In vitro selection for resistance against Fusarium equisetii in Robinia pseudoacacia L. (Special Issue: Tree micropropagation and tissue culture.)

摘要

The objective of this study was to develop resistance in vitro against Fusarium equisetii in Robinia pseudoacacia L. Callus was induced from cotyledon explants of R. pseudoacacia, a leguminous landscaping tree, on solid MS medium supplemented with different concentrations and combinations of 1-naphthalene acetic acid (NAA; 0.1-0.5 mg/l) and N6-benzyladenine (BA; 0.1-0.3 mg/l). Among them, 1.0 mg/l NAA and 1.0 mg/l BA was the best combination for callus induction, which was friable and light brown. Callus fresh weight increased and turned pale yellow after subculture. The effect of different concentrations of a toxic culture filtrate of Fusarium equisetii (Corda) Sacc. was investigated by plating friable callus on selective medium. Resistant calli were selected at 10% of the culture filtrate on which 15.33% calli survived, although no callus formed at higher concentrations of toxic culture filtrate. Shoots, which regenerated from resistant calli on Murashige and Skoog (MS) medium supplemented with 0.05 mg/l NAA and 0.6 mg/l BA, could root on half-strength MS medium containing 0.02% activated charcoal. Selected resistant plantlets, which survived on 2.5-10% of the culture filtrate compared to the control, showed reduced wilt incidence (approximately 70%) indicating a resistant response in tissues towards F. equisetii.