Stem cutting rhizogenesis in soſtwood graſting of <i>Philadelphus coronarius L. f. aureus nanus</i>

Abstract

Sweet mock orange f. golden dwarf (Philadelphus coronarius L. f. aureus nanus) is a promising ornamental shrub in green building within Central Russia. In the Orel Region, this species has a limited occurrence due to the lack of quality planting material, which warrants research into rhizogenesis of P. coronarius f. aureus nanus stem cuttings during soſtwood graſting. Trials were conducted during 2017-2019 in triplicate, 20 cuttings each, adhering to the common woody plant soſtwood graſting propagation technique. Two yearling types were used, side shoots and innovations. Experimental setups: 1 — control (water); 2 — aqueous indolebutyric acid (IBA) 50 mg/L at 18-h exposure; 3 — bottom cutting powdering with 0.5 g/kg active coal-IBA mixture; 4 — bottom cutting treatment with 50 mg/L IBA at 18-h exposure followed by powdering with 0.5 g/kg active coal-IBA mixture. Setup 2 (IBA 50 mg/L) rendered the highest positive effect on the rooting and reproduction of side shoot and innovation-derived stem cuttings. Te best cutting root system biometry (number and length of 1st order roots) was obtained in setup 2 with the innovation cuttings (10.50 roots of 4.53 cm) compared to the side-shoot ones (9.81 roots of 3.68 cm).