A spatiotemporal modeling approach for synergistic optimizing ethephon application to enhance sugar content in sugarcane

Sugarcane is a globally important sugar crop, and stalk sugar content is a primary determinant of its industrial value. While ethephon is a commonly used ripening agent known to enhance sugarcane sugar accumulation, systematic field studies evaluating its optimal application remain limited. This research addresses this gap by presenting a detailed investigation into the field application of ethephon to maximize sugar accumulation in sugarcane. Using the medium-to-late maturing sugarcane cultivar ‘ZZ9’, this study investigated the interactive effects of ethephon application concentration, timing, and harvest time on sugar accumulation. Employing a rigorous orthogonal experimental design and Response Surface Methodology (RSM), we systematically dissected the spatial (internode-dependent) and temporal (application and harvest timing-dependent) effects governing ethephon application efficacy. Foliar application of ethephon at varied concentrations significantly enhanced sugar content in sugarcane stalks, specifically affecting these immature internodes. Spatiotemporal application of ethephon revealed optimized results: applying 400 mg/L ethephon approximately 250 days after emergence, followed by harvesting 11 days later, increased stalk sugar content by 0.73% (a 4.4% improvement over the control). Further optimization using RSM established a robust regression model, which predicted that spraying 480 mg/L ethephon at 243 days after emergence, followed by harvesting 10 days post-application, would increase Brix by 0.817% in the 4 th internode, corresponding to a 12.16% relative enhancement compared to the control. Although ethephon application slightly reduced sugarcane yield and potentially accelerated leaf senescence, these effects were outweighed by the observed improvements in sugar enhancement under optimized conditions. This study successfully elucidated the optimal application parameters for ethephon to enhance sucrose accumulation in field-grown sugarcane. These findings provide a readily applicable protocol for growers aiming to improve sugar yields, offering valuable insight for enhancing cultivation efficiency and promoting sugar industry development. • Optimized ethephon application boosts 12.16% increase of sugarcane sugar. • First evidence: ethephon’s effect concentrated in young sugarcane internodes. • Model reveals optimal ethephon protocol: 480 mg/L at 243 days, harvest 10 days post. • Strategic ethephon use enhances sugar content without significant yield reduction. • New insights into ethephon application for improved sugarcane cultivation efficiency.