Abstract

Arbuscular mycorrhizae are the most widespread plant symbiosis on earth. This symbiosis is well-known for its positive impact on cultivated plant yields. Cocoa (Theobroma cacao) plays an important role in the economic prosperity of Côte d’Ivoire. However, cocoa yields remain low due to a loss of soil fertility and pest and disease damages. The myccorhizal symbiosis could be a way of resolving these constraints. However, its use requires the knowledge of the fungi symbionts. This study aimed at evaluating the diversity of arbuscular myccorhizal fungi (AMF) associated with cocoa in the Yamoussoukro region. Soil samples were collected from four cocoa fields. Spores from arbuscular myccorhizal fungi were extracted directly and after trapping by the wet-sieving method, then identified morphologically. Moreover, soil physical and chemical characteristics were determined and correlated with spore densities. Nine species of AMF belonging to the genera Glomus, Acaulospora and Gigaspora were found to be associated with cocoa. Glomus was the dominant genera. AMF spore densities were negatively correlated with phosphorus, magnesium and available potassium but positively with ammonium.

Key words: Arbuscular mycorrhizae, Theobroma cacao, Côte d’Ivoire, diversity.