You cross two pink rose plants and find that while some of the offspring are pink, some are red and some are white. You decide that you like the red flowers and would like to make more. What cross would you perform to produce the most red flowered plants? Your mother decides she would like some of the pink flowered roses. Which cross would give you the most pink flowered plants?
Since these roses produce three phenotypes--red, white and pink, this is an example of incomplete dominance. The red and white alleles are codominant and if one of each is present in offspring, it produces the pink color. This is an example of blending inheritance. Since neither allele is dominant, they are both expressed and produces the pink variety. To get the most pink flowers, a red and white rose plant must be mated. Red would have two red alleles--RR and white would have two white alleles--WW. In this cross, all of the offspring would inherit one red allele and one white allele-RW and would be 100 percent pink! To produce the most red flowers,you must cross two red plants. Their genotypes would be RR and RR and their crossing would yield 100 percent red flowers. If you cross a red --RR and a pink plant--RW, this would result in 50 percent red and 50 percent pink flowers.