Question

How are the selective breeding techniques of hybridization and inbreeding opposites?

Answer 1

Selective breeding usually involves choosing parents with particular characteristics to get breed together and produce offspring with more than one desirable characteristics. Humans have selectively been breeding plants and animals for thousands of years including crop plants with better yields.

Complete answer:

Hybridization	Inbreeding
1. Hybrid vigour mostly appears in progeny after hybridisation, where heterozygous conditions are usually achieved by crossing two unrelated organisms or varieties, e.g. crossing a pest-resistant Indian rice variety with a particularly high yielding Japanese rice variety.	1. Inbreeding allows organisms to retain unique characteristics by maintaining homozygosity when some organisms of the same variety are exactly crossed together, (e.g. in the cases of producing pups of particularly a dog breed) or when closely related organisms are being crossed (e.g. in case of producing racehorses).
2. This may provide some of the high yieldings yet resistant type hybrid rice plants in the next generation.	2. Repeated inbreeding may often result in the manifestation of some recessive harmful characters.
3. Hybridisation is sometimes done without practical purpose, e.g. crossing a lion with a tiger which does not provide any benefit to any species.	3. Inbreeding exactly erases variability from the gene pool, which is not a desirable situation or thing of interest for the well being of organisms.
4. Release of some hybrid organisms in nature, both are designed and unplanned, may alter the gene pools and ecosystems in near future.	4. Irresponsible inbreeding has also resulted in some poorly adapted animals.
5. Hybridisation is mostly practised by the agriculturists, for creating high yielding crops.	5. Inbreeding is commonly considered for developing show animals like dogs and horses.

Note: Most of the domestic animals and plants are the result of centuries of selective breeding. Disadvantages include a reduction in their genetic diversity and discomfort for animals that have very exaggerated characteristics.