Homozygosity of the berry color locus on chr 2 in Vitis vinifera cv. Dornfelder, Domina and Probus

Abstract

Achieving intense berry coloration and high phenolic ripeness represents a major challenge in cool climate viticulture, where lower temperatures often limit anthocyanin accumulation and the production of full-bodied red wines. Therefore, the selection of grapevinevarieties capable of synthesizing and accumulating sufficient levels of anthocyanins, while maintaining desirable agronomic andoenological traits, is of great importance for wine-growing regions under such climatic conditions. This study investigated the geneticand biochemical basis of enhanced berry coloration in the grapevine varieties ‘Dornfelder’, ‘Domina’, and ‘Probus’. All three cultivarswere identified as homozygous for the VvmybA1c allele at the berry color locus on chromosome 2, known as the black color allele. Homozygosity at this locus was associated with a significant increase in total anthocyanin concentration in berry skins compared to their parental varieties. The increased anthocyanin accumulation led to wines with higher color density, indicating an additive effect of coloralleles on the regulation of anthocyanin biosynthesis. Statistical analysis confirmed positive correlations between total anthocyanincontent, wine color density, and alcohol level, which could be described by a regression model. Among the studied cultivars, ‘Domina’ and ‘Dornfelder’ exhibited the highest color density in the resulting wines. Anthocyanin profiling demonstrated cultivar-specific composition patterns. Mono-glucosides were the predominant compounds in all three varieties, while secondary anthocyanin formsdiffered among cultivars. In ‘Probus’ and ‘Domina’, anthocyanin dimers were the second most abundant group, whereas in ‘Dornfelder’, 3-coumaroyl derivatives were present in higher amounts. Cluster analysis based on anthocyanin concentrations in berry skins and winesconfirmed the close genetic relationship between the homozygous cultivars and their parental lines. Overall, the results highlight the importance of genetic background in determining anthocyanin accumulation and wine color intensity, and demonstrate that anthocyanin composition can serve as a reliable biochemical marker for grapevine cultivar differentiation.