Pakistan Journal of Biological Sciences 6(19): 1644-1648 (2003)
Separation of Thornless Rose Chimeras into Their (Rosa sp.) Consistent Genotypes in vitro.
Fatih Ali Canli and Robert M. Skirvin

Abstract: To isolate a pure thornless rose, a thornless sport of Rosa multiflora ('Fairmount 1') was established in tissue culture. To determine whether sports were chimeral and consisted of both thorny and thornless tissue, the regenerants obtained in the tissue culture studies were assessed for the thorny or thornless condition both in vitro and ex vitro. Chimeral plants were expected to yield both thorny and thornless regenerants. Among these regenerants we expected to obtain a pure thornless rose. All tissue culture experiments with 'FM1' yield both thorny and thornless regenerants, clearly demonstrating that 'FM1' is chimeral. TDZ significantly affected segregation both in vitro and ex vitro. The percentage of thorny plants was highest at 14.4 µM TDZ and lowest with control (0 µM TDZ). The linear relationship between increasing TDZ concentrations and percentage of thorny plants ex vitro was significant. These results show rose chimeras can be separated into their component genotypes by growing them on media with high concentrations of TDZ (3.6, 5.4 7.2 and 14.5 µM TDZ). Also among 240 plants from the TDZ experiments, 21 plants were classified as thornless after a seven months in the greenhouse.

Thidiazuron (TDZ) is a plant growth regulator used in micropropagations to supplement media such as Murashige and Skoog medium. TDZ promotes plant organogenesis (shoot regeneration) and plant regeneration. Thidiazuron (TDZ) enables the production of virus-free stock plants, speeds up breeding, and provides new genotypes for the market.