Plant Growth Regulators (PGRs)

Plant Growth Regulators are organic or synthetic compounds that influence plant growth and development even in minute quantities. Their judicious use complements physical management practices like pruning and staking.

 

 

Functions of PGRs

• Stimulate or inhibit stem, root, and leaf growth.
• Promote or delay flowering and fruiting.
• Improve fruit size, yield, and quality.
• Enhance stress tolerance and post-harvest shelf life.

 

Major PGRs and Their Uses

Type	Common Examples	Key Functions
Auxins	IAA, NAA, IBA	Promote rooting, fruit set, apical dominance
Gibberellins	GA3	Stem elongation, fruit enlargement, parthenocarpy
Cytokinins	Kinetin, BAP	Cell division, branching, delay senescence
Ethylene	Ethephon	Induce flowering, fruit ripening, leaf or fruit abscission
Abscisic Acid	ABA	Stress tolerance, induce dormancy

 

Methods of Application

• Foliar spray: rapid absorption through leaves.
• Soil drenching: applied near the root zone for systemic effect.
• Seed treatment: improves germination and early vigor.
• Fruit dipping: regulates growth, ripening, or uniformity of fruits.

 

Precautions

• Correct concentration and timing are critical to avoid phytotoxicity.
• Follow crop-specific recommendations.
• Use in combination with other crop management practices for optimal effect