The use of viticultural and oenological performance of grapevines to identify terroirs: the example of Sauvignon blanc in Stellenbosch

The aim of this work was to study winemaking alternatives that will optimize the quality of the Tannat wines, taking advantage of the grape’s oenological potential.

Grapevine (Vitis vinifera L.) is a challenging plant species to transform and regenerate due to its complex genome and biological characteristics. This limits the development of cisgenic and gene-edited varieties. One hurdle is selecting the best starting tissue for the transformation process, much like isolating suitable tissue for protoplasts. One promising method involves delivering CRISPR/Cas components to protoplasts isolated from embryogenic calli, which are then induced to regenerate. However, this process is inefficient, time-consuming, and only applicable to a few genotypes. To enhance grapevine regeneration efficiency, the expression of developmental and plant growth regulators shows promise in escaping the recalcitrance encountered in traditional tissue culture methods.

The aim of this work was to analyze the variability in grape composition of the Tempranillo cultivar related to climatic conditions, in La Mancha Designation of Origin. Grape composition (sugar content, total acidity, pH, malic acid, and total and extractable anthocyanins) recorded during ripening, were analysed for the period 2000-2019. The weather conditions at daily time scale, recorded during the same period, were also evaluated. The relationships between grape parameters with climatic variables related to temperature and to water deficits, referring different periods between phenological events along the growing cycle, were evaluated using regression analysis. High variability in grape composition was observed in the period analysed. Total acidity varied between 3.7 and 7.3 gL-1 while malic acid varied between 1.2 and 4 gL-1. The extractable anthocyanins ranged between 526 and 972 mgL-1, and total anthocyanins ranged between 922 and 1388 mgL-1, being the lowest values recorded in the hottest year (2017). Total acidity decreased 0.77 gL-1 for an increase of 100 GDD, while malic acid decrease in 0.42 gL-1 for the same GDD increase, being the period between veraison and harvest the one that seemed to have higher influence on acidity. In addition, it was confirmed that increasing water deficits decreased acidity. Total and extractable anthocyanins increased in about 210 and 105 mgL-1, respectively, with an increase of 100 GDD from veraison to harvest, and the increase in water deficits favour the increase of anthocyanins, both total and extractable anthocyanins. Total and extractable anthocyanins concentration increased in 35 and 22 mgL-1 per an increase of 10 mm in the water deficit. These results can be of interest to understand the potential changes that grapes composition may suffer under future warmer climates.

Temperature and yeast nutrition profoundly impact wine quality and sensory attributes by modulating yeast aroma production and release during fermentation. While temperature and nitrogen’s individual effects are well-studied, their combined influence, including nutrient type and addition timing, remains underexplored. hence, this study aimed to investigate the simultaneous effects of these factors on fermentation kinetics, aroma production and sensory profile, particularly in a Chardonnay wine production selected as a quite aromatically neutral base.

The poster presents the results of the 3rd year of activity of the project “Characterization of the wine productions of the italian regions. The DOC wine Colli Piacentini Gutturnio”.