Question

Self-incompatibility is a device for I. ensuring cross-pollination.
II. preventing self-fertilisation.
III. ensuring self-fertilisation.
IV. genetic control for self-fertilisation. Choose the correct statements from those given above.

• A. I, II and III
• B. I, II, III and IV
• C. I, III and IV
• D. I, II and IV

Hint:

Self-incompatibility is a genetic mechanism that prevents self-fertilisation and promotes cross-pollination.

Answer 1

The Correct Option is D

Concept:
Self-incompatibility is a genetic mechanism in flowering plants. It prevents pollen from the same plant or genetically similar plant from fertilising the ovule.

Step 1: Check statement I.
Self-incompatibility prevents self-pollen from fertilising the ovule. So it promotes cross-pollination. Thus, statement I is correct.

Step 2: Check statement II.
Self-incompatibility prevents self-fertilisation. This is its main function. So, statement II is correct.

Step 3: Check statement III.
Self-incompatibility does not ensure self-fertilisation. It prevents self-fertilisation. So, statement III is incorrect.

Step 4: Check statement IV.
Self-incompatibility is genetically controlled. It works by recognition between pollen and pistil. So, statement IV is considered correct in the sense of genetic control related to prevention of self-fertilisation.

Step 5: Final conclusion.
The correct statements are: \[ I,\ II,\ IV \] Hence: \[ \boxed{\text{(D) I, II and IV}} \]