Chlormequat. Brilliant Growth Regulator
Chlormequat originally came to the market in the 1970’s; it is an organic compound that is used as a plant growth regulator. It is typically sold as the chloride salt, chlormequat chloride a colourless hygroscopic crystalline substance that is soluble in water and ethanol.
In the wheat plants acropetal (towards the shoot and root apices) transport of Chlormequat predominates, while in barley Chlormequat is transported in a basipetal direction (inward.)
In many ways it has been a victim of its own success with one body after another finding reason NOT to use it.
But it should not be forgotten that Chlormequat has also been called the "single most important inhibitor of gibberellins biosynthesis." As such, it inhibits cell elongation, resulting in thicker stalks, which are sturdier, this means harvesting of cereal crops can be improved where it is applied.
As a growth regulator it shortens the internodes and strengthen the stem walls by redirection of assimilates “outwards” rather than “upwards.” The reduction in internode length varies (7–20 cm) between varieties, the rates applied, crop growth stage and in part weather conditions.
To prevent lodging in winter wheat chlormequat may be applied at, and/or before, stem extension so that the lower internodes are shortened and strengthened.
Architecture varies enormously between crop types, wheat and barley, winter and spring.
1) Some varieties have long straw
2) Different varieties of wheat receiving the same treatments and in the same field grow to various heights.
3) Winter barley can sometimes end up “longer in the straw” when Chlormequat is applied.