  We have experimentally studied the fractional quantum Hall effect (FQHE) in
SiGe/Si/SiGe quantum wells in relatively weak magnetic fields, where the
Coulomb interaction between electrons exceeds the cyclotron splitting by a
factor of a few XX. Minima of the longitudinal resistance have been observed
corresponding to the quantum Hall effect of composite fermions with quantum
numbers $p$ = 1, 2, 3, and 4. Minima with $p$ = 3 disappear in magnetic fields
below 7 Tesla, which may be a consequence of the intersection or even merging
of the quantum levels of the composite fermions with different orientations of
the pseudo-spin, i.e., those belonging to different valleys. We have also
observed minima of the longitudinal resistance at filling factors $\nu$ = 4/5
and 4/11, which may be due to the formation of the second generation of the
composite fermions.
