The shape of seed and starch grain size in pisum sativum is controlled by gene Bb,so the inheritance of seed shaps shown …...... relationship, while the inheritance of starch grains show .........

Options

A. Dominant recessive , codominance
B. Incomplete dominance, codominance
C. Dominant-recessive , incomplete dominance
D. Codominance, incomplete dominance

Answer

To solve the question regarding the inheritance of seed shape and starch grain size in Pisum sativum (pea plants) controlled by the gene Bb, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Traits**:
- The traits in question are seed shape and starch grain size in Pisum sativum.
- The gene responsible for these traits is Bb.

2. **Understand the Dominance**:
- In the case of seed shape, the dominant allele (B) results in round seeds, while the recessive allele (b) results in wrinkled seeds.
- Therefore, the inheritance of seed shape follows a dominant-recessive relationship.

3. **Analyze Starch Grain Size**:
- The size of starch grains is also influenced by the same gene (Bb).
- When the genotype is homozygous dominant (BB), the starch grain size is large.
- When the genotype is homozygous recessive (bb), the starch grain size is small.
- However, when the genotype is heterozygous (Bb), the starch grain size is intermediate between large and small.

4. **Determine the Type of Inheritance for Starch Grain Size**:
- Since the heterozygous condition (Bb) results in an intermediate phenotype, this indicates that the inheritance of starch grain size follows incomplete dominance.

5. **Final Conclusion**:
- The inheritance of seed shape shows a dominant-recessive relationship.
- The inheritance of starch grain size shows incomplete dominance.

### Final Answer:
The shape of seed shows **dominant-recessive relationship**, while the inheritance of starch grain shows **incomplete dominance**.

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