Selective breeding
Charles Darwin discussed how selective breeding had been successful in producing change over time in his 1859 book, On the Origin of Species.
[6] Treatises as much as 2,000 years old give advice on selecting animals for different purposes, and these ancient works cite still older authorities, such as Mago the Carthaginian.
[7] The notion of selective breeding was later expressed by the Persian Muslim polymath Abu Rayhan Biruni in the 11th century.
The bees kill those of their kind who only eat, but do not work in their beehive.Selective breeding was established as a scientific practice by Robert Bakewell during the British Agricultural Revolution in the 18th century.
[9] These sheep were exported widely, including to Australia and North America, and have contributed to numerous modern breeds, despite the fact that they fell quickly out of favor as market preferences in meat and textiles changed.
Previously, cattle were first and foremost kept for pulling ploughs as oxen,[10] but he crossed long-horned heifers and a Westmoreland bull to eventually create the Dishley Longhorn.
For example, to breed chickens, a breeder typically intends to receive eggs, meat, and new, young birds for further reproduction.
Therefore, when purchasing initial breeding stock, the breeder seeks a group of birds that will most closely fit the purpose intended.
[13] A Soviet attempt to breed lab rats with higher intelligence led to cases of neurosis severe enough to make the animals incapable of any problem solving unless drugs like phenazepam were used.
[19] In addition, the ability for humans to stay within one place for food and create permanent settlements made the process move along faster.
Over time this reliance on plant breeding has created problems, as highlighted by the book Botany of Desire where Michael Pollan shows the connection between basic human desires through four different plants: apples for sweetness, tulips for beauty, cannabis for intoxication, and potatoes for control.
[22] Selective breeding in aquaculture holds high potential for the genetic improvement of fish and shellfish for the process of production.
[24] A suspected reason associated with the late realization of success in selective breeding programs in aquaculture was the education of the concerned people – researchers, advisory personnel and fish farmers.
This in turn led to failure in quantifying economic benefits that successful selective breeding programs produce.
Gjedrem (1979) showed that selection of Atlantic salmon (Salmo salar) led to an increase in body weight by 30% per generation.
A comparative study on the performance of select Atlantic salmon with wild fish was conducted by AKVAFORSK Genetics Centre in Norway.
[29] Kincaid et al. (1977) showed that growth gains by 30% could be achieved by selectively breeding rainbow trout for three generations.
[34] Cyprinids Selective breeding programs for the Common carp (Cyprinus carpio) include improvement in growth, shape and resistance to disease.
Schaperclaus (1962) showed resistance to the dropsy disease wherein selected lines suffered low mortality (11.5%) compared to unselected (57%).
[39] More recently, the response of the Channel Catfish to selection for improved growth rate was found to be approximately 80%, that is, an average of 13% per generation.
[41][42] Chilean oysters (Ostrea chilensis), selected for improvement in live weight and shell length showed a 10–13% gain in one generation.
Selective breeding programs show that O. edulis susceptibility to the infection differs across oyster strains in Europe.
A study carried out by Culloty et al. showed that 'Rossmore' oysters in Cork harbour, Ireland had better resistance compared to other Irish strains.
A selective breeding program at Cork harbour uses broodstock from 3– to 4-year-old survivors and is further controlled until a viable percentage reaches market size.
Ragone Calvo et al. (2003) selectively bred the eastern oyster, Crassostrea virginica, for resistance against co-occurring parasites Haplosporidium nelson (MSX) and Perkinsus marinus (Dermo).
[47] Argue et al. (2002) conducted a selective breeding program on the Pacific White Shrimp, Litopenaeus vannamei at The Oceanic Institute, Waimanalo, USA from 1995 to 1998.
Successful outcomes led to development of Super Shrimp, a selected line of L. stylirostris that is resistant to IHHNV infection.
Tang et al. (2000) confirmed this by showing no mortalities in IHHNV- challenged Super Shrimp post larvae and juveniles.
Conversely, selective breeding within aquaculture can create problems within the biodiversity of both stock and wild fish, which can hurt the industry down the road.
[54] Additionally, selective breeding can lead to a variety of issues including reduction of genetic diversity or physical problems.
