A rotor for a gas turbine is disclosed which includes alternating first and second set of rotor blades, the first set of rotor blades having a baseline profile and the second set of rotor blades having a profile with a cutback relative to the baseline profile, the cutback removing a portion of the baseline profile surrounding a maximum deflection point of a selected natural vibration mode. The cutback may be a tip trailing edge cutback at a span position located a distance away from the hub of at least 75% of the total span length. The selected natural vibration mode may be a natural vibration mode higher than the 1st natural vibration mode, more specifically may be the 3rd or 6th natural vibration mode.