According to the law of Independent Assortment in a dihybrid cross

Options

A. There are four genotypes in `F_(2)`
B. `F_(2)` contains 16 phenotypes
C. There is a single individual which is homozygous recessive for both the characters
D. It is not possible to forecast the different phenotypes.

Answer

### Step-by-Step Solution:

1. **Understanding the Law of Independent Assortment**:
- The law of independent assortment states that alleles for different traits segregate independently of one another during gamete formation. This means that the inheritance of one trait will not affect the inheritance of another trait.

2. **Setting Up a Dihybrid Cross**:
- In a dihybrid cross, we consider two traits, each with two alleles. For example, let’s consider the traits for seed shape (Round - R, Wrinkled - r) and seed color (Yellow - Y, Green - y).

3. **Gamete Formation**:
- Each parent can produce four types of gametes based on the combinations of alleles: RY, Ry, rY, and ry.

4. **F1 Generation**:
- When we cross two true-breeding parents (RRYY x rryy), all offspring in the F1 generation will be heterozygous (RrYy).

5. **F2 Generation**:
- When we self-fertilize the F1 generation (RrYy x RrYy), we can use a Punnett square to determine the genotypes of the F2 generation.

6. **Genotype and Phenotype Ratios**:
- The Punnett square for a dihybrid cross results in 16 squares. This means there are 16 possible genotype combinations in the F2 generation.
- The genotypes can be classified into 9 different genotypes, but they correspond to only 4 different phenotypes (Round Yellow, Round Green, Wrinkled Yellow, and Wrinkled Green).

7. **Identifying the Correct Option**:
- Based on the options provided:
- There are four phenotypes (Correct)
- There are 16 genotypes (Incorrect, there are 9 genotypes)
- There is a single individual which is homozygous recessive for both characters (Incorrect, there are multiple combinations)
- It is not possible to forecast the different phenotypes (Incorrect, it is possible)

8. **Conclusion**:
- The correct statement according to the law of independent assortment in a dihybrid cross is that there are four phenotypes in the F2 generation.