What does the term segregation mean in the context of plant breeding and genetics?

This term has two meanings in genetics and plant breeding. Segregation can refer to the separation of genes and their respective alleles during meiosis into new daughter cells. This is also referred to as Mendel’s first law or the Principle of Segregation.
Segregation—or a segregating population—can also refer to a population in which there is phenotypic variation. For example, a population may have both resistant and susceptible individuals with respect to bacterial spot.