Resumo

CORDEIRO, Iracema M. Castro Coimbra; LAMEIRA, Osmar Alves; OLIVEIRA, Francisco de Assis  e  WENDLING, Ivar. Rooting of juvenile cuttings of Bertholletia excelsa under different concentrations of indolebutyric acid. Agrociencia [online]. 2016, vol.50, n.2, pp.227-238. ISSN 2521-9766.

Recalcitrant behavior and slow and irregular germination are limiting factors for the production of Bertholletia excelsa seedling production, through the conventional process. The objective of this study was to evaluate the rooting of juvenile cuttings of B. excelsa associated to the application of indolebutyric acid (IBA) in subirrigation propagator. The experimental design was completely random with a factorial arrangement of 3x3x2 of treatments: three doses (0, 1000 and 3000 mg L-1) of IBA as growth regulator; three types of cuttings (apical, middle, basal); and two immersion times (1 s and 60 s). The data were analyzed with ANOVA and the treatment means were compared with the SNK test (p≤0.05). At 180 d the number and mean length of roots, percentage of rooting, presence of callus, and survival of the cuttings were evaluated. The results show that the middle and basal cuttings immersed for 1 s in 1000 mg L-1 of IBA had the highest percentages of rooting, 58.3 % and 41.7 %, respectively. The cuttings only presented, in average, the formation of a single root. The highest average root lengths were obtained with middle cuttings submerged for 1 s in 3000 mg L-1 of IBA (7.0 cm) and 1000 mg L-1 of IBA (6.4 cm). Thus, the IBA concentrations stimulate the surge of roots in different types of B. excelsa cuttings, the middle segment immersed in 1000 mg L-1 for 1 s is the most appropriate to increase the percentage of rooting, and the process of cuttings with B. excelsa juvenile material can be adopted for the vegetative propagation of the species.

Palavras-chave : Vegetative propagation; Amazon species; Bertholletia excelsa; growth regulator; indolebutyric acid; juvenile cuttings.

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