  We study a simple model where color sextet scalars violate baryon number at
tree level but do not give rise to proton decay. In particular, we include one
light and two heavy sextets with $\Delta B=2$ baryon number violating
interactions that induce neutron anti-neutron oscillations. This setup also
suggests an intimate connection to the generation of the observed baryon
asymmetry in the Universe via the out of equilibrium decay of the heavy sextet
scalars at around $10^{14}$ GeV. The large $SU(3)$-color charges of the scalar
fields involved in generating the baryon asymmetry motivate us to study
potentially significant washout effects. We numerically solve a set of
Boltzmann evolution equations and find restrictions on the available model
parameters imposed by successful high scale baryogenesis. Combining our new
numerical results for baryogenesis with $n\bar n$-oscillation predictions and
collider limits on the light sextet, we identify parameter regions where this
model can be probed by current and future experiments.
