Effect of Treating BOUGAINVILLEA GLABRA with Ethrel, Magnesium and Boron on Vegetative and Flowering Traits

This study was carried out during 2009 and 2010 seasons for examining the effect of ethrel, magnesium and boron either applied singly or in combinations on growth and flowering aspects of bougainvillea (Bougainvillea glabra). Spraying was done either in vegetative shoot stage or at flowering shoot stage with fully developed thorn inflorescence axis. Growth was greatly improved with spraying boric acid at 0.025 % and or magnesium sulphate at 0.05 %. The maximum values of plant height (111 and 112.7 cm. during both seasons) and leaf area (29 and 29.5 cm2 during both seasons) were recorded with spraying magnesium sulphate at 0.05 % in combined with boric acid at 0.025 % regardless the application of ethrel at vegetative shoot stage. Ethrel had no effect on growth aspects. Ethrel, magnesium and boron treatments effectively advanced time of flowering and promoted number of flowers per plant. Time of flowering (in days) from planting reached 18 days with spraying magnesium, boron and ethrel together at vegetative shoot or flowering shoot stages. The maximum number of flowers per plant (30 and 31 flowers during both seasons) was recorded with using magnesium, boron and ethrel at vegetative shoot stage. Dropping of leaves and flowers was enhanced with using ethrel at flowering shoot stage with fully developed thorn inflorescence. Production of ACC and Ethylen was enhanced with using ethrel lately. Spraying the plants with ethrel at 75 ppm at flowering stage recorded the maximum values of ACC (0.1 g nmole g^-1) and ethylene (1.41 and 1.43 nl g^-1 h^-1 during both seasons). For promoting growth and flower formation of bougainvillea glabra, it is advised to spray the plants once early at vegetative shoot stage (15 days after planting) with magnesium sulphate at 0.05 %, boric acid at 0.025 % and ethrel at 75 ppm.