Final answer:
In Mendel's experiments, true-breeding white and purple flowers resulted in all purple flowers in the F1 generation and a 3:1 ratio of purple to white flowers in the F2 generation, demonstrating the concept of dominant and recessive traits without blending.
Step-by-step explanation:
When Mendel used true-breeding white flowers and true-breeding purple flowers as the parental generation, the results showed that all of the hybrid offspring in the F1 generation had purple flowers. This is because the purple flower trait is dominant over the white. In the subsequent F2 generation, approximately three quarters of the plants had purple flowers and one quarter had white flowers, demonstrating that the white flower trait, although recessive and not expressed in the F1 generation, had not disappeared and could be expressed when two recessive alleles were present.
Mendel's results overturned the conventional wisdom of his time, which would have predicted that the hybrid flowers would be a blend of purple and white. Instead, his experiments demonstrated that traits are inherited as distinct units, and not blended. This experiment with flower color confirmed that the pea plants were physically identical other than in their flower color, ensuring that flower color was indeed a single-variable trait.