Biotechnological Methods for the Enhancement of the Propagation Rate in Roses

Abstract

ABSTRACTRoses, with their various species and hybrids, are not only favorite ornamental plants but are also important for the fragrant essential oils used in perfume manufacture. There is considerable interest in using biotechnology for commercial propagation of roses, due to the high proliferation rate achieved in a wide range of rose cultivars. Studies on the special requirements for multiple shoot development from axilllary buds and on the factors controlling “in vitro” rooting have been performed, resulting in the establishment of a protocol for long-term clonal micropropagation in various rose genotypes, including ground cover, miniature, thornless and cut rose cultivars. In the described protocol, the optimal hormone supplement for shoot proliferation consisted in benzylaminopurine (2 mg/l), giberellic acid (1 mg/l) and naphthyl acetic acid (0.1 mg/l), added either to the basal medium Murashige & Skoog (1962) or to Quoirin & Lepoivre (1977). The indole butyric acid (1 mg/l) added to the liquid nutrient formulations gave a high percentage of rooting of the “in vitro” developed shoots. Besides the phytohormone concentrations and combinations, it was proved the positive role of some ethylene inhibitors such as silver nitrate for reducing the premature leaf senescence and for facilitating a better shoot elongation and proliferation of “in vitro” cultured roses.