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D3.1.11—Self-incompatibility mechanisms

Self-incompatibility mechanisms prevent self-fertilization in flowering plants and reduce inbreeding by rejecting genetically similar or self pollen during pollination events.

Syllabus
First assessment 2025
Objective
D3.1.11
Level
SL

Exam analysis

Chance of appearing1%of analysed past papers
Latest appearanceMay 2025
Most common paperPaper1A
Typical marks1

Recent exam appearances

May 2025Paper1A ["SL"] · TZ219[ 1 ]D3.1.11—Self-incompatibility mechanisms
Practice this objective

Coverage 2025–2025 · Updated 16 Jul 2026

Concept essentials

  • Self-incompatibility prevents inbreeding rather than decreasing variation.
  • Recognition of self or similar alleles can block pollen success.
  • The mechanism promotes outcrossing and supports genetic diversity.
ConceptIB Biology SL