Improved berry and wine quality of Vitis vinifera L. cv. Gewürztraminer grown in an arid climate using a Y-shaped training system

Abstract

Recent global climatic changes have highlighted viticulture in arid/semiarid regions as an increasingly relevant study model. Grapes in arid regions face excessive solar irradiance, leading to more than 50 °C berry surface temperatures in exposed berries. The resultant oxidative stress, sunburn necrosis, and browning consistently reduce berry quality. Adapting an adequate training system to the climate and cultivar is a simple and inexpensive method to control the radiation regime. This study compares the berry and wine characteristics and compositional components of desert-grown Vitis vinifera L. cv. Gewürztraminer, trained on either a Vertical Shoot Positioning (VSP) system or a Y-shaped training system (SAYM, Sistema di Allevamendo ad Ypsilon Integralmente Meccanizzabile), a method with a higher canopy light interception. The SAYM training reduced direct radiation and concomitant heat in the cluster zone and significantly alleviated oxidative stress in berries in the 2016/17 season. In addition, SAYM-grown berries were preferable in terms of quality and productivity. Correspondingly, a sensorial analysis rated SAYM wines higher than VSP wines in all categories. Photosynthetic pigment content in the berries' skin showed similarities between VSP and SAYM, and a volatile compound analysis of the wines by GC-MS revealed a higher ester content in the wines derived from SAYM vines, along with a higher content of compounds linked to Gewürztraminer wine typicity (varietal characteristics such as esters, terpenoids, and alcohols).