which forces should be considered as responsible for torque

force which is not acting along center of mass would be resposible for torque.....

Effective Torque is the torque which is calculated about the ICR (Instantaneous Centre of Rotation).It is such a point which has 0 accelaration..while a body is under pure rotation without slipping..Slipping is absent means relative displacement,velocity and acc all are 0..That torque is effective...and so are the forces there..