GiESCO 2019 banner
IVES 9 IVES Conference Series 9 GiESCO 9 GiESCO 2019 9 Forcing vine regrowth in Vitis vinifera cv. Touriga nacional at Douro region

Forcing vine regrowth in Vitis vinifera cv. Touriga nacional at Douro region

Abstract

Context and purpose of the study ‐ Douro Region, characterized by a Mediterranean climate type and schist soils, is subjected to water and heat stresses conditions during summer. In some locations, the temperatures registered during berry maturation, lead to fruit ripen during warmer months, increasing the degradation of organic acids, tannins and phenolics that can negatively affect the quality of wines. Forcing vine regrowth is a new practice, being currently tested in Mediterranean countries, that aims to shift fruit ripening to cooler months of the year by pruning the plants after fruit set ‐ Crop Forcing (CF) ‐ removing all the leaves and bunches and leaving five buds per shoot, in order to reduce the negative effect of high temperatures during berry maturation on its quality.

Material and methods ‐ This work aims to study the effect of forcing vine regrowth in cv. ‘Touriga Nacional’ under Regulated Deficit Irrigation conditions, in vines irrigated with 30% of the evapotranspiration. Three modalities were established: vines with no forcing regrowth (Control ‐ CTRL), vines with CF set 15 days after fruit set (CF15) and plants with CF performed 30 days after fruit set (CF30). The effects on phenology, canopy development, berry development and fruit composition were assessed.

Results ‐ Plants subjected to CF15 were severely damaged after phenological stage of full bloom due to exceptional conditions to downy mildew (Plasmopara viticola) infections, boosted by the new phenological stages due to crop forcing. On the other hand, the crop forcing modality CF30 registered a delay of nearly two months in all phenological stages, since fruit set until harvest. Shorter internodes (50%) and lower leaf area (35%) were observed in CF30 when compared to the CTRL plants at ripening stage. The number of shoots at fruit set was also significantly different between the three treatments, with higher values in CF modalities and lower values in CTRL plants. In terms of yield, comparing CF30 th th (harvested in November, 27 ) and CRTL (harvest in October, 6 ), it was found that CF reduced the number of bunches (39%), the number of berries per bunch and the average berry weight (60%). Moreover, berries from the forced crop modalities (from grapes) had a pH slightly lower (3.35), higher titratable acidity (8.82 g/L) and lower ˚Brix (17.02˚Brix) when compared to CRTL, with pH values of 3.74, titratable acidity of 4.16 g/L and Brix of 23.93˚. Despite these results, further study should be carried out to evaluate the long‐term effects of CF and its applicability depending on the climatic conditions for each year.

DOI:

Publication date: June 22, 2020

Issue: GiESCO 2019

Type: Article

Authors

Inês L. CABRAL (1), Anabela CARNEIRO (1), Joana VALENTE (2), Fernando ALVES (2), Frank S. ROGERSON (2), Artur MOREIRA (2), Pedro LEAL da COSTA (2), Susana M.P. CARVALHO (1), Jorge QUEIROZ (1)

(1) GreenUPorto & DGAOT, Faculty of Sciences, University of Porto, Campus de Vairão, Rua da Agrária, 747, 4485-646 Vairão, Portugal
(2) Symington Family Estates, Travessa Barão de Forrester 86, 4431-901 Vila Nova de Gaia, Portugal 

Contact the author

Keywords

Douro region, crop forcing, grapevine, phenology, quality, yield

Tags

GiESCO 2019 | IVES Conference Series

Citation

Related articles…

Impact of the maturity and the duration of maceration on phenolic composition and sensorial quality of Divico wines

Following its approval in 2013 by Agroscope, Divico became the first interspecific grape variety in Switzerland with high resistance to downy mildew (Plasmopara viticola) and grey rot (Botrytis cinerea), and medium resistance to powdery mildew (Uncinula nectator). Extremely riche in color, Divico grapes showed great enological potential to different styles of wine. Quickly, many wine growers were interested in planting this promising variety. Many of its potential are to be explored in the coming years.

Uncovering the effectiveness of vineyard techniques used to delay ripening through meta-analysis

One of the most concerning trends associated with increasing heat and water stress is advanced ripening of grapes, which leads to harvesting fruit at higher sugar concentrations but lacking optimal phenolic (i.e. color and mouthfeel) and aromatic maturity. Mitigation techniques for this phenomenon have been studied for many years and practices to delay sugar accumulation have been identified, including antitranspirants, delayed pruning and late-source-limitation techniques. Evaluation of the efficacy of these vineyard practices has occurred across a wide range of environments, vintages, varieties and growing conditions. To assess the broader efficacy of these three vineyard practices, which are easy-to-implement and cost-effective, a meta-analytic approach was adopted using data retrieved from 43 original studies.

Machines and fire: developing a rapid detection system for grapevine smoke contamination using NIR spectroscopy and machine learning modelling

Bushfires are a common occurrence throughout Australia and their incidence is predicted to both rise and increase in severity due to climate change. Many of these bushfires occur in areas close to wine regions, which receive different levels of exposure to smoke. Wine produced from smoke-affected grapes are characterised by unpalatable smoky aromas such as “burning rubber”, “smoked meats” and “burnt wood”. These smoke tainted wines are unprofitable and result in significant financial losses for winegrowers.

Does foliar fertilization with Seaweed improve the productivity and quality of ‘Merlot’ grape must?

Developing technologies that help vines survive and produce in quantity and quality within current times is mandatory. In this sense, in the 2021/2022 agricultural harvest, the influence of the foliar application of seaweed – Laminaria japonica was studied, aiming at productivity and quality of the must in the ‘Merlot’ grape. In the city of “Santana do Livramento”, “Rio Grande do Sul” (RS), Brazil; in a 15-year-old commercial vineyard of ‘Merlot’ clone ENTAV-INRA® 347, grafted onto ‘SO4’ rootstock, the following treatments were applied on 6 occasions: No treatment (control) and; Foliar application of Laminaria japonica seaweed (commercial product: Exal (ALAS), 2 kg ha-1).

Effects of different antioxidant strategies on the phenolic evolution during the course of a white winemaking process

This work aimed to evaluate the evolution of phenolic compounds during white winemaking process up to bottling and 12 months storage, together with the influence of different antioxidant strategies