Heterosis in F₂ Generation Compared to F₁

Heterosis in the F₂ generation becomes:

Correct Answer: Half of F₁ generation

Heterosis is maximum in F₁ generation. In F₂ generation (produced by inter-se mating of F₁ × F₁), heterozygosity is reduced by 50%, and therefore heterosis is also reduced to half of F₁.

Key Points about Heterosis

• Heterosis depends on the extent of heterozygosity and non-additive gene action (Dominance + Over-dominance + Epistasis).
• At each generation of inter-se mating, heterozygosity reduces by 50%, and so does heterosis.
• Maximum hybrid vigour is in F₁ generation.
• Heterosis is commonly exploited in broilers, layers, swine, and sheep due to high fertility.
• Traits with low h² show high heterosis (reproductive traits), and vice versa.