There is no universally accepted treatment for the various species that make up the potatoes. We are following the treatment of Spooner D.M. Et al in 2007 in the 'Proceedings of the National. Academy of Science USA 104: 19398-19403', in which only four distinct genera are maintained - viz; Solanum ajanhuiri (diploid forms); Solanum curtilobum (pentaploid forms); Solanum juzepczukii (triploid forms) and Solanum tuberosum, which is subdivided into two cultivar-groups (Andigenum Group of upland Andean genotypes containing diploids, triploids and tetraploids, and the Chilotanum Group of lowland tetraploid Chilean landraces)[].

Common Name: Potato

General Information

Solanum tuberosum (the potato) is a perennial plant with a tuberous rootstock, growing around 1 metre tall.
One of the most widely grown food plants throughout the world, the potato is a very important staple food. It is very high yielding (50 tonnes or more per hectare have been achieved in some European countries, though at the other extreme yields of little more than 2 tonnes have been achieved in parts of Africa), it stores well and can be available all year round. The potato probably arose through cultivation from several wild species that can still be found growing in S. America. Many of these wild species can be used in breeding programmes for improved disease resistance etc.

Known Hazards

All green parts of the plant, including the green parts of tubers, are poisonous, containing an alkaloid called 'solanine'.[, , ]. These solanines are also produced in potato shoots when they sprout, even if the potato is in the dark and the shoots are not green[].

Botanical References

Range

Western S. America

Habitat

Not known in a truly wild situation.

Properties

Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Perennial
Height	1.00 m
Pollinators	Insects
Cultivation Status	Cultivated

Cultivation Details

The potato originated through cultivation from plants being grown at moderate to higher elevations in the tropics of South America. Plants succeed in temperate climates when grown as an annual, the tubers being planted in the spring and harvested in the summer to autumn as growth dies down. In the Tropics plants are rarely grown at elevations lower than 1,000 metres since yields are poor at low elevations[]. The plant is reported to tolerate an annual precipitation in the range of 90 - 4,100mm, and an annual temperature in the range of 3.6 to 27.8°c[]. Potatoes are a cool weather crop, the optimal temperature for growth of most cultivars being around 22°c when the plants are young, dropping to around 18°c as the tubers are formed[]. Growth of the tubers is best at soil temperature of 16 - 20°c, with usually no tubers formed above 30°c[]. The top-growth of potatoes is not frost hardy, though the tubers will tolerate a few degrees of frost if left in the ground[].
Succeeds in most soils, preferably in a sunny position[]. It performs well on a wide variety of soils, sandy loams, silt loams, loams, and peats[]. Dislikes wet or heavy clay soils[, ]. Prefers a slightly acid soil, the tubers are subject to scab on limy soils or those deficient in humus. Prefers a pH in the range 5.2 - 6.0, tolerating 4.2 - 8.3[, ]. Yields are best from plants grown in rich soils with plenty of organic matter[].
Potatoes are very widely grown throughout the world for their edible tubers, there are many named varieties[].
The potato probably arose through cultivation from several wild species that can still be found growing in S. America. Many of these wild species can be used in breeding programmes for improved disease resistance etc.
Potatoes should not be stored with apples because the ethylene gas released by the apples will cause the potatoes to go soft and develop a sour taste[].

Edible Uses

Root - raw or cooked. Potatoes are a very versatile food that can be used in a wide variety of ways. Having a mild flavour, and readily accepting the flavour of other foods, they can be eaten on a regular basis without becoming boring. Whilst occasionally eaten raw, they are most commonly cooked and can boiled, baked, fried, added to soups, stews etc[]. The cooked potato can also be dried and made into a powder and then used as a thickener in soups etc, or be added to cereal flours when making bread, biscuits etc[]. The potato is a very rich source of starch, but does not contain high quantities of other nutrients. When exposed to light, the skin turns green and contains the toxin solanine. Whilst eating a small quantity of green potato is unlikely to cause harm, it is probably wisest to remove any green part of the tuber before eating it.

The fresh petals of white-flowered varieties contain 0.2% rutin[].

Medicinal

Whilst mainly used as a staple food, potatoes do also have a number of medicinal virtues. A juice made from the tubers, when taken in moderation, can be helpful in the treatment of peptic ulcers, bringing relief from pain and acidity[]. Excessive doses of potato juice can be toxic - do not drink the juice of more than one large potato per day[]. A poultice has been made from boiling potatoes in water[]. This is applied as hot as can be borne to rheumatic joints, swellings, skin rashes, haemorrhoids etc[, ]. Peeled but uncooked potatoes have been pounded in a mortar and then applied cold as a soothing plaster to burns and scalds[]. Potato skins are used in India to treat swollen gums and to heal burns[].

The leaves are antispasmodic[, ].

The tubers contain very small quantities of atropine alkaloids. One property of these alkaloids is the reduction of digestive secretions, including acids produced in the stomach[].
The root and leaf diffusates of growing potato plants possess cardiotonic activity[].
Dried ethanol extracts of above-ground parts of the plant show marked hypotensive and myotropic action and a spasmolytic and soothing effect on intestinal musculature[].
Ethanol extracts of the leaves have antifungal properties, active against Phytophthora infestans[].
The leaves, seeds, and tuber extracts show antimicrobial activity against Gram-positive and Gram-negative bacteria[].

Agroforestry Uses:

Does well when grown after a crop of rye, Secale cereale[, ]. Grows well with legumes, sweet corn, cabbage, marigolds, horse radish, flax, dead nettles, sainfoin and nasturtiums[, ]. Grows badly with tomatoes, sunflowers, members of the cucumber family and raspberries[, ].

Other Uses

The tubers are a source of starch that is used in sizing cotton and to make industrial alcohol etc[, ]. It also has many other uses in industry[].

Ripe potato juice is an excellent cleaner of silks, cottons and woollens[]. The water in which potatoes have been boiled can be used to clean silver and to restore a shine to furniture[].

Emollient and cleansing face masks are made from potatoes, these are used to treat hard, greasy and wrinkled skins[].
The starch obtained from the tubers is used as an ingredient in commercial cosmetic preparations as an absorbent, binding and bulking agent, and a viscosity controller[].
The juice obtained from the tubers is used as an ingredient in commercial cosmetic preparations as a hair and skin conditioner[1243

The potato is a good source of biomass. When boiled with weak sulphuric acid, potato starch is changed into glucose and this can then be fermented into alcohol[].

Propagation

Seed - sow early spring in a greenhouse. When they are large enough to handle, prick the seedlings out into individual pots and plant them out into their permanent positions after the last expected frosts. If grown on fast it is possible to get a reasonable crop in the first year though the normal way of growing potatoes is from tubers. Seed from named varieties will not breed true to type but will usually give a good crop.
Division of tubers. Harvest in the autumn, store in a cool frost free place overwinter. Chit the potatoes to encourage the growth of sprouts in the new year and plant out in spring.