GiESCO 2019 banner
IVES 9 IVES Conference Series 9 GiESCO 9 GiESCO 2019 9 Is early defoliation a sustainable management practice for mediterranean vineyards? Case studies at the portuguese lisbon winegrowing region

Is early defoliation a sustainable management practice for mediterranean vineyards? Case studies at the portuguese lisbon winegrowing region

Abstract

Context and purpose of the study ‐ Recently early defoliation (ED) has been tested in several high‐ yielding grapevine varieties and sites aiming at reducing cluster compactness and hence, regulating yield and susceptibility to botrytis bunch rot infection. The reported results have been generally positive, encouraging growers to use this canopy management technique as an alternative for replacing the conventional time‐consuming cluster thinning and, simultaneously, as a sustainable practice to reduce the use of fungicides. However, ED increases berry sunburn risks and/or can induce carry‐over effects on vigor and node fruitfulness as shown in the two case studies reported in this work.

Material and methods ‐ Two ED experiments were set up at a commercial vineyard located in the Lisbon winegrowing region with the varieties Aragonez, syn. Tempranillo (2013‐2015) and Semillon (2018). In both experiments the ED treatment was compared with the non‐defoliated (ND; control) using a randomized complete block design with 4 replicates per treatment. The ED treatment consisted of the removal of 5‐6 basal leaves and any laterals at pre‐flowering. Vegetative (leaf area and pruning weight) and reproductive components (%fruit‐set, cluster number, cluster weight, yield) and berry composition were assessed.

Results ‐ In the Aragonez experiment total leaf area at harvest and pruning weight were significantly lower in ED vines. The ED treatment presented also a significantly lower fruit‐set, berry weight, cluster weight and compactness, as well as yield as compared to the control. In the third season ED presented a significantly lower cluster number indicating a negative carry‐over effect on bud initiation induced by the early source limitation. Regarding berry composition, ED showed a higher Brix and a lower titratable acidity than the control but no significant differences were detected on skin anthocyanins. The incidence and severity of botrytis bunch rot infection was significantly higher in the control treatment. In the Semillon experiment the ED treatment showed also a significantly lower leaf area, fruit‐set, berry weight, cluster weight, cluster compactness and yield. No significant differences were detected on berry composition except for Brix where ED showed a significantly higher value. Despite the low pressure of botrytis bunch rot infection the control presented the significantly highest incidence and severity. An heat event occurred during the first week of August induced a severe and significantly higher berry sunburn in the ED treatment. Our results show that pre‐bloom defoliation is a canopy management practice with high potential for regulating grape yield and with benefits for grape health.However, in Mediterranean climates, where water and heat stress can inhibit leaf area compensation, the negative effects observed either on berry sunburn and on node fruitfulness recommends to use this practice with care or even avoid it. 

DOI:

Publication date: June 19, 2020

Issue: GIESCO 2019

Type: Article

Authors

Carlos M. LOPES (1), Marta VENDEIRO, Ricardo EGIPTO (1), Olfa ZARROUK (2), M. Manuela CHAVES (2)

(1) LEAF, Instituto Superior de Agronomia, Universidade de Lisboa, Portugal
(2) Instituto de Tecnologia Química e Biológica, Oeiras, Portugal

Contact the author

Keywords

early defoliation, fruit‐set, grapevine, botrytis rot, berry sunburn

Tags

GiESCO 2019 | IVES Conference Series

Citation

Related articles…

Sustainable yield management through fruitfulness and bunch architecture manipulation

Vineyards are highly variable and this variation is largely driven by environmental conditions and seasonal variation. For example, warm temperatures

Le terre dei Lambruschi modenesi

La superficie vitata della provincia di Modena é per circa il 70% interessata dai Lambruschi, famiglia di vitigni tipica dei territori pianeggianti emiliani. Tra questi, i più rappresentativi sono il Lambrusco di Sorbara, il Lambrusco salamino e il Lambrusco grasparossa che, unico esempio, predilige gli ambienti collinari della provincia. Nel quinquennio 2001-2005 la Provincia di Modena ed il C.R.P.V. hanno coordinato la zonazione viticola di tutto il territorio dei Lambruschi modenesi, i cui risultati hanno consentito di individuare, in ciascuna zona D.O.C., alcune Terre in cui cias.

Pinot noir: an endemic or a flexible variety?

Pinot noir has its historical roots in Burgundy and is generally considered as an endemic vine variety which means that its adaptation is very specific to this environment

Climate and the evolving mix of grape varieties in Australia’s wine regions

The purpose of this study is to examine the changing mix of winegrape varieties in Australia so as to address the question: In the light of key climate indicators and predictions of further climate change, how appropriate are the grape varieties currently planted in Australia’s wine regions? To achieve this, regions are classified into zones according to each region’s climate variables, particularly average growing season temperature (GST), leaving aside within-region variations in climates. Five different climatic classifications are reported. Using projections of GSTs for the mid- and late 21st century, the extent to which each region is projected to move from its current zone classification to a warmer one is reported. Also shown is the changing proportion of each of 21 key varieties grown in a GST zone considered to be optimal for premium winegrape production. Together these indicators strengthen earlier suggestions that the mix of varieties may be currently less than ideal in many Australian wine regions, and would become even less so in coming decades if that mix was not altered in the anticipation of climate change. That is, grape varieties in many (especially the warmest) regions will have to keep changing, or wineries will have to seek fruit from higher latitudes or elevations if they wish to retain their current mix of varieties and wine styles.