EFEITO DE FITORREGULADORES E RIZOBACTÉRIAS PROMOTORAS DE CRESCIMENTO NA PRODUÇÃO DE MUDAS CLONAIS DE Pinus taeda

Abstract

The effects of application of different BAP dosages in miniclonal garden and the influence of the use of rhizobacteria on rooting of cuttings of P. taeda, as well as the mass selection of these isolated on seed germination in vitro and ex vitro were studied in this work. There was the mass selection of 128 bacterial isolates from soils of P. taeda plantations in different locations. The mass selection of bacteria was conducted in vitro by germination of P. taeda seeds microbiolized with bacteria in agar-water. The test was divided into two stages and tested 73 and 55 isolates respectively by step. The experimental design was DIC with 12 repetitions per treatment. Was evaluated at the end of 30 days the final germination percentage, seedling height and root length. Next, we performed a confirmatory test, where the top three bacterial isolates were subjected to two seed of P. taeda germination test, in vitro and ex vitro respectively, and tested different application forms of the bacterial suspension on both conditions. Was used the experimental design DIC in a factorial design with 10 replications. At the end of 90 days, ex vitro, was evaluated the germination and IVG. In the in vitro test, at the end of 30 days it was evaluate germination, seedling height and root length. BAP minigarden was applied at four different doses 0.0, 0.5, 2.5 and 10 mg.L?¹. The design was DBC, with four replications and 12 plants per block per treatment. The means of production shoots at 30, 90, 150 and 225 days were evaluated. It was performed still an experiment with two collections of cuttings, they had their bases immersed in bacterial suspension of two isolates before planted. The experimental design was completely randomized in a factorial arrangement of four doses of BAP x two bacterias with 10 repetitions per treatment. After 90 days was evaluated the percentage of rooting, height and stem diameter, the largest root length, dry mass of roots and shoots part and IQD. The mass selection experiment showed significant differences for the variables height and root length in two stages, and germination percentage in the second stage. In the experiment for confirmation of the three best isolates in vitro there was difference in the application form and isolated for IVG, where the application of the bacterial suspension in agar / water 10 days after seed inoculation was the best form of application, and 25D the best bacteria. In the experiment ex vitro there was difference for the isolated, also in IVG parameter, where the 25D was again superior to other treatments. In phytoregulator application experiment in P. taeda miniclonal garden doses of BAP did not influence the production of shoots. In cuttings rooting experiment, in the first collection, for the stem diameter the dose 10 mg L?¹ BAP and the two bacterial isolates were the best treatments. The hight suffered influence of the BAP, but no treatment was superior to witness. In the second collection there were no significant differences for any of the parameters.