Which statement about breeding is wrong?

Options

A. Continued inbreeding reduces fertility and productivity
B. By inbreeding pure lines cannot be evolved
C. Cross breeding allows desirable qualities of two different breeds to
be combined
D. inbreeding expeses harmful recessive genes that are eliminated by selection

Answer

### Step-by-Step Solution:

1. **Understanding Breeding**:
- Breeding refers to the reproduction of organisms to produce offspring. There are two main types: inbreeding and crossbreeding.

2. **Inbreeding**:
- Inbreeding involves mating genetically related individuals. This can lead to increased homozygosity, which means that the offspring are more likely to inherit the same alleles from both parents.

3. **Effects of Inbreeding**:
- Continuous inbreeding can lead to inbreeding depression, which reduces fertility and productivity. It can also result in the accumulation of harmful recessive traits, leading to increased mortality rates and decreased fitness.

4. **Crossbreeding**:
- Crossbreeding is the mating of genetically different organisms. This process can combine desirable traits from both parent organisms, resulting in offspring that may have superior qualities.

5. **Evaluating the Statements**:
- The first statement: "Continued inbreeding reduces fertility and productivity" is **true**.
- The second statement: "By inbreeding, pure lines cannot be evolved" is **false** because inbreeding is actually a method used to develop pure lines.
- The third statement: "Crossbreeding allows desirable qualities of two different breeds to be combined" is **true**.
- The fourth statement: "Inbreeding expresses harmful recessive genes which are eliminated by selection" is **true**.

6. **Identifying the Wrong Statement**:
- The only statement that is incorrect is the second one: "By inbreeding, pure lines cannot be evolved."

### Conclusion:
The wrong statement about breeding is: **"By inbreeding, pure lines cannot be evolved."**

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