To determie the genotype of a tall plant of `F_(2)` generation, Mendel crossed this plant with a dwarf plant. This cross represents a

Options

A. test cross
B. back cross
C. reciprocal cross
D. dihybrid cross

Explanation

To determine the genotype of a tall plant from the F2 generation, Mendel performed a cross between this tall plant and a dwarf plant. This type of cross is known as a test cross. Here’s a step-by-step explanation of why this is the case:

### Step-by-Step Solution:

1. **Understanding the Genotypes**:
- In Mendelian genetics, tall plants are typically represented by the dominant allele (T), while dwarf plants are represented by the recessive allele (t).
- The genotype of the tall plant could either be homozygous dominant (TT) or heterozygous (Tt).

2. **Purpose of the Cross**:
- The purpose of crossing the tall plant with a dwarf plant (tt) is to determine the genotype of the tall plant. Since the dwarf plant is homozygous recessive, it will only contribute recessive alleles (t).

3. **Performing the Test Cross**:
- When the tall plant (unknown genotype) is crossed with the dwarf plant (tt), the offspring's phenotypes will reveal the genotype of the tall parent.
- If the tall plant is homozygous dominant (TT), all offspring will be tall (Tt).
- If the tall plant is heterozygous (Tt), the offspring will show a 1:1 ratio of tall to dwarf plants (Tt:tt).

4. **Conclusion**:
- The cross between the tall plant and the dwarf plant is called a test cross because it tests the genotype of the tall plant by observing the phenotypes of the offspring.

### Final Answer:
This cross represents a **test cross**.

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