In petunias, some strains have flower petals that have a paler color compared to other strains. A true-breeding pale plant was p
ollinated by a true-breeding normal plant. All of the F1 offspring had pale petals. The F1 offspring were then pollinated by true-breeding normal plants. All of the F2 offspring had pale petals. Explain this pattern of inheritance.
It is maternal inheritance (cytoplasmic inheritance) of the gene for petal color.
Explanation:
In the given experiment, the color of the petal is regulated by maternal inheritance. In the first step, the true-breeding pale plant was pollinated by a true-breeding normal plant, therefore, all the F1 was identical in terms of petal color to the female plant (the true breeding pale plant).
In the second step, the F1 pale plants were pollinated by the true breeding normal plant. Again, the petal color in the progeny was determined that the female parent (the F1 pale plant). If true breeding normal plants will be pollinated by true breeding or F1 pale plant, the progeny will exhibit "normal phenotype" for petal color since the female plant has normal phenotype here.
