Vesicular arbuscular mycorrhizal fungi (VAM) are a symbiotic fungi belonging to phylum Glomeromycota, which interact with the root system of higher plants by producing external and internal hyphae, vesiculars and arbuscules. This study aimed to determine the efficiency of VAM fungi in increasing squash plant growth, plant root surface and its effect on physiological plant elements. Four mycorrhizal products; Bacto_Prof, Endomyk_Basic, Endomyk_ Conc and Endomyk_Prof were imported from Terrabioscience Company, Germany, contained Glomus intraradices. Each product was used in three doses; half, recommended and double dose according to the application rates and instructions indicated by the manufacturer. Endomyk_Basic was the most effective product in improving plant growth. Height of squash plants in the recommended dose treatment was enhanced significantly by all mycorrhizal products; Bacto_Prof, Endomyk_Basic, Endomyk_Conc and Endomyk_Prof by 17, 18, 19 and 13% in comparison to control plants, respectively. Double dose was the most effective treatment which increased squash plant growth and root weight. Concentration of nitrogen (N) and phosphorus (P) were markedly higher in root system than in shoot system. Mycorrhizal products increased N in roots by 6, 21, 17 and 11%, while P was enhanced by 21, 4, 9 and 8% for Bacto_Prof, Endomyk_Basic, Endomyk_Conc and Endomyk_Prof, respectively. Concentrations of fat in shoot was higher than root system, while in crude protein and fiber, the plant root was significantly higher than shoot system by 6 and 52%, respectively. For the carbohydrate concentration, shoot system was higher than root system by 97% increase. From the results of this study, it was concluded that all mycorrhizal products were effective on physiological plant content and plant growth more than non-treated plants.
