Polyphenol and Flavonoid Levels of Selected Morello and Amarelle Tart Cherry Cultivars (Prunus cerasus L.): Implications for Orchard Production and Consumer Selection

Tart cherries (Prunus cerasus L.) are valued for their high content of bioactive compounds, particularly polyphenols, flavonoids, and anthocyanins, which contribute to fruit quality and potential health benefits. However, data on phytochemical differences between Morello and Amarelle cultivars remain limited. In the present study, eleven tart cherry cultivars representing both groups were evaluated over two growing seasons (2024–2025) under identical orchard conditions. Dry matter, phenolic acids, flavonoids, and anthocyanins were quantified using HPLC methods, and the effects of cultivar, season, and their interaction were assessed by ANOVA. Significant differences were observed among cultivars and between seasons (p < 0.05). Kelleris 16 showed the greatest concentrations of total polyphenols and phenolic acids, whereas Łutówka was characterized by elevated levels of catechin, epigallocatechin, quercetin derivatives, and myricetin. Morello cultivars generally contained substantially higher flavonoid and anthocyanin concentrations than Amarelle cultivars. In contrast, selected Amarelle cultivars, particularly Szklanka Wielka, exhibited higher levels of chlorogenic and caffeic acids. Most polyphenolic compounds were more abundant in 2024 than in 2025, highlighting a strong seasonal effect, while anthocyanin levels remained comparatively stable in both seasons. Both genotype and growing season significantly influenced the phytochemical composition of tart cherries. Morello cultivars generally exhibited higher flavonoid and anthocyanin concentrations than Amarelle cultivars, whereas selected Amarelle cultivars contained higher levels of specific phenolic acids. These findings provide valuable information for cultivar selection and future studies on the nutritional and functional properties of tart cherry fruits.