WHY IS TOP HEAVIER THAN BOTTOM - YUKAWA AND MASS UNIFICATION IN SUSY MODEL

We examine whether the unification constraints on the Yukawa couplings and on the Higgs masses in the minimal supersymmetric Standard Model can be consistent with the observed mass pattern of the third generation fermions. The effects of the QCD interaction and the SU(2)R breaking owing to the U(1)Y gauge interaction and the absence of nu(tau)R are crucial. We observe that the parameter choice of "no-scale" supergravity is favored and the SUSY breaking scale has a lower bound, in order for the top quark to be much heavier than the bottom quark.