Evaluation of Effects of Mycorrhizal fungi and Azotobacter Bacteria on Growth, Quantity, Quality, and Antimicrobial Properties of Essential Oil of Fennel plant Foeniculum vulgare Mill

The combined effects of mycorrhizal fungi and Azotobacter bacteria alongside NPK fertilizer on growth, yield, essential oil quality, and antimicrobial properties of Foeniculum vulgare (fennel) were evaluated. Seed inoculation with biofertilizers and chemical fertilizer applications under controlled greenhouse conditions significantly enhanced plant height (112.5±2.9 cm), umbels per plant (39±3.6), thousand-seed weight (3.95±0.21 g), biological yield (4245±230 kg/ha), seed yield (1544±228 kg/ha), and harvest index (36.3±3.3%) compared to the control (p < 0.01). Essential oils extracted from treated plants demonstrated improved antimicrobial efficacy, with minimum inhibitory concentrations (MIC) against Aspergillus niger reduced by 50% to 62.5 μg/mL. Similar reductions in MIC values were observed for Penicillium digitatum, Escherichia coli, and Staphylococcus aureus. Minimum fungicidal and bactericidal concentrations (MFC/MBC) also decreased substantially with combined treatments. Results confirm that integrating biofertilizers enhances fennel growth, yield, and the antimicrobial potency of its essential oil, providing a sustainable alternative to chemical fertilizers in medicinal plant cultivation.