Percentage of inflated pod, wrinkled seed and axial flower obtained in F_2 generation of Mendel's monohybrid cross are respectively

Options

A. 75%, 75%, 25%
B. 25%, 50%,75%
C. 75%,50%,25%
D. 75%,25%,75%

Answer

To solve the question regarding the percentage of inflated pod, wrinkled seed, and axial flower obtained in the F2 generation of Mendel's monohybrid cross, we can follow these steps:

### Step 1: Understand the Traits
Mendel studied various traits in pea plants, and we need to identify the dominant and recessive traits for the three characteristics mentioned:
- **Pod Shape**: Inflated pod (dominant) vs. constricted pod (recessive)
- **Seed Shape**: Round seed (dominant) vs. wrinkled seed (recessive)
- **Flower Position**: Axial flower (dominant) vs. terminal flower (recessive)

### Step 2: Set Up the Crosses
1. **Pod Shape**:
- Cross: Inflated pod (FF) x Constricted pod (ff)
- F1 Generation: All offspring will be heterozygous (Ff), showing the dominant trait (inflated pod).

2. **F2 Generation**:
- Cross: Ff x Ff
- Genotypic ratio: 1 FF : 2 Ff : 1 ff
- Phenotypic ratio: 3 Inflated (FF or Ff) : 1 Constricted (ff)

### Step 3: Calculate the Percentage for Inflated Pod
- From the phenotypic ratio of 3:1, the percentage of inflated pods in the F2 generation is:
\[ \text{Percentage of Inflated Pod} = \frac{3}{4} \times 100 = 75\% \]

### Step 4: Seed Shape
1. **Seed Shape**:
- Cross: Round seed (RR) x Wrinkled seed (rr)
- F1 Generation: All offspring will be heterozygous (Rr), showing the dominant trait (round seed).

2. **F2 Generation**:
- Cross: Rr x Rr
- Genotypic ratio: 1 RR : 2 Rr : 1 rr
- Phenotypic ratio: 3 Round (RR or Rr) : 1 Wrinkled (rr)

### Step 5: Calculate the Percentage for Wrinkled Seed
- From the phenotypic ratio of 3:1, the percentage of wrinkled seeds in the F2 generation is:
\[ \text{Percentage of Wrinkled Seed} = \frac{1}{4} \times 100 = 25\% \]

### Step 6: Flower Position
1. **Flower Position**:
- Cross: Axial flower (AA) x Terminal flower (aa)
- F1 Generation: All offspring will be heterozygous (Aa), showing the dominant trait (axial flower).

2. **F2 Generation**:
- Cross: Aa x Aa
- Genotypic ratio: 1 AA : 2 Aa : 1 aa
- Phenotypic ratio: 3 Axial (AA or Aa) : 1 Terminal (aa)

### Step 7: Calculate the Percentage for Axial Flower
- From the phenotypic ratio of 3:1, the percentage of axial flowers in the F2 generation is:
\[ \text{Percentage of Axial Flower} = \frac{3}{4} \times 100 = 75\% \]

### Final Answer
Thus, the percentages of inflated pod, wrinkled seed, and axial flower in the F2 generation are:
- Inflated Pod: 75%
- Wrinkled Seed: 25%
- Axial Flower: 75%

### Summary of Results
- Inflated Pod: 75%
- Wrinkled Seed: 25%
- Axial Flower: 75%