Predictive Breeding for Wine Quality: From Sensory Traits to Grapevine Genome

In contrast to fruit and grape berry ripening, the biological processes causing ripening disorders are often much less understood, although shriveling disorders of fruits are manifold and contribute to yield losses and reduced fruit quality worldwide. Shrinking berries are a common feature for all shriveling disorders in grapevine although their timing of appearance during the berry ripening process and their underlying induction processes distinct them from each other. The sugar accumulation disorder Berry Shrivel (BS) is characterized by a suppression of sugar accumulation short after veraison resulting in berries low in sugar content and anthocyanins in berry skins, while the organic acid content is similar. Recent studies analyzed the biochemical, morphological and molecular processes affected in BS berries and linked early changes to the period of ripening onset [1,2].

In interaction with climate and genetic or human factors, the soil is a major component of the viticulture terroir. The mineral composition of the soil influences vine performance and wine sensory attributes. Among the elements that vines take from the soil, nitrogen is the one that has the strongest impact on vine physiology, vigor and grape composition. In addition to its major effect on primary metabolites in berries, nitrogen plays also a decisive role in the secondary metabolism, especially in the production of key compounds for berries quality, like volatile thiols, methoxypyrazines and glutathione (GSH).

Overarching surveys of QTL (Quantitative Trait Loci) studies in both model plants and staple crops have facilitated the access to information and boosted the impact of existing data on plant improvement activities. Today, the grapevine community is ready to take up the challenge of making the wealth of QTL information F.A.I.R.. To ensure that all valuable published data can be used more effectively, the myriad of identified QTLs have to be captured, standardised and stored in a dedicated public database.
As an outcome of the GRAPEDIA initiative, QTL-dedicated experts from around the world have gathered to compile the grapevine QTLome: the complete information (e.g., map positions, associated phenotypes) describing all experimentally supported QTLs for a specific trait.

In the course of this study, stabilisation (lees stirring in unclarified must) with skin contact and classic white wine vinification were compared for the Sauvignon blanc and Traminer varieties in Austria. The test wines were analysed for the volatile substances esters, free monoterpenes and fruity thiols

Insufficient acidity in grapes from warm(ing) climates is commonly corrected through addition of tartaric acid during vinification, and less so with other organic acids. One alternative approach involves bio-acidification with certain strains of Lachancea thermotolerans (LT) via lactic acid production during fermentation.