Description:The use of inducible gene expression systems is a rapidly developing area of plant molecular biological research. There is considerable interest in the use of these systems as research tools, not only because they allow expression of genes which may be, for example, developmentally lethal, but also because they allow for controlled experiments to be performed in a true isogenic background. They also have the potential to provide a means by which desired characters are expressed in field-based systems in the future.