  We used a recent grid of stellar models computed with and without rotation to
make predictions concerning the WR populations and the frequency of different
types of core-collapse SNe. Current rotating models were checked to provide
good fits to the following features: solar luminosity and radius at the solar
age, main-sequence width, red-giant and red-supergiant (RSG) positions in the
HRD, surface abundances, and rotational velocities. Rotating stellar models
predict that about half of the observed WR stars and at least half of the type
Ibc SNe may be produced through the single-star evolution channel. Rotation
increases the duration of the WNL and WNC phases, while reducing those of the
WNE and WC phases, as was already shown in previous works. Rotation increases
the frequency of type Ic SNe. The upper mass limit for type II-P SNe is \sim
19.0 MSun for the non rotating models and \sim 16.8 MSun for the rotating ones.
Both values agree with observations. Moreover, present rotating models provide
a very good fit to the progenitor of SN 2008ax. We discuss future directions of
research for further improving the agreement between the models and the
observations. We conclude that the mass-loss rates in the WNL and RSG phases
are probably underestimated at present. We show that up to an initial mass of
40 M\odot, a surface magnetic field inferior to about 200 G may be sufficient
to produce some braking. Much lower values are needed at the red supergiant
stage. We suggest that the presence/absence of any magnetic braking effect may
play a key role in questions regarding rotation rates of young pulsars and the
evolution leading to LGRBs.
