Growth and production of poinsettia var. Prestige Red by inoculation of plant growth-promoting rhizobacteria and fertilization doses

Abstract

Euphorbia pulcherrima is a plant with colorful bracts sold mainly at Christmas time, and is the most important ornamental container plant in the world. To produce healthy plants with high-quality standards, growers intensively apply pesticides and fertilizers, which increases production costs and promote environmental pollution. Plant growth-promoting rhizobacteria (PGPR) represent an environmentally friendly technological alternative for ornamental production. Therefore, this work evaluated the effect of three bacteria (Pseudomonas sp. CPO 2.78, Enterobacter sp. CPO 2.5, and Bacillus megaterium CPO 2.35) isolated from the rhizosphere of E. cyathophora on the vegetative and reproductive growth of E. pulcherrima var. Prestige Red in the presence of three doses of multipurpose Ultrasol fertilizer (0, 50% and 100%) after 236 days under greenhouse conditions. At vegetative stage (118 days), bacterial inoculation produced greater leaf area and higher leaf weight, total dry weight, and relative chlorophyll content, especially with the 50% fertilizer combination. At reproductive stage (236 days), inoculating a mixture of the three bacteria combined with 50% fertilizer increased leaf area, chlorophyll content, total dry weight, plant width, and number of branches. Overall, using PGPR plus 50% fertilizer improved growth and produc- tion of E. pulcherrima, and obtained a plant quality similar to that achieved without inoculation plus 100% fertilization.