Assessment of the Effect of Rhizobacterial Strains (PGPR) on Rooting in Rose Cuttings

Roses (Rosa spp.), members of the Rosaceae family, are widely cultivated ornamental plants with significant commercial value worldwide. Vegetative propagation of roses is typically achieved through cuttings; however, this process often results in substantial losses. This study investigated the effects of plant growth-promoting rhizobacteria (PGPR) applications on the rooting performance of garden rose cuttings. The PGPR strains used in the study were identified via PCR analyses for the presence of the indole acetic acid (IAA) gene region, and three different formulations were prepared: Formulation 1 contained only Bacillus subtilis, Formulation 2 contained only Bacillus cereus, and Formulation 3 was a mixture of Bacillus subtilis and Bacillus cereus. The results demonstrated that PGPR applications significantly enhanced the rooting rate of rose cuttings. Compared to the control group, the PGPR-treated cuttings exhibited a 50-60% increase in rooting rate, supporting seedling root development. These findings indicated that Bacillus species rhizobacteria had positive effects on the rooting process in rose cuttings. The study emphasizes the potential of using environmentally friendly biostimulants, such as PGPR, in the ornamental plant industry as an alternative to hormones and chemicals. In conclusion, it is recommended that PGPR-based biostimulants be considered as a sustainable and effective alternative for rose cultivation.