Paclobutrazol use in perennial fruit crops and its residual effects: A review

Abstract

Paclobutrazol (PBZ), a triazole derivative, has been effectively used to induce and manipulate flowering, fruiting and tree vigour in several perennial fruit crops. However its use in mango is quite common. Soil application of paclobutrazol has been efficacious in promoting flowering and increasing yield in many fruit crops. However, there are some conflicting reports on its impact on fruit quality parameters. Besides reducing gibberellins level, PBZ increases cytokinin contents, root activity and C: N ratio, whereas its influence on nutrient uptake lacks consistency. PBZ also affects microbial population and dehydrogenase activity in soil. PBZ has been characterized as an environmentally stable compound in soil and water environments with a half-life of more than a year under both aerobic and anaerobic conditions. However, its residue could not be detected above quantifiable level (0.01 ppm) in soils and fruits when applied in optimized rate. The potential of PBZ to contaminate groundwater at optimum concentrations is low however the risk of its exposure to aquatic life is high. PBZ is considered moderately hazardous for human beings with remote chance of being genotoxic and carcinogenic. In view of the above, optimized use of the PBZ to derive maximum benefit with least undesirable impact on food and environmental safety aspects is suggested.