Read the given paragraph to answer
In a certain plant, yellow fruit colour (Y) is dominant to green fruit colour (y) and round shape (R) is dominant to oval shape (r). The two genes involved are located on different chromosomes.
Which of the following will result when plant YyRr is self-pollinated ?

Options

A. `9 : 3 : 3: 1` ratio of phenotypes only
B. `9 : 3 : 3: 1` ratio of genotypes only
C. `1: 1: 1: 1` ratio of phenotypes only
D. `1:1:1:1` ratio of phenotypes and genotypes

Explanation

To solve the problem of determining the phenotypic ratio resulting from the self-pollination of a plant with the genotype YyRr, we will follow these steps:

### Step-by-Step Solution:

1. **Identify the Genotypes and Phenotypes**:
- The given genotype is YyRr.
- Here, Y (yellow fruit color) is dominant over y (green fruit color).
- R (round shape) is dominant over r (oval shape).

2. **Determine the Gametes**:
- For the genotype YyRr, we can produce four types of gametes:
- YR (Yellow, Round)
- Yr (Yellow, Oval)
- yR (Green, Round)
- yr (Green, Oval)

3. **Set Up the Punnett Square**:
- Create a 4x4 Punnett square to cross the gametes with themselves.
- The rows and columns will represent the gametes from each parent (YyRr x YyRr).

4. **Fill in the Punnett Square**:
- The combinations of gametes will yield the following genotypes:
- YYRR
- YYRr
- YyRR
- YyRr
- YYrr
- Yyrr
- yyRR
- yyRr
- yyrr

5. **Count the Phenotypes**:
- Now we categorize the resulting genotypes into phenotypes:
- Yellow, Round (YYRR, YYRr, YyRR, YyRr) - 9
- Yellow, Oval (YYrr, Yyrr) - 3
- Green, Round (yyRR, yyRr) - 3
- Green, Oval (yyrr) - 1
- This gives us a total of 9 Yellow Round, 3 Yellow Oval, 3 Green Round, and 1 Green Oval.

6. **Calculate the Phenotypic Ratio**:
- The phenotypic ratio is 9:3:3:1.

### Conclusion:
The result of self-pollinating the plant YyRr will yield a phenotypic ratio of **9:3:3:1**.