In terms of mass generation in the strong interaction without chiral symmetry breaking, we perform the first study for light scalar-quarks phi (colored scalar particles with 3(c) or idealized diquarks) and their color-singlet hadronic states using quenched SU(3)(c) lattice QCD with beta=5.70 (i.e., a similar or equal to 0.18 fm) and lattice size 16(3)x32. We investigate "scalar-quark mesons" phi(dagger)phi and "scalar-quark baryons" phi phi phi as the bound states of scalar-quarks phi. We also investigate the color-singlet bound states of scalar-quarks phi and quarks psi, i.e., phi(dagger)psi, psi psi phi, and phi phi psi, which we name "chimera hadrons." All the new-type hadrons including phi are found to have a large mass even for zero bare scalar-quark mass m(phi)=0 at a(-1)similar or equal to 1 GeV. We find a "constituent scalar-quark/quark picture" for both scalar-quark hadrons and chimera hadrons. Namely, the mass of the new-type hadron composed of m phi's and n psi's, Mm phi+n psi, approximately satisfies Mm phi+n psi similar or equal to mM(phi)+nM(psi), where M-phi and M-psi are the constituent scalar-quark and quark masses, respectively. We estimate the constituent scalar-quark mass M-phi for m(phi)=0 at a(-1)similar or equal to 1 GeV as M-phi similar or equal to 1.5-1.6 GeV, which is much larger than the constituent quark mass M-psi similar or equal to 400 MeV in the chiral limit. Thus, scalar quarks acquire a large mass due to large quantum corrections by gluons in the systems including scalar quarks. Together with other evidences of mass generation of glueballs and charmonia, we conjecture that all colored particles generally acquire a large effective mass due to dressed gluon effects. In addition, the large mass generation of pointlike colored scalar particles indicates that plausible diquarks used in effective hadron models cannot be described as the pointlike particles and should have a much larger size than a similar or equal to 0.2 fm.