Effect of different spraying levels of cycocle on vegetative growth and flowering of poinsettia pot plant (Euphorbia pulcherrima Willd.)

Poinsettia (Euphorbia pulcherrima) is a pot plant, which its colorful bracts form in short days. In order to increase the marketability of this plant, effect of spraying different concentrations of 2-chloroethyl-N, N, N-trimethyl-ammonium chloride (cycocle) growth retardant on the vegetative growth and flowering characteristics of poinsettia was investigated. The experiment was arranged in a completely randomized blocks design with three replications. Poinsettia plants were sprayed with different concentrations of cycocle (0, 500, 1000, 1500 and 2000 mg/L). At the harvest time, the vegetative characteristics, fresh and dry weight of aerial parts and roots, chlorophyll index and mineral elements’ concentration were measured. The results revealed that quality and quantity characteristics of poinsettia was significantly (P≤0.01) affected by various cycocle levels. Spraying the cycocle at 2000 mg/L increased chlorophyll content of the leaves. In 1500 mg/L chloromequat treatment, plant height was decreased; while number and area of bracts increased significantly as compared to the control. Also, effect of cycocle treatment on fresh and dry weight of leaf, stem, and roots was meaningful. Therefore, based on the obtained results, it seems that spraying of cycocle at 1500 mg/L level, made improving in the production characteristics of poinsettia.