Abstract:
Arbuscular mycorrhiza fungi (AMF), obligate symbionts, are important in the majority of
cultivated plant species in colonizing roots and supporting plant growth in adverse climatic
conditions. However, the abundance and quality of mycorrhizal colonization is affected by
land-use types, cropping systems and climate change. On the other hand, rhizospheric
mycorrhizae present in rhizospheric soils can be isolated for enhancing plant performance.
One such opportunity arises in the acclimatization of seedlings for adaptation to depleted
field conditions. Isolation and characterization of rhizospheric AMF species is important in
evaluating the efficiency of colonization especially in plants that have not been previously
evaluated such as papaya, which is well known for its high nutritive value. In this study, soils
were sampled from grass, banana and papaya plants’rhizosphere, from three different
papaya growing regions in Kenya; Mwea, Mitunguu and Juja. Spores were isolated using the
sucrose method. Spore abundance was done using a gridded Petri dish and morphologically
characterized using the International Culture Collection of Vesicular Arbuscular Mycorrhizal
Fungi (INVAM) database. At least 4 families, 10 genera and 41 species of glomeromycota
phylum were isolated from the 3 sampling sites. The families of glomeraceae (16 species)
and acaulosporaceae (14 species) dominated in Juja and Mwea Sub Counties. Glomus spp.
isolated from the rhizosphere of banana and grass plants were the most abundant, at
p≤0.05, in Juja while Diversispora spp (diversisporaceae) was the least abundant, at p≤0.05.
Mwea Sub County had the most spore abundance, at p≤0.05, compared to Mitunguu and
Juja. Mycorrhizal spores isolated from the grass family were the most abundant, at p≤0.05,
(Mwea, 41; Juja, 37; Mitunguu, 35.2) as opposed to banana and papaya plants. The results
showed that AMF spore abundance and diversity varies with different locations and the
associating plants.
Keywords: Arbuscular mycorrhiza fungi, rhizospheric, spores, sucrose.
