The interactions of genotype and several variables related to culture environment, including temperature pretreatment, conditioned medium and agar concentrations were examined in a series of experiments for their effects on percent anthers producing callus and number of embryoids produced per 100 anthers scored. Significant genotypic interaction was observed for both traits with all environmental variables except methods of medium conditioning. Such interactions involve both changes of response magnitude and changes of rank order of genotypes. The highest response frequencies observed were in excess of 30% of anthers callusing. Most lines examined responded relatively well to a culture regime utilizing a 4°C treatment for 7-14 d prior to anther excision, followed by float culture, without transfer and without preconditioning of the culture medium. The results indicate, however, that particular genotypes may have specific requirements with respect to various environmental conditions so that culture conditions may need to be adjusted, especially for the least responsive genotypes.