The influence of growth regulators and type of cuttings on sprouting and rooting of Commiphora swynnertonii (Burrt.) and Synadenium glaucescens (Pax.)

Abstract

Vegetative propagation through stem cuttings is useful for threatened plant species with abnormal flowering and fruiting behaviors, poor abilities to germinate, formulate seedlings or regenerate. This research investigates the impact of growth regulators on sprouting and rooting of C. swynnertonii and S. glaucescens. A Randomized Complete Block Design (RCBD) with 3 replications was used. The experiment involved 2 plant species; C. swynnertonii and S. glaucescens, 3 cutting types; softwood, semi-hardwood, and hardwood. Each cutting had a length of 25 cm to 30 cm. Two plant growth regulators (PGR); 1-Naphthaleneacetic acid (NAA) and Indole-3-acetic acid (IAA) were applied. Application of growth regulators NAA and IAA resulted into the tallest shoots (>100cm) from softwood, hardwood and semi hardwood types of cuttings of C. Sywnnertonii. Shoots from softwood and semi hardwood types of cuttings of S. glaucescens which were treated with NAA attained shoot length of 45 cm while the rest gave the shortest shoots of less than 40 cm. The use of NAA and IAA on softwood cuttings of S. glaucescens resulted into equally the highest rooting efficiency of 98% and 95% respectively. However, the same plant growth regulators NAA and IAA applied on semi hardwood cutting of C. sywnnertonii resulted in 60% and 30 % rooting respectively. Effects of growth regulators on both shoot and root formation was significantly dependent on plant species and environmental conditions. Therefore, we recommend a similar study to be carried out under different conditions to verify the results before recommending commercial cultivation using these treatments.