1. Plant Growth Regulators (PGR) are organic chemical substance, other than nutrients and vitamins which regulate the growth of plant when applied in small quantities. PGR are used in different forms like liquid, powder, paste etc. Classification of PGR: 1. Auxins: IAA, NAA, IBA, 2-4D, 4-CPA. 2. Gibberellins: GA 3. 3. Cytokinins: Kinetin, Zeatin 4. Ethylene: Ethereal 5. Abscissic acid Introduction:

2. Rooting of Cutting: Auxins are applied in the form of paste and solution and the concentrations of chemicals vary with plant species, types of cutting and method of application. Layering and Grafting: Auxins are applied to girdled portion of layers to promote root formation. It also promotes early union in grafting. Seed Germination: GA 3 enhances speed of seed germination in many plant species including cereals and pulses. Use of Plant Growth Regulators

3. Sprouting of Buds: Spraying of Ethrel, GA 3, IBA and cytokinin on crop plants induces sprouting of buds. Breaking of Dormancy: GA 3, Ethrel, NAA are used in breaking dormancy in seeds and buds. Inhibition Of Sprouting: Application of Maleic Hydrazide @ 2500 ppm 15 days before harvesting prevent sprouting of onion in storage. Soaking potato tuber in IAA @250 to 1000 ppm solution prolongs dormancy. Use of Plant Growth Regulators

4. Application in Powder form: PGR Powder dissolved in organic solvent mixed with moistened charcoal powder, soybean flour or wheat flour and prepare a uniform paste. The paste is allowed to stand until the solvent evaporates. Application in Lanoline paste: Most of the root promoting PGR are readily soluble in lanoline. A lanoline paste which promotes advantageous roots in plant is made by mixing PGR in lanoline and allowing it to cool. Methods of application of PGR:

5. Soaking Method: Measured quantity of PGR is dissolved in alcohol then dilute with distilled water to make required quantity and concentration of solution ( 20-2000 ppm). Cuttings are soaked in solution for 24 hours before planting. Aerosol Method: This method is popular in green houses, where the PGR solution is released through a small aerosol bottle / cylinder. Liquid gas soon evaporate leaving the PGR chemical in the air. Methods of application of PGR:

6. Vapour method: This method is suitable and practiced in green houses with good air, light and ventilation. The PGR is vaporized over a hot plate and allowed to disperse in green house. Methods of application of PGR: