“…Thidiazuron (TDZ) and 2-Cl-PBU (i.e., 1-phenyl-3-(1,2,3-thiadiazol-5-yl) urea and N-phenyl-N -[6-(2-chlorobenzothiazol)-yl] urea, respectively) are potent promotors of callus formation in eucalypts. Organogenesis can be induced using 0.89 µM BA with 0.91 µM TDZ, or 0.5 µM TDZ with 0.2 µM 2,4-D for E. globulus [127,128], 2 µM TDZ, or 0.23 µM TDZ with 0.05 µM NAA, or 3 µM TDZ with 0.1 µM NAA for E. grandis × E. urophylla [89,123,128], and 2.27 µM TDZ with 0.54 µM NAA, or 1.14 µM 2-Cl-PBU with 0.57 µM IAA for E. urophylla [89,111,112]. Picloram (i.e., 4-Amino-3,5,6-trichloro-2-pyridinecarboxylic acid) has been used alone at 20.7 µM for E. urophylla organogenesis [86] or at 0.04 µM in combination with 2.25 µM BA for E. gunnii Hook.f.…”