Optimizing in vitro photoperiod for improved morphogenesis in smoke tree (Cotinus coggygria Scop.)

Cotinus coggygria thrives in temperate zones, adapting to dry, rocky soils and aiding afforestation. Its bioactive compounds have medicinal and agricultural applications. Optimizing in vitro photoperiod conditions is crucial for improving its propagation efficiency. Therefore, the aim of our study was to determine whether photoperiod duration affects the morphogenesis of C. coggygria in vitro. Cultivation was carried out on a nutrient medium according to the Murashige and Scoog protocol (MS) and with the addition of 6-benzylaminopurine (BA) at a concentration of 0.2 mg/L and indole-3-butyric acid (IBA) at a concentration of 0.5 mg/L. The study determined the growth characteristics of C. coggygria microshoots after 6 weeks of cultivation in controlled conditions. One-way ANOVA analysis and factorial analysis were used to determine the photoperiod’s effect on the studied parameters of microshoots on different media. According to the results, high growth indices for C. coggygria regenerants were at 20/4-hour photoperiod and can be used at the propagation stage on MS medium supplemented with 0.5 mg/L IBA. The maximum percentage of rooted C. coggygria explants with a branched root system was obtained at an 8/16-hour photoperiod. To improve the efficiency of microclonal propagation technology and uniform development of the vegetative part of the shoots, we recommend using 8/16 h and 20/4 h photoperiods for full-fledged growth of the entire C. coggygria microshoots in vitr0 on 0.5 IBA medium.