Heterosis in F2 Generation
Heterosis in $F_{2}$ generation becomes:
- Half of $F_{1}$ generation — Correct Answer
- Not fix
- Double of $F_{1}$ generation
- None
Explanation:
Correct Answer: Half of F₁ generation
When F₁ (maximum heterosis) individuals intermate to produce F₂, heterozygosity is reduced by 50%. Since heterosis depends on heterozygosity and non-additive gene action, heterosis in F₂ is exactly half that of F₁.
Heterosis — Key Facts
- Definition: Increased performance of offspring over parents (hybrid vigour); term given by G.H. Shull
- Depends on: Extent of heterozygosity + Non-additive gene action (Dominance, Over-dominance, Epistasis)
- Inverse relationship with h²: Traits with low h² show high heterosis and vice versa
- Maximum heterosis: In F₁ generation
- F₂ heterosis: Half of F₁ (due to 50% reduction in heterozygosity by inter-se mating)
- Uses: Commercial broiler, layer, swine, and sheep production
Why Other Options Are Wrong
- Not fixed: Heterosis is not completely lost in F₂, only halved.
- Double of F₁: Incorrect — F₂ heterosis decreases due to segregation, it never doubles.
📚 About this Topic — Animal Genetics & Breeding
This multiple choice question is from Animal Genetics & Breeding, Animal Refresher. It has 4 options with a detailed explanation of the correct answer. Practice more MCQs from Animal Genetics & Breeding to strengthen your preparation.
