Characterizing the determinants of berry acidity in the grapevine

Abstract

Global warming is expected to be a major issue for grapevine productivity and sustainability in the long-term future. Major grapevine characteristics at berry level (physiological development and com-position) but also at the whole plant level (e.g. sugar accumulation, malic acid respiration, photosyn-thesis rate etc) are expected to be changed by elevated temperatures. In order to further decipher major berry physiology and development traits, data from two different experimental conditions and V.vinifera genotypes were used. The data set from experiment 1 was obtained from three genotypes (Merlot, G7 and G14 which are interspecific crossings of V. vinifera x V. rotundifolia, (macrovine) and possess the trait VDQA – “Vins de qualité à teneur réduite en alcool”, which produce wines with lower alcohol content. Plants were grown in open field conditions and berry development was mon-itored every week since early stages to over-ripeness providing a full berry development curve. In a second trial,76 genotypes were tested at two key stages, at green stage (just before ripening onset) and at ripe stage (maximum berry volume) to explore the diversity of primary metabolites and cations that exist in a progeny of microvine deriving from a cross. The progeny derived from a crossing of V3 microvine (female dwarf plant) with G14. Data analysis provided important information on berry development at limited number (8 berries maximum) and at large number (hundreds) scale for all parameters (glucose + fructose, tartartic acid,malic acid,potassium). In addition, complex berry pa-rameters such as titratable acidity were calculated on the basis of simple parameters (e.g. anions and cations). Finally, our results showed that the genetic variability of V. vinifera is potentially inter-esting to identify QTLs that can be used in breeding programs to develop new grapevine genotypes more suitable to climate change conditions