A type of plant that produces red flowers is crossed with a plant that produces white flowers. The alleles for flower color exhibit incomplete dominance, and all of their offspring have pink flowers. If two of the pink-flowered offspring were crossed, which of the following ratios of red, pink, and white flowers would you find in their offspring?
a. 0% red : 100% pink : 0% white
b. 25% red : 50% pink : 25% white
c. 33% red : 33% pink : 33% white
d. 50% red : 0% pink : 50% white

Question

A type of plant that produces red flowers is crossed with a plant that produces white flowers. The alleles for flower color exhibit incomplete dominance, and all of their offspring have pink flowers. If two of the pink-flowered offspring were crossed, which of the following ratios of red, pink, and white flowers would you find in their offspring?  
 a. 0% red : 100% pink : 0% white
 b. 25% red : 50% pink : 25% white
 c. 33% red : 33% pink : 33% white
 d. 50% red : 0% pink : 50% white

blues · Answer

Do a punnet square. You find that 1/4 are homozygous dominant, 1/4 are homozygous recessive and 2/4 = 1/2 are heterozygous. The only option which matches these allele distributions is b.