Plant growth regulators used to control excessive vegetative growth and prevent premature senescence in wheat can boost yields and income by regulating plant architecture, extending the lifespan of functional leaves, and enhancing stress resistance. The specific strategies are outlined below:
Common Plant Growth Regulators and Their Functions
Uniconazole / Paclobutrazol: Applied between the green-up stage and the early jointing stage, these agents shorten basal internodes, reduce plant height, and thicken stems. They control excessive growth to prevent lodging while avoiding premature senescence in later stages; Uniconazole, in particular, offers a shorter residual period and higher safety.
Diethyl aminoethyl hexanoate (DA-6):Enhances cellular metabolic activity and photosynthesis, delays leaf senescence, promotes nutrient transport during the grain-filling stage, and increases thousand-grain weight. It is suitable for use throughout the entire wheat growth cycle.
Brassinolide:An analogue of natural endogenous plant hormones; it is safe and residue-free throughout the growth cycle. It enhances resistance to cold, drought, and dry-hot winds. Application during the grain-filling stage significantly extends the lifespan of functional leaves and effectively prevents premature senescence. It can also be mixed with foliar fertilizers and pesticides to boost their efficacy.
Sodium Nitrophenolates (Atonik):Accelerates nutrient absorption and transport, promotes root development and seedling vigor, enhances overall plant stress resistance, and reduces issues related to premature senescence and yellowing in later stages.
Key Application Strategies
Growth Control Stage (Green-up to Early Jointing): Use 10% Uniconazole or 15% Paclobutrazol wettable powder. Dilute with 30–40 kg of water per unit area and spray evenly, ensuring no missed spots or overlapping applications to avoid excessive growth inhibition caused by over-application.
Anti-Senescence Stage (Flowering to Grain-Filling): Integrate this with the "One Spray, Three Preventions" (comprehensive pest, disease, and stress control) program. Mix Brassinolide and DA-6 with insecticides, fungicides, and potassium dihydrogen phosphate for a combined spray application. A single application achieves three goals—preventing pests and diseases, protecting against dry-hot winds, and preventing premature senescence—thereby extending the grain-filling period, significantly increasing grain number per spike and thousand-grain weight, and ultimately boosting yields and income.
