Plant Growth Regulators

What Is It?

  • Able to stimulate, enhance, promote, increase growth and development of a crop;
  • CFIA regulated through the Fertilizers Act;
  • They are not pesticides and DO NOT required MRLs (Maximum Residue Limits);
  • DO NOT affect the shipping and handling of the grains.

When & Why Use It?

PGRs are naturally occurring substances:

  • PGRs enhance early season vigor and drive maximum root growth.
  • They provide a consistent performance across a wide variety of crops and growing conditions.
  • They are required at LOW application rates.

What To Expect?

PGRs are designed to be incorporated into a well-balanced nutrition program to achieve:

  • Better nutrients uptake;
  • Enhanced growth and development;
  • Better seed/fruit/tuber set;
  • Crop standability;
  • Preserve yield and increase profitability.

Auxins (IBA, …) Cytokinins (Kinetin, …)
  • Auxins are known to activate cell elongation by increasing the level of elasticity of the cell walls.
  • Auxins stimulate ethylene production and inhibit the growth of buds. This effect is known as apical dominance.
  • They also promote adventitious and lateral root growth and development.
  • Auxins include 3-Indoleacetic acid (IAA), 3-Indolebutyric acid (IBA); 1-Naphthylacetic acid (NAA) among others.
  • Kinetin is the only Canadian registered cytokinin that can be used on a variety of crop species.
  • Kinetin is considered a “green” plant growth regulator.
  • Kinetin increases the rate of cell division, differentiation and growth.
  • It delays senescence in plant tissues, increases flower set, fruit formation and side branching.
  • Kinetin also increases flower set, fruit formation and side branching.

2 effects depending on application timing:

  • Early (3-5 leaf stage): increases the number of seeds per kernel/pod
  • Late (during reproductive stage & prior to grain fill): increases the Thousand Kernel Weight (TKW) and seed size
Gibberellins (GA3, …) Others
  • GA enables seed to overcome dormancy and promote the activity of the a-amylase, sprouting and emergence.
  • GA affects cell elongation.
  • GA can increase seed and fruit set when applied appropriately.
  • Ethylene aka the senescence and ripening PGR.
  • Abscisic acid aka dormin or dormic acid that encourages dormancy and controls stomata opening and water-use efficiency under stress conditions.
  • Brassinosteroids involved during the reproductive stage of certain plant species.