Starch synthesis gene in pea plant in heterozygous condition produces starch grain of intermediate size. This shown:

Options

A. Complete dominance
B. Incomplete dominance
C. Codominance
D. None of these

Answer

To solve the question regarding the starch synthesis gene in pea plants and its effect on starch grain size in a heterozygous condition, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Alleles**: The starch synthesis gene in pea plants has two alleles: a dominant allele (B) and a recessive allele (b). In a heterozygous condition, the genotype would be Bb.

2. **Understand the Cross**: When we cross two pea plants, one homozygous dominant (BB) and one homozygous recessive (bb), the offspring (F1 generation) will all be heterozygous (Bb).

3. **Phenotypic Expression**: In the case of the heterozygous condition (Bb), the starch grain size is observed to be of intermediate size. This indicates that the expression of the trait does not follow complete dominance, where one allele completely masks the other.

4. **Define Incomplete Dominance**: Incomplete dominance occurs when the phenotype of the heterozygote is intermediate between the phenotypes of the two homozygotes. For example, if one parent produces large starch grains and the other produces small starch grains, the heterozygous offspring will produce starch grains of intermediate size.

5. **Conclusion**: Since the question states that the heterozygous condition produces starch grains of intermediate size, this is a classic example of incomplete dominance. Therefore, the correct answer to the question is **incomplete dominance**.

### Final Answer:
The starch synthesis gene in pea plants in heterozygous condition produces starch grains of intermediate size, which is an example of **incomplete dominance**.