Arbuscular mycorrhizal (AM) species diversity and their root colonization patterns may vary in a plant species as influenced by soil environmental and biological factors. In the present study, sugarcane rhizospheric soils were collected from 41 main sugarcane producing tehsil places belonging to 10 districts from Maharashtra, India. Rhizospheric soil samples and roots were analyzed for spore density, relative abundance and frequency of AM spores at genus as well as at species level, extent of AM colonization in roots and various soil chemical properties. Soil sample from Jalgaon district possessed maximum spore density and AM root colonization. Genus Glomus exhibited highest relative abundance with maximum frequency of 32.55%. Species wise, Glomus fasciculatum possessed highest relative abundance and maximum frequency was observed in case of Glomus fasciculatum, Glomus intraradices, Glomus mosseae and Glomus versiforme. Maximum similarity of AM spores was recorded between Satara and Sangli districts which may be because of almost similar soil pH profile. Data obtained after cluster analysis represented the close relationship between spore density, AM root colonization and soil Cu, Zn and Fe concentrations. A statistically significant positive correlation was also found when AM spore density and root colonization was compared with soil Cu, Zn and Fe contents. This kind of data can be used to predict type of AM fungi to be used as bioinoculant in particular region.

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Symbiotic association between arbuscular mycorrhizal (AM) species and host plant roots improves plant growth and protects them from several abiotic stress factors. In the present study, the effect of Glomus mosseae and Glomus fasciculatum as an individual inoculation and in combination was studied on two legumes (Glycine max and Cyamopsis tetragonoloba) under soil salinity stress gradient [1.04 (control) to 8.26 dS/m]. Individual and co-inoculation of both the AM fungi alleviated adverse salt effect, with improvement in plant dry weight matter and biochemical parameters. However, these two isolates worked better in combination with respect to higher accumulation of soluble carbohydrate, reducing sugar, protein, proline concentration etc. C. tetragonoloba showed better response as compared to G. max in relation to improvement in nutritional profile under salt stress after AM treatment. As compared to non-mycorrhizal counterparts, co-inoculation with G. mosseae and G. fasciculatum in C. tetragonoloba enhanced total chlorophyll (14.83% at soil salinity of 3.78 dS/m), soluble carbohydrate (17.26% at soil salinity of 5.94 dS/m), proline (8.79% at soil salinity of 3.78 dS/m) while exposed to different soil salinity levels. Also, co-colonization with both the isolates showed more root colonization (%) and may be responsible for the better effect in salt stress alleviation. Electrolyte leakage of mycorrhizal plants was lowered at soil salinity gradient of 2.10 to 8.26 dS/m and hence, maintained membrane stability. These two isolates can be utilized as bio-inoculant in alleviation of adverse salt effect in soil in association with the two test legume plants.