  The system of N scalar particles with Grassmann-valued color charges plus the
color SU(3) Yang-Mills field is reformulated on spacelike hypersurfaces. The
Dirac observables are found and the physical invariant mass of the system in
the Wigner-covariant rest-frame instant form of dynamics (covariant Coulomb
gauge) is given. From the reduced Hamilton equations we extract the second
order equations of motion both for the reduced transverse color field and the
particles. Then, we study this relativistic scalar quark model, deduced from
the classical QCD Lagrangian and with the color field present, in the N=2
(meson) case. A special form of the requirement of having only color singlets,
suited for a field-independent quark model, produces a ``pseudoclassical
asymptotic freedom" and a regularization of the quark self-energy.
