A cross was made between tall and dwarf plant. In `F_(1)` plants were selfed, thetall and dwarf plants appeared in 3:1 ratio in `F_(2)` generation. This phenomenon is known as

Options

A. Dominance
B. Segregation
C. Hybridization
D. Crossing over

Answer

To solve the question regarding the cross between tall and dwarf plants, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Cross**:
- We start with a cross between two plants: one tall (dominant trait) and one dwarf (recessive trait).
- Let's denote the tall plant's allele as "T" (dominant) and the dwarf plant's allele as "t" (recessive).

2. **F1 Generation**:
- When these two plants are crossed, all offspring in the F1 generation will have the genotype "Tt" (heterozygous), which expresses the tall phenotype due to the dominance of the tall allele.
- Therefore, all F1 plants will be tall.

3. **Selfing F1 Generation**:
- When the F1 plants (Tt) are self-fertilized, we need to determine the genotypes of the F2 generation.
- The possible gametes from Tt are "T" and "t".

4. **Punnett Square Analysis**:
- We can set up a Punnett square to visualize the combinations of alleles in the F2 generation:
```
T t
------------
T | TT | Tt |
------------
t | Tt | tt |
```
- From the Punnett square, we can see the genotypes of the F2 generation:
- 1 TT (homozygous tall)
- 2 Tt (heterozygous tall)
- 1 tt (homozygous dwarf)

5. **Phenotypic Ratio**:
- The phenotypic ratio of the F2 generation is 3 tall (TT and Tt) to 1 dwarf (tt), which is expressed as 3:1.

6. **Identifying the Phenomenon**:
- The appearance of this 3:1 ratio in the F2 generation is a classic example of the **Law of Segregation**.
- The Law of Segregation states that during gamete formation, the two alleles for a trait separate from each other, so that each gamete carries only one allele for each trait.

### Conclusion:
The phenomenon observed in this genetic cross is known as **Segregation**.

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