If a cross between two plants produces offspring with 50% dominant character (A) and 50% recessive character (a), then the genotype of parents are

Options

A. `Aa xx Aa`
B. `Aa xx aa`
C. AA xx aa`
D. AA xx Aa`

Answer

To solve the problem, we need to determine the genotypes of the parent plants that produce offspring with a 50% dominant character and 50% recessive character.

### Step-by-Step Solution:

1. **Understanding Dominance and Recessiveness**:
- In genetics, dominant traits are represented by uppercase letters (e.g., A) and recessive traits by lowercase letters (e.g., a).

2. **Analyzing the Offspring Ratio**:
- The offspring ratio given is 50% dominant (A) and 50% recessive (a). This indicates that half of the offspring exhibit the dominant trait, while the other half exhibit the recessive trait.

3. **Determining Parental Genotypes**:
- To achieve a 50% dominant and 50% recessive ratio, one of the parents must contribute a dominant allele (A) and the other parent must contribute a recessive allele (a).
- The simplest way to achieve this is to have one parent be heterozygous (Aa) and the other parent be homozygous recessive (aa).

4. **Setting Up the Cross**:
- If we cross a heterozygous parent (Aa) with a homozygous recessive parent (aa), the possible offspring genotypes will be:
- From Aa: A and a
- From aa: a and a
- The resulting combinations will be:
- Aa (dominant)
- Aa (dominant)
- aa (recessive)
- aa (recessive)
- This results in a 1:1 ratio of dominant to recessive offspring.

5. **Conclusion**:
- Therefore, the genotypes of the parents are:
- One parent is heterozygous (Aa).
- The other parent is homozygous recessive (aa).

### Final Answer:
The genotypes of the parents are Aa (heterozygous) and aa (homozygous recessive).

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