Effects of Cutting Time, Auxin Treatment, and Cutting Position on Rooting of the Green-wood Cuttings and Growth Characteristics of Transplanted Cuttings in the Adult Prunus yedoensis

Abstract

This study was conducted to develop an efficient mass propagation method for the mature Prunus yedoensis Matsumura (43 to 58 years old). Cutting was conducted depending on cutting time, auxin treatments (IBA and NAA treatments mixed with talc powder), and cuttings position on shoots in a plastic house equipped with a fog system without heating. Rooted cuttings were transplanted to a nursery bed, and their growth characteristics were investigated in order to check whether the cuttings are successful or not for roadside tree planting. The average rooting rate was highly significant (P < 0.0001) in all treatments: cutting on June 1st (61.4%) was more than two times greater in rooting rate than that on August 1st (23.6%); IBA 1,000 mg.L-1 (90.8%) and IBA 500 mg.L-1 (89.2%) showed much greater rooting rates than those of the other treatments; upper part of the cuttings treated with IBA 1,000 mg.L-1 showed the highest rooting rate, 96.7%. The interactions among treatments in the average rooting rate were also significant. There were significant differences (P < 0.0001) among the auxin treatments in the survival rate of leafed cuttings transplanted to a nursery bed. The average survival rate was 46.5%, and IBA 1,000 mg.L-1 treatment was the highest in leafed cuttings 79.2%, but most of leafless cuttings were dead. There were significant differences (P < 0.0001) among the cuttings, grafts, and in the seedlings height, diameter at root collar, the number of roots, branches, and leaves, etc., and the cuttings was the best. We can expect a possibility of mass propagation of improved P. yedoensis Matsumura and a high planting survival rate through the transplanting of cuttings to a nursery bed in which the cuttings should be the following conditions: cutting in June to July, use of the upper part of cuttings, IBA treatment, and rooting in August in a cutting-greenhouse equipped with a fog system.