The forced vertical oscillations of a single dust particle trapped in a standing striation are investigated. The particle oscillations associated with the displacement of the striation are induced by square wave modulation of the discharge current. Amplitude-frequency characteristics with respect to pressure are measured. The resonance frequency, the logarithmic decrement and the amplitude of resonance peak are determined. In order to obtain the eigenfrequency value, the phase shift of the forced dust particle oscillations is measured and the velocity resonance investigated. The calculation of the dust particle charge is made with the help of the eigenfrequency. A quantitative description of the resonance behaviour of the dust particle based on the theory of the forced harmonic oscillator is made. The Q-factor of a dusty plasma system is measured for the first time, and the obtained value compared with Q-factors of dusty plasma oscillatory systems previously investigated in rf plasma.