Responses to Propagation Substrate and Rooting Hormone Products to Facilitate Asexual Propagation of Silene chalcedonica and Silene coronaria

Abstract

Many ornamentals are commercially propagated by cuttings, which is an easy and cost-effective propagation method. Silene L. is a promising genus for extensive use as a landscape ornamental due to its drought tolerance, profuse flowering, and perennial characteristic. Silene is readily cross pollinated, so to ensure genetic purity for breeding and cultivar release, an asexual cutting propagation protocol needs to be established. Adventitious rooting of cuttings of Silene chalcedonica (L.) E.H.L. Krause and Silene coronaria (L.) Clairv. were evaluated using two different propagation substrates and three different root-promoting hormone products. Rooting percentage of S. chalcedonica cuttings was improved by Dip ‘N’ Grow treatment (1,000 mg·L−1), which contains 1% indole-3-butyric acid and 0.5% 1-napthaleneacetic acid, and Hormex Rooting Powder No. 1 (1,000 mg·L−1), which contains 0.10% indole-3-butyric acid; however, 89% of S. coronaria cuttings rooted readily in vermiculite without an auxin treatment. Therefore, rooting success of stem cuttings was highly species related. Because of the relatively low rooting percentage seen in vermiculite (46%) and in perlite (63%) using Dip ’N Grow auxin treatment for S. chalcedonica, an effective stem cutting propagation method still needs to be explored for this species.