GLUINO CONTRIBUTION TO THE 3-LOOP BETA-FUNCTION IN THE MINIMAL SUPERSYMMETRIC STANDARD MODEL

We deduce the gluino contribution to the three-loop QCD beta function within the minimal supersymmetric standard model (MSSM) from its stand ard QCD expression. The result is a first step in the computation of t he full MSSM three-loop beta function. In addition, in the case of a l ight gluino it provides the strong three-loop SUSY correction to the e xtrapolation of the strong coupling constant from the low energy regim e to the Z region and up to the squark threshold.