1. **Rr x rr**:
   - Rr (parent 1) x rr (parent 2)
   - Possible genotypes in the F1 generation: Rr and Rr
   - Possible eye colors: Red eyes (Rr) only
2. **rr x RR**:
   - rr (parent 1) x RR (parent 2)
   - Possible genotypes in the F1 generation: Rr and Rr
   - Possible eye colors: Red eyes (Rr) only
3. **Rr x Rr**:
   - Rr (parent 1) x Rr (parent 2)
   - Possible genotypes in the F1 generation: RR, Rr, Rr, and rr
   - Possible eye colors: Red eyes (RR, Rr) and white eyes (rr)