Abstract: The infective abilities of three mycorrhizal species of Glomus intraradices(Gi),Glomus manihotis(Gm) and Glomus etunicatum(Ge),to the roots of cassava,Manihot esculenta,and their effects on growth of cassava were studied by potted culture.All three arbuscular mycorrhizae(AM) fungi could form the typical Arum-type structure of AM after inoculation.Amony them,both Gi and Gm could produce spores within the roots.The inocula of Gi and the mixed Gi and Gm(2G) showed faster and higher infective abilities, while that of Gm had slower infection rates at the early stages of cassava growth.However,the infection rates of Gm remained more stable in the late stages than those of Gi and 2G.By comparison,the infective ability of Ge inoculum was poor.All the treatments including Gi,Gm and 2G showed greater growth in height than those in controlled treatment(control,CK).However,only 2G had significant difference from CK in both height growth and aboveground biomass accumulation at harvest.Differences among Gi,Gm and CK were not significant.The biomass of cassava with Ge inoculation was even lower than CK,which might reveal that Ge had a negative effect on cassava growth.