- A Repeated self-incompatible crosses occurring between unrelated parent breeding lines over time
- B Repeated self-fertilization of F2 plants until homozygosity is ~99%, useful for QTL mapping
- C Backcrossing alone, without any intervening self-fertilization steps taking place
- D Vegetative cloning of a single heterozygous parent plant repeatedly over time
Correct answer: B. Repeated self-fertilization of F2 plants until homozygosity is ~99%, useful for QTL mapping
Explanation: RILs: F2 plants are self-fertilized for 6-8 generations. Resulting lines are nearly 100% homozygous but carry a mosaic of the two parental genomes. Invaluable for QTL mapping and marker-assisted selection.
Concept context
Flower structure, pollination, double fertilization, and seed/fruit development — the highest-scoring Class 12 biology chapter in NEET.
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