Gibberellin Biosynthesis Inhibition and Flowering Science
Paclobutrazol is a triazole plant growth regulator that inhibits the oxidation of ent-kaurene to ent-kaurenoic acid, blocking the biosynthesis of gibberellins in plant meristems. By lowering internal gibberellin levels, it shifts carbohydrate allocation from vegetative leaf flushes toward reproductive flower bud differentiation.
Treated mango trees exhibit compact canopy growth, reduced internodal elongation, and heavy, uniform panicle emergence.
- Regulates alternate bearing: Overcomes the irregular bearing cycle in sensitive mango cultivars (such as Alphonso, Kesar, and Dashehari).
- Induces early flowering: Shifts panicle initiation 3 to 4 weeks earlier, allowing growers to harvest early for premium market prices.
- Synchronized panicle set: Ensures uniform bloom across the entire tree canopy, simplifying pest management and fruit harvesting.
- Tree age requirement: Strictly recommended for mature mango trees older than 7 to 10 years; never apply to juvenile saplings.
Soil Collar Drenching and Application Technique
Paclobutrazol is absorbed primarily by active feeder roots and translocated acropetally via xylem vascular channels to growing shoot tips.
Application must be performed through directed soil collar drenching during post-harvest dormancy (typically July to September).
- Dosing rule: Calculate dose precisely based on canopy diameter (canopy spread in meters multiplied by recommended active ingredient per meter).
- Application method: Excavate a narrow 10 to 15 cm furrow around the tree trunk at a distance of 1 to 1.5 meters, pour diluted Cultar solution uniformly, and cover with soil.
- Post-application irrigation: Irrigate the root zone immediately to facilitate active chemical uptake by subterranean roots.
- Avoid annual over-dosing: Regular application requires periodic holiday years to prevent excessive canopy stunting.
Official source
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Common questions
What is Cultar (Paclobutrazol) used for in mango cultivation?
It is applied to mature mango trees to suppress unwanted vegetative growth, break biennial bearing cycles, and induce early uniform flowering.
When is the correct time to apply Cultar to mango trees?
Apply it via soil root drenching 3 to 4 months before natural flowering, typically between July and September depending on local regional climates.
Can Cultar be applied to young, non-bearing mango saplings?
No, Cultar should never be applied to trees younger than 7 years, as it severely stunts vegetative canopy development.
General guidance, not personal advice. For your farm, ask your local Krishi Vigyan Kendra or agriculture officer.
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