The objective of this research was to evaluate the effectiveness to induce the multiplication of shoots in the BRS Nordestina and CSRN 142 castor bean genotypes, in the explant apical meristem, determining the best treatment with the thidiazuron (TDZ) growth regulator and to indicate the satisfactory concentration of the indoleacetic acid (AIA) for the ex vitro rooting. The Murashige and Skoog medium, was used supplemented with TDZ in the concentrations 0 (control); 0.5, 1.0, 2.0, 5.0 e 10.0 mg L-1, with three explants per flask, in randomized blocks. The evaluations were made after 45 days of cultivation, being analyzed the number of brunches for explant and the percentage of necrosis. In the ex vitro rooting, the use of AIA was made, in the concentrations 0, 0.125, 0.25, 0.5 and 1.0 g L-1 in the acclimatization substrate. It was observed that the concentration of 0.5 mg L-1 of TDZ provided the best results in vitro proliferation, reaching 16.9 brunch for explant. In the ex vitro rooting, the most promising treatment was substrate + 0.125 g L-1 of AIA, with 75% of rooted plants. It was verified that the TDZ induces the over brunching in the two genotypes and that the ex vitro rooting is a viable alternative for the programs of plants improvement.
Ricinus communis; biotechnology; growth regulators
