Arbuscular mycorrhizal fungi (AMF) are important obligate symbionts of most cultivated plant species, colonizing roots and supporting plant growth. This study was carried out to identify indigenous arbuscular mycorrhizal fungal spores in selected farms behind the Faculty of Agriculture, University of Port Harcourt, Nigeria. Three test crops namely: cassava, maize, fluted pumpkin were selected for this study while Pigweed (Amaranthus retroflexus) was a Control. Rhizosphere soil and root sub-samples were collected per crop from topsoil (0 – 15 cm) and subsoil (15 – 30 cm). The collected soils were prepared and subjected to various analyses to determine soil physicochemical properties. Wet sieving and decanting method were employed for extraction of spores while slide method was used for estimation of degree of colonization. Spore taxonomic identification was conducted by comparison with reference descriptions from the International Culture Collection of Vesicular Arbuscular Mycorrhizal Fungi (INVAM). Data were subjected to analysis of variance (ANOVA) using XLSTAT 2022 version package. Ecological indices: Relative Spore Density (RD), Relative Isolation Frequency (RIF), and Importance Value (IV), were calculated. The results showed that six genera: Glomus, Acaulospora, Gigaspora, Entrophospora, Paraglomus and Scutteslopora were identified. The Soil pH of the entire study area (range = 5.93 to 6.35) falls within the suitable pH range for AMF distribution. The exchangeable cations, soil pH, available phosphorus, potassium, clay content; were among the main factors responsible for the variation in AMF community structure. The percentage root colonization (%) among the crops are as follows: maize (51.94), cassava (48.46), fluted pumpkin (42.93) and control (15.63). Generally, the root mycorrhizal colonization degree and spore density were significantly higher (P < 0.05) in topsoil (41.63 and 21.09) than subsoil (8.74 and 6.48) across all identified genera. The superiority of Glomus in soils may be related to its functional relevance and ease of propagation in soil ecosystem. AMF source of biofertilizer could be adopted as alternative source of soil amendment for cultivation of crops especially maize, cassava and fluted pumpkin which are staple food in the sampled location.
Anozie et al. (Fri,) studied this question.