Mepiquat chloride and Chlormequat chloride are both commonly used plant growth regulators. They differ distinctly in their roles and applications regarding controlling excessive vegetative growth, promoting tillering, and improving fruit/grain set, making them suitable for different crop scenarios.
I. Comparison of Core Functions
Controlling Excessive Growth
Chlormequat chloride acts rapidly by inhibiting gibberellin synthesis; shortened internodes are visible within 3–5 days, with an effect lasting 15–20 days, and it is safer for dicotyledonous crops. Mepiquat chloride has a milder effect, carries a lower risk of phytotoxicity, and gradually inhibits leggy growth, avoiding over-suppression.
Promoting Tillering
Both agents can break apical dominance, promoting the emergence of low-position tillers in crops like wheat, resulting in more robust tillers and an increased number of spikes per mu. Mepiquat chloride is often formulated with Uniconazole for enhanced safety; Chlormequat chloride is typically applied during the late tillering stage of wheat to thicken tiller stems.
Improving Fruit/Grain Set
Proper use facilitates nutrient transport to the spike or fruit, reducing instances of barren stalks or unfilled tips. On corn, Chlormequat chloride helps prevent excessively high ear placement. Mepiquat chloride can be applied during the flowering stage without disrupting normal blooming; it aids in improving pollination quality, thereby indirectly increasing the fruit or grain set rate.
II. Application Strategies for Major Crops
Wheat:Spray at the 3–5 leaf stage (combined with foliar fertilizer) to promote tillering; control growth and prevent lodging in later stages. | Apply during late tillering to inhibit basal internode elongation and enhance cold resistance.
Corn:Spray as needed at the 7–10 leaf stage for milder growth control. | Apply 15–20g per mu at the 8–10 leaf stage to dwarf the plant and prevent lodging.
Cotton/Fruit Trees:Apply small amounts frequently throughout the season to control growth; safe for shoot control during flowering. | Target spraying during the vigorous growth phase; do not apply during the young fruit stage.
