Which one / ones of following is/are correct regarding the Mendelian dihybrid cross?
A. The F2 phenotypic ratio is 9:3:3:1
B. Law of independent assortment can be explained on the basis of the cross.
C. F2 generation is obtained through the cross between Fq plants.
D. The gametes produced by F1 plants are of 4 types in 1:1:1:1 ratio

Options

A. A,B,C
B. A,B,C,D
C. B,D
D. A,B,C

Answer

To analyze the statements regarding the Mendelian dihybrid cross, we will evaluate each option step by step.

### Step 1: Evaluate Statement A
**Statement A:** The F2 phenotypic ratio is 9:3:3:1.

**Explanation:** In a dihybrid cross, when two heterozygous parents (RrYy x RrYy) are crossed, the F2 generation typically exhibits a phenotypic ratio of 9:3:3:1. This ratio represents the combinations of dominant and recessive traits for two traits being studied.

**Conclusion:** Statement A is **correct**.

### Step 2: Evaluate Statement B
**Statement B:** Law of independent assortment can be explained on the basis of the cross.

**Explanation:** The law of independent assortment states that alleles for different traits segregate independently of one another during gamete formation. This can be demonstrated through a dihybrid cross, where the inheritance of one trait does not affect the inheritance of another trait.

**Conclusion:** Statement B is **correct**.

### Step 3: Evaluate Statement C
**Statement C:** F2 generation is obtained through the cross between F1 plants.

**Explanation:** The F2 generation is indeed obtained from the self-fertilization (selfing) of F1 plants. When F1 plants (RrYy) are crossed with each other, they produce the F2 generation.

**Conclusion:** Statement C is **correct**.

### Step 4: Evaluate Statement D
**Statement D:** The gametes produced by F1 plants are of 4 types in a 1:1:1:1 ratio.

**Explanation:** In a dihybrid cross, the F1 generation (RrYy) produces four types of gametes: RY, Ry, rY, and ry. However, these gametes do not occur in a 1:1:1:1 ratio; they occur in a 1:1:1:1 ratio only when considering the combinations of alleles. Thus, the statement is misleading because it implies equal proportions without clarifying the context.

**Conclusion:** Statement D is **incorrect**.

### Final Conclusion
The correct statements regarding the Mendelian dihybrid cross are:
- A: Correct
- B: Correct
- C: Correct
- D: Incorrect

### Summary of Correct Statements
- A, B, and C are correct regarding the Mendelian dihybrid cross.

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