How do incomplete dominance and codominance improve the quality of plant and animal breeds?

During incomplete dominance both the allelic genes in a chromosome in dominant condition inherit a character in the off-springs. When only one gene out of the allelic pair is dominant and its counterpart is recessive, we get incomplete expression. For example a pea plant with red flowers is crossed with another plant having white flowers, the f1 plants are pink flowered. On selfing of f1 plants we get f2 progeny in the ratio of 1 red: 2 pink : 1 white flowered plants. These pink flowered plants show incomplete dominance.