Joseph A. Fiola

Effect of thidiazuron, light fluence rates and kanamycin on in vitro shoot organogenesis from excised Rubus cotyledons and leaves

Thidiazuron (TDZ), a substituted urea with cytokinin activity, was significantly more effective than benzyladenine (BA) at inducing organogenesis from detached Rubus cotyledons and leaves. The optimal TDZ concentration for organogenesis from cotyledons and leaves was 5–10 µM and 5–20 µM, respectively; however, shoot organogenesis occurred at TDZ concentrations of 0.5–5.0 µM. Light fluence rates from 0–81 µmol m-2 s-1 of continuous fluorescent light did not affect the percentage of organogenesis from cotyledons. Two weeks of continuous dark did not enhance the percentage of regeneration from leaf explants. Kanamycin, an antibiotic used to screen for transformation, severely reduced cotyledon growth and regeneration at concentrations as low as 10 mgl-1, and completely inhibited shoot organogenesis at 50 mgl-1.