Question

Assertion :Self-incompatibility is a genetic mechanism which prevents self-pollination and thereby fertilisation by inhibiting either pollen germination or pollen tube growth in the pistil. Reason: In gametophytic self-incompatibility, the incompatibility reaction is determined by the genotype of the sporophytic tissue of the plant from which the pollen is derived.

• A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
• B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
• C. Assertion is correct but Reason is incorrect
• D. Both Assertion and Reason are incorrect

Answer 1

The correct option is C Assertion is correct but Reason is incorrect

Self-incompatibility refers to the inability of pollen from a flower to germinate on the stigma of the same flower (or other flower of same plant). Depending on the origin of factors determining the mating types two categories of self-incompatibility have been recognized.
(i) Gametophytic self-incompatibility (GSI). The incompatibility process is determined by the genotype of male gametophyte (pollen) itself, e.g., Liliaceae, Poaceae, Solanaceae.

(ii) Sporophytic self-incompatibility (SSI). The incompatibility process is controlled by the genotype of the sporophytic tissue of the plant from which the pollen is derived, e.g., Asteraceae, Brassicaceae.

So, the correct answer is 'Assertion is correct but Reason is incorrect'.