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 (garden pea), we will analyze the genetic relationships involved.

### Step-by-Step Solution:

1. **Identify the Genes and Alleles**:
The seed shape and starch grain size in Pisum sativum are controlled by the gene Bb, where:
- B = dominant allele
- b = recessive allele

2. **Inheritance of Seed Shape**:
- The seed shape is determined by the alleles B and b.
- The homozygous dominant genotype (BB) produces round seeds, while the homozygous recessive genotype (bb) produces wrinkled seeds.
- The heterozygous genotype (Bb) also produces round seeds due to the dominance of the B allele.
- Therefore, the inheritance of seed shape follows a **dominant-recessive relationship**.

3. **Inheritance of Starch Grain Size**:
- The starch grain size is influenced by the same alleles (B and b).
- The homozygous dominant genotype (BB) produces large starch grains, while the homozygous recessive genotype (bb) produces small starch grains.
- The heterozygous genotype (Bb) results in starch grains of intermediate size, which indicates that the expression of the trait is not purely dominant or recessive.
- This type of inheritance, where the phenotype of the heterozygote is intermediate between the two homozygotes, is known as **incomplete dominance**.

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