Question

Given below are two statements, one is labelled as Assertion (A) and other one labelled as Reason (R).

Assertion (A): The diploid wild species of potato are self-incompatible due to gametophytic self-incompatibility system.
Reason (R): A dominant self-incompatibility inhibitor gene (Sli) has been identified in the wild species of Solanum chacoense.

In light of the above statements, choose the correct answer from the options given below.

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

Hint:

The Sli gene is of extreme commercial importance today as it is utilized to develop self-compatible inbred lines of diploid potatoes.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Self-incompatibility (SI) prevents self-fertilization in many diploid wild potato species. Understanding genes that inhibit this system is crucial for developing diploid inbred lines.

Step 2: Detailed Explanation:
Assertion (A) is true because most diploid wild potato species are indeed self-incompatible, regulated by a multi-allelic single-locus gametophytic self-incompatibility (GSI) system.
Reason (R) is true because a dominant self-incompatibility inhibitor gene, designated as Sli, was discovered and characterized in the wild diploid species Solanum chacoense.
However, the presence of the inhibitor gene (Sli) acts to overcome/break self-incompatibility, leading to self-compatibility. It is not the biological reason why these species are self-incompatible in the first place.
Thus, both statements are true, but (R) is not the correct explanation of (A).

Step 3: Final Answer:
Hence, both statements are true, but (R) is not the correct explanation of (A).