Specificity and mode of action of BTS 44584 and chlormequat chloride on wheat and soybeans

The selective action of the growth retardants chlormequat chloride and BTS 44584 on the growth of wheat and soybean was investigated. Chlormequat chloride retarded the growth of wheat whether applied as a seed soak, foliar spray or soil drench, at concentrations from 10^-2 M to 10^-4 M, although effectiveness depended on the age of the plant at application. BTS 44584 retarded the growth of wheat only when applied to the seeds. In soybeans, chlormequat chloride did not retard elongation growth when applied as a seed soak but showed some effects when applied as a foliar spray and more especially as a soil drench. Irrespective of the type of application, treatment with BTS 44584 retarded growth of soybeans. Thus, the selective action of the two compounds was not solely related to different species but also to timing and mode of application.