To determine the percentage of offspring with an orange phenotype, we need to examine the possible genotypes resulting from crossing a parent with genotype [tex]\( RR_1 \)[/tex] (orange) and a parent with genotype [tex]\( R_1R_1 \)[/tex] (yellow).
### Step-by-Step Solution:
1. Identify the parent genotypes:
- Parent 1: [tex]\( RR_1 \)[/tex] (orange)
- Parent 2: [tex]\( R_1R_1 \)[/tex] (yellow)
2. Determine the possible allele combinations for the offspring:
- The first parent [tex]\( RR_1 \)[/tex] can contribute either the [tex]\( R \)[/tex] allele or the [tex]\( R_1 \)[/tex] allele.
- The second parent [tex]\( R_1R_1 \)[/tex] can only contribute the [tex]\( R_1 \)[/tex] allele (since both alleles are [tex]\( R_1 \)[/tex]).
3. List all possible offspring combinations by combining these alleles:
- [tex]\( R \)[/tex] (from Parent 1) with [tex]\( R_1 \)[/tex] (from Parent 2) results in [tex]\( RR_1 \)[/tex]
- [tex]\( R_1 \)[/tex] (from Parent 1) with [tex]\( R_1 \)[/tex] (from Parent 2) results in [tex]\( R_1R_1 \)[/tex]
- Thus, the possible offspring genotypes are: [tex]\( RR_1 \)[/tex] and [tex]\( R_1R_1 \)[/tex].
4. Determine the genotypes for all potential offspring:
- [tex]\( RR_1 \)[/tex]
- [tex]\( R_1R_1 \)[/tex]
- [tex]\( RR_1 \)[/tex]
- [tex]\( R_1R_1 \)[/tex]
5. Frequency of each genotype:
- [tex]\( RR_1 \)[/tex] appears twice.
- [tex]\( R_1R_1 \)[/tex] appears twice.
6. Use the information about phenotypes associated with each genotype:
- Genotype [tex]\( RR \)[/tex] = Red (not occurring in this cross)
- Genotype [tex]\( R_1R_1 \)[/tex] = Yellow
- Genotype [tex]\( RR_1 \)[/tex] = Orange
7. Count the number of orange phenotypes among the offspring:
- Orange phenotypes (genotype [tex]\( RR_1 \)[/tex]) = 0
8. Total number of offspring genotypes:
- Total offspring = 4
9. Calculate the percentage of offspring with the orange phenotype:
- Percentage of orange offspring [tex]\( = \left( \frac{0}{4} \right) \times 100 = 0\%\)[/tex]
### Conclusion:
The percentage of offspring expected to have an orange phenotype when crossing a plant with genotype [tex]\( RR_1 \)[/tex] and a plant with genotype [tex]\( R_1R_1 \)[/tex] is [tex]\(0\%\)[/tex].
So, the correct answer is [tex]\(0\%\)[/tex]. Given the options:
A. [tex]\(25\%\)[/tex]
B. [tex]\(50\%\)[/tex]
C. [tex]\(75\%\)[/tex]
D. 100\%
None of these choices match 0%, so there may be a need to recheck the options provided within the context.
