Minimal Quark-Lepton Symmetry Model and Possible Limits on Z'-Mass from TRISTAN and Lep200

A minimal extension of the Standard Model containing the four-color quark-lepton symmetry is discussed. Some features of an additional $Z^{\mathrm{\prime }}$-boson originated from this symmetry are investigated and the limits on $m_{Z^{\mathrm{\prime }}}$ from the current TRISTAN data and the possible limits on $m_{Z^{\mathrm{\prime }}}$ from the future LEP200 collider are obtained.