Yield and quality performances of tomato “plum” inoculated with arbuscular mycorrhizal fungi in saline soils

In order to evaluate the effects of beneficial microorganisms on greenhouse tomato “plum” grown under salinity conditions, research was carried out in Naples (southern Italy), by evaluating two arbuscular mycorrhizal fungi (AMF) treatments (Micoseeds Plus by Msbiotech, Myco Apply DR by Sumitomo, and a non-inoculated control) in factorial combinations with four soil electrical conductivities (1, 2, 3 or 4 mS cm-1 EC), by using a split plot design with three replicates. The mycorrhizal index increased from 1 to 2 mS cm-1 in plant roots inoculated with AMF, whereas in the control it decreased when the soil EC increased from 1 to 3 mS cm-1; the control attained lower values of mycorrhizal index than AMF treatments at any soil EC. AMF inoculated plants matured two days later than the control plants, but showed higher yield at all soil ECs. The plants grown under the 4 mS cm-1 soil EC matured four days earlier compared to 1 mS cm-1; the inoculation with beneficial microorganisms resulted in the best production performance under the 3 mS cm-1 soil EC due to both higher fruit number and mean weight, whereas the control plants attained the highest yield under both 2 and 3 mS cm-1 soil EC. The highest values of fruit dry residue and soluble solids as well as polyphenols, ascorbic acid and lycopene content were recorded under both of the AMF inoculations, and 4 mS cm-1 soil EC. The application of beneficial microorganisms as an environmentally friendly tool resulted in the improvement of tomato yield and quality performances both in normal and in saline soils.