Establishment of an Efficient Regeneration System of Rosa ‘Pompon Veranda’

Roses are one of the most essential ornamental flowers in the world. At present, traditional techniques such as cross breeding are mainly used in rose breeding. The inefficiency of the in vitro regeneration system has become the limiting step for the innovation and genetic improvement of rose germplasm resources. A tissue culture rapid propagation system of Rosa ‘Pompon Veranda’ was established using the stem segments with shoots as the initial experimental material. The results showed that the best disinfection method was to soak the explants in 75% ethanol for 1 min, and then soak them in 15% sodium hypochlorite solution for 15 min. The contamination rate was only about 6%. The best rooting medium for tissue culture seedlings was 1/2MS with 0.1 mg∙L−1 NAA, and the rooting rate can reach around 95%. On this basis, calluses were induced by using leaflets of tissue-cultured seedlings as explants. The results showed that the optimal medium for inducing callus tissue was MS + 5.0 mg∙L−1 2,4-D, with an induction rate of 100%. The calluses were cultured in the medium of MS with 0.01 mg∙L−1 NAA, 1.5 mg∙L−1 TDZ and 0.1 mg∙L−1 GA3 for 12 days in the dark and then transferred to light conditions. The differentiation rate of callus was 10.87%. On the medium of MS with 0.5 mg∙L−1 6-BA, 0.004 mg∙L−1 NAA and 0.1 mg∙L−1 GA3, the shoots could regenerate into whole plants. This study has established an in vitro regeneration system of R. ‘Pompon Veranda’, which is a key perquisite for the subsequent establishment of its genetic transformation system. Moreover, this method will also be an important reference for studies on quality traits such as floral scent and prickles of Rosa plants.