The objective of this study was to determine the fungal species forming arbuscular mycorrhizal (AM) inhabiting in traditional agroforestry systems with cacao (Theobroma cacao L.). Five agroecosystems located in farms from the humid tropics in Ecuadorian central region were sampled, particularly the farms ‘La Represa’, ‘La Propiedad’, ‘La Union’, ‘Fatima’ and ‘Mi Recuerdo’ located in Quevedo and Valencia cantons of Los Rios province. Soil and root samples were collected during the dry season between June and December of 2009. The fungi genera found were: Gigaspora, Acaulospora, Glomus and Scutellospora. In all sites sampled, Glomus was the most representative genus in terms of amount of spores found per gram of soil, while Gigaspora was the genus of which fewer spores were found. The percentage of existing level of mycorrhizal colonization in T. cacao was also assessed, with the highest percentage found in samples collected from farms ‘Mi Recuerdo’ and ‘La Union’, whilst the lowest percentage was found in the roots of T. cocoa collected from ‘La Propiedad’ farm.
Keywords: Theobroma cacao L., agroforestry, arbuscular mycorrhiza.