Microclimate manipulation: leveraging the microclimatic differences created by diverse trellis systems to investigate the metabolic plasticity of Vitis vinifera cv. Chenin blanc in a model vineyard

Abstract

Field-grown crops such as grapevines, rely on ambient environmental conditions for growth and development. Grapevine growth and performance is intricately linked to the specific cultivar/rootstock (genotype) combination, interactions with the environment (macro-, meso- and microclimate), and management practices that influence sun exposure, photosynthetic activity as well as crop load. Selecting an appropriate trellising system over the long term is still crucial for controlling and assessing possible grapevine growth and, consequently, the quality of the resulting grapes and wine. Integrated studies where basic viticultural workflows are merged with robust experimental design to study and understand the genotype X environment X management (GxExM) interactions of grape cultivars are essential to future proof grape and wine production in the current era of climatic changes taking effect in most of the grape-growing areas of the world. Globally, Chenin blanc is known for being adaptable to a wide range of growing conditions, and in South Africa, has resulted in its vinification to a variety of different wine styles. In this study, we have access to a Chenin Blanc model vineyard where the cultivar was planted to 19 different trellis systems. We will present data regarding the impact of the modification of the microclimate, as a result of the configuration of six divergent trellis systems. The systems chosen comprise untrellised vines, vertically shoot positioning systems as well as single and double split canopies (2K2T, Lyre, High Wire Perold, 7-strand double lengthened, posted vines and bush vines). The impacts on phenology, physiology (growth, morphology, resource allocation), viticultural parameters, as well as the plasticity of metabolites used by Chenin Blanc to counter microclimatic extremes will be highlighted.