Cultivar-Dependent Variation in Phenolic Compounds, Anthocyanin Profile, and Fruit Quality Traits in Romanian Blueberry (Vaccinium corymbosum L.)

The blueberry (Vaccinium corymbosum L.) is known for its high content of bioactive compounds, which are widely recognized for their health-promoting properties. This study aimed to characterize the fruit quality, total phenolic content (TPC), total monomeric anthocyanin content (TMA), anthocyanin profile and antioxidant activity of the nine Romanian V. corymbosum genotypes (‘Augusta’, ‘Azur’, ‘Delicia’, ‘Lax’, ‘Pastel’, ‘Prod’, ‘Safir’, ‘Simultan’, and ‘Vital’) over three consecutive harvest seasons (2023–2025). Significant genotype- and year-dependent variation was observed for all parameters. ‘Lax’ consistently accumulated the highest total anthocyanin content across all three seasons, while ‘Simultan’ exhibited the highest antioxidant activity and total monomeric anthocyanin content. ‘Prod’ consistently recorded the lowest phytochemical values despite achieving the highest firmness in 2025. UPLC analysis identified 10 anthocyanins, covering all five major anthocyanidin classes. Strong positive correlations were found between TPC, TMA, and antioxidant activity. These results confirm that genotype is the primary determinant of blueberry phytochemical composition, as indicated by the largest effect sizes in the two-way ANOVA, with harvest year and genotype × year interaction as statistically significant but secondary modulating factors, and identify ‘Lax’, ‘Simultan’, and ‘Safir’ as promising cultivars for nutraceutical and breeding applications.