The distribution of Arbuscular mycorrhizal fungi and the mycotrophy of cassava in the soils semiarid tropics of Tamilnadu in relation to physico-chemical properties, nutrient status, depth and types of soils were studied. he native AM spore populations were significantly low and ranged from 90-170 100 g of soil. The cassava root colonization by native mycorrhizal fungi ranged from 38.85 to 56.50 per cent. The organic carbon content of the different soil samples was poor and ranged from 0.38 to 0.62 per cent. A positive correlation existed between organic carbon content and AM root colonization. The overall efficiency of both introduced and indigenous cultures was ranked in the order of G fasciculatum > G mossae>Arbuscular mycorrhizal sp NM-1>Acaulosporalaevis>Acaulosporasp NM-3 >Gigaspora margarita> Arbuscular mycorrhizal sp, NM -2 >Gigaspora.
