Abstract: This study examined the regulatory effects of exogenous single and combined applications of 2,4-epibrassinolide (EBR) and sucrose (Suc) on the ripening process, color formation and fruit quality of winter-grown ‘Benihoppe’ strawberries under protected cultivation. Experimental data showed that all treatments significantly increased the a* value (redness) and anthocyanin accumulation, while decreasing the L* value (lightness) of strawberries compared with the control (water). Among them, treatment with 100 mmol/L sucrose was the most effective, resulting in a 43.1% increase in pelargonidin-3-glucoside content and a 42.3% increase in cyanidin content at 28 days after treatment relative to the control. EBR treatment at 1 µmol/L significantly increased individual fruit mass by 14.7% compared with the control. Sugar and organic acid composition analysis revealed that treatment with 100 mmol/L sucrose significantly increased the contents of fructose, sucrose, and glucose by 10.7%, 6.3%, and 11.6%, respectively, while significantly decreasing the contents of oxalic acid, malic acid, and citric acid, with a 40.3% reduction in malic acid. Both single 1 µmol/L EBR and its combination with sucrose effectively elevated glucose content and suppressed malic acid accumulation. Combined treatment with 100 mmol/L sucrose and 1 µmol/L EBR stimulated the biosynthesis of catechin and p-coumaric acid, while sucrose alone mainly upregulated p-coumaric acid accumulation. In conclusion, exogenous 100 mmol/L sucrose treatment can simultaneously optimize the ripening process, appearance, color, sensory flavor, and nutritional quality of winter-grown strawberries, representing an economical and effective production regulation measure.

Key words: strawberry; 2,4-epibrassinolide; sucrose; fruit ripening; color formation; synergistic regulation