A breeder is growing pea plants that are either tall (T) or…

A breeder is growing pea plants that are either tall (T) or dwarf (t) stature and tall is dominant over dwarf. The peas also have either red (R) flowers or white (r) flowers. He finds that when tall plants with red flowers are crossed with dwarf plants with white flowers that all the offspring are tall and have pink flowers (F1).   What type of dominance is controling flower color?