Symbiosis, zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA 24 (1998) 235-246 Balaban, Philadelphia/Rehovot 235 zyxwvutsrqpon Interactions between Saprotrophic zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPON Fusarium Strains and Arbuscular Myco rr hizas of Soybean Plants zyxwvutsrqponmlkjihgfedcbaZ I. GARCIA-ROMERA 1, J.M. GARCIA-GARRIDO!, J. MARTINl, S. FRACCHIA 2, M.T. MUJICA 2, A. GODEAS2, and J.A. OCAMPOl * 1 Departamento de Microbiologia, Estacion Experimental de/ Zaidin, CSIC, Profesor Albareda 1, 18008 Granada, Spain, Fax. +34-58-129600, E-mail. jocampo@eez.csic.es; and 2 Departamento de Ciencias Biol6gicas, 4° II Pabellon, Universidad de Buenos Aires, 1428 Buenos Aires, Argentina Received June 3, 1997; Accepted October 17, 1997 Abst rac t We studied the effect of inoculation with the saprotrophic fungi Fusarium concolor-2183, F. equiseti-91, F. graminearum-122, F. lateritium-2317, F. moniliforme- 379, F. oxysporum-93, F. oxysporum-738, F. oxysporum-126, F. solani-51, F. solani- 339, F. solani-2584 and F. stilboide-2169 on soybean (Glycine max) in unsterile and sterilized soils and in soils with or without arbuscular mycorrhizal (AM) inoculation with Glomus mosseae, in a greenhouse trial. Plant dry weight of non AM soybean was unaffected by the presence of any zyxwvutsrqponmlkjihgfedcbaZYXWVUTS Fusar ium . In contrast, AM colonization increased under all experimental conditions when F. oxysporum-738, F. oxysporum-126 or F. stilboide-2169 was used, and AM plant shoot dry weight increased in the presence of F. oxysporum-93, F. oxysporum-738, F. oxysporum-126 or F. solani-51. Synergistic effect of some Fusarium strains on G. mosseae but not effect of the AM fungus on the saprotrophic fungi were found. Keywords: Arbuscular mycorrhizas, Fuearium, Glomus mosseae, Glycine max, saprotrophic fungi *rhe author to whom correspondence should be sent. 0334-5114/98/$05.50 ©1998 Balaban