Propagation of Castanopsis sclerophylla by Stem Cuttings

Abstract

Abstract Two experiments were conducted to develop a protocol for propagation of Castanopsis sclerophylla (Lindley & Paxton) Schottky by stem cuttings. In the first experiment completed in 2000, stem cuttings were taken on three dates representing three growth stages (softwood, semi-hardwood, or hardwood). Semi-hardwood and hardwood cuttings were treated with 0, 2500 (0.25%), 5000 (0.5%), 7500 (0.75%), or 10,000 (1.0%) ppm of the free acid of indolebutyric acid (IBA) dissolved in 50% isopropyl alcohol, whereas softwood cuttings were treated with the same concentrations of the potassium (K) salt of IBA (K-IBA) dissolved in distilled water. Cuttings were placed in a raised greenhouse bench and rooted under intermittent mist. Cuttings taken at the semi-hardwood and hardwood stages began to drop their leaves after approximately 2 weeks and the majority eventually died, with negligible rooting of surviving cuttings. The response of the softwood cuttings to K-IBA was quadratic with the greatest rooting (63%) at 7500 ppm K-IBA. Seventy softwood cuttings that rooted were potted for observance of overwinter survival. Of these, 90% produced a flush of growth during the summer, with 80% overwinter survival. In the second experiment conducted in 2001, semi-hardwood cuttings were taken and treated with 0, 2500 (0.25%), 5000 (0.5%), 7500 (0.75%), or 10,000 (1.0%) ppm K-IBA and placed in a raised greenhouse bench with intermittent mist for rooting as in the first experiment. Results were similar to the semi-hardwood cuttings treated in the first experiment with the free acid of IBA, indicating semi-hardwood cuttings do not root and that the auxin and/or isopropyl alcohol were not toxic to the cuttings.