Identification and relative abundance of native arbuscular mycorrhizal fungi associated with oil-seed crops and maize (Zea mays L.) in derived savannah of Nigeria

Abstract

A field survey was conducted to assess root colonization, spore densities and relative abundance of native arbuscular mycorrhizal fungi (AMF) based on morphological aspects. Roots and rhizosphere soil samples were collected from established fields of selected oil seed crops [soybean (Glycine max L.), sesame (Sesamum indicum) and sunflower (Helianthus annuus)] and maize (Zea mays L.) grown in derived savannah agro-ecology of Southwest Nigeria. The mean percentage of AMF colonization across all crops was 60.8%, ranging from 34% to 87.5%, with highest root colonization observed in soybean. The spore densities retrieved from the different rhizospheres were relatively high, varying from 124 to 298 spores per 50 g dry soil, with highest spore densities observed in maize rhizosphere soils. The spore densities in the soil significantly correlated (r = 0.52, and P <0.05) with the root colonization. A total of 4 morphologically classifiable genera (Glomus, Gigaspora, Acaulospora, and Scutellospora) of AMF within the phylum Glomeromycota were detected. The dominant genus was Glomus in all the crops with highest relative abundance of 60.9%, followed by Acaulospora (21.3%) and Scutellospora (12.8%), with lowest relative abundance of AM spores observed for Gigaspora (5%). This study could contribute significantly to a better understanding of AMF community structure in derived savannah agro-ecology of Nigeria.