This study aims to evaluate the microcuttings production in the micropropagation system via clumps of axillary buds in a clone of Eucalyptus grandis x E. urophylla, subjected to different types of containers and substrates. Clumps with six to eight differentiated buds of Eucalyptus grandis x E. urophylla established in vitro were used to test containers (polypropylene pot -500 ml, glass flask -250 ml; acrylic flask with gas exchange (AFGE) -250 ml; and test-tube -55 ml capacity) in a semisolid medium specific for Eucalyptus in a period of 35 days. For the substrates test, acrylic flask with gas exchange (AFGE) were used with different substrates (agar, average particle size vermiculite, and vermiculite: cellulose fiber in a 2:1 ratio) in a period of 35 days. The tests were installed in a completely randomized design (CRD). We evaluated the number of shoots larger than 0.5 cm per clump of bud, the number of microcuttings produced larger than 2 cm, the length of the longest microcutting (cm) and shoot vigor. Based on the obtained results, it was possible to observe that the best container to produce microcuttings larger than 2 cm was the polypropylene pot (500 ml). Glass flask (250 ml) was more advantageous to achieve greater production of microcuttings per square meter due to its capacity of better densification. The best substrates to produce microcutting larger than 2 cm using acrylic flask with gas exchange (AFGE) containers were agar or vermiculite. Keywords:In vitro propagation; plant tissue culture; vegetative propagation. Abbreviations: AFGE_acrylic flask with gas exchange, APDM_aerial part dry mass, APFM_aerial part fresh mass, BAP_6-benzylaminopurine, BIOAGRO_Institute of Biotechnology Applied to Agriculture, CO 2 _carbon dioxide, CRD_completely randomized design, JADS_culture medium specific for Eucalyptus (Correia et al., 1995), HCl_chloridric acid, IBA_indole-3-butyric acid, LMC_length of the largest microcutting (cm), NAA_naphthaleneacetic, NaOH_ sodium hydroxide, NMC > 2 cm_number of microcuttings larger than 2 cm, NMC > 2 cm m -2 _number of microcuttings larger than 2 cm m -2 , NS > 0.5 cm_shoots larger than 0.5 cm, NS> 2 cm m -2 _number of shoots larger than 0.5 cm m -2 , PVP-30_polyvinylpyrrolidone, RDM _root dry mass, RFM_root fresh mass, RT%_root percentage.

This study aims to evaluate the effect of IBA concentrations and microcuttings successive collections in the micropropagation of Eucalyptus grandis x E. urophylla and Eucalyptus urophylla x E. globulus clones. Clumps containing six to eight buds of clones established in vitro were transferred to a 250 mL glass flask in JADS semisolid medium. Successive collections were performed every 20 days for Eucalyptus grandis x E. urophylla clone and every 30 days for Eucalyptus urophylla x E. globulus clone. The following variables were evaluated under in vitro conditions: number of shoots > 0.5 cm, number of microcuttings > 2 cm, length of the longest microcutting, and shoots vigor. Under ex vitro conditions, in the greenhouse and shade house, the following variables were evaluated: seedling height, percentage of survival, stem diameter, percentage of root observed at the lower end of the tube, and seedling vigor. In full sun (ex vitro), the following variables were analyzed: seedling height, stem diameter, survival, number of roots, root volume, seedling vigor, and shoot and root dry matter. Good in vitro microcuttings productivity was observed over the successive collections. IBA levels were adjusted for each clone, ranging from 0.25 to 0.50 mg L-1 for Eucalyptus grandis x E. urophylla clone, and from 0.75 to 1.0 mg L-1 for Eucalyptus urophylla x E. globulus clone. IBA concentrations led to residual effects under ex vitro conditions, providing good rooting and survival for Eucalyptus grandis x E. urophylla and Eucalyptus urophylla x E. globulus clones at IBA concentrations between 0.25 and 0.50 mg L-1 and between 0.50 and 1.0 mg L-1, respectively.

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