In a hybrid cross, the maximum number of phenotypes would be
(a) 8
(b) 4
(c) 2
(d) 16

Options

A. 8
B. 4
C. 2
D. 16

Answer

To solve the question regarding the maximum number of phenotypes in a hybrid cross, we will follow these steps:

### Step 1: Understand the Types of Crosses
A hybrid cross typically refers to a genetic cross between two different homozygous individuals. In this case, we will focus on a dihybrid cross, which involves two traits.

### Step 2: Identify the Traits
Let's consider two traits, each with two alleles. For example, we can use:
- Trait 1: Seed color (Yellow - dominant, represented as Y; Green - recessive, represented as y)
- Trait 2: Seed shape (Round - dominant, represented as R; Wrinkled - recessive, represented as r)

### Step 3: Determine the Parental Genotypes
In a dihybrid cross, we can take one parent as homozygous dominant for both traits (YYRR) and the other as homozygous recessive for both traits (yyrr).

### Step 4: Produce the F1 Generation
When we cross these two parents (YYRR x yyrr), all offspring in the F1 generation will be heterozygous for both traits (YyRr). This means they will all display the dominant phenotypes: Yellow and Round seeds.

### Step 5: Self-Pollinate the F1 Generation
Next, we self-pollinate the F1 generation (YyRr x YyRr) to produce the F2 generation.

### Step 6: Determine the Phenotypic Ratios
The phenotypic ratio for a dihybrid cross is typically 9:3:3:1. This means:
- 9 offspring will have the dominant traits (Yellow and Round)
- 3 offspring will have one dominant and one recessive trait (Yellow and Wrinkled)
- 3 offspring will have the other dominant and recessive trait (Green and Round)
- 1 offspring will have both recessive traits (Green and Wrinkled)

### Step 7: Count the Number of Phenotypes
From the above ratios, we can see that there are four distinct phenotypes:
1. Yellow and Round
2. Yellow and Wrinkled
3. Green and Round
4. Green and Wrinkled

### Conclusion
Thus, the maximum number of phenotypes produced in a dihybrid cross is **4**. Therefore, the correct answer is **(b) 4**.

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