  We observe minima of the longitudinal resistance corresponding to the quantum
Hall effect of composite fermions at quantum numbers $p=1$, 2, 3, 4, and 6 in
an ultraclean strongly interacting bivalley SiGe/Si/SiGe two-dimensional
electron system. The minima at $p=3$ disappear below a certain electron
density, although the surrounding minima at $p=2$ and $p=4$ survive at
significantly lower densities. Furthermore, the onset for the resistance
minimum at a filling factor $\nu=3/5$ is found to be independent of the tilt
angle of the magnetic field. These surprising results indicate the intersection
or merging of the quantum levels of composite fermions with different valley
indices, which reveals the valley effect on fractions.
