Effects of donor tree ages and plant growth regulators on the softwood cutting propagation of Hippophae rhamnoides

The rooting effects of donor plant age, plant growth regulators and their concentrations on stem cuttings from Russian seabuckthorn were investigated. The factors mentioned above were highly significant (P001) for all studied parameters and the rooting effects of stem cuttings form 1-year-old donor tree were better than from 2-year-old one. NAA was more effective than IBA and ABT2among plant growth regulators and the 200 mg/L concentration of plant growth regulator was the best. Overall, applying 200 mg/L concentration of NAA to treat 1-year-old donor tree cuttings for 30 min could achieve the best rooting, with the rooting rate, root number and average root length being 88.87%, 10.8 item/panicle and 10.47 cm, respectivly. Meanwhile, the interaction among the factors also had significant effects on rooting of softwood cuttings. The interactive effects of donor age×plant growth regulators were significant for percent rooting. The interactive effects of plant growth regulators×concentration and age×plant growth regulator concentration were highly significant for percent rate, root number and average root length. The interactive effects of donor tree age×the concentration of plant growth regulators×plant growth regulators were highly significant for rooting rate of H. rhamnoides.