Paclobutrazol (PBZ; IUPAC name: (2RS, 3RS)-1-(4-chlorophenyl)-4, 4-dimethyl-2-(1H-1, 2, 4-triazol-1-yl) pentan-3-ol) is a triazol derivative and an antagonist of gibberellins. It has been shown to inhibit shoot growth in various perennial fruit trees. Paclobutrazol application reduced the number of shoots, transforming trees into a more desirable, spur-type growth habit as the vegetative sink was reduced. This compound induces an early and intense flowering, diminishing vegetative growth and reducing the extension of buds, allowing for ripening and the initiation of apical buds inflorescence. Besides, it also increases fruit set, the years following application as a carryover effect. An increase in return bloom is a common response to paclobutrazol treatment and has been reported for various fruit crops. Paclobutrazol is widely used to advance harvest maturity in various fruit crops and it improves fruit quality in terms of accelerated colour development, delayed and synchronized fruit maturation and control of preharvest fruit drop. It is known to improve fruit physical and fruit chemical characteristics. Fruit calcium is increased for 2–3 years due to carry over effect. It helps in the maintenance of better fruit quality during storage and influences nutrient uptake in various fruit crops including stone fruits. It has been characterized as an environmentally stable compound in soil and water environments with a long half-life under both aerobic and anaerobic conditions.
Part of the book: Prunus