Exploitation of Inbred Lines in Poultry
Inbred lines are mainly used in poultry breeding to exploit-
- Heritability
- Inbreeding depression
- Heterosis — Correct Answer
- All of the above
Explanation:
Correct Answer: Heterosis
Inbred lines are developed in poultry by sustained inbreeding (full-sib mating for generations) to produce highly homozygous, genetically uniform lines. These lines perform poorly themselves (inbreeding depression), but when crossed together they produce commercial chicks with explosive heterosis (hybrid vigour) — superior growth, egg production, feed efficiency.
Why Heterosis is Maximized from Inbred Lines
- Inbred lines are maximum homozygous (AA or aa at most loci)
- When two different inbred lines are crossed → offspring are maximum heterozygous (Aa at most loci)
- Maximum heterozygosity → maximum heterosis (hybrid vigour)
- Heterosis: Increased performance of F₁ over mean of parents; depends on non-additive gene action
Application in Poultry
| Step | Process | Result |
|---|---|---|
| 1. Develop inbred lines | Full-sib mating × many generations; Fx ≥ 0.375 | Highly homozygous uniform lines (poor performance) |
| 2. Cross inbred lines | Line A × Line B (or 3-way/4-way crosses) | Maximum heterosis in commercial F₁ hybrids |
| 3. Commercial production | Sell F₁ hybrids to producers | High performance broilers / layers |
📚 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.
