  Adding a gluino mass term to N=1 supersymmetric Yang-Mills theory breaks
supersymmetry softly. In order to approach the supersymmetric continuum limit
in numerical simulations with the Wilson action, the bare gluino mass has to be
tuned to the limit of vanishing renormalised gluino mass. This can be done
efficiently by means of the mass of the adjoint pion, which is, however, an
unphysical particle. We discuss how the adjoint pion can be defined in the
framework of partially quenched chiral perturbation theory. A relation between
its mass and the mass of the gluino, analogous to the Gell-Mann-Oakes-Renner
relation of QCD, can be derived.
