OCCURRENCE AND MORPHOLOGY OF ENDORHIZAL FUNGI IN CROP SPECIES

Abstract

We surveyed 45 crop species in 39 genera of 21 families to explore the incidence and morphology of endorhizal fungal associations in roots. The survey indicated that 42 of the 45 crop species examined were associated with arbuscular mycorrhizal (AM) fungi. In addition, 20 of the mycorrhizal crop species were also associated with dark septate endophyte (DSE) fungi. Twenty crops had Arum-type and 22 had intermediate type AM morphologies. AM morphology has been described for the first time in 27 crop species. Three crop species lacked AM fungal association. Myristica fragrans though lacking AM association had DSE fungal association. The extent of colonization in roots ranged from 41% to 97% for AM and <1% to 61% for DSE fungi in the different crop species. Similarly, AM fungal spore numbers in the rhizosphere ranged between 4 and 60 spores 25 g -1 of soil. Twelve AM fungal spore morphotypes belonging to Acaulospora, Gigaspora, Glomus and Scutellospora were isolated from the rhizosphere soils. Although root length colonization by AM fungi was not correlated to AM fungal spore numbers, it was significantly and negatively correlated to DSE fungal colonization. The evidence presented in this paper for the first time revealed 19 crop species to be hosts for DSE fungi.