Identificación de agentes causales de la contaminación microbiana durante la micropropagación de Musa spp.

Abstract

The research was carried out in the Biology Laboratory of the Facultad de Ciencias Agrarias of the Universidad Nacional de Asunción, to identify the causal agents of microbial contamination during the micropropagation of banana (Musa spp.). Eighty shoots
of 30-40 cm were used, from which the meristems were extracted and grown in MS culture media (Murashige and Skoog, 1962) with the addition of 1 g.L^-1 of activated carbon as antioxidant. The disinfection treatment consisted of immersion in a NaClO solution (10%) for five minutes. The experimental design used was completely randomized with eighty repetitions, each apex constituting an experimental unit. The variables evaluated were: percentage of survival, percentage of contamination of explants, and causal agent. For the identification of the fungal microorganisms the optical microscope was used.The bacteria were passaged into Petri dishes containing the routine medium 523 by Kado and Heskett (1970), and incubated at 25-30 °C in an inverted position during three days. Subsequently, the Gram staining technique was performed. The genera Aspergillus, Penicillium, Fusarium and Gram negative bacteria were found to be the cause of contamination, in the in vitro establishment phase, of meristematic banana apices.