Effect of leaf‐to‐fruit ratios on phenolic and sensory profiles of Malbec wines from single high‐wire‐trellised vineyards

Abstract

BACKGROUND The single high‐wire system is a free canopy trellis system suitable for warm to hot climates. In a global warming scenario, it arouses as a technological solution since it prevents berry overheating and sunburn. Canopy management practices manipulate leaf‐to‐fruit ratios, affecting berry and wine composition. We aimed to evaluate the phenolic and sensory profiles of Malbec wines from single high‐wire trellised vineyards in a hot region in Mendoza (Argentina) and to assess the effect of varying leaf‐to‐fruit ratios on these attributes. We manipulated leaf‐to‐fruit ratios by varying shoot trimming (experiment 1: 0.45 m, 0.80 m, and untrimmed) and winter pruning severity (experiment 2: 16, 24, 32, and >32 countable buds per meter). We characterized wine attributes by a descriptive analysis, color by the CIELAB space, and global phenolics compounds and anthocyanins by high‐performance liquid chromatography with diode array detection. RESULTS We found that wines where shoots were trimmed to 0.80 m or left untrimmed had similar and greater intensity of color, violet hue, astringency, and alcohol and a richer aroma profile than wines where shoots were trimmed to 0.45 m. Meanwhile, wines from 16 and >32 buds/m treatments (the latter simulating a box pruning) were similar to each other and had higher color intensity, violet hue, acidity, alcohol, and astringency and a more complex aroma profile than the other pruning treatments. CONCLUSIONS The best quality wines were achieved by leaving 16 or >32 buds/m and by trimming shoots to 0.80 m or leaving them untrimmed. The modulation of cultural practices in sprawling canopies offers the potential to produce wines with different styles in hot regions. © 2020 Society of Chemical Industry

Modeling Carbon Balance and Sugar Content of Vitis vinifera under Two Different Trellis Systems

“…This suggested a higher number of berries/clusters in SHW, which was probably determined by a better fruit set and/or a smaller berry drop after fruit set as a result of the greater cluster shading in the SHW canopy [ 42 , 43 ]. The yield ranged from +9% (2014) to +11% (2015) in SHW compared to VSP, primarily as a function of cluster weight, in accordance with the results of other authors [ 37 ]. Moreover, the vine size in this trial was relatively small overall, with pruning weights around 0.4–0.5 kg/vine (data not shown), indicating that vines were moderately vigorous on this site; nevertheless, both training systems were quite balanced in terms of yield and pruning weight, as shown by the Ravaz index ( Table 1 ).…”

“…In 2014, significant differences between treatments were found in the mid–final part of the season (90–150 days after sprouting (DAS), July–August), evidencing an increase in photosynthesis (23–25% depending on sampling time) and transpiration (17–28% depending on sampling time) for VSP when compared with SHW. This lower net assimilation rate in SHW around veraison is linked to the shading of mature and fully functional leaves (8–10 nodes), which is caused by the typical falling vegetation of this training system [ 37 , 38 , 39 , 40 ]. Moreover, in 2014, lower values of photosynthesis and transpiration were detected from 115 DAS onwards (August) in comparison with the period between 90 and 110 DAS (July) due to lower rainfall amounts in August than in July ( Figure 1 ).…”

“…Since dry matter accumulation can be strongly influenced by the season [ 34 ] and by the training system of the vines [ 35 ], this experiment was conducted over two growing seasons, comparing the widespread traditional vertical shoot positioning trellis with the single high wire trellis—an ancient free canopy system that has recently started to be taken into consideration and prevents berry overheating thanks to its falling vegetation [ 36 , 37 ]. Therefore, the present study had the further purpose of helping to clarify if the single high wire trellis can be considered as a technological solution for a viticulture that is severely challenged by global warming.…”

Impact of trellis systems and rootstocks on global phenolic composition and antioxidant activity of ‘Isabel Precoce’ grapes produced during rainy seasons in semi-arid region of Brazil

“…However, factors such as the position of the bunches, determined by the canopy architecture of each trellis system, and the rootstock behavior, all contribute to variations in components that together comprise the pigments that characterize fruit color (Leão et al, 2016). In addition, cultural practices that promote lowering the leaf-to-fruit ratio affect the chromatic characteristics, as observed by Ahumada et al (2021) in Malbec wines.…”

“…The mean values corresponding to the association of the treatments trellis systems and harvest seasons are represented. CV = coefficient of variation Ahumada et al (2021) emphasized that a larger canopy expansion induced a higher accumulation of soluble solids in 'Malbec' grapes. In this study, lyre and VSP provided the highest soluble solids contents in grapes, as did rootstock 'IAC 572'.…”