GiESCO 2019 banner
IVES 9 IVES Conference Series 9 GiESCO 9 GiESCO 2019 9 Colored hail‐nets as a tool to improve vine water status: effects on leaf gas exchange and berry quality in Italia table grape

Colored hail‐nets as a tool to improve vine water status: effects on leaf gas exchange and berry quality in Italia table grape

Abstract

Context and purpose of the study ‐ Protecting table grape vineyards with white hail‐nets is a common practice in Southern Italy. Hail‐nets result in shading effects of 10‐20 %, depending on their density and type of weave, thus they act as a low shading nets and modify the vineyard microclimate. Darker nets are more opaque to solar radiation, increasing the shading effects. Colored nets have been introduced in horticultural crops aiming to alter the amount and composition of light available at canopy level, in order to getparticular light‐induced effects on microclimate, plant physiology, growth and production. Yellow and red nets are among the most studied. However, by now, results of different studies are not always consistent with each other. The present study aimed at assessing the performance of Italia table grape grapevine under yellow and red hail‐nets, with a particular interest to the chance of modulating the microenvironment to support the vine water status under the semi‐arid conditions of Southern Italy, evaluating also the effects exerted on the grape quality.

Material and methods ‐ The study was run in 2014 and 2015, in the BT province of Apulia region, on Italia covered with white, yellow and red nets, all having mesh of about 3×5 mm. PAR, air temperature and RH were monitored in warm hours of typical days of mid‐ and late‐ July and August. Leaf gas exchange and stem water potentials were measured. Leaf area was assessed ceptometrically. At harvest, berry fresh weight, skin color, juice total soluble solid concentration (TSS) and titratable acidity (TA), main skin and pulp phenol contents, and berry antioxidant activity (AA) were determined.

Results – Respect to the white net,the colored ones reduced the PAR available for canopy (especially the red net) and increased air temperature and RH (especially the yellow net). On average, they lowered the air VPD along the canopy profile by ~10% and improved the vine water status from 33 % (yellow net) to 38 % (red net). However, this improvement did not enhance the leaf gas exchange measured at maximum PAR 2 interception (~1450 ~mol/m /s); on the contrary, the leaf transpiration, and even more the net CO2 uptake, tent to be lowered by yellow net, but not, or at a little extent, by the red net. The leaf area did not change. According to literature, yellow color depresses the transmissivity of red and blue wavelengths, active on photoreceptors that stimulate stomata opening and PSII efficiency. At harvest, on average, the patterns of berry and bunch weight were similar to those of leaf gas exchange (especially to the transpiration one); the yellow component of the skin color decreased with both colored nets; the TSS/TA ratio increased. The skin phenol contents were lowered by the red net but not, or a very little extent, by the yellow one; the berry antioxidant activity progressively decreased passing from the white to the yellow and to the red net. In conclusion, under the trial conditions, the yellow and red hail‐nets did not influence the performance of Italia grapevine in univocal way. Some responses seemed more related to their low shading effects, while others to their spectrometric effects. They rose significantly the vine water status compared to the white net, but this improvement did not enhance other physiological parameters or any berry quality attributes.

 

DOI:

Publication date: June 22, 2020

Issue: GiESCO 2019

Type: Article

Authors

Laura de PALMA (1), Patrizio LIMOSANI (1), Vittorino NOVELLO (2)

(1) University of FOGGIA-SAFE, Via Napoli 25, I-71122, Foggia, Italy
(2) University of Turin-DiSAFA, Largo Braccini 2, I-10095, Grugliasco (TO), Italy

Contact the author

Keywords

Grapevine, Microenvironment, Ecophysiology, Maturity indices, Phenol contents, Berry antioxidant activity

Tags

GiESCO 2019 | IVES Conference Series

Citation

Related articles…

Analysis of Cabernet Sauvignon and Aglianico winegrape (V. vinifera L.) responses to different pedo-climatic environments in southern Italy

Water deficit is one of the most important effects of climate change able to affect agricultural sectors. In general, it determines a reduction in biomass production, and for some plants, as in the case of grapevine, it can endorse fruit quality. The monitoring and management of plant water stress in the vineyard

Grapevine sugar concentration model in the Douro Superior, Portugal

Increasingly warm and dry climate conditions are challenging the viticulture and winemaking sector. Digital technologies and crop modelling bear the promise to provide practical answers to those challenges. As viticultural activities strongly depend on harvest date, its early prediction is particularly important, since the success of winemaking practices largely depends upon this key event, which should be based on an accurate and advanced plan of the annual cycle. Herein, we demonstrate the creation of modelling tools to assess grape ripeness, through sugar concentration monitoring. The study area, the Portuguese Côa valley wine region, represents an important terroir in the “Douro Superior” subregion. Two varieties (cv. Touriga Nacional and Touriga Franca) grown in five locations across the Côa Region were considered. Sugar accumulation in grapes, with concentrations between 170 and 230 g l-1, was used from 2014 to 2020 as an indicator of technological maturity conditioned by meteorological factors. The climatic time series were retrieved from the EU Copernicus Service, while sugar data were collected by a non-profit organization, ADVID, and by Sogrape, a leading wine company. The software for calibrating and validating this model framework was the Phenology Modeling Platform (PMP), version 5.5, using Sigmoid and growing degree-day (GDD) models for predictions. The performance was assessed through two metrics: Roots Mean Square Error (RMSE) and efficiency coefficient (EFF), while validation was undertaken using leave-one-out cross-validation. Our findings demonstrate that sugar content is mainly dependent on temperature and air humidity. The models achieved a performance of 0.65

Elucidating vineyard site contributions to key sensory molecules: Identification of correlations between elemental composition and volatile aroma profile of site-specific Pinot noir wines

The reproducibility of elemental profile in wines produced across multiple vintages has been previously reported using grapes from a single scion clone of Vitis vinifera L. cv. Pinot noir. The grapevines were grown on fourteen different vineyard sites, from Oregon to southern California in the U.S.A., which span distances from approximately hundreds of meters to 1450 km, while elevations range from near sea level to nearly 500 m. In addition, sensorial (i.e. aroma, taste, and mouthfeel) and chemical (i.e. polyphenolic and volatile) differences across the different vineyard sites have also been observed among these wines at two aging time points. While strong evidence exists to support that grapes grown in different regions can produce wines with unique chemical and sensorial profiles, even when a single clone is used, the understanding of growing site characteristics that result in this reproducible differentiation continues to emerge. One hypothesis is that the elemental profile that a vineyard site imparts to the grape berries and the resulting wine is an important contributor to this differentiation in chemistry and sensory of wines. For example, various classes of enzymes that catalyze the formation of key aroma compounds or their precursors require specific metals. In this work, we begin to report correlations between elemental and volatile aroma profiles of site-specific Pinot noir wines, made under standardized winemaking conditions, that have been previously shown to be distinguished separately by these chemical analyses.

How can historical cultivars mitigate the effects of climate change?

IFV, INRAe and the national network “Partenaires de la Sélection Vigne” representing 37 organizations from the different wine regions, have been working increasingly closely over the last 2 decades towards the preservation of the French varietal patrimony. There are approximately 600 patrimonial varieties according to INRAe and SupAgro Montpellier experts, including ancient cultivars (400) and intravarietal crossbreeds obtained since the 19th century. In the context of a drastic reduction in such varieties from the mid 1980’s in favor of mainstream varieties, it was essential to carry out an inventory of old vines and vineyards. INRAe Vassal collection plays a key role here as it holds the largest diversity available, along with a rich bibliography and herbariums, offering us the opportunity to document and double check the identity of a cultivar, consolidating the expertise of ampelographers. The work is carried out in several stages, from verifying the existence of a variety in a small region, through to rehabilitation. During this session, the authors present the process that leads to the official registration of a variety. After this, IFV selection center takes over to initiate the process of selection and propagation. A specific focus within regions such as the Alps, Champagne and the South-West will provide details of the full procedure. Bia, Bouysselet, Chardonnay rose, Mecle and the aptly named Tardif, are some of the cultivars that have followed this procedure. Furthermore, a recent regulation established by INAO on “varieties of interest for adaptation purposes” might boost uptake by growers. Since 2006, 36 historical cultivars have been registered. Most of these have been neglected in the past due to late maturity, lack of sugar and high titratable acidity at harvest time. Such characteristics are today considered as positive qualities, not only in mitigation of the effects of climate change, but also as an opportunity for restoring diversity…

Climate, Viticulture, and Wine … my how things have changed!

The planet is warmer than at any time in our recorded past and increasing greenhouse emissions and persistence in the climate system means that continued warming is highly likely. Climate change has already altered the basic framework of growing grapes for wine production worldwide and will likely continue to do so for years to come. The wine sector can continue to play an important role in leading the agricultural sector in addressing climate change. From developing on…