Strategies for the selection of uncontaminated Eucalyptus explants for shoot multiplication in a temporary immersion system (RITA®) in a commercial laboratory

Abstract

The potential high yields of Eucalyptus shoot multiplication achieved with a temporary immersion culture system such as RITA^® are compromised by losses caused by microbial contamination particularly bacteria, characteristic of the explants used to initiate the cultures. Disinfection of the explants through antibiotic treatments has on occasion been effective but this approach is unreliable and costly. In the present study, antibiotics were found to have only a bacteriostatic and not a curative effect. A strategy was, therefore, required to achieve uncontaminated explants via a rapid and accurate screening procedure. Of the approaches tested, that which was considered most appropriate for a commercial laboratory involved inducing bud break on a semi-solid medium, screening axillary buds for endogenous contamination on a semi-selective microbial medium and initiating RITA^® cultures with buds identified as being microbial-free.

Keywords: Antibiotics, axillary buds, liquid culture, micropropagation

Southern African Forestry Journal No. 206, 2006: 13-21