Response of Vegetative and Flowering Growth of Common Myrtle (Myrtus Communis L.) to Pinching, Foliar Application of Benzyladenine and Compound NPK Fertilization

Abstract

Common myrtle (Myrtus communis L.) is a popular ornamental and medicinal evergreen shrub that is used for its attractive foliage, fragrant blossoms and essential oils. Its vegetative growth and flowering characteristics will have a significant impact on its commercial and landscape value and will need to be improved. Hence, the present study was performed to assess the effects of the combination of pinching, foliar application of benzyladenine (BA) and compound NPK fertilization separately on some vegetative and flowering characteristics of common myrtle. The experiment was designed as a factorial experiment with Randomized Complete Block Design (RCBD). The following treatments were tested: 2 pinching treatments (non-pinched and pinched), 3 concentrations of BA (0, 75 and 150 mg L-¹), and 3 NPK fertilizer levels (0, 5 and 10 g L-¹). The following characteristics were evaluated: plant height, leaf area, leaf number growth rate, average flower number, and flower diameter. All the experimental factors and their interactions were found to be significant for the evaluated traits. The plant height was the highest in non-pinched plants while pinching resulted in the highest leaf area, leaf number, flower number and flower diameter. The vegetative growth and flowering performance increased in a progressive manner as the level of BA and the NPK fertilizer was increased. However, the combination of the pinching with BA and NPK application with 150 mg L-1 and 10 g L-1 respectively, yielded the maximum number of leaves per plant (2908.7), flowers per plant (42.06) and flower diameter (1.98 cm). The plants with the highest BA and NPK rates resulted in the tallest plants (48.33 cm) while the lowest rates (1.00 cm) were from non-pinched plants. Finally, it can be concluded that the combination of pinching and foliar fertilization with 150 mg L-¹ benzyladenine and 10 g L-¹ NPK is an effective cultural practice to enhance vegetative growth, flowering performance and ornamental quality of Myrtus communis L. and thus it is recommended for use in commercial nursery production and landscape cultivation.