  The hadronization of an expanding partonic fireball is studied within the
Parton-Hadron-Strings Dynamics (PHSD) approach which is based on a dynamical
quasiparticle model (DQPM) matched to reproduce lattice QCD results in
thermodynamic equilibrium. Apart from strong parton interactions the expansion
and development of collective flow is found to be driven by strong gradients in
the parton mean-fields. An analysis of the elliptic flow $v_2$ demonstrates a
linear correlation with the spatial eccentricity $\epsilon$ as in case of ideal
hydrodynamics. The hadronization occurs by quark-antiquark fusion or 3 quark/3
antiquark recombination which is described by covariant transition rates. Since
the dynamical quarks become very massive, the formed resonant 'pre-hadronic'
color-dipole states ($q\bar{q}$ or $qqq$) are of high invariant mass, too, and
sequentially decay to the groundstate meson and baryon octets increasing the
total entropy. This solves the entropy problem in hadronization in a natural
way. Hadronic particle ratios turn out to be in line with those from a
grandcanonical partition function at temperature $T \approx 170$ MeV.
