A grain is a small, hard, dry fruit ( caryopsis ) – with or without an attached hull layer – harvested for human or animal consumption. A grain crop is a grain-producing plant. The two main types of commercial grain crops are cereals and legumes .
73-425: After being harvested, dry grains are more durable than other staple foods , such as starchy fruits ( plantains , breadfruit , etc.) and tubers ( sweet potatoes , cassava , and more). This durability has made grains well suited to industrial agriculture , since they can be mechanically harvested , transported by rail or ship, stored for long periods in silos , and milled for flour or pressed for oil . Thus,
146-532: 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
219-468: 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
292-587: 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
365-474: 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
438-422: 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
511-479: 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
584-542: 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
657-529: 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
730-806: A significant proportion of the intake of other nutrients as well. For humans , a staple food of a specific society may be eaten as often as every day or every meal, and most people live on a diet based on just a small variety of food staples. Specific staples vary from place to place, but typically are inexpensive or readily available foods that supply one or more of the macronutrients and micronutrients needed for survival and health: carbohydrates , proteins , fats , minerals , and vitamins . Typical examples include grains ( cereals and legumes ), seeds , nuts and root vegetables ( tubers and roots ). Among them, cereals ( rice , wheat , oat , maize , etc.), legumes ( lentils and beans ) and tubers (e.g. potato , taro and yam ) account for about 90% of
803-410: 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
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#1732772070415876-439: 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
949-405: 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
1022-413: 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
1095-457: 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
1168-409: 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
1241-457: Is easily stored and transported with limited spoilage, unlike other agricultural products. Healthy grain supply and trade is important to many societies, providing a caloric base for most food systems as well as important role in animal feed for animal agriculture . The grain trade is as old as agricultural settlement, identified in many of the early cultures that adopted sedentary farming. Major societal changes have been directly connected to
1314-465: Is growing. 2013 Rice is most commonly cooked and eaten as separate entire grains, but most other staple cereals are milled into a flour or meal that can be used to make bread , noodles , pasta , porridge and mushes like mealie pap (although both can be eaten either as grains or ground into flour). Root vegetables can be mashed and used to make porridge -like dishes such as poi and fufu . Pulses (such as chickpeas , from which gram flour
1387-473: Is made) and starchy root vegetables (such as canna rhizomes) can also be made into flour. Consumed in isolation, staple foods do not provide the full range of essential nutrients . The nutrient-deficiency disease pellagra is associated with a diet consisting primarily of maize , while the disease beriberi is associated with a diet of refined white rice . Scurvy can result from a lack of vitamin C , also known as ascorbic acid. One author indicated that
1460-458: 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
1533-565: Is sometimes grown as a perennial . Winter varieties are hardy enough to be planted in the autumn, becoming dormant in the winter, and harvested in spring or early summer; spring varieties are planted in spring and harvested in late summer. The term cereal is derived from the name of the Roman goddess of grain crops and fertility, Ceres . Cereals were domesticated in the Neolithic , some 8,000 years ago. Wheat and barley were domesticated in
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#17327720704151606-498: 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
1679-533: The Andes —were also staples centuries ago. Oca tubers, ulluku tubers and grain amaranth are other foods that may have been historical Andean staples. Pemmican made from dried meat and fat was a staple of the Plains Indians of North America . Most staple foods are currently produced using modern, conventional farming practices. However, the production of staple food using organic farming methods
1752-600: 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,
1825-747: The Fertile Crescent ; rice was domesticated in East Asia, and sorghum and millet were domesticated in West Africa. Maize was domesticated by Indigenous peoples of the Americas in southern Mexico about 9,000 years ago. In the 20th century, cereal productivity was greatly increased by the Green Revolution . This increase in production has accompanied a growing international trade , with some countries producing large portions of
1898-663: The Prairies where the Sioux herded bison , and the Arctic , where the Sami people herd reindeer . The dominant staple foods in different parts of the world are a function of weather patterns, local terrain, farming constraints, acquired tastes and ecosystems . For example, the main energy source staples in the average African diet are cereals (46 percent), roots and tubers (20 percent) and animal products (7 percent). In Western Europe
1971-625: The developing world , accounting for roughly 40 percent of the food eaten by half the population of sub-Saharan Africa . Roots and tubers are high in carbohydrates , calcium , and vitamin C , but low in protein . Cassava root , for example, is a major food staple in the developing world, a basic food source for around 500 million people. With economic development and free trade, many countries have shifted away from low- nutrient-density staple foods to higher-nutrient-density staples, as well as towards greater meat consumption . Some foods like quinoa —a pseudocereal grain that originally came from
2044-486: The grain market is a major global commodity market that includes crops such as maize , rice , soybeans , wheat and other grains. Grains and cereal are synonymous with caryopses , the fruits of the grass family . In agronomy and commerce, seeds or fruits from other plant families are called grains if they resemble caryopses. For example, amaranth is sold as " grain amaranth ", and amaranth products may be described as "whole grains". The pre-Hispanic civilizations of
2117-647: The pith of the sago palm tree ), and large, fleshy fruits (e.g. breadfruit , breadnut , coconut and plantains ). Staple foods may also include processed food products (depending on the region) such as olive oil , coconut oil , and sugar . Generally, staple foods are those eaten in bulk that supply energy to humans, predominantly in the form of sugars and carbohydrates , and so are mainly plant-based, as meats and eggs are predominantly protein and fat , though dairy products provide all these. However, not all places are suitable for agriculture , and so pastoralism can be favoured instead, as it has
2190-685: 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
2263-684: The Andes had grain-based food systems, but at higher elevations none of the grains was a cereal . All three grains native to the Andes ( kaniwa , kiwicha , and quinoa ) are broad-leafed plants rather than grasses such as corn, rice, and wheat. A cereal is a grass cultivated for its edible grain. Cereals are the world's largest crops, and are therefore staple foods . They include rice , wheat , rye , oats , barley , millet , and maize . Edible grains from other plant families, such as buckwheat and quinoa , are pseudocereals . Most cereals are annuals , producing one crop from each planting, though rice
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2336-449: 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
2409-563: 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
2482-545: 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
2555-615: 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
2628-499: The advantage that animals can live off of land unsuitable for agricultural crops and consume the local plant matter that is otherwise inedible to humans and convert that into foods - meat , offal , fat , eggs and milk - that humans can eat. Animals can therefore provide staples to human diets in inhospitable ecosystems such as deserts , steppe , taiga , tundra , and mountainous terrains . Specific examples include herding in regions such as Mongolia where sheep are herded,
2701-590: 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
2774-427: 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
2847-420: The cereal supply for other countries. Starchy grains from broadleaf (dicot) plant families: Pulses or grain legumes , members of the pea family , have a higher protein content than most other plant foods, at around 20%, while soybeans have as much as 35%. As is the case with all other whole plant foods, pulses also contain carbohydrates and fat. Common pulses include: Oilseed grains are grown primarily for
2920-484: The creation of the first temporary settlements and the division of society into classes. This assumption that grain agriculture led to early settlements and social stratification has been challenged by James Scott in his book Against the Grain . He argues that the transition from hunter-gatherer societies to settled agrarian communities was not a voluntary choice driven by the benefits of increased food production due to
2993-438: 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
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3066-409: 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
3139-452: The extraction of their edible oil . Vegetable oils provide dietary energy and some essential fatty acids . They are also used as fuel and lubricants. Ancient grains is a marketing term used to describe a category of grains and pseudocereals that are purported to have been minimally changed by selective breeding over recent millennia, as opposed to more widespread cereals such as corn , rice and modern varieties of wheat , which are
3212-694: 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,
3285-409: The grain and unable to remove themselves; explosions caused by fine particles of grain dust , and falls . Staple food A staple food , food staple , or simply staple , is a food that is eaten often and in such quantities that it constitutes a dominant portion of a standard diet for an individual or a population group, supplying a large fraction of energy needs and generally forming
3358-735: The grain trade, such as the fall of the Roman Empire . From the early modern period onward, grain trade has been an important part of colonial expansion and international power dynamics. The geopolitical dominance of countries like Australia, the United States, Canada and the Soviet Union during the 20th century was connected with their status as grain surplus countries. Those who handle grain at grain facilities may encounter numerous occupational hazards and exposures . Risks include grain entrapment , where workers are submerged in
3431-400: 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
3504-411: 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
3577-452: 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
3650-491: 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
3723-593: 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
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#17327720704153796-663: 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
3869-402: The long storage potential of grains, but rather that the shift towards settlements was a coerced transformation imposed by dominant members of a society seeking to expand control over labor and resources. The grain trade refers to the local and international trade in cereals such as wheat , barley , maize , and rice , and other food grains . Grain is an important trade item because it
3942-437: The main staples in the average diet are animal products (33 percent), cereals (26 percent), and roots and tubers (4 percent). Most of the human population lives on a diet based on one or more of the following staples: cereals ( rice , wheat , maize (corn), millet , and sorghum ), roots and tubers ( potatoes , cassava , yams and taro ), and animal products such as meat, milk, eggs, cheese and fish. Regional staples include
4015-409: 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
4088-461: The nutritional value of some staple foods are negatively affected by higher levels of carbon dioxide , as occurs in climate change . The following table shows the nutrient content of 10 major staple vegetable foods in raw form on a dry weight basis to account for their different water contents. Raw grains are not edible and cannot be digested, so they must be cooked, sprouted, or otherwise prepared for human consumption. In sprouted and cooked form,
4161-511: 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
4234-552: 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
4307-433: The plants rye , soybeans , barley , oats , and teff . Just 15 plant crops provide 90 percent of the world's food energy intake (exclusive of meat), with rice , maize , and wheat comprising 2/3 of human food consumption. These three are the staples of about 80 percent of the world population, and rice feeds almost half of humanity. Roots and tubers, meanwhile, are important staples for over one billion people in
4380-420: 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
4453-702: 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,
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#17327720704154526-522: The product of thousands of years of selective breeding. Ancient grains are often marketed as being more nutritious than modern grains, though their health benefits over modern varieties have been disputed by some nutritionists . Because grains are small, hard and dry, they can be stored, measured, and transported more readily than can other kinds of food crops such as fresh fruits, roots and tubers. The development of grain agriculture allowed excess food to be produced and stored easily which could have led to
4599-820: The relative nutritional and anti-nutritional contents of each of these grains are different from that of the raw form of these grains, as shown. Potatoes also must be cooked, but should not be sprouted. The highlighted values show the highest nutrient density among these 10 staples. Other foods, consumed in smaller quantities, may have nutrient densities different from these values. raw yellow dent corn raw unenriched long-grain white rice raw hard red winter wheat raw potato with flesh and skin raw cassava raw green soybeans raw sweet potato raw sorghum raw yam raw plantains unofficial Selective breeding Selective breeding (also called artificial selection )
4672-887: 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
4745-515: 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,
4818-621: 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
4891-1210: The world's food calorie intake. Early agricultural civilizations valued the crop foods that they established as staples because, in addition to providing necessary nutrition , they generally are suitable for storage over long periods of time without decay. Such nonperishable foods are the only possible staples during seasons of shortage, such as dry seasons or cold temperate winters, against which times harvests have been stored. During seasons of surplus, wider choices of foods may be available. Staple foods are derived from either plant or animal products that are digestible by humans and can be supplied in substantial quantities. Common plant-based staples include cereals (e.g. rice , wheat , maize , millet , barley , oats , rye , spelt , emmer , triticale and sorghum ), starchy tubers (e.g. potato , sweet potato , yam and taro ) or root vegetables (e.g. cassava , turnip , carrot , rutabagas ), and dried legumes ( lentils and beans ). Animal-based staples include various types of meat (typically livestock and poultry ), fish , eggs , milk and dairy products (e.g. cheese ). Other staple foods include sago (derived from
4964-417: 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
5037-440: 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
5110-564: 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
5183-485: 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
5256-646: 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
5329-680: 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
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