Enraizamento de estacas de rosa sp. sob a inoculação de bactérias promotoras do crescimento vegetal

Abstract

Plant growth promoting bacteria today represent a viable alternative for the growth of a more sustainable agriculture, without losing their desire to increase productivity and product quality. In the cultivation of flowers and ornamental plants, the aforementioned wishes are a necessity for success amidst the current competitive and demanding market, especially related to rose bushes, cut or vase. The production of roses seedlings with low cost and better quality will allow a more competitive product. Thus, the objective of this work was to evaluate bacterial strains of different genera regarding the promotion of plant growth and rooting of Rosa sp. For this purpose, 24 bacterial strains of the genera Pseudomonas, Burkholderia, Pantoea, Stenotrophomonas, Enterobacter and Bacillus isolated from sugarcane (Saccharum officinarum) and soybean (Glycine max) were used. They were selected based on their characteristics of plant growth promotion, such as: biological nitrogen fixation, inorganic phosphate solubilization, indole acetic acid (AIA) production. The stakes of Rosa sp. were submitted to a completely randomized design with the number of treatments equivalent to the number of bacterial genera evaluated, plus three treatments: control (CONT = Control treatment without inoculation / without indole butyric acid IBA; IBA1000 = Control treatment with indole butyric acid at 1000 ppm / no inoculation IBA1500 = control with indole butyric acid at 1500 ppm / no inoculation). With 10 replicates per treatment. After the inoculation and application of the AIB at 1000 and 1500 ppm, the cuttings were placed in polyethylene bags in the greenhouse. Adventitious rhizogenesis characteristics, such as root size (measured by a 60 cm ruler), number of adventitious roots, fresh root mass, root dry mass (packed in sacks) paper and oven dried at 60 ° C until constant dry weight is obtained). Regarding the development of the aerial part of the plant, the size of the branch was evaluated. The analysis of variance was applied by the Tukey test at 1% of probability using the SISVAR statistical program for the data evaluated. The treatment with bacteria of the genus Bacillus was highlighted, overcoming the controls CONT, AIB1500 and resembling the control treatment AIB1000 in all the characteristics of rhizogenesis evaluated, being affirmed as a viable biotechnological alternative, providing improvement in the quality of the root system, increasing the quality of seedlings and reducing mortality, producing seedlings with better conditions to go to the field.