In the cross YYRR `xx` yyrr, the number of green coloured seeds in `F_(2)` generation is

Options

A. `8//16`
B. `6//16`
C. `4//16`
D. `2//16`

Answer

To solve the problem regarding the number of green-colored seeds in the F2 generation from the cross YYRR (round yellow) and yyrr (wrinkled green), we will follow these steps:

### Step 1: Understand the Parental Genotypes
- The parental genotypes are YYRR (homozygous round yellow) and yyrr (homozygous wrinkled green).
- Here, Y (yellow) is dominant over y (green), and R (round) is dominant over r (wrinkled).

### Step 2: Determine the F1 Generation
- The F1 generation will be obtained by crossing YYRR with yyrr.
- All offspring in the F1 generation will have the genotype YyRr (round yellow) because they inherit one dominant allele from each parent.

### Step 3: Perform a Dihybrid Cross for F2 Generation
- To find the F2 generation, we need to cross the F1 individuals (YyRr x YyRr).
- We can set up a Punnett square for this dihybrid cross.

### Step 4: Determine the F2 Generation Ratio
- The phenotypic ratio for a dihybrid cross (YyRr x YyRr) is 9:3:3:1.
- 9 Round Yellow (YYRR, YYRr, YyRR, YyRr)
- 3 Round Green (YYrr, Yyrr)
- 3 Wrinkled Yellow (yyRR, yyRr)
- 1 Wrinkled Green (yyrr)

### Step 5: Identify the Number of Green Seeds
- In the F2 generation, the green seeds are represented by the genotypes:
- Round Green (Yyrr) = 3
- Wrinkled Green (yyrr) = 1
- Therefore, the total number of green seeds = 3 (Round Green) + 1 (Wrinkled Green) = 4.

### Step 6: Calculate the Total Number of Offspring
- The total number of offspring in the F2 generation is 16 (from the 9:3:3:1 ratio).
- The fraction of green seeds in the F2 generation is 4 out of 16.

### Step 7: Simplify the Ratio
- The ratio of green seeds in the F2 generation can be simplified:
- 4/16 = 1/4.

### Conclusion
- Therefore, the number of green-colored seeds in the F2 generation is **4**.

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