The genotype of a plant showing the dominant phenotype can be determined by

Options

A. Test cross
B. Dihybrid cross
C. Pedigree analysis
D. Back cross

Answer

To determine the genotype of a plant showing the dominant phenotype, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Phenotype and Genotype**:
- The phenotype is the observable characteristic (e.g., flower color), while the genotype is the genetic makeup (e.g., homozygous dominant or heterozygous).

2. **Identify the Dominant Phenotype**:
- In this case, the plant shows a dominant phenotype, which means it could either be homozygous dominant (TT) or heterozygous (Tt).

3. **Perform a Test Cross**:
- A test cross involves crossing the plant with an individual that is homozygous recessive (tt). This helps to determine the unknown genotype of the dominant phenotype plant.

4. **Analyze the Possible Outcomes**:
- If the dominant phenotype plant is homozygous dominant (TT), the offspring will all show the dominant phenotype (Tt).
- If the dominant phenotype plant is heterozygous (Tt), the offspring will show a mix of dominant (Tt) and recessive (tt) phenotypes.

5. **Conclusion**:
- By analyzing the offspring's phenotypes from the test cross, you can determine whether the dominant phenotype plant is homozygous (TT) or heterozygous (Tt).

### Final Answer:
The genotype of a plant showing the dominant phenotype can be determined by **test cross**.