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The potato () is a starchy tuberous vegetable native to the Americas that is consumed as a
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 an ...
in many parts of the world. Potatoes are underground stem tubers of the plant ''Solanum tuberosum'', a
perennial In horticulture, the term perennial ('' per-'' + '' -ennial'', "through the year") is used to differentiate a plant from shorter-lived annuals and biennials. It has thus been defined as a plant that lives more than 2 years. The term is also ...
in the nightshade family Solanaceae. Wild potato
species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...
can be found from the southern United States to southern Chile. Genetic studies show that the cultivated potato has a single origin, in the area of present-day southern
Peru Peru, officially the Republic of Peru, is a country in western South America. It is bordered in the north by Ecuador and Colombia, in the east by Brazil, in the southeast by Bolivia, in the south by Chile, and in the south and west by the Pac ...
and extreme northwestern
Bolivia Bolivia, officially the Plurinational State of Bolivia, is a landlocked country located in central South America. The country features diverse geography, including vast Amazonian plains, tropical lowlands, mountains, the Gran Chaco Province, w ...
. Potatoes were domesticated there about 7,000–10,000 years ago from a species in the '' S. brevicaule'' complex. Many varieties of the potato are cultivated in the
Andes The Andes ( ), Andes Mountains or Andean Mountain Range (; ) are the List of longest mountain chains on Earth, longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range ...
region of South America, where the species is indigenous. The Spanish introduced potatoes to Europe in the second half of the 16th century from the Americas. They are a staple food in many parts of the world and an integral part of much of the world's food supply. Following millennia of selective breeding, there are now over 5,000 different varieties of potatoes. The potato remains an essential crop in Europe, especially Northern and Eastern Europe, where per capita production is still the highest in the world, while the most rapid expansion in production during the 21st century was in southern and eastern Asia, with China and India leading the world production as of 2023. Like the
tomato The tomato (, ), ''Solanum lycopersicum'', is a plant whose fruit is an edible Berry (botany), berry that is eaten as a vegetable. The tomato is a member of the nightshade family that includes tobacco, potato, and chili peppers. It originate ...
and the nightshades, the potato is in the genus '' Solanum''; the aerial parts of the potato contain the toxin solanine. Normal potato tubers that have been grown and stored properly produce glycoalkaloids in negligible amounts, but, if sprouts and potato skins are exposed to light, tubers can become toxic.


Etymology

The English word "potato" comes from Spanish , in turn from
Taíno The Taíno are the Indigenous peoples of the Caribbean, Indigenous peoples of the Greater Antilles and surrounding islands. At the time of European contact in the late 15th century, they were the principal inhabitants of most of what is now The ...
', which means " sweet potato", not the plant now known as simply "potato". The name "spud" for a potato is from the 15th century ''spudde'', a short and stout knife or dagger, probably related to Danish ''spyd'', "spear". Through semantic change, the general sense of ''short and thick'' was transferred to the tuber from around 1840. At least seven languages—Afrikaans, Dutch, Low Saxon, French, (West) Frisian, Hebrew, Persian and some variants of German—use a term for "potato" that means "earth apple" or "ground apple", from an earlier sense of both pome and
apple An apple is a round, edible fruit produced by an apple tree (''Malus'' spp.). Fruit trees of the orchard or domestic apple (''Malus domestica''), the most widely grown in the genus, are agriculture, cultivated worldwide. The tree originated ...
, referring in general to a (''apple-shaped'') fruit or vegetable.


Description

Potato plants are herbaceous
perennial In horticulture, the term perennial ('' per-'' + '' -ennial'', "through the year") is used to differentiate a plant from shorter-lived annuals and biennials. It has thus been defined as a plant that lives more than 2 years. The term is also ...
s that grow up to high. The stems are hairy. The leaves have roughly four pairs of leaflets. The flowers range from white or pink to blue or purple; they are yellow at the centre, and are insect-pollinated. The plant develops
tuber Tubers are a type of enlarged structure that plants use as storage organs for nutrients, derived from stems or roots. Tubers help plants perennate (survive winter or dry months), provide energy and nutrients, and are a means of asexual reproduc ...
s to store nutrients. These are not roots but stems that form from thickened rhizomes at the tips of long thin
stolon In biology, a stolon ( from Latin ''wikt:stolo, stolō'', genitive ''stolōnis'' – "branch"), also known as a runner, is a horizontal connection between parts of an organism. It may be part of the organism, or of its skeleton. Typically, animal ...
s. On the surface of the tubers there are "eyes," which act as sinks to protect the vegetative buds from which the stems originate. The "eyes" are arranged in helical form. In addition, the tubers have small holes that allow breathing, called lenticels. The lenticels are circular and their number varies depending on the size of the tuber and environmental conditions. Tubers form in response to decreasing day length, although this tendency has been minimized in commercial varieties. After flowering, potato plants produce small green fruits that resemble green cherry tomatoes, each containing about 300 very small
seed In botany, a seed is a plant structure containing an embryo and stored nutrients in a protective coat called a ''testa''. More generally, the term "seed" means anything that can be Sowing, sown, which may include seed and husk or tuber. Seeds ...
s.


Phylogeny

Like the
tomato The tomato (, ), ''Solanum lycopersicum'', is a plant whose fruit is an edible Berry (botany), berry that is eaten as a vegetable. The tomato is a member of the nightshade family that includes tobacco, potato, and chili peppers. It originate ...
, potatoes belong to the genus '' Solanum'', which is a member of the nightshade family, the Solanaceae. That is a diverse family of flowering plants, often poisonous, that includes the mandrake ('' Mandragora''), deadly nightshade ('' Atropa''), and tobacco ('' Nicotiana''), as shown in the outline phylogenetic tree (many branches omitted). The most commonly cultivated potato is ''S. tuberosum''; there are several other species. The major species grown worldwide is ''S. tuberosum'' (a tetraploid with 48 chromosomes), and modern varieties of this species are the most widely cultivated. There are also four diploid species (with 24 chromosomes): ''S. stenotomum'', ''S. phureja'', ''S. goniocalyx'', and ''S. ajanhuiri''. There are two triploid species (with 36 chromosomes): '' S. chaucha'' and ''S. juzepczukii''. There is one pentaploid cultivated species (with 60 chromosomes): ''S. curtilobum''. There are two major subspecies of ''S. tuberosum''. The Andean potato, ''S. tuberosum andigena'', is adapted to the short-day conditions prevalent in the mountainous equatorial and tropical regions where it originated. The Chilean potato ''S. tuberosum tuberosum'', native to the
Chiloé Archipelago The Chiloé Archipelago (, , ) is a group of islands lying off the coast of Chile, in the Los Lagos Region. It is separated from mainland Chile by the Chacao Channel in the north, the Sea of Chiloé in the east and the Gulf of Corcovado in the s ...
, is in contrast adapted to the long-day conditions prevalent in the higher latitude region of southern Chile.


History


Domestication

Wild potato
species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...
occur from the southern United States to southern Chile. The potato was first domesticated in southern
Peru Peru, officially the Republic of Peru, is a country in western South America. It is bordered in the north by Ecuador and Colombia, in the east by Brazil, in the southeast by Bolivia, in the south by Chile, and in the south and west by the Pac ...
and northwestern
Bolivia Bolivia, officially the Plurinational State of Bolivia, is a landlocked country located in central South America. The country features diverse geography, including vast Amazonian plains, tropical lowlands, mountains, the Gran Chaco Province, w ...
by pre-Columbian farmers, around
Lake Titicaca Lake Titicaca (; ; ) is a large freshwater lake in the Andes mountains on the border of Bolivia and Peru. It is often called the highest navigable lake in the world. Titicaca is the largest lake in South America, both in terms of the volume of ...
. Potatoes were domesticated there about 7,000–10,000 years ago from a species in the '' S. brevicaule'' complex. The earliest archaeologically verified potato tuber remains have been found at the coastal site of Ancon (central
Peru Peru, officially the Republic of Peru, is a country in western South America. It is bordered in the north by Ecuador and Colombia, in the east by Brazil, in the southeast by Bolivia, in the south by Chile, and in the south and west by the Pac ...
), dating to 2500 BC. The most widely cultivated variety, ''Solanum tuberosum tuberosum'', is indigenous to the
Chiloé Archipelago The Chiloé Archipelago (, , ) is a group of islands lying off the coast of Chile, in the Los Lagos Region. It is separated from mainland Chile by the Chacao Channel in the north, the Sea of Chiloé in the east and the Gulf of Corcovado in the s ...
, and has been cultivated by the local indigenous people since before the Spanish conquest.


Spread

Following the Spanish conquest of the Inca Empire, the Spanish introduced the potato to Europe in the second half of the 16th century as part of the
Columbian exchange The Columbian exchange, also known as the Columbian interchange, was the widespread transfer of plants, animals, and diseases between the New World (the Americas) in the Western Hemisphere, and the Old World (Afro-Eurasia) in the Eastern Hemis ...
. The staple was subsequently conveyed by European mariners (possibly including the Russian-American Company) to territories and ports throughout the world, especially their colonies. European and colonial farmers were slow to adopt farming potatoes. However, after 1750, they became an important food staple and field crop and played a major role in the European 19th century population boom. According to conservative estimates, the introduction of the potato was responsible for a quarter of the growth in Old World population and urbanization between 1700 and 1900. However, lack of
genetic diversity Genetic diversity is the total number of genetic characteristics in the genetic makeup of a species. It ranges widely, from the number of species to differences within species, and can be correlated to the span of survival for a species. It is d ...
, due to the very limited number of varieties initially introduced, left the crop vulnerable to disease. In 1845, a plant disease known as late blight, caused by the fungus-like oomycete '' Phytophthora infestans'', spread rapidly through the poorer communities of western Ireland as well as parts of the
Scottish Highlands The Highlands (; , ) is a historical region of Scotland. Culturally, the Highlands and the Scottish Lowlands, Lowlands diverged from the Late Middle Ages into the modern period, when Scots language, Lowland Scots language replaced Scottish Gae ...
, resulting in the crop failures that led to the Great Irish Famine. The International Potato Center, based in
Lima Lima ( ; ), founded in 1535 as the Ciudad de los Reyes (, Spanish for "City of Biblical Magi, Kings"), is the capital and largest city of Peru. It is located in the valleys of the Chillón River, Chillón, Rímac River, Rímac and Lurín Rive ...
, Peru, holds 4,870 types of potato
germplasm Germplasm refers to genetic resources such as seeds, tissues, and DNA sequences that are maintained for the purpose of animal and plant breeding, conservation efforts, agriculture, and other research uses. These resources may take the form of s ...
, most of which are traditional landrace cultivars. In 2009, a draft sequence of the potato genome was made, containing 12 chromosomes and 860 million base pairs, making it a medium-sized plant genome. It had been thought that most potato
cultivar A cultivar is a kind of Horticulture, cultivated plant that people have selected for desired phenotypic trait, traits and which retains those traits when Plant propagation, propagated. Methods used to propagate cultivars include division, root a ...
s derived from a single origin in southern
Peru Peru, officially the Republic of Peru, is a country in western South America. It is bordered in the north by Ecuador and Colombia, in the east by Brazil, in the southeast by Bolivia, in the south by Chile, and in the south and west by the Pac ...
and extreme Northwestern
Bolivia Bolivia, officially the Plurinational State of Bolivia, is a landlocked country located in central South America. The country features diverse geography, including vast Amazonian plains, tropical lowlands, mountains, the Gran Chaco Province, w ...
, from a species in the '' S. brevicaule'' complex. DNA analysis however shows that more than 99% of all current varieties of potatoes are direct descendants of a subspecies that once grew in the lowlands of south-central Chile. Most modern potatoes grown in North America arrived through European settlement and not independently from the South American sources. At least one wild potato species, '' S. fendleri'', occurs in North America; it is used in breeding for resistance to a
nematode The nematodes ( or ; ; ), roundworms or eelworms constitute the phylum Nematoda. Species in the phylum inhabit a broad range of environments. Most species are free-living, feeding on microorganisms, but many are parasitic. Parasitic worms (h ...
species that attacks cultivated potatoes. A secondary center of genetic variability of the potato is Mexico, where important wild species that have been used extensively in modern breeding are found, such as the hexaploid '' S. demissum'', used as a source of resistance to the devastating late blight disease ('' Phytophthora infestans''). Another relative native to this region, '' Solanum bulbocastanum'', has been used to genetically engineer the potato to resist potato blight. Many such wild relatives are useful for breeding resistance to ''P. infestans''. Little of the diversity found in '' Solanum'' ancestral and wild relatives is found outside the original South American range. This makes these South American species highly valuable in breeding. The importance of the potato to humanity is recognised in the
United Nations The United Nations (UN) is the Earth, global intergovernmental organization established by the signing of the Charter of the United Nations, UN Charter on 26 June 1945 with the stated purpose of maintaining international peace and internationa ...
International Day of Potato, to be celebrated on 30 May each year, starting in 2024.


Breeding

Potatoes, both ''S. tuberosum'' and most of its wild relatives, are self-incompatible: they bear no useful fruit when self-pollinated. This trait is problematic for crop breeding, as all sexually-produced plants must be hybrids. The gene responsible for self-incompatibility, as well as mutations to disable it, are now known. Self-compatibility has successfully been introduced both to diploid potatoes (including a special line of ''S. tuberosum'') by CRISPR-Cas9. Plants having a 'Sli' gene produce pollen which is compatible to its own parent and plants with similar S genes. This gene was cloned by Wageningen University and Solynta in 2021, which would allow for faster and more focused breeding. Diploid hybrid potato breeding is a recent area of potato genetics supported by the finding that simultaneous homozygosity and fixation of donor alleles is possible. Wild potato species useful for breeding blight resistance include ''Solanum desmissum'' and ''S. stoloniferum'', among others.


Varieties

There are some 5,000 potato varieties worldwide, 3,000 of them in the
Andes The Andes ( ), Andes Mountains or Andean Mountain Range (; ) are the List of longest mountain chains on Earth, longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range ...
alone — mainly in Peru, Bolivia, Ecuador, Chile, and Colombia. Over 100 cultivars might be found in a single valley, and a dozen or more might be maintained by a single agricultural household. The European Cultivated Potato Database is an online collaborative database of potato variety descriptions updated and maintained by the Scottish Agricultural Science Agency within the framework of the European Cooperative Programme for Crop Genetic Resources Networks—which is run by the International Plant Genetic Resources Institute. Around 80 varieties are commercially available in the UK. For culinary purposes, varieties are often differentiated by their waxiness: floury or mealy ''baking'' potatoes have more starch (20–22%) than waxy ''boiling'' potatoes (16–18%). The distinction may also arise from variation in the comparative ratio of two different potato starch compounds: amylose and amylopectin. Amylose, a long-chain molecule, diffuses from the starch granule when cooked in water, and lends itself to dishes where the potato is mashed. Varieties that contain a slightly higher amylopectin content, which is a highly branched molecule, help the potato retain its shape after being boiled in water. Potatoes that are good for making potato chips or potato crisps are sometimes called "chipping potatoes", which means they meet the basic requirements of similar varietal characteristics, being firm, fairly clean, and fairly well-shaped. Immature potatoes may be sold fresh from the field as "" or "" potatoes and are particularly valued for their taste. They are typically small in size and tender, with a loose skin, and flesh containing a lower level of starch than other potatoes. In the United States they are generally either a Yukon Gold potato or a red potato, called gold creamers or red creamers respectively. In the UK, the Jersey Royal is a famous type of new potato. Dozens of potato
cultivar A cultivar is a kind of Horticulture, cultivated plant that people have selected for desired phenotypic trait, traits and which retains those traits when Plant propagation, propagated. Methods used to propagate cultivars include division, root a ...
s have been selectively bred specifically for their skin or flesh
color Color (or colour in English in the Commonwealth of Nations, Commonwealth English; American and British English spelling differences#-our, -or, see spelling differences) is the visual perception based on the electromagnetic spectrum. Though co ...
, including gold, red, and blue varieties. These contain varying amounts of phytochemicals, including carotenoids for gold/yellow or
polyphenol Polyphenols () are a large family of naturally occurring phenols. They are abundant in plants and structurally diverse. Polyphenols include phenolic acids, flavonoids, tannic acid, and ellagitannin, some of which have been used historically as ...
s for red or blue cultivars. Carotenoid compounds include provitamin A alpha-carotene and beta-carotene, which are converted to the essential nutrient,
vitamin A Vitamin A is a fat-soluble vitamin that is an essential nutrient. The term "vitamin A" encompasses a group of chemically related organic compounds that includes retinol, retinyl esters, and several provitamin (precursor) carotenoids, most not ...
, during digestion. Anthocyanins mainly responsible for red or blue pigmentation in potato cultivars do not have nutritional significance, but are used for visual variety and consumer appeal. In 2010, potatoes were bioengineered specifically for these pigmentation traits.


Genetic engineering

Genetic research has produced several genetically modified varieties. 'New Leaf', owned by Monsanto Company, incorporates genes from '' Bacillus thuringiensis'' (source of most ''Bt'' toxins in transcrop use), which confers resistance to the Colorado potato beetle; 'New Leaf Plus' and 'New Leaf Y', approved by US regulatory agencies during the 1990s, also include resistance to
viruses A virus is a submicroscopic infectious agent that replicates only inside the living cells of an organism. Viruses infect all life forms, from animals and plants to microorganisms, including bacteria and archaea. Viruses are found in almo ...
.
McDonald's McDonald's Corporation, doing business as McDonald's, is an American Multinational corporation, multinational fast food chain store, chain. As of 2024, it is the second largest by number of locations in the world, behind only the Chinese ch ...
, Burger King, Frito-Lay, and
Procter & Gamble The Procter & Gamble Company (P&G) is an American multinational consumer goods corporation headquartered in Cincinnati, Ohio. It was founded in 1837 by William Procter and James Gamble. It specializes in a wide range of personal health/con ...
announced they would not use genetically modified potatoes, and Monsanto published its intent to discontinue the line in March 2001. Potato starch contains two types of glucan, amylose and amylopectin, the latter of which is most industrially useful. Waxy potato varieties produce waxy potato starch, which is almost entirely amylopectin, with little or no amylose. BASF developed the ' Amflora' potato, which was modified to express
antisense RNA Antisense RNA (asRNA), also referred to as antisense transcript, natural antisense transcript (NAT) or antisense oligonucleotide, is a single stranded RNA that is complementary to a protein coding messenger RNA (mRNA) with which it hybridizes, and ...
to inactivate the gene for granule bound starch synthase, an enzyme which catalyzes the formation of amylose. 'Amflora' potatoes therefore produce starch consisting almost entirely of amylopectin, and are thus more useful for the starch industry. In 2010, the European Commission cleared the way for 'Amflora' to be grown in the European Union for industrial purposes only—not for food. Nevertheless, under EU rules, individual countries have the right to decide whether they will allow this potato to be grown on their territory. Commercial planting of 'Amflora' was expected in the Czech Republic and Germany in the spring of 2010, and Sweden and the Netherlands in subsequent years. The 'Fortuna' GM potato variety developed by BASF was made resistant to late blight by introgressing two resistance genes, and , from '' S. bulbocastanum'', a wild potato native to Mexico. is a nucleotide-binding leucine-rich repeat (NB-LRR/NLR), an R-gene-produced immunoreceptor. In October 2011, BASF requested cultivation and marketing approval as a feed and food from the EFSA. In 2012, GMO development in Europe was stopped by BASF. In November 2014, the United States Department of Agriculture (USDA) approved a genetically modified potato developed by Simplot, which contains genetic modifications that prevent bruising and produce less acrylamide when fried than conventional potatoes; the modifications do not cause new proteins to be made, but rather prevent proteins from being made via
RNA interference RNA interference (RNAi) is a biological process in which RNA molecules are involved in sequence-specific suppression of gene expression by double-stranded RNA, through translational or transcriptional repression. Historically, RNAi was known by ...
. Genetically modified varieties have met public resistance in the U.S. and in the European Union.


Cultivation


Seed potatoes

Potatoes are generally grown from "seed potatoes", tubers specifically grown to be free from disease and to provide consistent and healthy plants. To be disease free, the areas where seed potatoes are grown are selected with care. In the US, this restricts production of seed potatoes to only 15 states out of all 50 states where potatoes are grown. These locations are selected for their cold, hard winters that kill pests and summers with long sunshine hours for optimum growth. In the UK, most seed potatoes originate in
Scotland Scotland is a Countries of the United Kingdom, country that is part of the United Kingdom. It contains nearly one-third of the United Kingdom's land area, consisting of the northern part of the island of Great Britain and more than 790 adjac ...
, in areas where westerly winds reduce
aphid Aphids are small sap-sucking insects in the Taxonomic rank, family Aphididae. Common names include greenfly and blackfly, although individuals within a species can vary widely in color. The group includes the fluffy white Eriosomatinae, woolly ...
attacks and the spread of potato virus pathogens.


Phases of growth

Potato growth can be divided into five phases. During the first phase, sprouts emerge from the seed potatoes and root growth begins. During the second,
photosynthesis Photosynthesis ( ) is a system of biological processes by which photosynthetic organisms, such as most plants, algae, and cyanobacteria, convert light energy, typically from sunlight, into the chemical energy necessary to fuel their metabo ...
begins as the plant develops leaves and branches above-ground and
stolon In biology, a stolon ( from Latin ''wikt:stolo, stolō'', genitive ''stolōnis'' – "branch"), also known as a runner, is a horizontal connection between parts of an organism. It may be part of the organism, or of its skeleton. Typically, animal ...
s develop from lower leaf axils on the below-ground stem. In the third phase the tips of the stolons swell, forming new
tuber Tubers are a type of enlarged structure that plants use as storage organs for nutrients, derived from stems or roots. Tubers help plants perennate (survive winter or dry months), provide energy and nutrients, and are a means of asexual reproduc ...
s, and the shoots continue to grow, with flowers typically developing soon after. Tuber bulking occurs during the fourth phase, when the plant begins investing the majority of its resources in its newly formed tubers. At this phase, several factors are critical to a good yield: optimal soil moisture and temperature, soil nutrient availability and balance, and resistance to pest attacks. The fifth phase is the maturation of the tubers: the leaves and stems senesce and the tuber skins harden. New tubers may start growing at the surface of the soil. Since exposure to light leads to an undesirable greening of the skins and the development of solanine as a protection from the sun's rays, growers cover surface tubers. Commercial growers cover them by piling additional soil around the base of the plant as it grows (called "hilling" up, or in British English "earthing up"). An alternative method, used by home gardeners and smaller-scale growers, involves covering the growing area with mulches such as straw or plastic sheets. At farm scale, potatoes require a well-drained neutral or mildly acidic soil ( pH 6 or 7) such as a sandy loam. The soil is prepared using deep tillage, for example with a chisel plow or ripper. In areas where irrigation is needed, the field is leveled using a landplane so that water can be supplied evenly. Manure can be added after initial irrigation; the soil is then broken up with a disc harrow. The potatoes are planted using a potato planter machine in rows apart. At garden scale, potatoes are planted in trenches or individual holes some deep in soil, preferably with additional organic matter such as garden compost or manure. Alternatively, they can be planted in containers or bags filled with a free-draining compost. Potatoes are sensitive to heavy frosts, which damage them in the ground or when stored. File:Planting Potatoes.jpg, Planting File:Tractors in Potato Field.jpg, Field in Fort Fairfield, Maine File:Potato plants.jpg, Immature potato plants File:Potato bag cultivation.JPG, Potatoes grown in a tall bag are common in gardens as they minimize digging.


Pests and diseases

The historically significant '' Phytophthora infestans'', the cause of late blight, remains an ongoing problem in Europe and the United States. Other potato diseases include '' Rhizoctonia'', '' Sclerotinia'', '' Pectobacterium carotovorum'' (black leg), powdery mildew, powdery scab and leafroll virus. Insects that commonly transmit potato diseases or damage the plants include the Colorado potato beetle, the potato tuber moth, the green peach aphid ('' Myzus persicae''), the potato aphid, '' Tuta absoluta'', beet leafhoppers, thrips, and
mite Mites are small arachnids (eight-legged arthropods) of two large orders, the Acariformes and the Parasitiformes, which were historically grouped together in the subclass Acari. However, most recent genetic analyses do not recover the two as eac ...
s. The Colorado potato beetle is considered the most important insect defoliator of potatoes, devastating entire crops. The potato cyst nematode is a microscopic worm that feeds on the roots, thus causing the potato plants to wilt. Since its eggs can survive in the soil for several years, crop rotation is recommended.


Harvest

On a small scale, potatoes can be harvested using a hoe or spade, or simply by hand. Commercial harvesting is done with large potato harvesters, which scoop up the plant and surrounding earth. This is transported up an apron chain consisting of steel links several feet wide, which separates some of the earth. The chain deposits into an area where further separation occurs. The most complex designs use vine choppers and shakers, along with a blower system to separate the potatoes from the plant. The result is then usually run past workers who continue to sort out plant material, stones, and rotten potatoes before the potatoes are continuously delivered to a wagon or truck. Further inspection and separation occurs when the potatoes are unloaded from the field vehicles and put into storage. Potatoes are usually cured after harvest to improve skin-set. Skin-set is the process by which the skin of the potato becomes resistant to skinning damage. Potato tubers may be susceptible to skinning at harvest and suffer skinning damage during harvest and handling operations. Curing allows the skin to fully set and any wounds to heal. Wound-healing prevents infection and water-loss from the tubers during storage. Curing is normally done at relatively warm temperatures () with high humidity and good gas-exchange if at all possible.


Storage

Storage facilities need to be carefully designed to keep the potatoes alive and slow the natural process of sprouting which involves the breakdown of starch. It is crucial that the storage area be dark, ventilated well, and, for long-term storage, maintained at temperatures near . For short-term storage, temperatures of about are preferred.Potato storage, value Preservation: Temperatures below convert the starch in potatoes into sugar, which alters their taste and cooking qualities and leads to higher acrylamide levels in the cooked product, especially in deep-fried dishes. The discovery of acrylamides in starchy foods in 2002 has caused concern, but it is not likely that the acrylamides in food, even if it is somewhat burnt, causes cancer in humans. Chemicals are used to suppress sprouting of tubers during storage. Chlorpropham is the main chemical used, but it has been banned in the EU over toxicity concerns. Alternatives include ethylene, spearmint and orange oils, and 1,4-dimethylnaphthalene. Under optimum conditions in commercial warehouses, potatoes can be stored for up to 10–12 months. The commercial storage and retrieval of potatoes involves several phases: first ''drying'' surface moisture; ''wound healing'' at 85% to 95%
relative humidity Humidity is the concentration of water vapor present in the air. Water vapor, the gaseous state of water, is generally invisible to the human eye. Humidity indicates the likelihood for precipitation (meteorology), precipitation, dew, or fog t ...
and temperatures below ; a staged ''cooling phase''; a ''holding'' phase; and a ''reconditioning'' phase, during which the tubers are slowly warmed.
Mechanical ventilation Mechanical ventilation or assisted ventilation is the Medicine, medical term for using a ventilator, ventilator machine to fully or partially provide artificial ventilation. Mechanical ventilation helps move air into and out of the lungs, wit ...
is used at various points during the process to prevent condensation and the accumulation of carbon dioxide.


Production

In 2023, world production of potatoes was 383 million
tonne The tonne ( or ; symbol: t) is a unit of mass equal to 1,000  kilograms. It is a non-SI unit accepted for use with SI. It is also referred to as a metric ton in the United States to distinguish it from the non-metric units of the s ...
s, led by China with 25% of the total and India as a major secondary producer (table). The world dedicated to potato cultivation in 2010; the world average yield was . The United States was the most productive country, with a nationwide average yield of . New Zealand farmers have demonstrated some of the best commercial yields in the world, ranging between 60 and 80 tonnes per hectare, some reporting yields of 88 tonnes of potatoes per hectare. There is a big gap among various countries between high and low yields, even with the same variety of potato. Average potato yields in developed economies ranges between . China and India accounted for over a third of world's production in 2010, and had yields of respectively. The yield gap between farms in developing economies and developed economies represents an opportunity loss of over of potato, or an amount greater than 2010 world potato production. Potato crop yields are determined by factors such as the crop breed, seed age and quality, crop management practices and the plant environment. Improvements in one or more of these yield determinants, and a closure of the yield gap, could be a major boost to food supply and farmer incomes in the developing world. The food energy yield of potatoes—about —is higher than that of maize (), rice (), wheat (), or
soybean The soybean, soy bean, or soya bean (''Glycine max'') is a species of legume native to East Asia, widely grown for its edible bean. Soy is a staple crop, the world's most grown legume, and an important animal feed. Soy is a key source o ...
s ().


Effects of climate change on production

Climate change Present-day climate change includes both global warming—the ongoing increase in Global surface temperature, global average temperature—and its wider effects on Earth's climate system. Climate variability and change, Climate change in ...
is predicted to have significant effects on global potato production. Like many crops, potatoes are likely to be affected by changes in atmospheric
carbon dioxide Carbon dioxide is a chemical compound with the chemical formula . It is made up of molecules that each have one carbon atom covalent bond, covalently double bonded to two oxygen atoms. It is found in a gas state at room temperature and at norma ...
, temperature and precipitation, as well as interactions between these factors. As well as affecting potatoes directly, climate change will also affect the distributions and populations of many potato diseases and pests. While the potato is less important than
maize Maize (; ''Zea mays''), also known as corn in North American English, is a tall stout grass that produces cereal grain. It was domesticated by indigenous peoples in southern Mexico about 9,000 years ago from wild teosinte. Native American ...
,
rice Rice is a cereal grain and in its Domestication, domesticated form is the staple food of over half of the world's population, particularly in Asia and Africa. Rice is the seed of the grass species ''Oryza sativa'' (Asian rice)—or, much l ...
,
wheat Wheat is a group of wild and crop domestication, domesticated Poaceae, grasses of the genus ''Triticum'' (). They are Agriculture, cultivated for their cereal grains, which are staple foods around the world. Well-known Taxonomy of wheat, whe ...
and
soybean The soybean, soy bean, or soya bean (''Glycine max'') is a species of legume native to East Asia, widely grown for its edible bean. Soy is a staple crop, the world's most grown legume, and an important animal feed. Soy is a key source o ...
s, which are collectively responsible for around two-thirds of all calories consumed by humans (both directly and indirectly as animal feed), it still is one of the world's most important food crops. Altogether, one 2003 estimate suggests that future (2040–2069) worldwide potato yield would be 18–32% lower than it was at the time, driven by declines in hotter areas like Sub-Saharan Africa, unless farmers and potato cultivars can adapt to the new environment. Potato plants and crop yields are predicted to benefit from the CO2 fertilization effect, which would increase photosynthetic rates and therefore growth, reduce water consumption through lower transpiration from stomata and increase starch content in the edible tubers. However, potatoes are more sensitive to soil water deficits than some other staple crops like wheat. In the UK, the amount of arable land suitable for rainfed potato production is predicted to decrease by at least 75%. These changes are likely to lead to increased demand for
irrigation Irrigation (also referred to as watering of plants) is the practice of applying controlled amounts of water to land to help grow crops, landscape plants, and lawns. Irrigation has been a key aspect of agriculture for over 5,000 years and has bee ...
water, particularly during the potato growing season. Potatoes grow best under temperate conditions. Temperatures above have negative effects on potato crops, from physiological damage such as brown spots on tubers, to slower growth, premature sprouting, and lower starch content. These effects reduce crop yield, affecting both the number and the weight of tubers. As a result, areas where current temperatures are near the limits of potatoes' temperature range (e.g. much of
sub-Saharan Africa Sub-Saharan Africa is the area and regions of the continent of Africa that lie south of the Sahara. These include Central Africa, East Africa, Southern Africa, and West Africa. Geopolitically, in addition to the list of sovereign states and ...
) will likely suffer large reductions in potato crop yields in the future. On the other hand, low temperatures reduce potato growth and present risk of frost damage.


Changes in pests and diseases

Climate change is predicted to affect many potato pests and diseases. These include: * Insect pests such as the potato tuber moth and Colorado potato beetle, which are predicted to spread into areas currently too cold for them. *
Aphid Aphids are small sap-sucking insects in the Taxonomic rank, family Aphididae. Common names include greenfly and blackfly, although individuals within a species can vary widely in color. The group includes the fluffy white Eriosomatinae, woolly ...
s which act as vectors for many potato viruses and will spread under increased temperatures. * Pathogens causing potato blackleg disease (e.g. Dickeya) grow and reproduce faster at higher temperatures. * Bacterial infections such as Ralstonia solanacearum will benefit from higher temperatures and spread more easily through flash flooding. * Late blight benefits from higher temperatures and wetter conditions. Late blight is predicted to become a greater threat in some areas (e.g. in Finland) and become a lesser threat in others (e.g. in the United Kingdom).


Adaptation strategies

Potato production is expected to decline in many areas due to hotter temperatures and decreased water availability. Conversely, production is predicted to become possible in high altitude and latitude areas where it has been limited by frost damage, such as in
Canada Canada is a country in North America. Its Provinces and territories of Canada, ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, making it the world's List of coun ...
and
Russia Russia, or the Russian Federation, is a country spanning Eastern Europe and North Asia. It is the list of countries and dependencies by area, largest country in the world, and extends across Time in Russia, eleven time zones, sharing Borders ...
. This will shift potato production to cooler areas, mitigating much of the projected decline in yield. However, this may trigger competition for land between potato crops and other land uses, mostly due to changes in water and temperature regimes. The other approach is through the development of varieties or cultivars which would be more adapted to altered conditions. This can be done through 'traditional' plant breeding techniques and genetic modification. These techniques allow for the selection of specific traits as a new cultivar is developed. Certain traits, such as heat stress tolerance, drought tolerance, fast growth/early maturation and disease resistance, may play an important role in creating new cultivars able to maintain yields under stressors induced by climate change. For instance, developing cultivars with greater heat stress tolerance would be critical for maintaining yields in countries with potato production areas near current cultivars' maximum temperature limits (e.g.
Sub-Saharan Africa Sub-Saharan Africa is the area and regions of the continent of Africa that lie south of the Sahara. These include Central Africa, East Africa, Southern Africa, and West Africa. Geopolitically, in addition to the list of sovereign states and ...
, India). Superior drought resistance can be achieved through improved water use efficiency (amount of food produced per amount of water used) or the ability to recover from short drought periods and still produce acceptable yields. Further, selecting for deeper root systems may reduce the need for irrigation.


Nutrition

In a reference amount of , a boiled potato with skin supplies 87 calories and is 77% water, 20%
carbohydrate A carbohydrate () is a biomolecule composed of carbon (C), hydrogen (H), and oxygen (O) atoms. The typical hydrogen-to-oxygen atomic ratio is 2:1, analogous to that of water, and is represented by the empirical formula (where ''m'' and ''n'' ...
s (including 2% dietary fiber in the skin and flesh), 2%
protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residue (biochemistry), residues. Proteins perform a vast array of functions within organisms, including Enzyme catalysis, catalysing metab ...
, and contains negligible fat (table). The protein content is comparable to other starchy vegetable staples, as well as grains. Boiled potatoes are a moderate source (10–19% of the Daily Value, DV) of vitamin C (14% DV) and the B vitamins, vitamin B6 and pantothenic acid (table). Other than a moderate source of
potassium Potassium is a chemical element; it has Symbol (chemistry), symbol K (from Neo-Latin ) and atomic number19. It is a silvery white metal that is soft enough to easily cut with a knife. Potassium metal reacts rapidly with atmospheric oxygen to ...
(13% DV), boiled potatoes do not supply significant amounts of dietary minerals (table). The potato is rarely eaten raw because raw potato starch is poorly digested by humans. Depending on the cultivar and preparation method, potatoes can have a high glycemic index (GI) and so are often excluded from the diets of individuals trying to follow a low-GI diet. There is a lack of evidence on the effect of potato consumption on obesity and diabetes. In the UK, potatoes are not considered by the
National Health Service The National Health Service (NHS) is the term for the publicly funded health care, publicly funded healthcare systems of the United Kingdom: the National Health Service (England), NHS Scotland, NHS Wales, and Health and Social Care (Northern ...
as counting or contributing towards the recommended daily five portions of fruit and vegetables, the 5-A-Day program.


Toxicity

Raw potatoes contain toxic glycoalkaloids, of which the most prevalent are solanine and chaconine. Solanine is found in other plants in the same family, Solanaceae, which includes such plants as deadly nightshade ('' Atropa belladonna''), henbane ('' Hyoscyamus niger'') and tobacco ('' Nicotiana'' spp.), as well as food plants like tomato. These compounds, which protect the potato plant from its predators, are especially concentrated in the aerial parts of the plant. The tubers are low in these toxins, unless they are exposed to light, which makes them go green. Exposure to light, physical damage, and age increase glycoalkaloid content within the tuber. Different potato varieties contain different levels of glycoalkaloids. The '
Lenape The Lenape (, , ; ), also called the Lenni Lenape and Delaware people, are an Indigenous peoples of the Northeastern Woodlands, Indigenous people of the Northeastern Woodlands, who live in the United States and Canada. The Lenape's historica ...
' variety, released in 1967, was withdrawn in 1970 as it contained high levels of glycoalkaloids. Since then, breeders of new varieties test for this, sometimes discarding an otherwise promising
cultivar A cultivar is a kind of Horticulture, cultivated plant that people have selected for desired phenotypic trait, traits and which retains those traits when Plant propagation, propagated. Methods used to propagate cultivars include division, root a ...
. Breeders try to keep glycoalkaloid levels below . However, when these commercial varieties turn green, their solanine concentrations can go well above this limit, with higher levels in the potato's skin.


Uses


Culinary

Potato dishes vary around the world. Peruvian cuisine naturally contains the potato as a primary ingredient in many dishes, as around 3,000 varieties of the tuber are grown there. Chuño is a freeze-dried potato product traditionally made by Quechua and Aymara communities of
Peru Peru, officially the Republic of Peru, is a country in western South America. It is bordered in the north by Ecuador and Colombia, in the east by Brazil, in the southeast by Bolivia, in the south by Chile, and in the south and west by the Pac ...
and
Bolivia Bolivia, officially the Plurinational State of Bolivia, is a landlocked country located in central South America. The country features diverse geography, including vast Amazonian plains, tropical lowlands, mountains, the Gran Chaco Province, w ...
. In the UK, potatoes form part of the traditional dish
fish and chips Fish and chips is a hot dish consisting of batter (cooking), battered and fried fish, served with French fries, chips. Often considered the national dish of the United Kingdom, fish and chips originated in England in the 19th century. Today, ...
. Roast potatoes are commonly served as part of a Sunday roast dinner and mashed potatoes form a major component of several other traditional dishes, such as shepherd's pie, bubble and squeak, and bangers and mash. New potatoes may be cooked with mint and are often served with butter. In Germany,
Northern Europe The northern region of Europe has several definitions. A restrictive definition may describe northern Europe as being roughly north of the southern coast of the Baltic Sea, which is about 54th parallel north, 54°N, or may be based on other ge ...
(Finland, Latvia and especially Scandinavian countries), Eastern Europe (Russia,
Belarus Belarus, officially the Republic of Belarus, is a landlocked country in Eastern Europe. It is bordered by Russia to the east and northeast, Ukraine to the south, Poland to the west, and Lithuania and Latvia to the northwest. Belarus spans an a ...
and
Ukraine Ukraine is a country in Eastern Europe. It is the List of European countries by area, second-largest country in Europe after Russia, which Russia–Ukraine border, borders it to the east and northeast. Ukraine also borders Belarus to the nor ...
) and Poland, newly harvested, early ripening varieties are considered a special delicacy. Boiled whole and served un-peeled with dill, these "new potatoes" are traditionally consumed with Baltic herring. Puddings made from grated potatoes ( kugel, kugelis, and potato babka) are popular items of
Ashkenazi Ashkenazi Jews ( ; also known as Ashkenazic Jews or Ashkenazim) form a distinct subgroup of the Jewish diaspora, that Ethnogenesis, emerged in the Holy Roman Empire around the end of the first millennium Common era, CE. They traditionally spe ...
, Lithuanian, and Belarusian cuisine. Cepelinai, the national dish of
Lithuania Lithuania, officially the Republic of Lithuania, is a country in the Baltic region of Europe. It is one of three Baltic states and lies on the eastern shore of the Baltic Sea, bordered by Latvia to the north, Belarus to the east and south, P ...
, are
dumpling Dumplings are a broad class of dishes that consist of pieces of cooked dough (made from a variety of starchy sources), often wrapped around a filling. The dough can be based on bread, wheat or other flours, or potatoes, and it may be filled wi ...
s made from boiled grated potatoes, usually stuffed with minced meat. In Italy, in the
Friuli Friuli (; ; or ; ; ) is a historical region of northeast Italy. The region is marked by its separate regional and ethnic identity predominantly tied to the Friulians, who speak the Friulian language. It comprises the major part of the autono ...
region, potatoes serve to make a type of pasta called gnocchi. Potato is used in northern China where rice is not easily grown, a popular dish being (''qīng jiāo tǔ dòu sī''), made with green pepper, vinegar and thin slices of potato. In the winter, roadside sellers in northern China sell roasted potatoes. File:Flickr - cyclonebill - Pommes frites med salatmayonnaise.jpg , ''Pommes frites'', also called chips and French fries File:Peru PapasRellenas2.jpg , Papa rellena File:Baked Potato (3662019664).jpg , Baked potato with sour cream and chives File:Bauernfrühstück-01.jpg , German ("farmer's breakfast") File:Cepelinai 2, Vilnius, Lithuania - Diliff.jpg , Cepelinai


Other uses

Potatoes are sometimes used to brew alcoholic spirits such as
vodka Vodka ( ; is a clear distilled beverage, distilled alcoholic beverage. Its varieties originated in Poland and Russia. Vodka is composed mainly of water and ethanol but sometimes with traces of impurities and flavourings. Traditionally, it is ...
, poitín, akvavit, and
brännvin Brännvin (Swedish language, Swedish spelling; see ) is an old Nordic countries, Nordic term for distilled beverage, distilled liquor, generally from potatoes, grain, or (formerly) sawdust brandy, wood cellulose etc, and is today primarily used a ...
.Ermochkine, Nicholas and Iglikowski, Peter (2003). ''40 degrees east : an anatomy of vodka'', Nova Publishers, p. 65, . Potatoes are used as fodder for livestock. They may be made into silage which can be stored for some months before use. Potato starch is used in the food industry as a thickener and binder for soups and sauces, in the textile industry as an adhesive, and in the paper industry for the manufacturing of papers and boards. Potatoes are commonly used in plant research. The consistent parenchyma tissue, the clonal nature of the plant and the low metabolic activity make it an ideal model tissue for experiments on wound-response studies and electron transport.


Cultural significance


In mythology

In Inca mythology, a daughter of the earth mother Pachamama, Axomamma, is the goddess of potatoes. She ensured the fertility of the soil and the growth of the tubers. According to Iroquois mythology, the first potatoes grew out of Earth Woman's feet after she died giving birth to her twin sons, Sapling and Flint.


In art

The potato has been an essential crop in the Andes since the
pre-Columbian era In the history of the Americas, the pre-Columbian era, also known as the pre-contact era, or as the pre-Cabraline era specifically in Brazil, spans from the initial peopling of the Americas in the Upper Paleolithic to the onset of European col ...
. The Moche culture from Northern
Peru Peru, officially the Republic of Peru, is a country in western South America. It is bordered in the north by Ecuador and Colombia, in the east by Brazil, in the southeast by Bolivia, in the south by Chile, and in the south and west by the Pac ...
made ceramics from the earth, water, and fire. This pottery was a sacred substance, formed in significant shapes and used to represent important themes. Potatoes are represented anthropomorphically as well as naturally. During the late 19th century, numerous images of potato harvesting appeared in European art, including the works of Willem Witsen and Anton Mauve. Van Gogh's 1885 painting '' The Potato Eaters'' portrays a family eating potatoes. Van Gogh said he wanted to depict peasants as they really were. He deliberately chose coarse and ugly models, thinking that they would be natural and unspoiled in his finished work. Jean-François Millet's ''The Potato Harvest'' depicts peasants working in the plains between Barbizon and Chailly. It presents a theme representative of the peasants' struggle for survival. Millet's technique for this work incorporated paste-like pigments thickly applied over a coarsely textured canvas.Johnston, W.R., Nineteenth Century Art: From Romanticism to Art Nouveau, The Walters Art Gallery, p.56, File:Papamuseolarco.jpg, Potato ceramic from the Moche culture File:Jean-François Millet - The Potato Harvest - Walters 37115.jpg , '' The Potato Harvest'' by Jean-François Millet, 1855 (
Walters Art Museum The Walters Art Museum is a public art museum located in the Mount Vernon, Baltimore, Mount Vernon neighborhood of Baltimore, Maryland. Founded and opened in 1934, it holds collections from the mid-19th century that were amassed substantially ...
) File:Bastien Lepage Saison d-Octobre Recolte des pommes de terre.jpg , ''The potato harvest'' by Jules Bastien-Lepage, 1877, National Gallery of Victoria File:Van-willem-vincent-gogh-die-kartoffelesser-03850.jpg , '' The Potato Eaters'' by Van Gogh, 1885 ( Van Gogh Museum) File:Anker Die kleine Kartoffelschälerin 1886.jpg , ''Girl peeling potatoes'' by Albert Anker, 1886, oil on canvas


In popular culture

Invented in 1949, and marketed and sold commercially by
Hasbro Hasbro, Inc. (; a syllabic abbreviation of its original name, Hassenfeld Brothers) is an American multinational corporation, multinational toy manufacturing and entertainment holding company founded on December 6, 1923 by Henry, Hillel and Herma ...
in 1952, Mr. Potato Head is an American toy that consists of a plastic potato and attachable plastic parts, such as ears and eyes, to make a face. It was the first toy ever advertised on television. In the 2015 science fiction film ''The Martian'', the protagonist, a stranded astronaut and botanist named Mark Watney, cultivates potatoes on Mars using Martian soil fertilized with frozen feces.


See also

* Great Famine (Ireland) * Irish potato candy * List of potato dishes * List of potato museums * Loy (spade), a form of early spade used in Ireland for the cultivation of potatoes * New World crops * Potato battery * International Year of the Potato


References


Further reading

*
''Atlas of Wild Potatoes''
(2002), Systematic and Ecogeographic Studies on Crop Genepools 10, International Plant Genetic Resources Institute (IPGRI), * ''Economist''. "Llamas and mash"
''The Economist'' 28 February 2008
* * * Gauldie, Enid (1981). The Scottish Miller 1700–1900. Pub. John Donald. . * Hawkes, J.G. (1990). ''The Potato: Evolution, Biodiversity & Genetic Resources'', Smithsonian Institution Press, Washington, DC * * * McNeill, William H. "How the Potato Changed the World's History." ''Social Research'' (1999) 66#1 pp. 67–83. Fulltext: Ebsco, by a leading historian * * Ó Gráda, Cormac. ''Black '47 and Beyond: The Great Irish Famine in History, Economy, and Memory.'' (1999). 272 pp. * Ó Gráda, Cormac, Richard Paping, and Eric Vanhaute, eds. ''When the Potato Failed: Causes and Effects of the Last European Subsistence Crisis, 1845–1850.'' (2007). 342 pp.  . 15 essays by scholars looking at Ireland and all of Europe * Reader, John. ''Propitious Esculent: The Potato in World History'' (2008), 315pp a standard scholarly history * Salaman, Redcliffe N. (1989) The World Potato Atlas
released by the International Potato Center in 2006 and regularly updated. * World Geography of the Potato a
UGA.edu
released in 1993. * Zuckerman, Larry. ''The Potato: How the Humble Spud Rescued the Western World.'' (1998). 304 pp. Douglas & McIntyre. . {{Sister bar ">d=Q10998 , b=Cookbook:Potato , wikt=potato , c=Solanum tuberosum , species=Solanum tuberosum , auto=1 Potatoes Crops originating from Bolivia Crops originating from indigenous Americans Crops originating from Peru">Crops originating from indigenous Americans">Crops originating from Bolivia Crops originating from indigenous Americans Crops originating from Peru Crops originating from South America Northern Irish cuisine Edible Solanaceae Flora of the Andes Irish cuisine Plants described in 1753 Root vegetables Solanum Staple foods Stoloniferous plants Tubers