The characteristics of the mobility of the individual 60° dislocations in Czochralski grown Si1-xGex bulk single crystals with different Ge content (x = 0 - 5.5 at. %) have been studied. Starting stresses for the dislocation motion, increasing with Ge concentration, have been revealed. The temperature and the stress dependences of the dislocation velocity have been plotted. It is found that dislocation velocity rises with stress more sharply in samples with higher Ge content The intermittent loading technique has been used to study the kinetics of the dislocation kink pair formation and relaxation. It is revealed that duration of the kink pair relaxation increases significantly with Ge concentration. Possible reasons of the effect are discussed.