IN-VITRO AND EX-VITRO ROOTING OF MICROPROPAGATED SHOOTS USING 3 GREENASH (FRAXINUS-PENNSYLVANICA) CLONES

Shoot multiplication using seedling materials was achieved by subcultu re on Murashige and Skoog salts with Gamborg's B5 vitamins (MSB5) medi um containing a combination of 5 mu M 6-benzyladenine (BA), 5 mu M thi diazuron (TDZ), and 1 mu M indole-3-butyric acid (IBA) with three gree n ash (Fraxinus pennsylvanica) clones, SD1009 (South Dakota origin), S D2002 (South Dakota origin), and KA2018 (Kansas origin). Shoots were r ooted using in vitro and ex vitro methods. For in vitro rooting studie s, elongated shoots were transferred to rooting plugs supplied with li quid MSB5 medium containing a 3x3 factorial arrangement of two differe nt auxins, a-naphthaleneacetic acid (NAA) and IBA, at three concentrat ions (0, 5, and 10 mu M). The most effective treatment for in vitro ro ot number, root length, and shoot height was 5 mu M IBA. The three clo nes also were tested for ex vitro rooting using a quick dip in 1 mM NA A, 1 mM IBA, or control (no auxin). The maximal ex vitro rooting respo nse occurred when shoot explants of the three clones were dipped in 1 mM IBA. Significant clonal differences were noted in response to in vi tro and ex vitro rooting treatments. Rooted plantlets were acclimated to the greenhouse.