Despite its interesting agricultural traits, Swingle citrumelo (Citrus paradisi Macfad. 'Duncan' × Poncirus trifoliata L. Raf.) rootstock exhibits severe incompatibility when grafted with Pera sweet orange [Citrus sinensis (L.) Osb.] scions, and this fact limits its use for propagation purposes. Nonetheless, the existence of certain Pera sweet orange clones that are compatible with Swingle citrumelo represents a substantial gain for the entire citrus industry. This study investigated the compatibility between seven Pera sweet orange clones and Swingle citrumelo rootstock, regarding the presence of a necrotic line at the graft union junction, the difference in diameter between rootstock and scion, the influence of clonal cleaning by micrografting, and the horticultural performance of the selected combinations. No trees died because of grafting incompatibility, even after twenty years (trial I), except for clone CV1, or after six years and nine months (trial II) from planting. The rootstock/scion trunk diameter ratiowas not related to the presence of a necrotic line in the graft-union region. Additionally, these variables did not influence fruit yield and quality, and they were not affected by clonal cleaning or preimmunisation of the old Pera sweet orange clones.

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Ananas comosus var. erectifolius is a bromeliad native of the Amazon Complex has aroused great interest of the industries due to a softness, strength and low density of fibers extracted from its leaves. The frequent demand and effective protocols for in vitro regeneration and establishment of species, of commercial and environmental interest, encourages studies of organogenesis induced by growth regulators. The rhizogenesis or in vitro rooting is the last step of the regeneration process and is often considered the greatest challenge to be overcome. Rhizogenesis of Ananas comosus var. erectifolius was evaluated under the influence of the growth regulators naphthalene acetic acid (NAA) and indole butyric acid (IBA). Seven experiments were performed using different concentrations of growth regulators on solid MS medium under controlled environmental conditions. The results will improve the laboratorial protocols of induction, multiplication, elongation and production of root biomass for A. comosus var. erectifolius. The in vitro rooting was feasible and better results were observed using 1.0 mg L-1 NAA + 1.0 mg L-1 IBA.