The Effect of Trichoderma harzianum and Azospirillum brasilense on Some Tomato Plant and Fruit Characteristics Under Different Irrigation Conditions

This study evaluated tomato plants' physiological and biochemical changes influenced by the Trichoderma harzianum and the Azospirillum brasilense . Irrigation regime was experimented at four levels (no irrigation, 50%, 75%, and 100% of water requirement), and biological fertilizer was examined at four levels (no application, Trichoderma , Azospirillum , and Trichoderma  +  Azospirillum ). The results demonstrated that the highest fresh and dry root weights and leaf area, were observed under the 100% irrigation regime combined with the application of biological fertilizers, particularly Trichoderma . Additionally, chlorophyll content was higher under a 100% irrigation regime with biological fertilizers. In contrast, the highest exchanges of carotenoids (22%), anthocyanin (18%), glucose (79%), sucrose (96%), and total sugar (121%) were obtained in no irrigation cultivation treatment. Conversely, the assessment of fruit characteristics revealed that the highest fresh and dry fruit weights were achieved under the 100% irrigation regime combined with applying biological fertilizers, particularly Trichoderma . Azospirillum treatment and combining Trichoderma with Azospirillum also achieved the lowest levels of fruit firmness, total soluble solids, and anthocyanin in fruits under a 100% irrigation regime. In conclusion, using Trichoderma and simultaneous application of Trichoderma and Azospirillum in tomato cultivation is recommended to improve plant characteristics, yield, and water stress tolerance.