Analysis of Compounds with Oenological Interest in Somatic Variants of Grapevines

Grapevine varieties can be identified genetically by microsatellite markers. However, these molecular markers are not available to discriminate between somatic mutations that give rise to clones. Therefore, the study of compounds with oenological interest could be used to identify variability in grapevine somatic variants. In this research, sugars (glucose, fructose), acids (tartaric and malic acid) and polyphenols (22 phenolic compounds, including 13 anthocyanins) were analyzed in grape berries of two somatic variants known with different names—‘Graciano’ and ‘Tintilla de Rota’—cultivated in the same vineyard under warm climate conditions. The organic acid results show significant differences between the performance of the two accessions. Regarding phenolic compound (excluding anthocyanins) content, significant differences were observed between the two accessions. Kaempferol, caftaric acid and epicatechin were the compounds responsible for the reported differences. Differences in anthocyanin content showed opposite behavior between ‘Tintilla de Rota’ and ‘Graciano’. In this sense, ‘Graciano’ accession showed an increase in all forms of anthocyanins, with a remarkable increment of peonidin 3-O-glucoside. Principal component analysis of polyphenolic compounds revealed clearly distinguished behaviors concerning these compounds, besides showing similar tendencies between the two accessions during the ripening stage. These results could allow for the discrimination of the two accessions into somatic variants highlighting their individual identity