Effects of substrate, phenological cutting stage, and auxin concentration on rooting of Cotinus obovatus Raf.

Abstract

A study was conducted to determine the effects of substrate, phenological stage of cuttings and auxin concentrations on the rooting of Texas smoke tree (Cotinus obovatus Raf). Softwood, semi-hardwood and hardwood cuttings were treated with either a 0 mg/L (ppm) 5000 mg/L (ppm), 10000 mg/L (ppm), or 15000 mg/L (ppm) potassium salts of indolebutyric acid (K-IBA) and placed in either 50% peat: 50% perlite or 100% perlite rooting substrates. Cuttings were placed under an intermittent mist system in a greenhouse for 8 weeks. Softwood cuttings rooted in both substrates but the 50% peat : 50% perlite substrate produced better quality-rooted cuttings. Softwood cuttings peaked at 8,000 to 10,000 mg/L (ppm) K-IBA. Semi-hardwood and hardwood cuttings rooted only in the 100% perlite substrate. In 100% perlite substrate the optimal concentration for semi-hardwood cuttings was approximately 12000 mg/L (ppm) K-IBA. while hardwood rooting was maximized at 15000 mg/L (ppm) K-IBA or more.