Effects of different auxin (IBA) concentrations on rooting of common lantana (Lantana camara) and glossy abelia (Abelia x Grandiflora) cuttings

Nurseries involved in the production of ornamental shrubs for use in public and private green areas propagate plants by cuttings. Enhancing and optimizing the rooting process is important for the quality of the plants and the success of the subsequent transplant. To this end, the study analyzed the morphology of adventitious roots developed from median stem cuttings of two ornamental shrubs, Lantana camara and Abelia grandiflora, treated with an auxin plant growth regulator. The study compared the application of four different IBA (Rhizopon, available commercially) concentrations (0, 0.5, 1.0, and 2%) to two cultivars of Lantana (cv 1 Coccinella and cv 2 Yellow) and two of Abelia (cv1 Rupestris and cv 2 Eduard Goucher). Median cuttings were taken from the mother plants and placed in honeycomb containers filled with a commercial rooting substrate. The experimental design was complete randomization, with three replicates for each treatment, for a total of 48 experimental units. Root morphology was analyzed using the WinRHIZO software and rooting percentages were determined. Results indicate that IBA treatment significantly influences root morphology 54 days after cutting. In Lantana, 2% IBA produced an increase in length (+ 36%), surface area (+ 45%), tips (+ 40%); in the forks, however, 1% IBA yielded a 39% increase compared to the untreated control. CV1 showed a more extended root system than CV2. In Abelia, 0.5% IBA yielded results comparable to the highest dose (2%); the CV2 root system was more developed than that of CV1.