Row Orientation and Defoliation Effects on Grape Composition ofVitis viniferaL. Agiorgitiko in Nemea (Greece)

Yorgos Kotseridis,Stefanos Koundouras,Serafeim Theocharis,Evangelia Chorti,Stamatina Kallithraka,Konstantinos Boulokostas

doi:10.1051/e3sconf/20185001039

Yorgos Kotseridis, Stefanos Koundouras + Show 4 more

Open Access

https://doi.org/10.1051/e3sconf/20185001039

Copy DOI

Abstract

Vineyard row orientation and canopy side exert a significant role in determining grape microclimate. The latter can be further manipulated by selective defoliation in the bunch zone. The aim of this study was to investigate the combined effects of row orientation and basal leaf removal on grape ripening of Vitis vinifera L. cv. Agiorgitiko in Nemea, Southern Greece. The experiment was conducted in 2017, on two adjacent vineyard blocks planted in 1990 on a flat site with two row orientations, North-South and East-West. Both blocks were grafted onto 41B rootstock and trained on a double cordon vertical trellis with uniform vineyard operations. Defoliation treatments included full leaf removal in the bunch zone performed at berry set and a non defoliated control, replicated three times in both blocks. Grapes were sampled at three time points from veraison to harvest from all canopy sides (i.e. E and W on North-South oriented rows and N and S on East-West oriented rows) and defoliation treatments and were analyzed for yield components and berry chemical composition. In addition, approximately 5 kg of grapes were collected from all plots and processed according to a standard winemaking protocol. Total yield and berry mass were lowest in the W-exposed and in the defoliated grapes. Must sugar and acid content, as well as wine alcohol and acidity did not depend on either factor. Skin anthocyanins and phenolics generally increased with defoliation. Skin anthocyanins and total berry phenolics were highest for north-south oriented rows, in the grapes of the cooler canopy side (E). Wines made from grapes of the E and W canopy sides showed the highest wine color, phenolic richness and the lowest pH. No interaction between row orientation and defoliation was detected for any of the measured parameters. According to the results, the E-facing grapes on the north-south oriented rows showed generally a superior grape and wine composition for Agiorgitiko variety, under the semiarid conditions of the Nemea area.

Highlights

Bunch zone defoliation is a very common viticultural practice applied to manipulate canopy microclimate
It has been suggested that photosynthetically active radiation (PAR) absorption by the grapevine canopy is higher in north–south and northeast–southwest than in east–west row orientations for latitudes between 30 and 50°N [6]
It has been shown that east–west row orientations [7] can result in reduced growth, yield and total dry mass per vine compared to north–south and northeast–southwest orientations in Chardonnay grown in the Northern hemisphere, while juice total soluble solids and pH were not affected

Summary

Introduction

Bunch zone defoliation is a very common viticultural practice applied to manipulate canopy microclimate. It modifies bunch light environment, inducing a positive effect on skin anthocyanins of grape berries [1]. It promotes air circulation into the canopy, reducing humidity and subsequently the risks of fungal infection [2]. Vineyard row orientation is an important factor determining canopy microclimate and grape berry composition. It has been suggested that photosynthetically active radiation (PAR) absorption by the grapevine canopy is higher in north–south and northeast–southwest than in east–west row orientations for latitudes between 30 and 50°N [6].

Objectives

Methods

Conclusion