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


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.



Publication date: June 22, 2020

Issue: GiESCO 2019

Type: Article


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


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


GiESCO 2019 | IVES Conference Series


Related articles…

Building of a hierarchy of wines based on terroirs: an initiative from the producers of Muscadet

The Muscadet area is situated in the southeast of Nantes, close to the Atlantic coast. It constitutes the western extension
of the French vineyard “Loire Valley”. The Muscadet is renowned and often spontaneously linked to a white wine.
However it remains misconceived as an ordinary wine, lacking authenticity.

How the physical components of the terroir can differently intervene in French wines DPO definitions.Example of Côte de Nuits in Burgundy

European regulations describe what elements must be given in the specifications of DPO determination ; mainly production conditions, links between quality and products characteristics and the physical traits of the production area. These elements are given in the “link to terroir” paragraph relating natural and human factors, detailed product characteristics linked to the geographical area and at last interactions between product originality and the geographical area.

Vignobles sur les pentes en Bourgogne : l’aube d’un nouveau modèle de l’Antiquité au Moyen Âge

La découverte d’une vigne gallo-romaine en plaine à Gevrey-Chambertin (Côte-d’Or) constitue un point important pour la compréhension de la construction des terroirs viticoles de Bourgogne. Sa situation en plaine constitue pour nous le point de départ d’une large réflexion sur la mise en place du modèle de viticulture de coteau qui prévaut en Bourgogne et sur les facteurs de ce changement de norme de qualité viticole. Les sources mobilisées pour cette approche interdisciplinaire et diachronique sont géomorphologiques, archéologiques et textuelles.

Everything else, it’s work ”Socio-cultural dimensions of terroir among Bordeaux winemakers

In 2010, the OIV adopted a resolution that defines ‘terroir’. The OIV definition understands terroir as the result of the interactions between the physical specificities of a space and human labor, with an emphasis on the subsequently produced collective knowledge (OIV-VITI 333-2010); by doing so, it alludes to the social and cultural dimensions of terroir.

Swiss program for the creation of fungal disease resistant grape varieties in Switzerland

Grapevine breeding is part of the research program of Agroscope in Switzerland since 1965. From 1965 to 1995, the aim of the Vitis vinifera crosses was to obtain a high resistance to grey rot (Botrytis cinerea), one of the most virulent fungal pathogens in the Swiss vineyard. In 2021, the grape varieties released from this first breeding program covered 936 ha of the 15’000 ha of the Swiss vineyard.
In 1996, a second breeding program aimed at obtaining, by classical interspecific hybridization, grape varieties resistant to downy mildew (Plasmopara viticola) and powdery mildew (Erisyphe necator) and less sensitive to grey rot (Botrytis cinerea). In order to accelerate and make the selection process more reliable, an early biochemical test was developed based on the natural defense mechanisms of the vine against downy mildew (stilbene phytoalexins). The synthesis of stilbenes (i.e., resveratrol and its oxidized dimers - and -viniférine) and pterostilbenes (methylated derivative) is among the most efficient induced defense mechanisms of grapevine against fungal pathogens on both the leaves and the clusters.