Effects of Timing of CPPU Applications on Rabbiteye Blueberries

Abstract

A series of field and greenhouse experiments were conducted at two locations in Georgia to determine how rabbiteye blueberries (Vaccinium ashei Reade) respond to different timings of application of the growth regulator [N-(2-chloro-4-pyridyl)-N′-phenylurea (CPPU)]. In all tests, a CPPU rate of 15 mg·L−1 was used, and timings of applications were based on days after flowering (DAF). Overall, results indicate that a positive response in fruit set or berry size can occur with applications of CPPU depending on cultivar and timing of application. As with many growth regulators, the effect can vary, and these experiments indicate that the timing of CPPU application is critical in achieving the most desirable response. Collectively, data suggest an optimum window of application of CPPU to rabbiteye blueberries is between 7 and 21 DAF with the most probable success being from an application made around 14 ± 3 DAF.