Actinorhizal host-specificity of Chinese Frankia strains

Cross-inoculation studies of numerous Frankia strains of Asian origin, primarily Chinese, were undertaken to determine whether previously described host specificity groups (HSG) were valid. Each strain was inoculated onto seedlings of Alnus glutinosa, Casuarina cunninghamiana, Elaeagnus angustifolia and My rica cerifera in solution culture, and the presence of nodules scored after eight weeks. All strains tested fell into three of the four HSG descriptions of Baker (1987). Our results indicate that among pure cultured Frankia strains derived from Asia there exists less diversity than those of North America and Europe, in regard to host specificity.