Terroir 2020 banner
IVES 9 IVES Conference Series 9 Leaf removal to regulate fruit ripening in Cabernet-Sauvignon

Leaf removal to regulate fruit ripening in Cabernet-Sauvignon

Abstract

Aim: Under the effects of climate change it is becoming increasingly common to observe excessively fast sugar accumulation while anthocyanin and flavour development are lagging behind. Understanding the impact of different leaf removal techniques on ripening will provide vineyard managers with a canopy management strategy suitable for regulating sugar accumulation, phenolic maturity and flavour ripeness, thereby helping to mitigate these negative effects. The aim of this research was to quantify the impacts of three different leaf removal techniques on the canopy architecture and ripening of Cabernet Sauvignon.

Methods and Results: Treatments were performed at veraison (~14 °Brix) and included: i) Control, ii) Leaf plucking around the bunches iii) Leaf plucking the top two thirds of shoots apical to the bunches, and iv) Shoot trimming. On the date of harvest no significant difference in grape TSS was observed between treatments. Other results including the effect of the treatments on acidity, anthocyanins, phenolics, and tannins were somewhat inconclusive.

Conclusions:

While various other studies have shown the potential to achieve slower grape sugar accumulation without affecting the concentration of anthocyanins, phenolics, and tannins, the results of this study do not indicate a decrease in the rate of grape sugar accumulation as a result of the investigated defoliation techniques.

Significance and Impact of the Study: Given the cost of implementing these treatments the results of this study do not support the use of these methods for the purpose of delaying fruit ripening in a hot Australian climate.

DOI:

Publication date: March 25, 2021

Issue: Terroir 2020

Type : Video

Authors

Patrick O’Brien1, Cassandra Collins1,2, Roberta De Bei1*

1The University of Adelaide, School of Agriculture, Food and Wine, Waite Research Institute, PMB 1 Glen Osmond, 5064, South Australia, Australia.
2ARC Industrial Transformation Training Centre for Innovative Wine Production, Waite Research Institute, PMB 1 Glen Osmond, 5064, South Australia, Australia

Contact the author

Keywords

Delayed ripening, leaf removal, shoot trimming, canopy management, Cabernet-Sauvignon

Tags

IVES Conference Series | Terroir 2020

Citation

Related articles…

Système de Classification Climatique Multicritères (CCM) Géoviticole

Le travail concerne en premier la méthodologie de caractérisation du climat des vignobles, à l’échelle du macroclimat des régions viticoles du monde (géoviticulture). Trois indices climatiques viticoles synthétiques

Chemometric profiling of Pinot noir wine from south tyrol as a tool to reach wine style goals

AIM: Pinot Noir (PN) wines produced in South Tyrol were profiled with the aim to provide guidelines for the oenologist to reach specific winemaking goals in terms of typicity and quality.

Wine aging : a bottleneck Story ?

The sporadic oxidation of white wines remains an open question, making wine shelf life a subjective debate. Through a multidisciplinary synoptic approach performed as a remarkable case study on aged bottles of white wine, this work unraveled a yet unexplored route for uncontrolled oxidation.

The plantation frame as a measure of adaptation to climate change

The mechanization of vineyard work originally led to a reduction in planting densities due to the lack of machinery adapted to the vineyard. The current availability of specific machinery makes it possible to establish higher planting densities. In this work, three planting densities (1.40×0.80 m, 1.80×1 m and 2.20×1.20 m, corresponding to 8928, 5555 and 3787 plants/ha respectively) were studied with four varieties autochthonous of Galicia (northwestern Spain): Albariño and Treixadura (white), Sousón and Mencía (red). The vines were trained in a vertical shoot positioning system using a single Royat cordon, and pruned to spurs with two buds each. Agronomic data (yield, pruning wood weight, Ravaz index) and oenological data in must were collected. The higher planting density (1.40×0.80 m) had no significant effect on grape yield per vine in white varieties, although production per hectare was much higher due to the greater number of plants. In red varieties, this planting density resulted in a significantly lower production per vine, compensated by the greater number of plants. In addition, it significantly reduced the Brix degree in the must of the Albariño, Treixadura and Sousón varieties, and increased the total acidity in the latter two and Mencía. It also caused an increase in extractable and total anthocyanins and IPT in red grapes. The effects of high planting density on grapes are of great interest for the adaptation of varieties in the context of climate change. In the future, it could be advisable to modify the limits imposed by the appellations of origin on the planting density of these varieties in order to obtain more balanced wines.

Oxidability of wines made from Spanish minority grape varieties

The phenolic profile of a wine plays an essential role in its oxidative capacity and in both white and red wines it defines its shelf life[1]. The study of minority varieties to produce wines with peculiar characteristics necessarily includes the phenolic and oxidative characterization of the wines produced. This paper presents the study of wines made from 24 minority and majority white and red grape varieties, focusing on phenolic characteristics (total phenols, slightly polymerized phenols, highly polymerized phenols, anthocyanins…), color, as well as parameters related to the oxidability of the wines and their capacity to consume oxygen [2].