Application of different concentrations of licorice and willow extracts as rooting stimulator in hardwood cuttings of olive (Oleaeuropaea L.)

Rooting in hardwood cuttings of olive was investigated at the College of Agricultural Engineering Sciences, University of Sulaimani, Kurdistan Region-Iraq under application of licorice and willow extracts with concentrations of (0, 3, 6 and 9 g.L-1). The extracts were prepared from licorice root and willow shoots in 25% ethanol heated in a water bath at 40ºC for 3 hours, refrigerated for 24 hours and filtered through filter paper. The hardwood cuttings of olive cv. (Sorani) were taken from basal part of one-year-old suckers then soaked in the licorice and willow extract concentrations for 1 hour. The results revealed that the highest (66.66%) rooting was achieved in the cuttings soaked in 6 and 9 g.L-1 licorice extract for 1 hour, they were not different in comparison with control cuttings which gave (49.99%), but rooting percentage was reduced (38.8%) in the cuttings soaked in 6g.L-1 willow extract. The cuttings soaked in 9 g.L-1 willow extract and 6 g.L-1 licorice extract gave the best root number, root length, shoot length, shoot diameter and leaf number. Generally, depending on the obtained results in this study, 6 and 9 g.L-1 licorice extract with 9 g.L-1 willow extract have possibility to use as an alternative to induce root formation and improve root and shoot quality of the cuttings in olive.