The offspring resulting from the cross of two red flowered plants are 3/4 red and 1/4 white. The most likely genotype of the red flowered plants is _____ .
A) homozygous dominant
B) heterozygous
C) homozygous recessive
D) impossible to tell from this information

Question

Quizplus · Accepted Answer

The fact that the offspring are 3/4 red and 1/4 white suggests that one parent was homozygous dominant (RR) and the other was heterozygous (Rr). When the two are crossed, the Punnett square predicts that the offspring will be 3/4 red (RR or Rr) and 1/4 white (rr). Therefore, the most likely genotype of the red flowered plants is heterozygous (Rr). Option A (homozygous dominant) would result in all red offspring, while option C (homozygous recessive) would result in all white offspring, neither of which match the observed ratio. Option D (impossible to tell) is incorrect, as the observed ratio provides enough information to make a reasonable inference about the parent genotype.

The Offspring Resulting from the Cross of Two Red Flowered