The Effect of Cutting Type and Auxin Treatment on Rooting of Cupressus cashmeriana, Poster Board #149

Cupressus cashmeriana is an ornamental evergreen conifer with little information published on vegetative propagation.  Two experiments were conducted to determine the effects auxin and cutting type on adventitious rooting.  Experiment 1 evaluated three cutting treatments (softwood, hardwood, and mallet) and four auxin treatments consisting of 0, 2500, 5000, and 10000 ppm potassium indole-3-butyric acid (K-IBA).  At 8, 12, 16, 20, and 24 weeks, cuttings were removed from the rooting substrate and evaluated.  Experiment 2 evaluated the same cutting types as experiment 1 and auxin treatments consisted of 5000 ppm K-IBA, 5000 ppm naphthalene acetic acid (NAA), 2500 ppm K-IBA in combination with 2500 ppm NAA and zero auxin applied.  After 140 d, roots were weighed.  In experiment 1, softwood and hardwood cuttings had significantly higher rooting ratings than mallet cuttings.  At weeks 20 and 24, cuttings treated with 0 ppm K-IBA had rooting percentages significantly higher than cuttings treated 10,000 ppm, while cuttings treated with 2,500 and 5,000 ppm were intermediate.  The results of experiment 2 were similar to experiment 1 in that soft and hardwood cuttings had higher rooting percentages compared to mallet cuttings.  The effect of auxin treatment was non-significant.  Results indicate various rates or types of auxin may not be beneficial, and can even have a negative effect on rooting of C. cashmeriana.  Additionally, successful rooting of C. cashmeriana occurs more often with soft and hardwood cuttings compared to mallet cuttings.  This research suggests that the age of plant material from which cuttings are taken is one of the most significant factors for successful rooting C. cashmeriana.