67-488: The Comtois horse ( French pronunciation: [kɔ̃twa] ) is a draft horse that originated in the Jura Mountains on the border between France and Switzerland . The Comtois is a light draft horse , with a large head, straight neck, stocky and powerful body and deep girth. They have long, straight backs and short, strong legs with a little feathering and muscular hindquarters. The Comtois sometimes shows
134-532: A crossbreed , and crossbred plants are called hybrids . Flowers, vegetables and fruit-trees may be bred by amateurs and commercial or non-commercial professionals: major crops are usually the provenance of the professionals. In animal breeding artificial selection is often combined with techniques such as inbreeding , linebreeding , and outcrossing . In plant breeding , similar methods are used. Charles Darwin discussed how selective breeding had been successful in producing change over time in his 1859 book, On
201-468: A 34–48% higher survival rate. Selection for growth in Penaeid shrimps yielded successful results. A selective breeding program for Litopenaeus stylirostris saw an 18% increase in growth after the fourth generation and 21% growth after the fifth generation. Marsupenaeus japonicas showed a 10.7% increase in growth after the first generation. Argue et al. (2002) conducted a selective breeding program on
268-587: A 4% increase after one generation and a 15% increase after two generations. Chilean oysters ( Ostrea chilensis ), selected for improvement in live weight and shell length showed a 10–13% gain in one generation. Bonamia ostrea is a protistan parasite that causes catastrophic losses (nearly 98%) in European flat oyster Ostrea edulis L. This protistan parasite is endemic to three oyster-regions in Europe. Selective breeding programs show that O. edulis susceptibility to
335-474: A bloodline superior in certain respects to the original base stock. Such animals can be recorded with a breed registry , the organization that maintains pedigrees and/or stud books . However, single-trait breeding, breeding for only one trait over all others, can be problematic. In one case mentioned by animal behaviorist Temple Grandin , roosters bred for fast growth or heavy muscles did not know how to perform typical rooster courtship dances, which alienated
402-422: A certain purpose, or may intend to use some type of crossbreeding to produce a new type of stock with different, and, it is presumed, superior abilities in a given area of endeavor. For example, to breed chickens, a breeder typically intends to receive eggs, meat, and new, young birds for further reproduction. Thus, the breeder has to study different breeds and types of chickens and analyze what can be expected from
469-479: A certain set of characteristics before he or she starts breeding them. Therefore, when purchasing initial breeding stock, the breeder seeks a group of birds that will most closely fit the purpose intended. Purebred breeding aims to establish and maintain stable traits, that animals will pass to the next generation. By "breeding the best to the best," employing a certain degree of inbreeding , considerable culling, and selection for "superior" qualities, one could develop
536-506: A day. Overfeeding can lead to obesity, and risk of laminitis can be a concern. The largest horse in recorded history was probably a Shire born in 1846 named Sampson (renamed Mammoth). He stood 218 cm (21.2 hands) high, and his peak weight was estimated at 1,524 kilograms (3,360 lb). At over 193 cm (19 hands), a Shire gelding named Goliath (1977–2001) was the Guinness Book of World Records record holder for
603-491: A docile temperament. While indispensable to generations of pre-industrial farmers, draft horses are used today for a multitude of purposes, including farming, draft horse showing , logging, recreation, and other uses. Draft breeds have been crossbred with light riding breeds such as the Thoroughbred to create sport horses or warmbloods . While most draft horses are used for driving , they can be ridden and some of
670-404: A million draft horses were used during World War I . The British were importing American draft horses to supplement their dwindling stock even before America joined the war, preferring Percheron crosses which they said had "great endurance, fine physique, soundness, activity, willingness to work, and almost unfailing good temper". British buyers were buying 10,000 to 25,000 American horses and mules
737-524: A month, eventually making up about two-thirds of British Army war horses. In the late 19th century and early 20th century, thousands of draft horses were imported from Western Europe into the United States . Percherons came from France, Belgians from Brabant , Shires from England, Clydesdales from Scotland. Many American draft breed registries were founded in the late 19th century. The Percheron, with 40,000 broodmares registered as of 1915,
SECTION 10
#1732782415099804-542: A scientific practice by Robert Bakewell during the British Agricultural Revolution in the 18th century. Arguably, his most important breeding program was with sheep. Using native stock, he was able to quickly select for large, yet fine-boned sheep, with long, lustrous wool. The Lincoln Longwool was improved by Bakewell, and in turn the Lincoln was used to develop the subsequent breed, named
871-529: 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. Selective breeding programs for aquatic species provide better outcomes compared to terrestrial livestock. This higher response to selection of aquatic farmed species can be attributed to the following: Selective breeding in aquaculture provide remarkable economic benefits to
938-410: A single, recognizable breed, and purebreds with recorded lineage are called pedigreed . Crossbreeds are a mix of two purebreds, whereas mixed breeds are a mix of several breeds, often unknown. Animal breeding begins with breeding stock, a group of animals used for the purpose of planned breeding. When individuals are looking to breed animals, they look for certain valuable traits in purebred stock for
1005-412: A source of horsepower for farming, hauling freight and moving passengers. The advent of railroads increased demand for working horses, as a growing economy still needed transport over the 'last mile' between the goods yard or station and the final customer. Even in the 20th century, until motor vehicles became an affordable and reliable substitute, draft horses were used for practical work. Over half
1072-439: A specific trait can evolve in response to selection. A single-generation method of breeding is not as accurate or direct. The process is also more practical and easier to understand than sibling analysis. Selective breeding is better for traits such as physiology and behavior that are hard to measure because it requires fewer individuals to test than single-generation testing. However, there are disadvantages to this process. This
1139-655: A stronger horse with better legs. Today, they are second only to the Belgian Draught in number in France . In the sixteenth century, these horses were used as a cavalry and artillery horse, and were present in the armies of Louis XIV and later Napoleon Bonaparte . The Comtois is used today for hauling wood in the pine forests of the Jura in the mountainous regions of the Massif Central , and for working in
1206-483: A tendency towards sickle hocks. These horses are generally bay silver , but they can also be black silver , bay , black , and chestnut . They usually stand 1.50–1.65 metres (14.3–16.1 hands ) high and weigh 650–800 kg (1,430–1,760 lb). The Comtois horse breed is an old breed of horse that is believed to have descended from horses brought by the Burgundians of northern Germany to France during
1273-456: A variety of duties. One type of horse-powered work was the hauling of heavy loads, plowing fields, and other tasks that required pulling ability. A heavy, calm, patient, and well-muscled animal was desired for this work. Conversely, a light, more energetic horse was needed for riding and rapid transport. Thus, to the extent possible, a certain amount of selective breeding was used to develop different types of horse for different types of work. It
1340-536: Is a bit slower than lighter horse breeds, more akin to that of ponies, requiring less feed per pound of body weight. This is possibly due to their calmer nature. Nonetheless, because of their sheer size, most require a significant amount of feed per day. Generally a supplement to balance nutrients is preferred over a large quantity of grain. They consume hay or other forage from 1.5% to 3% of their body weight per day, depending on work level. They also can drink up to 95 litres; 21 imperial gallons (25 US gal) of water
1407-683: Is a common misunderstanding that the Destrier that carried the armoured knight of the Middle Ages had the size and conformation of a modern draft horse, and some of these Medieval war horses may have provided some bloodlines for some of the modern draft breeds. The reality was that the high-spirited, quick-moving Destrier was closer to the size, build, and temperament of a modern Andalusian or Friesian . There also were horses of more phlegmatic temperaments used for pulling military wagons or performing ordinary farm work which provided bloodlines of
SECTION 20
#17327824150991474-405: Is a necessary component of selective breeding. Additionally, selective breeding can lead to a variety of issues including reduction of genetic diversity or physical problems. The process of selective breeding can create physical issues for plants or animals such as dogs selectively bred for extremely small sizes dislocating their kneecaps at a much more frequent rate then other dogs. An example in
1541-413: Is also used in research to produce transgenic animals that breed "true" (i.e., are homozygous ) for artificially inserted or deleted genes. Selective breeding in aquaculture holds high potential for the genetic improvement of fish and shellfish for the process of production. Unlike terrestrial livestock, the potential benefits of selective breeding in aquaculture were not realized until recently. This
1608-457: Is because a single experiment done in selective breeding cannot be used to assess an entire group of genetic variances, individual experiments must be done for every individual trait. Also, due to the necessity of selective breeding experiments to require maintaining the organisms tested in a lab or greenhouse , it is impractical to use this breeding method on many organisms. Controlled mating instances are difficult to carry out in this case and this
1675-409: Is because high mortality led to the selection of only a few broodstock , causing inbreeding depression, which then forced the use of wild broodstock. This was evident in selective breeding programs for growth rate, which resulted in slow growth and high mortality. Control of the reproduction cycle was one of the main reasons as it is a requisite for selective breeding programs. Artificial reproduction
1742-458: Is not uncommon for fish to escape the nets or pens that they are kept in, especially in mass. If these fish are farmed in areas they are not native to they may be able to establish themselves and outcompete native populations of fish, and cause ecological harm as an invasive species. Furthermore, if they are in areas where the fish being farmed are native too their genetics are selectively bred rather than being wild. These farmed fish could breed with
1809-498: Is the process by which humans use animal breeding and plant breeding to selectively develop particular phenotypic traits (characteristics) by choosing which typically animal or plant males and females will sexually reproduce and have offspring together. Domesticated animals are known as breeds , normally bred by a professional breeder , while domesticated plants are known as varieties , cultigens , cultivars , or breeds. Two purebred animals of different breeds produce
1876-596: The Amish and Mennonites . Draft horses are still used for logging , a forestry management practice to remove logs from dense woodland where there is insufficient space for mechanized vehicles or for other conservation considerations. Draft horse breeds have played a significant role in the development of many warmblood breeds, popular today in advanced level equine sports. Small areas still exist where draft horses are widely used as transportation due to legislation preventing automotive traffic, such as on Mackinac Island in
1943-600: The English Leicester (or Leicester Longwool), which is primarily kept for wool production. Bakewell was also the first to breed cattle to be used primarily for beef. Previously, cattle were first and foremost kept for pulling ploughs as oxen , but he crossed long-horned heifers and a Westmoreland bull to eventually create the Dishley Longhorn . As more and more farmers followed his lead, farm animals increased dramatically in size and quality. In 1700,
2010-490: The tractor , reduced the need for the draft horse. Many were sold to slaughter for horse meat and a number of breeds went into significant decline. Today, draft horses can be seen in horse shows , pulling competitions , heavy horse trials, parades pulling large wagons , and pulling tourist carriages. However, they are still seen on some smaller farms in the US and Europe. They are particularly popular with agrarian groups such as
2077-685: The 1859 first edition of his work On the Origin of Species , in Chapter IV: Natural Selection, and in Chapter VI: Difficulties on Theory: Slow though the process of selection may be, if feeble man can do much by his powers of artificial selection, I can see no limit to the amount of change, to the beauty and infinite complexity of the co-adaptations between all organic beings, one with another and with their physical conditions of life, which may be effected in
Comtois horse - Misplaced Pages Continue
2144-449: The New (or Dishley) Leicester. It was hornless and had a square, meaty body with straight top lines. 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. Bloodlines of these original New Leicesters survive today as
2211-563: The Origin of Species . Its first chapter discusses selective breeding and domestication of such animals as pigeons , cats , cattle , and dogs . Darwin used artificial selection as an analogy to propose and explain the theory of natural selection but distinguished the latter from the former as a separate process that is non-directed. The deliberate exploitation of selective breeding to produce desired results has become very common in agriculture and experimental biology. Selective breeding can be unintentional, for example, resulting from
2278-545: The Pacific White Shrimp, Litopenaeus vannamei at The Oceanic Institute, Waimanalo, USA from 1995 to 1998. They reported significant responses to selection compared to the unselected control shrimps. After one generation, a 21% increase was observed in growth and 18.4% increase in survival to TSV. The Taura Syndrome Virus (TSV) causes mortalities of 70% or more in shrimps. C.I. Oceanos S.A. in Colombia selected
2345-615: The Ropsha carp. The results showed a 30–40% to 77.4% improvement of cold tolerance but did not provide any data for growth rate. An increase in growth rate was observed in the second generation in Vietnam. Moav and Wohlfarth (1976) showed positive results when selecting for slower growth for three generations compared to selecting for faster growth. Schaperclaus (1962) showed resistance to the dropsy disease wherein selected lines suffered low mortality (11.5%) compared to unselected (57%). Growth
2412-613: The United States. Management of a large draft horse can be costly, including feed, shoeing, and veterinary care. Although many draft horses can work without a need for shoes, if they are required, farriers may charge twice the price to shoe a draft horse as a light riding horse because of the extra labor and specialized equipment required. Historically, draft horses were shod with horseshoes that were significantly wider and heavier than those for other types of horses, custom-made, often with caulkins . The draft horse's metabolism
2479-590: The average weight of a bull sold for slaughter was 370 pounds (168 kg). By 1786, that weight had more than doubled to 840 pounds (381 kg). However, after his death, the Dishley Longhorn was replaced with short-horn versions. He also bred the Improved Black Cart horse, which later became the Shire horse . Charles Darwin coined the term 'selective breeding'; he was interested in
2546-427: 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. In a form of reciprocal evolution humans have influenced these plants as much as the plants have influenced the people that consume them, is known as coevolution . Selective plant breeding
2613-438: The domestication of wild plants into uniform and predictable agricultural cultigens . These high-yielding varieties have been particularly important in agriculture. As crops improved, humans were able to move from hunter-gatherer style living to a mix of hunter-gatherer and agriculture practices. Although these higher yielding plants were derived from an extremely primitive version of plant breeding, this form of agriculture
2680-409: The eastern oyster, Crassostrea virginica , for resistance against co-occurring parasites Haplosporidium nelson (MSX) and Perkinsus marinus (Dermo). They achieved dual resistance to the disease in four generations of selective breeding. The oysters showed higher growth and survival rates and low susceptibility to the infections. At the end of the experiment, artificially selected C. virginica showed
2747-694: The fish for four generations, spawning dates were 13–15 days earlier. Cyprinids Selective breeding programs for the Common carp ( Cyprinus carpio ) include improvement in growth, shape and resistance to disease. Experiments carried out in the USSR used crossings of broodstocks to increase genetic diversity and then selected the species for traits like growth rate, exterior traits and viability, and/or adaptation to environmental conditions like variations in temperature. Kirpichnikov et al. (1974) and Babouchkine (1987) selected carp for fast growth and tolerance to cold,
Comtois horse - Misplaced Pages Continue
2814-763: The fourth century. It is believed that they have been bred in Franche-Comté and in the Jura Mountains since the sixth century. In the Middle Ages they were used as war horses. They were bred in Franche-Comté and in the Jura Mountains In the 19th century, other draft horses such as the Norman , Boulonnais , and Percheron were bred into the Comtois, and more recently the Ardennes was used to produce
2881-400: The idea in his book titled India , which included various examples. The agriculturist selects his corn, letting grow as much as he requires, and tearing out the remainder. The forester leaves those branches which he perceives to be excellent, whilst he cuts away all others. The bees kill those of their kind who only eat, but do not work in their beehive. Selective breeding was established as
2948-411: The idea of "farmers" experimenting with agriculture. In addition, the ability for humans to stay within one place for food and create permanent settlements made the process move along faster. During this transitional period, crops began to acclimate and evolve with humans encouraging humans to invest further into crops. Over time this reliance on plant breeding has created problems, as highlighted by
3015-452: The increasing demands of growing populations. 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. Although there is great potential to improve aquaculture due to the current lack of domestication, it is essential that the genetic diversity of the fish are preserved through proper genetic management, as we domesticate these species. It
3082-491: The industry, the primary one being that it reduces production costs due to faster turnover rates. When selective breeding is carried out, some characteristics are lost for others that may suit a specific environment or situation. This is because of faster growth rates, decreased maintenance rates, increased energy and protein retention, and better feed efficiency. Applying genetic improvement programs to aquaculture species will increase their productivity. Thus allowing them to meet
3149-593: 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. Over the years 'Rossmore' oysters have shown to develop lower prevalence of B. ostreae infection and percentage mortality. Ragone Calvo et al. (2003) selectively bred
3216-626: The lighter draft breeds are capable performers under saddle. Draft horses are recognizable by their extremely muscular build. They tend to have broad, short backs with powerful hindquarters. In general, they are taller and tend to have heavier bone and a more upright shoulder than riding horses, producing conformation that is well suited for pulling. Many draft breeds have heavier hair, called feathering on their lower legs. Draft breeds range from approximately 163 to 193 cm (16 to 19 hands) high and from 640 to 910 kg (1,400 to 2,000 lb). Humans domesticated horses and used them to perform
3283-663: The long course of time by nature's power of selection. We are profoundly ignorant of the causes producing slight and unimportant variations; and we are immediately made conscious of this by reflecting on the differences in the breeds of our domesticated animals in different countries,—more especially in the less civilized countries where there has been but little artificial selection. Animals with homogeneous appearance, behavior, and other characteristics are known as particular breeds or pure breeds, and they are bred through culling animals with particular traits and selecting for further breeding those with other traits. Purebred animals have
3350-461: The modern draft horse. Records indicate that even medieval drafts were not as large as those today. Of the modern draft breeds, the Percheron probably has the closest ties to the medieval war horse. By the 19th century horses weighing more than 730 kilograms (1,600 lb) that also moved at a quick pace were in demand. Tall stature, muscular backs, and powerful hindquarters made the draft horse
3417-409: The natives which could be problematic In the sense that they would have been bred for consumption rather than by chance. Resulting in an overall decrease in genetic diversity and rendering local fish populations less fit for survival. If proper management is not taking place then the economic benefits and the diversity of the fish species will falter. Selective breeding is a direct way to determine if
SECTION 50
#17327824150993484-511: The performance of select Atlantic salmon with wild fish was conducted by AKVAFORSK Genetics Centre in Norway. The traits, for which the selection was done included growth rate, feed consumption, protein retention, energy retention, and feed conversion efficiency. Selected fish had a twice better growth rate, a 40% higher feed intake, and an increased protein and energy retention. This led to an overall 20% better Fed Conversion Efficiency as compared to
3551-552: The plant world is the Lenape potatoes were selectively bred for their disease or pest resistance which was attributed to their high levels of toxic glycoalkaloid solanine which are usually present only in small amounts in potatoes fit for human consumption. When genetic diversity is lost it can also allow for populations to lack genetic alternatives to adapt to events. This becomes an issue of biodiversity, because attributes are so wide-spread they can result in mass epidemics. As seen in
3618-420: The process as an illustration of his proposed wider process of natural selection . Darwin noted that many domesticated animals and plants had special properties that were developed by intentional animal and plant breeding from individuals that showed desirable characteristics, and discouraging the breeding of individuals with less desirable characteristics. Darwin used the term "artificial selection" twice in
3685-702: The process of human cultivation; and it may also produce unintended – desirable or undesirable – results. For example, in some grains, an increase in seed size may have resulted from certain ploughing practices rather than from the intentional selection of larger seeds. Most likely, there has been an interdependence between natural and artificial factors that have resulted in plant domestication. Selective breeding of both plants and animals has been practiced since early prehistory ; key species such as wheat , rice , and dogs have been significantly different from their wild ancestors for millennia, and maize , which required especially large changes from teosinte , its wild form,
3752-887: The roosters from hens and led the roosters to kill the hens after mating with them. 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. The observable phenomenon of hybrid vigor stands in contrast to the notion of breed purity. However, on the other hand, indiscriminate breeding of crossbred or hybrid animals may also result in degradation of quality. Studies in evolutionary physiology , behavioral genetics , and other areas of organismal biology have also made use of deliberate selective breeding, though longer generation times and greater difficulty in breeding can make these projects challenging in such vertebrates as house mice . The process of plant breeding has been used for thousands of years, and began with
3819-515: The survivors of the disease from infected ponds and used them as parents for the next generation. They achieved satisfying results in two or three generations wherein survival rates approached levels before the outbreak of the disease. The resulting heavy losses (up to 90%) caused by Infectious hypodermal and haematopoietic necrosis virus (IHHNV) caused a number of shrimp farming industries started to selectively breed shrimps resistant to this disease. Successful outcomes led to development of Super Shrimp,
3886-571: The vineyards in the Arbois area. They are also bred for the French horsemeat industry. Draft horse A draft horse (US) or draught horse (UK), also known as dray horse , carthorse , work horse or heavy horse , is a large horse bred to be a working animal hauling freight and doing heavy agricultural tasks such as plowing . There are a number of breeds, with varying characteristics, but all share common traits of strength, patience, and
3953-621: The wild stock. Atlantic salmon have also been selected for resistance to bacterial and viral diseases. Selection was done to check resistance to Infectious Pancreatic Necrosis Virus (IPNV). The results showed 66.6% mortality for low-resistant species whereas the high-resistant species showed 29.3% mortality compared to wild species. Rainbow trout ( S. gairdneri ) was reported to show large improvements in growth rate after 7–10 generations of selection. Kincaid et al. (1977) showed that growth gains by 30% could be achieved by selectively breeding rainbow trout for three generations. A 7% increase in growth
4020-420: The world's tallest living horse (until his death). Big Jake (2001–2021), an American Belgian standing 210.2 cm (20.275 hands), held the record for tallest living horse from 2010 until his death in 2021. As of 2024, there is no living record holder. The following breeds of horse are considered draft breeds: Selective breeding Selective breeding (also called artificial selection )
4087-509: Was America's most numerous draft breed at the turn of the 20th century. A breed developed exclusively in the U.S. was the American Cream Draft , which had a stud book established by the 1930s. Beginning in the late 19th century, and with increasing mechanization in the 20th century, especially following World War I in the US and after World War II in Europe, the popularity of the internal combustion engine, and particularly
SECTION 60
#17327824150994154-417: Was an investment that the people who grew them were planting then could have a more varied diet. This meant that they did not completely stop their hunting and gathering immediately but instead over time transition and ultimately favored agriculture. Originally this was due to humans not wanting to risk using all their time and resources for their crops just to fail. Which was promptly called play farming due to
4221-440: Was not achieved because of the difficulties in hatching or feeding some farmed species such as eel and yellowtail farming. 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. The education of fish biologists paid less attention to quantitative genetics and breeding plans. Another
4288-564: Was recorded per generation for rainbow trout by Kause et al. (2005). In Japan, high resistance to IPNV in rainbow trout has been achieved by selectively breeding the stock. Resistant strains were found to have an average mortality of 4.3% whereas 96.1% mortality was observed in a highly sensitive strain. Coho salmon ( Oncorhynchus kisutch ) increase in weight was found to be more than 60% after four generations of selective breeding. In Chile, Neira et al. (2006) conducted experiments on early spawning dates in coho salmon. After selectively breeding
4355-485: Was seen to increase by 12–20% in selectively bred Iictalurus punctatus . 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. Selection for live weight of Pacific oysters showed improvements ranging from 0.4% to 25.6% compared to the wild stock. Sydney-rock oysters ( Saccostrea commercialis ) showed
4422-646: Was selectively bred in Mesoamerica . Selective breeding was practiced by the Romans . 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 . The notion of selective breeding was later expressed by the Persian Muslim polymath Abu Rayhan Biruni in the 11th century. He noted
4489-680: Was the failure of documentation of the genetic gains in successive generations. This in turn led to failure in quantifying economic benefits that successful selective breeding programs produce. Documentation of the genetic changes was considered important as they help in fine tuning further selection schemes. Aquaculture species are reared for particular traits such as growth rate, survival rate, meat quality, resistance to diseases, age at sexual maturation, fecundity, shell traits like shell size, shell color, etc. 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
#98901