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Question

The variation of kemel color in com plants is an inherited trait. R is the dominant allele for red kernels in a com plant and r is the recessive allele for yellow kernels

What is the probability that a com plant with the genotype Rr crossed with a com plant ir will have offspring with the genotype rr?

Express your answer as a fraction using numerals for numbers and/ for the fraction bar. Do not include spaces.

Answer 1

The possible genotypes of the offspring from a cross between a Rr (red kernel) plant and a rr (yellow kernel) plant can be determined using a Punnett square.

1. The alleles from the Rr parent can be R or r.
2. The alleles from the rr parent can only be r.

The Punnett square looks like this:

      r      r
    -----------
R |   Rr     Rr
    -----------
r |   rr     rr

The possible genotypes of the offspring are:

• Rr (2 occurrences)
• rr (2 occurrences)

Out of a total of 4 possible genotypes, 2 of them are rr.

Thus, the probability of obtaining offspring with the genotype rr is:

\[ \frac{2}{4} = \frac{1}{2} \]

So, the final answer is:

1/2