If a plant with genotype `R_(1)R_(2)R_(0)R_(0)` produces potatoes of 240 gram weight, while `r_(1)r_(1)r_(0)r_(0)` produces potatoes 100 grams in weight. What will be the weight of potatoes in a plant `R_(1)R_(1)R_(0)r_(0)`?

Options

A. 215g
B. 225g
C. 205g
D. 195g

Answer

To solve the problem of determining the weight of potatoes produced by a plant with the genotype `R_(1)R_(1)R_(0)r_(0)`, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Given Information**:
- The genotype `R_(1)R_(2)R_(0)R_(0)` produces potatoes weighing 240 grams.
- The genotype `r_(1)r_(1)r_(0)r_(0)` produces potatoes weighing 100 grams.

2. **Determine the Weight Difference**:
- Calculate the difference in weight between the dominant phenotype (240 grams) and the recessive phenotype (100 grams).
- Weight difference = 240 grams - 100 grams = 140 grams.

3. **Identify the Number of Contributing Alleles**:
- The total number of alleles involved in the dominant phenotype is 4 (R1, R2, R0, R0).
- This means there are 4 alleles contributing to the weight of the potatoes.

4. **Calculate Contribution per Dominant Allele**:
- To find the contribution of each dominant allele, divide the weight difference by the number of alleles.
- Contribution per dominant allele = 140 grams / 4 = 35 grams.

5. **Determine the Genotype of Interest**:
- The genotype `R_(1)R_(1)R_(0)r_(0)` has three dominant alleles (R1, R1, R0) and one recessive allele (r0).

6. **Calculate Total Contribution from Dominant Alleles**:
- The total contribution from the three dominant alleles is:
- Total contribution = 3 (dominant alleles) * 35 grams = 105 grams.

7. **Add the Contribution from the Recessive Allele**:
- Since the recessive phenotype contributes 100 grams, we add this to the contribution from the dominant alleles.
- Total weight = 100 grams (from recessive) + 105 grams (from dominant) = 205 grams.

8. **Final Answer**:
- The weight of potatoes produced by the plant with the genotype `R_(1)R_(1)R_(0)r_(0)` will be **205 grams**.