  We present K-band images of 31 radio quasars selected from the B3-VLA quasar
sample. A new method has been developed to detect and restore the host galaxies
of these quasars. We have detected the host galaxies of 16 of them. Using these
data together with previous data from the B3-VLA quasars (Carballo et al. 1998,
hereafter Paper I) and literature data from other samples, we have analyzed a
sample of 69 hosts of radio quasars, covering a redshift range between 0<z<3.
  The host galaxies are large (r_e}~15kpc) and luminous elliptical galaxies
(~75% of them brighter than L_*), with an evolution similar to that of radio
galaxies. A significant fraction (~40%) of them shows evidence of a possible
collision/merging process. They follow a mu_e-r_e relation similar to that of
normal elliptical galaxies. The morphological and photometric similarities
between these galaxies and radio galaxies in this wide range of redshifts is a
good test of the reliability of unification schemes. All of them show little
evolution from z=3 to the present epoch. Their K-z distribution is consistent
with a no-evolution model, with a fraction of the dispersion due to differences
in radio power. We have found a correlation between the quasar radio power and
the host luminosity. We have also found a correlation between the host and
nuclear source luminosities. These correlations could be induced by a physical
relation between the central black hole and the bulge mass (Magorrian et al.
1998).
