Studies on The Status of Arbuscular Mycorrhizal Fungi on The Fodder Crop Sorghum bicolor (L.) Moench

Sorghum bicolor (L.) Moench, commonly called maize grass, belongs to the family Poaceae. It is used as a fodder grass and is commercially cultivated in the Tiruchirappalli district of Tamil Nadu, South India. Four different localities of the Tiruchirappalli district were selected for the present investigation. The soil types of the four localities ranged from red sandy, red brown sandy to red brown sandy clay. Although the colonisation of Arbuscular Mycorrhizae (AM) in the roots of S. bicolor was positive in all the four study localities, the species of AM fungi colonising the roots varied. The percentage of root colonisation ranged from 52.0% to 94.5%. A total of 18 AM fungal species were isolated from the rhizosphere soils of the S. bicolor, of which only 4 were found to be colonised in the roots. The total spore counts varied between 122 and 582 per 100 gm of soil. Glomus aggregatum, G. etunicatum and Acaulospora bireticulata were the dominant forms and these 3 species showed 100% frequency in all the study areas.