Interactive Effects of Monosodium Glutamate and Paclobutrazol on Growth and Flower Induction of Dendrobium Orchid

Abstract

Dendrobium is one of the most widely cultivated ornamental orchids in Indonesia, valued for its aesthetic appeal and commercial potential. However, its relatively slow vegetative growth and long period to reach the flowering stage often hinder efficient production. The use of plant growth regulators and biostimulants can be an effective strategy to accelerate growth and promote flowering. This study aimed to evaluate the effects of Monosodium Glutamate (MSG) and paclobutrazol (PBZ) on the growth and floral induction of Dendrobium orchids and to determine the most effective combination for optimal performance. The experiment was arranged using a Randomized Block Design (RBD) with two factors, namely four MSG dosages (0 g/L, 7.5 g/L, 10 g/L, and 12.5 g/L) and three paclobutrazol concentrations (0 ppm, 200 ppm, and 400 ppm). Each treatment combination was replicated five times. Observations were made on plant height, number of leaves, days to flower initiation, and number of flowers per spike. Results showed that the interaction between MSG and paclobutrazol significantly influenced both vegetative and flowering parameters. The combination of 7.5 g/L MSG and 200 ppm paclobutrazol resulted in the most favorable response, producing taller plants, more leaves, earlier flower initiation, and a higher number of flowers compared to other treatments. Excessive paclobutrazol concentration tended to suppress vegetative growth without further improving flowering performance. These findings indicate that applying 7.5 g/L MSG together with 200 ppm paclobutrazol can effectively promote balanced growth and enhance floral development in Dendrobium orchids, offering practical benefits for commercial orchid cultivation in tropical environments.