Final answer:
The color trait in petunias exhibits incomplete dominance, where a violet flower results from the blending of blue and red alleles. Upon crossing two violet petunias, one expects a mix of colors indicating the inheritance pattern. Flowering plants present a wide variety of color due to their evolutionary background.
Step-by-step explanation:
The student's question pertains to the inheritance pattern of flower color in petunias and how this trait is characterized. When a blue petunia is crossed with a red petunia, all resulting flowers are violet. This suggests incomplete dominance, a situation where neither allele is dominant over the other, and the phenotype is a blend of both parents' traits. When two violet petunias are crossed, the most probable result is a mix of violet and red flowers, assuming a 1:1 ratio based on Mendelian genetics. This further supports the concept of incomplete dominance as the violet flower must contain alleles for both red and blue colors.
The incomplete dominance is evident because the resulting flower color is not one of the parental colors, but a mixture or blend of both. Therefore, in the case of the cross between two violet petunias, one would expect approximately a 1:2:1 ratio of red to violet to blue flowers if violet is a result of the incomplete dominance between blue and red alleles.
Flowering plants like the petunia also show remarkable diversity and adaptations, illustrating that they evolved from a common ancestor and have diversified into various forms and colors, such as the ones seen in dense blazing star and purple coneflower, each possessing a similar basic morphology but varying in appearance.