Influence of Paclobutrazol on Vegetative Growth, Nutrient Content, Flowering and Yield of Mango (Mangifera indica L.) and Its Residual Dynamics

Present study aimed to assess the efficacy of Paclobutrazol (PBZ) in mango in terms of vegetative growth, leaf nutrient status, flowering, yield, and fruit quality. Moreover, residual dynamics of PBZ in soil and plant parts was also assessed. Studies were conducted under tropical hot and humid climatic conditions of eastern India during 2013-2017 on 15-year-old trees of mango var. Arka Neelachal Kesari. Paclobutrazol was applied at 0.25–1.0 gram active ingradient (g ai m-1) canopy spread in soil during September. Results indicated that PBZ significantly reduced Trunk Cross Sectional Area (TCSA), shoot length, and leaf area. There was a reduction in leaf N and K contents, whereas the levels of Ca, Mg, Cu and Zn were increased in PBZ-treated plants. PBZ advanced floral bud break and increased flowering intensity, percentage of bisexual flowers, fruit yield, and yield efficiency. Higher concentration of PBZ aggravated shoot and panicle compaction. PBZ tended to increase Total Soluble Solids (TSSs) but pulp content and pulp/stone ratio were unaffected. PBZ residues in soil persisted for 9 months at higher rate of application, whereas at lower rate residues reached non-detectable level within 5-6 months after application. Fruits were free from PBZ residue, irrespective of dose. Application of PBZ at lower dose (0.25 g ai m-1 canopy spread) was not only efficacious in enhancing flower induction and yield without affecting plant growth but also exhibited high rate of depletion in soil.