A plant of `"F"_(1)` generation with genotype AABbCC. On selfing of this plant what is the phenotypic ratio in `"F"_(2)` generation?

Options

A. `3:1`
B. `9:3:3:1`
C. `1:2:1`
D. `27:9:9:9:3:3:3:1`

Answer

To determine the phenotypic ratio in the F2 generation from a plant with the genotype AABbCC, we will follow these steps:

### Step 1: Identify the Genotype of the F1 Generation
The genotype of the F1 generation is AABbCC. This means:
- A is homozygous dominant (AA)
- B is heterozygous (Bb)
- C is homozygous dominant (CC)

### Step 2: Determine the Gametes Produced by the F1 Generation
To find out the gametes produced by the F1 plant, we need to consider the alleles:
- For A (AA), the only gamete produced is A.
- For B (Bb), the gametes produced are B and b.
- For C (CC), the only gamete produced is C.

Thus, the possible gametes from AABbCC are:
- ABC
- AbC

### Step 3: Set Up the Punnett Square
Now, we can set up a Punnett square to determine the genotypes of the F2 generation. Since the F1 plant can produce two types of gametes (ABC and AbC), we can set up a 2x2 Punnett square:

| | ABC | AbC |
|-------|-------|-------|
| **ABC** | AABBC | AABbC |
| **AbC** | AABBC | AABbC |

### Step 4: Determine the Genotypes from the Punnett Square
From the Punnett square, we can see the following combinations:
1. AABBC (homozygous dominant for A and B, homozygous dominant for C)
2. AABbC (homozygous dominant for A, heterozygous for B, homozygous dominant for C)

### Step 5: Identify the Phenotypes
Now, we need to identify the phenotypes based on the genotypes:
- AABBC and AABbC will both show the dominant phenotypes for A, B, and C.
- The only time we will see a different phenotype is when we have the homozygous recessive for B (bb), but since we do not have any bb in our combinations, we will not see that phenotype.

### Step 6: Calculate the Phenotypic Ratio
Since all combinations lead to the dominant phenotypes (A and C are dominant), we will have:
- Dominant phenotype (A_B_C): 3 (from AABBC and AABbC)
- Recessive phenotype (only bb): 1 (not present in this case)

Thus, the phenotypic ratio in the F2 generation is 3:1.

### Conclusion
The phenotypic ratio in the F2 generation from the selfing of the plant with genotype AABbCC is **3:1**.