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.
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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.
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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 |
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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.
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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