Growth and yield promoting effect of artificial mycorrhization on field tomato at different irrigation regimes

Plant inoculation with formulations of vesicular–arbuscular mycorrhiza (VAM) can be a sustainable tech-nique for the improvement of tomato yield and plant resistance to biotic and abiotic stresses. Combinationof artificial plant mycorrhization with water deficit irrigation could be an effective agronomical techniquefor the optimization of water use efficiency of tomato in the areas with a limited water availability. A2-year research on field tomato was undertaken in Southern Italy (40◦24N; 16◦48E; 10 m a.s.l.) to eval-uate the effects on crop growth, yield, and fruit quality of the combination of seedling inoculation withtwo VAM formulations, alone or integrated with plant growth promoting rhizobacteria (PGPR), withdifferent irrigation regimes (restoration of 0%, 50%, and 100% of maximum crop evapotranspiration). Asplit-plot experimental design with three reps was followed, with irrigation regimes in the main plotsand mycorrhizal treatments in the subplots. Both VAM treatments, either with or without PGPR, demon-strated to be highly and rapidly effective on plant growth, as significantly increasing growth of tomatoseedlings and plant biomass at mid and end of both crops compared to the non-inoculated control.Positive effects of mycorrhizal inoculation were extended also to marketable yield, mainly as a resultof an increased number and weight of fruits. Both VAM inocula did not significantly affect fruit qualityparameters, though increased water use efficiency of marketable yield. Both irrigation regimes positivelyaffected tomato growth and marketable yield, whereas the fruit quality was better in less- and non-watered plants. Adversely to expectations, no synergism was found between artificial mycorrhizationand irrigation regimes.