Question

a horticulturalist wants to produce geraniums with specific characteristics. she knows that the trait of red flowers is governed by the allele r (rr and rr) and the trait of white flowers is governed by the allele r(rr). the horticulturalist plans to cross a geranium that is true - breeding for red flowers with a geranium that is true - breeding for white flowers. which punnett square best describes this cross?

Explanation:

Step1: Determine parent genotypes

The true - breeding red - flowered geranium has genotype RR and the true - breeding white - flowered geranium has genotype rr.

Step2: Set up Punnett square

The white - flowered parent (rr) can only contribute r alleles, so r is placed on the top of the Punnett square (across the columns). The red - flowered parent (RR) can only contribute R alleles, so R is placed on the left side (down the rows).

Step3: Fill in Punnett square

When we combine the alleles, we get Rr in each box of the Punnett square.

Answer:

The Punnett square with R on the left - hand side (down the rows) and r, r across the top (columns) resulting in Rr in each of the four boxes best describes the cross.