Abstract

NAVROSKI, Marcio C.; REINIGER, Lia R. S.  and  PEREIRA, Mariane O.. In vitro elongation of Eucalyptus dunnii shoots for different genotypes and concentrations of naphathalene acetic acid (NAA). Rev. de Ciências Agrárias [online]. 2015, vol.38, n.1, pp.79-86. ISSN 0871-018X.

The objective of this study was to evaluate the effect of different concentrations of naphthalene acetic acid (NAA) associated with the fixed concentration of 6-benzylaminopurine (BAP) on in vitro elongation of shoots derived from previously multiplied genotypes of Eucalyptus dunnii. Shoots were prepared and inoculated under aseptic conditions in nutrient broth 1/2MS. The experiment was conducted in a completely randomized design in a factorial scheme 5 x 6, in which the levels of the factor "A" referred to the different genotypes (labeled 2, 3, 4, 6, 7 and 10) and levels of factor "B", the NAA concentrations (0, 0.25, 0.5, 0.75 and 1 mg L^-1). The experiment was performed with five repetitions of a bottle containing three explants. Thirty days after inoculation of the explants was rated the number of elongated shoots, average length (mm) of shoots and formation of hyperhydricity (%). The genotypes showed different behavior in elongation phase, demonstrating the possibility of selection in vitro. The addition of 0.5 mg L^-1 NAA increased the number of elongated shoots and increased the length of the shoots. Concentrations higher than 0.5 mg L^-1 NAA exhibit increased formation of hyperhydric structures, damaging the shoots elongation. The proper balance of auxin/cytokinin and the selection of suitable genotypes is critical to the success of shoots in vitro elongation of E. dunnii.

Keywords : clonal forestry; micropropagation; growth regulators.

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