In a cross, offsprings were 25% yellow round, 25% yellow wrinkled, 25% green round, 25% green wrinkled. Of which cross these results were obtained ?

Options

A. YYRR x yyrr
B. Yy Rr x YyRr
C. YyRR x yyrr
D. YyRr x yyrr

Answer

To determine the cross that results in the offspring phenotypes of 25% yellow round, 25% yellow wrinkled, 25% green round, and 25% green wrinkled, we can follow these steps:

### Step 1: Identify the Traits
We need to identify the traits involved in this cross. The traits mentioned are:
- Seed color: Yellow (dominant) and Green (recessive)
- Seed shape: Round (dominant) and Wrinkled (recessive)

### Step 2: Determine the Genotypes of the Parents
To achieve the given phenotypic ratios, we can deduce the genotypes of the parents. The dominant traits are represented by capital letters:
- Round shape (R) and Yellow color (Y)
- Wrinkled shape (r) and Green color (y)

We need to consider a cross between a homozygous dominant and a homozygous recessive for both traits:
- Parent 1: Round Yellow (RRYY)
- Parent 2: Wrinkled Green (rryy)

### Step 3: Perform the Dihybrid Cross
When we perform a dihybrid cross between these two parents:
- The gametes from Parent 1 (RRYY) will only produce one type of gamete: RY.
- The gametes from Parent 2 (rryy) will also produce one type of gamete: ry.

When we cross these, all offspring (F1 generation) will be heterozygous (RrYy), expressing the dominant traits (Round Yellow).

### Step 4: Self-Fertilization of F1 Generation
Next, we need to self-fertilize the F1 generation (RrYy):
- The gametes produced by RrYy will be: RY, Ry, rY, and ry.

### Step 5: Create a Punnett Square
We can set up a Punnett square with the gametes from the F1 generation:
```
RY Ry rY ry
-------------------------
RY | RRY Y | RRYy | RrYY | RrYy |
-------------------------
Ry | RRYy | Rryy | RrYy | Rryy |
-------------------------
rY | RrYY | RrYy | rrYY | rrYy |
-------------------------
ry | RrYy | Rryy | rrYy | rryy |
```

### Step 6: Analyze the Offspring Ratios
From the Punnett square, we can see the phenotypic ratios:
- Round Yellow (R_Y_): 9
- Round Green (R_yy): 3
- Wrinkled Yellow (rrY_): 3
- Wrinkled Green (rryy): 1

However, to achieve the 25% for each phenotype, we need to consider a different cross.

### Step 7: Identify the Correct Cross
To achieve equal ratios of 25% for each phenotype, we need a cross where both parents are heterozygous for both traits:
- Parent 1: RrYy (Round Yellow)
- Parent 2: RrYy (Round Yellow)

### Conclusion
The correct cross that results in the offspring phenotypes of 25% yellow round, 25% yellow wrinkled, 25% green round, and 25% green wrinkled is a dihybrid cross between two heterozygous parents (RrYy x RrYy).