Cross a true-breeding blue flower with a true-breeding yellow flower?

Suppose you cross a true-breeding blue flower with a true-breeding yellow flower. In the next generation, all of the flowers are blue. What does this outcome tell you about the allele for blue flowers?


A.


The blue allele is sex-linked.





B.


The blue allele is recessive to the yellow allele.





C.


The blue allele is dominant to the yellow allele.





D.


The blue allele shows incomplete dominance.

Cross a true-breeding blue flower with a true-breeding yellow flower?
Call the allele for blue flowers B and the one for yellow flowers Y.





A true-breeding specimen must be homozygous, so the blue flowers must have the genotype BB and the yellow ones must be YY. (If a flower were BY, it could pass either color to its offspring, so some of the offspring wouldn't be the same color, so it wouldn't be true-breeding.)





Now when you cross a flower with genotype BB with one with genotype YY, all the offspring will be BY.





If a BY flower appears blue, then the blue allele must be dominant.





Therefore C is the correct answer.
Reply:enough of the punnet square crap, it will be green!!!
Reply:I would have to believe that the blue allele is dominant to the yellow allele, however, upon subsequent generations, you may find yellow flowers or color striated flowers thrown in. Just my opinion. I'm not a botanist or geneticist...not even close.
Reply:c