Number of chromosome groups at each equatorial plate of metaphase I of a plant having 2n = 60 chromosomes, will be

Options

A. 60
B. 120
C. 180
D. 30

Answer

To solve the question regarding the number of chromosome groups at each equatorial plate of metaphase I for a plant with a diploid number (2n) of 60 chromosomes, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Diploid Number**: The diploid number (2n) represents the total number of chromosomes in a somatic cell. In this case, 2n = 60 means there are 60 chromosomes in total.

2. **Calculate the Haploid Number**: The haploid number (n) is half of the diploid number. This is calculated as:
\[ n = \frac{2n}{2} = \frac{60}{2} = 30 \]
Therefore, the haploid number is 30.

3. **Identify the Process**: The question refers to metaphase I of meiosis, which is the stage where homologous chromosomes (bivalents or tetrads) align at the equatorial plate.

4. **Determine the Chromosome Groups**: During metaphase I, homologous chromosomes pair up to form tetrads. Each tetrad consists of two homologous chromosomes. Since there are 30 chromosomes in the haploid set, they will form 30 tetrads.

5. **Conclusion**: Therefore, at the equatorial plate of metaphase I, there will be 30 chromosome groups (each group represents a tetrad).

### Final Answer:
The number of chromosome groups at each equatorial plate of metaphase I is **30**.

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