Effect of irrigation regimes and arbuscular mycorrhizal fungus on some agronomic traits of saffron (Crocus sativus L.) in different planting media

In order to evaluate the effect of two isolates of arbuscular mycorrhizal fungus in saffron rhizosphere on some of saffron agronomic traits under different irrigation regimes, an experiment was conducted as split plots factorial in a randomized completely design with three replications at the Institute of Soil and Water Research, Karaj, Iran. The treatments consisted of three irrigation regimes (normal irrigation (control), irrigation cut off at the beginning of the growing season and at the beginning and middle of the growing season) as the main factors, three organic planting media (no organic fertilizer, vermicompost (20 t.ha-1) and biochar (10 t.ha-1) and arbuscular mycorrhizal fungal in three levels (no application, isolate a and isolate b) as a sub factors. Molecular findings indicated that, both strains isolated from saffron rhizosphere belonged to Rhizophagus irregularis. The results showed that the interaction effect of water stress and planting media on economic yield and also, the interaction effect of water stress, planting media and R. irregularis fungus on leaf number, fresh and dry weights and corm weight and diameter per pot were significant. The highest yield (0.062 g/pot) belonged to the full irrigation with biochar. Meanwhile, the highest leaves number (180), fresh and dry weights (90.2 and 23.96 g, respectively) and corm weight (7.67 g) and diameter (2.38 cm) per pot were obtained at full irrigation with biochar and Rhizophagus irregularis isolate b. In general, the use of biochar fertilizer with Rhizophagus irregularis isolate b had the greatest effect on the measured traits of saffron in different irrigation regimes.