Final answer:
Mendel's pea plant experiments used a monohybrid cross to demonstrate the inheritance of flower color, revealing that red color (or violet) is dominant over white and follows a 3:1 ratio in the F2 generation. This confirmed the principles of segregation and dominance in genetic inheritance.
Step-by-step explanation:
Inheritance of Flower Color in Mendel's Pea Plants
In the historic experiment by Gregor Mendel involving pea plants, purple and white flower color traits were observed to follow a particular pattern of inheritance. Starting with the parental (P) generation, Mendel crossed true-breeding red flower plants with true-breeding white flower plants, producing an F1 generation that had all red (or violet) flowers, demonstrating the dominance of the red flower trait.
Upon self-pollination of these F1 plants, the F2 generation showed a phenotypic ratio where approximately 75% of the plants had red flowers and 25% had white flowers. These results suggest that red flower color is a dominant trait, while white flower color is a recessive trait. The phenotypic ratio in the F2 generation was approximately 3:1, indicating that the F1 plants were heterozygous for the flower color trait.
The fact that the white flower trait reappeared in the F2 generation at a significant frequency, but not in the F1 generation, supports the principle of segregation. This shows that each parent contributes one allele for each trait and that the alleles separate or segregate during gamete formation, resulting in the reemergence of the recessive trait in the F2 generation when two recessive alleles come together. Mendel's reciprocal cross, which showed the same 3:1 ratio irrespective of the flower color of the pollen or ovum, further demonstrated that traits are not affected by whether they come from male or female parents.
Overall, these experiments led to the establishment of foundational principles in the inheritance of traits, forming the basis of what we now know as Mendelian genetics.