The production of pink flowered plants from a cross between a red flowered plant and a white flowered plant is an example of

The answer is 'hybridization'. This is the crossing of two genetically different individuals, resulting in offspring with a genotype and set of traits that are different from that of both parents. Within plants, the new traits are often advantageous, as the hybrid may have traits which make it more competitive.
Gregor Mendel’s early experiments using  pea plants used the concept of hybridization to study inheritance.