Question

Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A): The hybrid cells formed by the fusion of two unrelated diploid protoplasts combine a set of three genomes from the parents.
Reason (R): Partial or complete elimination of nuclear genome before regeneration leads to the formation of cybrid plants.
In the light of the above statements, choose the most appropriate answer from the options given below:

• A. Both (A) and (R) are correct and (R) is the correct explanation of (A)
• B. Both (A) and (R) are correct but (R) is not the correct explanation of (A)
• C. (A) is correct but (R) is not correct
• D. (A) is not correct but (R) is correct

Hint:

Hybrid = Nucleus A + Nucleus B.
Cybrid = Nucleus A + Cytoplasm (A + B).
If two diploids ($2+2$) meet, they make a 4n hybrid, not a 3n one.

Answer 1

The Correct Option is B

Step 1: Understanding the Question:

We evaluate Assertion (A) on hybrid cells from fusion of two unrelated diploid protoplasts and Reason (R) on cybrid formation.

Step 2: Detailed Explanation:

• Assertion (A): As per the NTA final key, this statement is accepted as correct.

• Reason (R): Partial or complete elimination of the nuclear genome of one parent before regeneration gives cybrids (cytoplasmic hybrids), which is a correct statement.

• Cybrid formation is a different outcome from the true hybrid described in (A), so (R) does not explain (A).

Step 3: Final Answer:
Both (A) and (R) are correct but (R) is not the correct explanation of (A). The correct option is (B).