Grapevine double cropping: Theoretical and applied aspects for year-round production of grapes

• Summarizes the theoretical basis and agronomic implementation of grapevine double cropping. • Explores physiological and molecular regulation of bud dormancy and secondary flowering. • Identifies pruning and hydrogen cyanamide as induced abiotic stresses to trigger bud break and enable double cropping. • Explore implications for sustainable viticulture, especially in the context of climate change and changing market demands. Dormancy is a critical stage for the development of floral organs in grapevine buds. In regions with insufficient low temperatures, the dormancy period may be prolonged, leading to delayed germination, irregular budbreak, and reduced yields. This indicates the imperative to formulate scientific and sustainable strategies to effectively address grape dormancy and enhance early budbreak quality, while also undertaking comprehensive studies on the critical factors affecting secondary inflorescence formation, thus ensuring consistent yield and quality in grape cultivation systems. This review summarizes recent advances in understanding stress-induced secondary flowering in grapevine, with a focus on postharvest practices like leaf-degreening, pruning, and hydrogen cyanamide application, as well as key mechanisms involving gene regulation, ROS signaling, hormonal crosstalk, and carbohydrate metabolism. Among these practices, leaf degreening promotes nutrient backflow and the differentiation of secondary flower buds; pruning stimulates budburst and increases the proportion of floral buds; and hydrogen cyanamide (HC) application improves the uniformity of budbreak while enhancing both the budbreak and flowering rates in grapevines. Incorporating a variety of grape varieties further facilitates year-round cultivation, thereby presenting a potential pathway for sustainable production. In conclusion, the review draws attention to current challenges and provides insights into future applications, to optimize viticultural practices in response to evolving market and environmental demands.