SUMMARY
Cannabis sativa is an annual herbaceous plant, known worldwide for thousands of years. The propose of this study was to evaluate the effect co-inoculation of Trichoderma harzianum and arbuscular mycorrhizal fungi (AMF) on growth of root system and yield in plants of industrial cannabis variety ‘Uso’. A greenhouse experiment took place in the Laboratory of Agronomy at Agricultural University of Athens. The experiment was designed according to Randomized block design with 2 treatments AMF & Trichoderma (AMF&TRCH) application and Trichoderma without AMF application (TRCH) and 3 replications. Trichoderma species have the ability to colonize the rhizosphere of plants, thereby improving the development of the root system. Arbuscular mycorrhizal fungi can form symbiotic relationships with most plants, including species of great economic interest such as industrial hemp. The combined use of Trichoderma harzianum and AMF provoked a synergistic effect increasing the root mass density, bud length and CBD yield per plant. During AMF&TRCH treatment the number of buds, bud dry matter and yield were higher than the TRCH treatment, on the contrary AMF colonization and root volume decreased. In conclusion the supply of AMF&Trichoderma had positive effect on AMF percentage, root and agronomic characteristics.