Efficiency improvement of Juniper trees mass propagation through in vitro shoot multiplication

Juniperus procera is an endangered medicinal tree found in Saudi Arabia. Juniper trees face numerous challenges with seed production, germination and limited clonal propagation potential. Therefore, alternate techniques for reproducing Juniperus procera are essential for large-scale production. The main propose of the current research was establishment of an in vitro shoot multiplication protocol for J. procera. Explants were initially cultured in Murashige and Skoog (MS) media with varying combinations of benzyl amino purine (BAP), than the sprouted shoots were sub-cultured on MS media with different combination of BAP and naphthaleneacetic acid (NAA); rooting potential was examined on both MS and olive medium (OM) media supplemented with indole-3-butyric acid (IBA). The concentration of BAP at 1.0 mg/l showed the highest survival rate (70%) followed by 0.5 mg/l then the control treatment. Similarly, concentration of BAP at 1.0 mg/l produced a higher number of responded explants (2.66) and shoot number (2.67) compared with the other treatments. In multiplication media BAP at 2.0 mg/l without NAA produced higher percent of responded shoots; the lower concentrations of BAP gave lower response. The highest shoot number was observed into multiplication medium supplemented with BAP at 2.0 mg/l then by BAP at 2.0 mg/l +0.2 mg/l NAA. Meanwhile, shoot length showed a different trend in this experiment, as the highest shoot length occurred at the control treatment (0.0 BAP +0.0 NAA) followed by all BAP treatments, while addition of NAA to BAP into multiplication medium gave lower shoots length. Juniper shoots are hardly to root as, most of the treatments were inefficient. OM medium was responsible for rooting only when addition of IBA was implemented. The maximum percentage of rooted shoots was obtained with olive medium supplemented with IBA at 1.0 mg/l. According to the obtained results Juniper is a recalcitrant species to in vitro conditions; the multiplication rate highly depends on BAP concentration. Also, Juniper shoots have a low rooting potential, and most of the examined treatments were inefficient. Future studies are required to improve the current in vitro propagation potential.