point. These sentinel vines (72 to 80 per vineyard block) were flagged for identification to be used for data collection. A Raven Invicta 115 GPS receiver (Raven Industries, Sioux Falls, SD) with a built-in differential GPS correction receiver giving positions with accuracy of 1-1.4 m was used in May 2005 to geo- reference each sentinel vine and to delineate the shape and size of each vineyard block. Viticultural data collection Soil water content (SWC; %) and leaf ψ measurements were taken bi-weekly in each vineyard (every 10 to 14 days) from sentinel vines between the end of June and early September (beginning of fruit set to pre- harvest) as described in Willwerth and Reynolds (2020). Soil analyses including pH, organic matter concentration (OM), elemental concentration, cation exchange capacity (CEC), and base saturation (BS) were performed on one soil sample collected from every fourth sentinel vine (Willwerth and Reynolds 2020). For each sentinel vine, data were collected annually at vine dormancy for weight of cane prunings as an estimate of vine vigor (“vine size”). YieldFor components Review (yield per vine; Only clusters per vine; cluster weight; berries per cluster; berry weight) were either measured directly or calculated from measured variables during harvest each season. Fruit was sorted based on treatments and retained for winemaking. Clusters were counted from each sentinel vine and

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