Effects of pinching, Cycocel and B-nine treatments on branching habit of pot poinsettia (Euphobia pulcherrima willd)

Abstract

Poinsettia (Euphorbia pulcherrima Willd) is a popular pot plant in many countries and there is a high potential to introduce it to the Sri Lankan floriculture markets. Naturally, poinsettia becomes colourful under short day conditions. However, artificial induction of flowers is necessary for it to produce marketable plants throughout the year. In the natural condition, plants show a vigorous growth and the height is undesirable to accept as a pot plant. Hence, pinching and application of growth retardants were practiced in this study to obtain short bushy plants. Potted rooted cuttings of Euphobia pulcherrima Willd were subjected to single and double pinching and to cycocel and B-nine applications, in 12 combinations. Significantly greater height reduction of shoots (20 cm) and highest number of shoots per plant (36) were obtained when the plants were exposed to double pinching followed by 1500 ppm cycocel application at 14 day intervals. Application of plant growth regulator, B-nine (5000 ppm) did not exert much effect on reducing the shoot height. However, it had some effect on increased shoot production in combination with double pinch. Double pinch gave significantly greater height reduction and increased shoot number when growth regulators were applied.