In a certain variety of tulips there are four alleles for flower color. Violet CV is dominant over red CR, which is dominant over pink CP, which is dominant over white c. A violet tulip CVc is crossed with a pink tulip CPc. What is the phenotypic ratio of the offspring?

The genes responsible for the flower colour of the tulips do actually have four traits, and four different alleles for each one of them. The violet colour is dominant of all, represented by Cv. The red is recessive to violet, but dominant to others, represented by Cr. The pink is dominant to white, but recessive to others represented by Cp and the white is recessive to all, represented by c.

In the plant with heterozygous violet flowers, the genotype is Cvc. So the gametes produced by the plant will be Cv and c.

In the plant with heterozygous pink flowers, the genotype is Cpc. So the gametes produced by the plant will be Cp and c.

So the offspring probability will be CvCp, Cvc, Cpc and cc.

As violet is dominant over both pink and white, so CvCp and Cvc are violet, while Cpc is pink and cc is white. So the ratio of violet to pink to white would be 2:1:1.