To investigate the effects of nano-iron chelate fertilizer and different concentration of methanol on morphological traits of sweet basil (Ocimum basilum L.), an experiment was carried out at the Research farm of Institute of Medicinal Plants, ACECR. A factorial experiment based on randomized complete design (RCD) with three replications was followed in this study. Results showed that morphological traits were significantly affected by different concentration of methanol and nano-iron chelate fertilizer. The lowest plant height was obtained by utilization of nano-iron chelate fertilizer at 0.5 g.l-1 concentration together with methanol at 20% concentration and application of methanol at 20% concentration lonely. Different concentrations of methanol and interaction between nano-iron chelate fertilizer and methanol at different concentrations had significant effects on number of branches per plant. There wasn’t significant difference between utilization of methanol at 30% and 20% concentration in respect of leaf number and the highest leaf number was obtained by these treatments. Application of nano-iron chelate fertilizer at 0.5, 1 and 1.5 g.l-1 concentration had similar effects on leaf number and the highest of leaf number was gained by these treatments. However the lowest leaf number was observed in non-application of nanoiron chelate fertilizer.
