Terroir 2004 banner
IVES 9 IVES Conference Series 9 Shoot positioning: effect on physiological, vegetative and reproductive parameters

Shoot positioning: effect on physiological, vegetative and reproductive parameters

Abstract

[English version below]

On a étudié durant deux saisons de croissance (2002/2003 et 2003/2004) l’effet de l’orientation vertical des rameaux sur les paramètres physiologiques, végétatifs et reproductifs dans la région de Stellenbosch dans un vignoble du cépage Merlot sur 99 R conduite à espalier et taillé a cordon coursonné. Les vignes étaient espacées 2.7 x 1.5 m. L’irrigation a été appliquée quand la baie avait la dimension d’un pois et a la véraison.
Les rameaux ont été placés verticalement à la nouaison ,à la dimension d’un pois de la baie, à la véraison et trois semaines après la véraison. Après leur placement vertical les rameaux ont été tout de suite écimés à 100-155cm. Le positionnement vertical et l’écimage des rameaux n’ont pas eu aucun effet sur la croissance des entre cœurs, mais ils ont eu un effet fort sur la position de les entre coeurs sur la longueur du rameau principal. Depuis la nouaison et jusqu’à la véraison on a eu une bonne distribution de la lumière qui a favorit l’uniformité de la maturation et la qualité du raisin. Le potentiel hydrique foliaire et le potentiel de tige des feuilles basales et apicales et l’activité photosynthétique sont diminués durant le cycle végétatif. Une régression significative a été trouvée pour les feuilles apicales entre la tige et le potentiel de tige et le potentiel hydrique foliaire.
Le placement vertical des rameaux jusqu’à la véraison a induit un’augmentation significative du degré °Brix, du contenu d’acide malique et du saccharose, et une faible diminution de l’acide tartrique. Le niveau du glucose a été le plus haute dans les traitements dimension d’un pois et véraison. Aucune différence significative entre les traitements a été trouve pour le pH. L’époque de traitement pre-véraison a amélioré la couleur de la peau de la baie.
Aucune difficulté pratique a été vérifiée quand les rameaux ont été manipulés dans les première époque tandis que à les époques véraison et post-véraison on a eu difficulté à manipuler les rameaux a cause de la lignification et de la présence des vrilles. Les grappes sont très sensibles aux dommages et à la pourriture. Il s’agit de considérations importantes dans les terroirs où la gestion soigneuse du vignoble est très difficile.

The effect of vertical shoot positioning and topping at different times during two growth seasons (2002/03 and 2003/04) on physiological, vegetative and reproductive parameters was investigated in a vertically trellised Merlot/R99 vineyard located in the Stellenbosch area. Vines were spaced 2.7 x 1.5 m in north-south orientated rows. Micro-sprinkler irrigation was applied at pea size berry and at véraison stages. Shoots were positioned at berry set, pea size, véraison and post-véraison stages (3 weeks after véraison). After being positioned, they were immediately topped. Before positioning the canopy was in a “natural” condition with shoots hanging freely. Soil water typically varied according to the progress in the season and with soil depth, decreasing towards the end of the season and increasing with depth. The primary shoot length of the positioned shoots was on average approximately 100 – 115 cm, being restricted by the relatively low trellising system. Shoot positioning and topping had no marked effect on the growth of secondary shoots, but they had a noticeable effect on the position of secondary shoots along the length of the primary shoots. Pea-size shoot positioning induced slightly lower light conditions in the bunch zone, because of the low position of secondary shoot development on primary shoots. In spite of this, pre-vèraison shoot positioning treatments allowed good all-round light distribution, which would promote uniform bunch ripening and grape quality. The basal and apical stem and leaf water potential and photosynthetic activity decreased during the season as the leaves aged and the plants lost water. A significant correlation was found for apical leaves between stem and leaf water potential. 
Earlier shoot positioning (up to véraison) significantly increased the °Balling level of the must. Early shoot positioning (up to véraison) increased malic acid and sucrose contents, whereas tartaric acid contents were slightly reduced and glucose contents were higher in pea size and véraison treatments. No significant differences between treatments were found for must pH. The earlier shoots were positioned, the more water was lost by the skins, resulting in a concentration of skin contents. Pre-véraison shoot positioning and topping improved the colour of the skins. 
No practical difficulty was experienced when shoots were positioned early in the season, i.e. at berry set and pea size stages, whereas at and after véraison proper vertical positioning was primarily restricted by shoot lignification and the tightness of tendrils on the wires. Bunches were also very sensitive to damage, which led to bunch rot and a reduction in yield. These are important considerations in terroirs where timely management is difficult. 

DOI:

Publication date: January 12, 2022

Issue: Terroir 2004

Type: Article

Authors

A. Pisciotta (1), R. Di Lorenzo (1) M.G.Barbagallo (1), C.G. Volschenk (2) & J.J. Hunter (2)

(1) Dipartimento di Colture Arboree, Università degli Studi di Palermo, Viale delle Scienze 11, 90128 – Palermo, Sicily, Italy
(2) ARC Infruitec-Nietvoorbij, Private Bag X5026, 7599 Stellenbosch, South Africa

Contact the author

Keywords

Merlot, shoot positioning, vegetative growth, reproductive growth, photosynthesis, water potential, light interception, grape composition

Tags

IVES Conference Series | Terroir 2004

Citation

Related articles…

Spatial determination of areas in the Western Balkans region favorable for organic production

In problematic conditions for production of grapes and wine caused by the COVID-19 pandemic and the resulting occurrence of wine surpluses, producers are increasingly turning to the innovative viticulture and winemaking of products that are more appealing to the market and the consumers. On the other hand, consumption of the food safety or organic products, and therefore of organic grapes and wine, is increasingly common in the world, in particular in Europe. The Regional Rural Development Standing Working Group (SWG RRD), as a regional intergovernmental organization gathers actors in the viticulture and winemaking sector from states and territories of the Western Balkans (South-East Europe) in the Expert Working Group for Wine, with the aim of improving viticulture and winemaking in this region through joint activities. In accordance with the aforementioned, the SWG RRD is working on advancing organic production of grapes and wine, and on recognition of specificities of the terroir of wine-growing areas in Western Balkans. In addition, as part of the project “Facilitation of Exchange and Advice on Wine Regulations in Western Balkan Countries” helmed by the German Federal Ministry of Food and Agriculture, in addition to harmonization of relevant legislation with EU regulations, efforts are being invested towards recognition of organic wines. Within activities and project implemented by this organization, expert analyses and scientific research of the terroir of Western Balkans were carried out, and some of the results are presented in this paper.

A multidisciplinary approach to evaluate the effects of the training system on the performance of “Aglianico del Vulture” vineyards

Vineyards are complex agro-ecosystems with high spatial and temporal variability. An efficient training system may counteract the adverse effects of this variability. Moreover, considering the climate change issues, choosing an efficient training system that enhances water use and protects the vines from radiative thermal stress has become a priority for the farmers. A multidisciplinary approach that assesses the soil-crop-yield-wine relationships of vineyards in a distributed and holistic way could bring added knowledge on the behavior of the different training systems. This ongoing research aimed to implement a multidisciplinary approach to study the behavior of “Aglianico del Vulture” grapevines trained with two different systems: a spurred cordon (SC) and an “Alberello in parete” (AL), grown in a high-quality wine production area of Basilicata region (Italy). The approach merged several methods and scales of soil, ecophysiology, must/wine quality, and spectral data collection to assess the influence of the training system. Homogeneous zones (HZs) in both training systems were defined through a procedure based on geomorphological classification, unmanned aerial vehicles (UAV) images analysis, and a traditional soil survey supported by geophysical scanning. During the 2021 season, TDR probes monitored soil water content, while grapevine health status was assessed using eco-physiological measurements (LWP, chlorophyll content, PSII photosynthetic efficiency, LAI, and point-based field spectroscopy). These grapevine in-vivo measurements validated the spectral vegetation indexes (NDVI, RENDVI, CVI, and TVI) derived from the UAV multispectral imagery, which monitored the grapevine status in a distributed and non-invasive way. Grape yield, quality of berries, must and wine were measured to assess the effects of the training systems. The first experimental year results showed the variability of the vineyards and revealed relationships among soil parameters, crop characteristics, and vegetation indices of the SC and AL training systems. This multidisciplinary study could bring new insights into the vineyard training system’s effects on grape yield and wine quality.

Assessment of climate change impacts on water needs and growing cycle on grapevine in three DOs of NE Spain

This study assessed the suitability of grapevine growing in three DOs (Empordà, Pla de Bages and Penedès) of Catalonia (NE Spain) over the 21st century. For this purpose, an estimation of water needs and agroclimatic and phenological indicators was made. Climate change impacts were estimated at 1 km pixel resolution using temperature and precipitation projections from several general circulation models (GCM) and two climate change scenarios: RCP 4.5 (stabilization scenario) and RCP 8.5 (worst-case scenario). Potential crop evapotranspiration (following FAO procedure) and a daily water balance considering soil water holding capacity were used to estimate actual evapotranspiration of vines and, finally, water needs. Dynamics would be similar in the three DOs studied although the magnitude of impact differs. Water needs would be 2 and 3 times greater (ranging from 0 to more than 1500 m3/ha) than current water needs at both climate change scenarios. Moreover, blooming date would advance from 3 to 6 weeks, harvest date from 1 to 2.5 months, resulting in growing cycles from 10 to 80 days shorter. It should also be noted that frost risk would decrease from 6 to 76%, the number of days with temperatures above 30ºC during ripening would rise from 48 to 500% and tropical nights (minimum temperature >20ºC) at ripening would increase from 28 to 150%, depending on the scenario and the DOs. The impacts of climate change in the three DOs could result in significant limitations for grapevine cultivation and wine production if adaptive strategies are not applied. This result could serve as a basis for the design of specific and particular adaptation strategies to improve and maintain vineyards in the DOs studied and could be extrapolated to similar DOs and regions.

How does aromatic composition of red wines, resulting from varieties adapted to climate change, modulate fruity aroma?

One of the major issues for the wine sector is the impact of climate change linked to the increasing temperatures which affects physicochemical parameters of the grape varieties planted in Bordeaux vineyard and consequently, the quality of wine. In some varietals, the attenuation of their fresh fruity character is accompanied by the accentuation of dried-fruit notes [1]. As a new adaptive strategy on climate change, some winegrowers have initiated changes in the Bordeaux blend of vine varieties [2]. This study intends to explore the fruitiness in wines produced from grape varieties adapted to the future climate of Bordeaux. 10 commercial single–varietal wines from 2018 vintage made from the main grape varieties in the Bordeaux region (Cabernet franc, Cabernet-Sauvignon and Merlot) as well as from indigenous grape varieties from the Mediterranean basin, such as Cyprus (Yiannoudin), France (Syrah), Greece (Agiorgitiko and Xinomavro), Portugal (Touriga Nacional) and Spain (Garnacha and Tempranillo), were selected among 19 samples using sensory descriptive analyses. Both sensory and instrumental analyses were coupled, to investigate their fruity aroma expression. For sensory analysis, samples were prepared from wine, using a semi preparative HPLC method which preserves wine aroma and isolates fruity characteristics in 25 specific fractions [3,4]. Fractions of interest with intense fruity aromas were sensorially selected for each wine by a trained panel and mixed with ethanol and microfiltered water to obtain fruity aromatic reconstitutions (FAR) [5]. A free sorting task was applied to categorize FAR according to their similarities or dissimilarities, and different clusters were highlighted. Instrumental analysis of the different FAR and wines demonstrated variations in their molecular composition. Results obtained from sensory and gas chromatography analysis enrich the knowledge of the fruity expression of red wines from “new” grape varieties opening up new perspectives in wine technology, including blending, thus providing new tools for producers.

Late frost protection in Champagne

Probably one of the most counterintuitive impacts of climate change on vine is the increased frequency of late frost. Champagne, due to its septentrional position is historically and regularly affected by this meteorological hazard. Champagne has therefore developed a strong experience in frost protection with first experiments dating from the end of 19th century. Frost protection can be divided in two parts: passive and active. Passive protection includes all the methods that do not seek to modify the vine’s environment or resistance at the time of frost. The most iconic passive protection in Champagne is the establishment of the individual reserve. This reserve allows to stock a certain quantity of clear wine during a surplus year to compensate a meteorological hazard like frost during the following years. Other common passive methods are the control of planting area (walls, bushes, topography), the choice of grape variety, late pruning, or the impact of grass cover and tillage. Active frost protection is also divided in two parts. Most of the existing techniques tend to modify vine’s environment. Most of the time they provide warmth (candles, heaters, windmills, heating cables…), or stabilise bud’s temperature above a lethal threshold (water sprinkling). The other way to actively fight is to enhance the resistance of buds to frost (elicitors). The Comité Champagne evaluates frost protection methods following three main axes: the efficiency, the profitability, and the environmental impact through a lifecycle assessment. This study will present the results on both passive and active protection following these three axes.