EFFECT OF PLANT GROWTH REGULATORS ON EXPRESSION OF YELLOW CANOPY SYNDROME IN SUGARCANE

MANY POTENTIAL FACTORS thought to drive the severity of Yellow Canopy Syndrome (YCS) expression in sugarcane have been previously studied, yet no factor has been proven to be a reliable predictor of YCS severity. Attempts to correlate YCS severity with water stress, genotype, crop class, rainfall patterns, and other agronomic drivers have been largely unsuccessful. In 2015 a field trial investigated the influence of crop age on YCS. Results showed that younger, rapidly growing sugarcane were more severely YCS-affected than older, more mature cane. This paper discusses a further exploration of these findings through the application of plant growth regulators to commercially-grown cane during the YCS season. Results showed a significant reduction in YCS severity in sugarcane treated with Paclobutrazol (PAC) and aviglycine (AVG) and an increase in severity in the gibberellic acid (GA) treatment. Biomass results were mixed, with GA showing reduced biomass while PAC and AVG were similar to untreated control. These findings suggest a possible link between plant growth rate and YCS severity.