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Sweet potato
Sweet potato
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Sweet potato
Several elongated reddish brown tubers
Sweet potato tubers

Secure  (NatureServe)[2]
Scientific classification Edit this classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Clade: Asterids
Order: Solanales
Family: Convolvulaceae
Genus: Ipomoea
Species:
I. batatas
Binomial name
Ipomoea batatas

The sweet potato or sweetpotato[a] (Ipomoea batatas) is a dicotyledonous plant in the morning glory family, Convolvulaceae. Its sizeable, starchy, sweet-tasting tuberous roots are used as a root vegetable,[3][4] which is a staple food in parts of the world. Cultivars of the sweet potato have been bred to bear tubers with flesh and skin of various colors. Moreover, the young shoots and leaves are occasionally eaten as greens. The sweet potato and the potato are only distantly related, both being in the order Solanales. Although darker sweet potatoes are often known as "yams" in parts of North America, they are even more distant from actual yams, which are monocots in the order Dioscoreales.[5]

The sweet potato is native to the tropical regions of South America in what is present-day Ecuador.[6][7] Of the approximately 50 genera and more than 1,000 species of Convolvulaceae, I. batatas is the only crop plant of major importance—some others are used locally (e.g., I. aquatica "kangkong" as a green vegetable), but many are poisonous. The genus Ipomoea that contains the sweet potato also includes several garden flowers called morning glories, but that term is not usually extended to I. batatas. Some cultivars of I. batatas are grown as ornamental plants under the name tuberous morning glory, and used in a horticultural context. Sweet potatoes can also be called yams in North America. When soft varieties were first grown commercially there, there was a need to differentiate between the two. Enslaved Africans had already been calling the 'soft' sweet potatoes 'yams' because they resembled the unrelated yams in Africa.[8] Thus, 'soft' sweet potatoes were referred to as 'yams' to distinguish them from the 'firm' varieties.

Description

[edit]
The flowers, buds, and leaves of the sweet potato, which resemble those of the morning glory
Seeds

The plant is a herbaceous perennial vine, bearing alternate triangle-shaped or palmately lobed leaves and medium-sized sympetalous flowers. The stems are usually crawling on the ground and form adventitious roots at the nodes. The leaves are screwed along the stems. The leaf stalk is 13 to 51 centimetres (5 to 20 inches) long. The leaf blades are very variable, 5 to 13 cm (2 to 5 in) long, the shape is heart-, kidney- to egg-shaped, rounded or triangular and spear-shaped, the edge can be entire, toothed or often three to seven times lobed, cut or divided. Most of the leaf surfaces are bare, rarely hairy, and the tip is rounded to pointed. The leaves are mostly green in color, but the accumulation of anthocyanins, especially along the leaf veins, can make them purple. Depending on the variety, the total length of a stem can be between 0.5 and 4 metres (1+12 and 13 feet). Some cultivars also form shoots up to 16 m (52 ft) in length. However, these do not form underground storage organs.[citation needed]

The hermaphrodite, five-fold and short-stalked flowers are single or few in stalked, zymous inflorescences that arise from the leaf axils and stand upright. It produces flowers when the day is short. The small sepals are elongated and tapering to a point and spiky and (rarely only 7) 10 to 15 millimetres (38 to 58 in) long, usually finely haired or ciliate. The inner three are a little longer. The 4 to 7 cm (1+12 to 2+34 in) long, overgrown and funnel-shaped, folded crown, with a shorter hem, can be lavender to purple-lavender in color, the throat is usually darker in color, but white crowns can also appear. The enclosed stamens are of unequal length with glandular filaments. The two-chamber ovary is upper constant with a relatively short stylus.[citation needed] Seeds are only produced from cross-pollination.[9]

The flowers open before sunrise and stay open for a few hours. They close again in the morning and begin to wither. The edible tuberous root is long and tapered, with a smooth skin whose color ranges between yellow, orange, red, brown, purple, and beige. Its flesh ranges from beige through white, red, pink, violet, yellow, orange, and purple. Sweet potato cultivars with white or pale yellow flesh are less sweet and moist than those with red, pink or orange flesh.[10]

Taxonomy

[edit]
Roots of the Taizhong6 cultivar compared to those of its two closest wild relatives: I. trifida and I. triloba[11]

The sweet potato originates in South America in what is present-day Ecuador.[6][7] The domestication of sweet potato occurred in either Central or South America.[12] In Central America, domesticated sweet potatoes were present at least 5,000 years ago,[13] with the origin of I. batatas possibly between the Yucatán Peninsula of Mexico and the mouth of the Orinoco River in Venezuela.[14] The cultigen was most likely spread by local people to the Caribbean and South America by 2500 BCE.[15]

I. trifida, a diploid, is the closest wild relative of the sweet potato, which originated with an initial cross between a tetraploid and another diploid parent, followed by a second complete genome duplication event.[16] The oldest radiocarbon dating remains of the sweet potato known today were discovered in caves from the Chilca Canyon, in the south-central zone of Peru, and yield an age of 8080 ± 170 BC.[17][18]

Transgenicity

[edit]

The genome of cultivated sweet potatoes contains sequences of DNA from Agrobacterium (sensu lato; specifically, one related to Rhizobium rhizogenes), with genes actively expressed by the plants.[19] The T-DNA transgenes were not observed in closely related wild relatives of the sweet potato.[19] Studies indicated that the sweet potato genome evolved over millennia, with eventual domestication of the crop taking advantage of natural genetic modifications.[19] These observations make sweet potatoes the first known example of a naturally transgenic food crop.[19][20][21][22]: 141 [23][24]

Cultivation

[edit]

Dispersal history

[edit]
Seikei Zusetsu (~1800)

Before the arrival of Europeans to the Americas, sweet potato was grown in Polynesia, generally spread by vine cuttings rather than by seeds.[25] Sweet potato has been radiocarbon-dated in the Cook Islands to 1210–1400 CE.[26] A common hypothesis is that a vine cutting was brought to central Polynesia by Polynesians who had traveled to South America and back, and spread from there across Polynesia to Easter Island, Hawaii and New Zealand.[27][28] Genetic similarities have been found between Polynesian peoples and indigenous Americans including the Zenú, a people inhabiting the Pacific coast of present-day Colombia, indicating that Polynesians could have visited South America and taken sweet potatoes prior to European contact.[29] Dutch linguists and specialists in Amerindian languages Willem Adelaar and Pieter Muysken have suggested that the word for sweet potato is shared by Polynesian languages and languages of South America: Proto-Polynesian *kumala[30] (compare Rapa Nui kumara, Hawaiian ʻuala, Māori kūmara) may be connected with Quechua and Aymara k'umar ~ k'umara. Adelaar and Muysken assert that the similarity in the word for sweet potato is proof of either incidental contact or sporadic contact between the Central Andes and Polynesia.[31]

Some researchers, citing divergence time estimates, suggest that sweet potatoes might have been present in Polynesia thousands of years before humans arrived there.[32][33] However, the present scholarly consensus favours the pre-Columbian contact model.[34][35]

The sweet potato arrived in Europe with the Columbian exchange. It is recorded, for example, in Elinor Fettiplace's Receipt Book, compiled in England in 1604.[36][37]

Sweet potatoes were first introduced to the Philippines during the Spanish colonial period (1521–1898) via the Manila galleons, along with other New World crops.[38] It was introduced to the Fujian of China in about 1594 from Luzon, in response to a major crop failure. The growing of sweet potatoes was encouraged by the Governor Chin Hsüeh-tseng (Jin Xuezeng).[39]

Sweet potatoes were also introduced to the Ryukyu Kingdom, present-day Okinawa, Japan, in the early 1600s by the Portuguese.[40][41][42] Sweet potatoes became a staple in Japan because they were important in preventing famine when rice harvests were poor.[42][43] Aoki Konyō helped popularize the cultivation of the sweet potato in Japan, and the Tokugawa bakufu sponsored, published, and disseminated a vernacular Japanese translation of his research monograph on sweet potatoes to encourage their growth more broadly.[44] Sweet potatoes were planted in Shōgun Tokugawa Yoshimune's private garden.[45] It was first introduced to Korea in 1764.[46] Kang P'il-ri and Yi Kwang-ryŏ embarked on a project to grow sweet potatoes in Seoul in 1766, using the knowledge of Japanese cultivators they learned in Tongnae starting in 1764. The project succeeded for a year but ultimately failed in winter 1767 after Kang's unexpected death.[47]

Names

[edit]

Although the soft, orange sweet potato is often called a "yam" in parts of North America, the sweet potato is very distinct from the botanical yam (Dioscorea), which has a cosmopolitan distribution,[48] and belongs to the monocot family Dioscoreaceae. A different crop plant, the oca (Oxalis tuberosa, a species of wood sorrel), is called a "yam" in many parts of the world.[49]

Although the sweet potato is not closely related botanically to the common potato, they have a shared etymology. The first Europeans to taste sweet potatoes were members of Christopher Columbus's expedition in 1492. Later explorers found many cultivars under an assortment of local names, but the name which stayed was the indigenous Taíno name of batata. The Spanish combined this with the Quechua word for potato, papa, to create the word patata for the common potato.[50]

Though the sweet potato is also called batata (בטטה) in Hebrew, this is not a direct loan of the Taíno word. Rather, the Spanish patata was loaned into Arabic as batata (بطاطا), owing to the lack of a /p/ sound in Arabic, while the sweet potato was called batata ḥilwa (بطاطا حلوة); literally ('sweet potato'). The Arabic batata was loaned into Hebrew as designating the sweet potato only, as Hebrew had its own word for the common potato, תפוח אדמה (tapuakh adama, literally 'earth apple'; compare French pomme de terre).

Some organizations and researchers advocate for the styling of the name as one word—sweetpotato—instead of two, to emphasize the plant's genetic uniqueness from both common potatoes and yams and to avoid confusion of it being classified as a type of common potato.[51][52][53] In its current usage in American English, the styling of the name as two words is still preferred.[54]

In Argentina, Colombia, Venezuela, Puerto Rico, and the Dominican Republic, the sweet potato is called batata. In Brazil, the sweet potato is called batata doce. In Mexico, Bolivia, Peru, Chile, Central America, and the Philippines, the sweet potato is known as camote (alternatively spelled kamote in the Philippines), derived from the Nahuatl word camotli.[55][56] In Peru and Bolivia, the general word in Quechua for the sweet potato is apichu, but there are variants used such as khumara, kumar (Ayacucho Quechua), and kumara (Bolivian Quechua),[57] strikingly similar to the Polynesian name kumara and its regional Oceanic cognates (kumala, umala, ʻuala, etc.[58]), which has led some scholars to suspect an instance of pre-Columbian trans-oceanic contact.[59] This theory is also supported by genetic evidence.[60]

In Australia, about 90% of production is devoted to the orange cultivar 'Beauregard',[61] which was originally[62][63] developed by the Louisiana Agricultural Experiment Station in 1981.[64]

In New Zealand, the Māori varieties bore elongated tubers with white skin and a whitish flesh,[65] which points to pre-European cross-Pacific travel.[66] Known as kumara (from the Māori language kūmara), the most common cultivar now is the red 'Owairaka', but orange ('Beauregard'), gold, purple and other cultivars are also grown.[67][68]

Habitat

[edit]

The plant does not tolerate frost. It grows best at an average temperature of 24 °C (75 °F), with abundant sunshine and warm nights. Annual rainfalls of 750–1,000 mm (30–39 in) are considered most suitable, with a minimum of 500 mm (20 in) in the growing season. The crop is sensitive to drought at the tuber initiation stage 50–60 days after planting, and it is not tolerant to waterlogging, which may cause tuber rots and reduce the growth of storage roots if aeration is poor.[69]

Sweet potato sprouting "slips"
Sweet potato harvest in Nash County, North Carolina, United States

Depending on the cultivar and conditions, tuberous roots mature in two to nine months. With care, early-maturing cultivars can be grown as an annual summer crop in warm temperate areas, such as the Eastern United States and China. Sweet potatoes rarely flower when the daylight is longer than 11 hours, as is normal outside of the tropics. They are mostly propagated by stem or root cuttings or by adventitious shoots called "slips" that grow out from the tuberous roots during storage. True seeds are used for breeding only.[9]

They grow well in many farming conditions and have few natural enemies; pesticides are rarely needed. Sweet potatoes are grown on a variety of soils, but well-drained, light- and medium-textured soils with a pH range of 4.5–7.0 are more favorable for the plant.[4] They can be grown in poor soils with little fertilizer. However, sweet potatoes are very sensitive to aluminium toxicity and will die about six weeks after planting if lime is not applied at planting in this type of soil.[4] As they are sown by vine cuttings rather than seeds, sweet potatoes are relatively easy to plant. As the rapidly growing vines shade out weeds, little weeding is needed. A commonly used herbicide to rid the soil of any unwelcome plants that may interfere with growth is DCPA, also known as Dacthal. In the tropics, the crop can be maintained in the ground and harvested as needed for market or home consumption. In temperate regions, sweet potatoes are most often grown on larger farms and are harvested before first frosts.[citation needed]

Sweet potatoes are cultivated throughout tropical and warm temperate regions wherever there is sufficient water to support their growth.[70] Sweet potatoes became common as a food crop in the islands of the Pacific Ocean, South India, Uganda and other African countries.[71]

A cultivar of the sweet potato called the boniato is grown in the Caribbean; its flesh is cream-colored, unlike the more common orange hue seen in other cultivars. Boniatos are not as sweet and moist as other sweet potatoes, but their consistency and delicate flavor are different from the common orange-colored sweet potato.[citation needed]

Sweet potato production – 2020
(millions of tonnes)
 China 48.9
 Malawi 6.9
 Tanzania 4.4
 Angola 1.7
 Ethiopia 1.6
World 89.5
Source: FAOSTAT
of the United Nations[72]

Sweet potatoes have been a part of the diet in the U.S. for most of its history, especially in the Southeast. The annual per capita consumption of sweet potatoes in the United States is only about 1.5–2 kg (3+124+12 lb), down from 13 kg (29 lb) in 1920. "Orange sweet potatoes (the most common type encountered in the US) received higher appearance liking scores compared with yellow or purple cultivars."[73] Purple and yellow sweet potatoes were not as well liked by consumers compared to orange sweet potatoes "possibly because of the familiarity of orange color that is associated with sweet potatoes."[73]

In the Southeastern U.S., sweet potatoes are traditionally cured to improve storage, flavor, and nutrition, and to allow wounds on the periderm of the harvested root to heal.[74] Proper curing requires drying the freshly dug roots on the ground for two to three hours, then storage at 29–32 °C (85–90 °F) with 90 to 95% relative humidity from five to fourteen days. Cured sweet potatoes can keep for thirteen months when stored at 13–15 °C (55–59 °F) with >90% relative humidity. Colder temperatures injure the roots.[75][76]

Production

[edit]

In 2020, global production of sweet potatoes was 89 million tonnes, led by China with 55% of the world total (table). Secondary producers were Malawi, Tanzania, and Nigeria.[72] It is the fifth most important food crop in developing countries.[77] Studies are being done to develop a salt tolerant variety to combat the effects of climate change.[77][78]

Diseases

[edit]

Sweet potato suffers from Sweet potato chlorotic stunt virus (a Crinivirus).[79] In synergy with other any of a large number of other viruses, Untiveros et al., 2007 finds SPCSV produces an even more severe symptomology.[79] I. batatas suffers from several Phytophthoras including P. carotovorum, P. odoriferum, and P. wasabiae.[80]

Uses

[edit]

Nutrition

[edit]
Sweet potato, cooked, baked in skin, without salt
Nutritional value per 100 g (3.5 oz)
Energy378 kJ (90 kcal)
20.7 g
Starch7.05 g
Sugars6.5 g
Dietary fiber3.3 g
0.15 g
2.0 g
Vitamins and minerals
VitaminsQuantity
%DV
Vitamin A equiv.
107%
961 μg
107%
11509 μg
Thiamine (B1)
9%
0.11 mg
Riboflavin (B2)
8%
0.11 mg
Niacin (B3)
9%
1.5 mg
Vitamin B6
17%
0.29 mg
Folate (B9)
2%
6 μg
Vitamin C
22%
19.6 mg
Vitamin E
5%
0.71 mg
MineralsQuantity
%DV
Calcium
3%
38 mg
Iron
4%
0.69 mg
Magnesium
6%
27 mg
Manganese
22%
0.5 mg
Phosphorus
4%
54 mg
Potassium
16%
475 mg
Sodium
2%
36 mg
Zinc
3%
0.32 mg
Other constituentsQuantity
Water75.8 g

"Sweet potato". USDA Database. Archived from the original on 3 April 2019. Retrieved 24 March 2021.
Percentages estimated using US recommendations for adults,[81] except for potassium, which is estimated based on expert recommendation from the National Academies.[82]
Raw sweet potato
Nutritional value per 100 g (3.5 oz)
Energy359 kJ (86 kcal)
20.1 g
Starch12.7 g
Sugars4.2 g
Dietary fiber3 g
0.1 g
1.6 g
Vitamins and minerals
VitaminsQuantity
%DV
Vitamin A equiv.
79%
709 μg
79%
8509 μg
Thiamine (B1)
7%
0.078 mg
Riboflavin (B2)
5%
0.061 mg
Niacin (B3)
3%
0.557 mg
Pantothenic acid (B5)
16%
0.8 mg
Vitamin B6
12%
0.209 mg
Folate (B9)
3%
11 μg
Vitamin C
3%
2.4 mg
Vitamin E
2%
0.26 mg
MineralsQuantity
%DV
Calcium
2%
30 mg
Iron
3%
0.61 mg
Magnesium
6%
25 mg
Manganese
11%
0.258 mg
Phosphorus
4%
47 mg
Potassium
11%
337 mg
Sodium
2%
55 mg
Zinc
3%
0.3 mg
Other constituentsQuantity
Water77.3 g

"Sweet potato, raw". USDA Database. Archived from the original on 3 April 2019. Retrieved 24 March 2021.
Percentages estimated using US recommendations for adults,[81] except for potassium, which is estimated based on expert recommendation from the National Academies.[82]

Cooked sweet potato (baked in skin) is 76% water, 21% carbohydrates, 2% protein, and contains negligible fat (table). In a 100-gram reference amount, baked sweet potato provides 359 kilojoules (86 kilocalories) of food energy, and rich contents (20% or more of the Daily Value, DV) of vitamin A (120% DV), vitamin C (24% DV), manganese (24% DV), and vitamin B6 (20% DV). It is a moderate source (10–19% DV) of some B vitamins and potassium. Between 50% and 90% of the sugar content is sucrose.[83] Maltose content is very low, but baking can increase the maltose content from between 10% and 20%.[83]

Sweet potato cultivars with dark orange flesh have more beta-carotene (converted to a higher vitamin A content once digested) than those with light-colored flesh, and their increased cultivation is being encouraged in Africa where vitamin A deficiency is a serious health problem.[84] Sweet potato leaves are edible and can be prepared like spinach or turnip greens.[85]

Comparison to other food staples

[edit]

The table below presents the relative performance of sweet potato (in column)[G] to other staple foods on a dry weight basis to account for their different water contents. While sweet potato provides less edible energy and protein per unit weight than cereals, it has higher nutrient density than cereals.[86]

According to a study by the United Nations Food and Agriculture Organization, sweet potatoes are the most efficient staple food to grow in terms of farmland, yielding approximately 290,000 kilojoules per hectare (28,000 kcal/acre) daily.[87]

Nutrient content of 10 major staple foods per 100 g dry weight[88]
Staple Maize (corn)[A] Rice, white[B] Wheat[C] Potatoes[D] Cassava[E] Soybeans, green[F] Sweet potatoes[G] Yams[Y] Sorghum[H] Plantain[Z] RDA
Water content (%) 10 12 13 79 60 68 77 70 9 65
Raw grams per 100 g dry weight 111 114 115 476 250 313 435 333 110 286
Nutrient
Energy (kJ) 1698 1736 1574 1533 1675 1922 1565 1647 1559 1460 8,368–10,460
Protein (g) 10.4 8.1 14.5 9.5 3.5 40.6 7.0 5.0 12.4 3.7 50
Fat (g) 5.3 0.8 1.8 0.4 0.7 21.6 0.2 0.6 3.6 1.1 44–77
Carbohydrates (g) 82 91 82 81 95 34 87 93 82 91 130
Fiber (g) 8.1 1.5 14.0 10.5 4.5 13.1 13.0 13.7 6.9 6.6 30
Sugar (g) 0.7 0.1 0.5 3.7 4.3 0.0 18.2 1.7 0.0 42.9 minimal
Minerals [A] [B] [C] [D] [E] [F] [G] [Y] [H] [Z] RDA
Calcium (mg) 8 32 33 57 40 616 130 57 31 9 1,000
Iron (mg) 3.01 0.91 3.67 3.71 0.68 11.09 2.65 1.80 4.84 1.71 8
Magnesium (mg) 141 28 145 110 53 203 109 70 0 106 400
Phosphorus (mg) 233 131 331 271 68 606 204 183 315 97 700
Potassium (mg) 319 131 417 2005 678 1938 1465 2720 385 1426 4700
Sodium (mg) 39 6 2 29 35 47 239 30 7 11 1,500
Zinc (mg) 2.46 1.24 3.05 1.38 0.85 3.09 1.30 0.80 0.00 0.40 11
Copper (mg) 0.34 0.25 0.49 0.52 0.25 0.41 0.65 0.60 - 0.23 0.9
Manganese (mg) 0.54 1.24 4.59 0.71 0.95 1.72 1.13 1.33 - - 2.3
Selenium (μg) 17.2 17.2 81.3 1.4 1.8 4.7 2.6 2.3 0.0 4.3 55
Vitamins [A] [B] [C] [D] [E] [F] [G] [Y] [H] [Z] RDA
Vitamin C (mg) 0.0 0.0 0.0 93.8 51.5 90.6 10.4 57.0 0.0 52.6 90
Thiamin (B1) (mg) 0.43 0.08 0.34 0.38 0.23 1.38 0.35 0.37 0.26 0.14 1.2
Riboflavin (B2) (mg) 0.22 0.06 0.14 0.14 0.13 0.56 0.26 0.10 0.15 0.14 1.3
Niacin (B3) (mg) 4.03 1.82 6.28 5.00 2.13 5.16 2.43 1.83 3.22 1.97 16
Pantothenic acid (B5) (mg) 0.47 1.15 1.09 1.43 0.28 0.47 3.48 1.03 - 0.74 5
Vitamin B6 (mg) 0.69 0.18 0.34 1.43 0.23 0.22 0.91 0.97 - 0.86 1.3
Folate Total (B9) (μg) 21 9 44 76 68 516 48 77 0 63 400
Vitamin A (IU) 238 0 10 10 33 563 4178 460 0 3220 5000
Vitamin E, alpha-tocopherol (mg) 0.54 0.13 1.16 0.05 0.48 0.00 1.13 1.30 0.00 0.40 15
Vitamin K1 (μg) 0.3 0.1 2.2 9.0 4.8 0.0 7.8 8.7 0.0 2.0 120
Beta-carotene (μg) 108 0 6 5 20 0 36996 277 0 1306 10500
Lutein+zeaxanthin (μg) 1506 0 253 38 0 0 0 0 0 86 6000
Fats [A] [B] [C] [D] [E] [F] [G] [Y] [H] [Z] RDA
Saturated fatty acids (g) 0.74 0.20 0.30 0.14 0.18 2.47 0.09 0.13 0.51 0.40 minimal
Monounsaturated fatty acids (g) 1.39 0.24 0.23 0.00 0.20 4.00 0.00 0.03 1.09 0.09 22–55
Polyunsaturated fatty acids (g) 2.40 0.20 0.72 0.19 0.13 10.00 0.04 0.27 1.51 0.20 13–19
[A] [B] [C] [D] [E] [F] [G] [Y] [H] [Z] RDA

A raw yellow dent corn
B raw unenriched long-grain white rice
C raw hard red winter wheat
D raw potato with flesh and skin
E raw cassava
F raw green soybeans
G raw sweet potato
H raw sorghum
Y raw yam
Z raw plantains
/* unofficial

Culinary

[edit]

The starchy tuberous roots of the sweet potato are by far the most important product of the plant. In some tropical areas, the tubers are a staple food crop. The tuber is often cooked before consumption as this increases its nutrition and digestibility, although the American colonists in the Southeast ate raw sweet potatoes as a staple food.[89]

The vines' tips and young leaves are edible as a green vegetable with a characteristic flavor. Older growths may be used as animal fodder.[90]

Africa

[edit]
A seller peeling a sweet potato in Ghana

Amukeke (sun-dried slices of root) and inginyo (sun-dried crushed root) are a staple food for people in northeastern Uganda.[90] Amukeke is mainly served for breakfast, eaten with peanut sauce. Inginyo is mixed with cassava flour and tamarind to make atapa. People eat atapa with smoked fish cooked in peanut sauce or with dried cowpea leaves cooked in peanut sauce. Emukaru (earth-baked root) is eaten as a snack anytime and is mostly served with tea or with peanut sauce. Similar uses are also found in South Sudan.

The young leaves and vine tips of sweet potato leaves are widely consumed as a vegetable in West African countries (Guinea, Sierra Leone and Liberia, for example), as well as in northeastern Uganda, East Africa.[90] According to FAO leaflet No. 13 – 1990, sweet potato leaves and shoots are a good source of vitamins A, C, and B2 (riboflavin), and according to research done by A. Khachatryan, are an excellent source of lutein.

In Kenya, Rhoda Nungo of the home economics department of the Ministry of Agriculture has written a guide to using sweet potatoes in modern recipes.[91] This includes uses both in the mashed form and as flour from the dried tubers to replace part of the wheat flour and sugar in baked products such as cakes, chapatis, mandazis, bread, buns and cookies. A nutritious juice drink is made from the orange-fleshed cultivars, and deep-fried snacks are also included.

In Egypt, sweet potato tubers are known as batata (بطاطا) and are a common street food in winter, when street vendors with carts fitted with ovens sell them to people passing time by the Nile or the sea.[92] The cultivars used are an orange-fleshed one as well as a white/cream-fleshed one. They are also baked at home as a snack or dessert, drenched with honey.

In Ethiopia, the commonly found cultivars are black-skinned, cream-fleshed and called bitatis or mitatis. They are cultivated in the eastern and southern lower highlands and harvested during the rainy season (June/July). In recent years,[when?] better yielding orange-fleshed cultivars were released for cultivation by Haramaya University as a less sugary sweet potato with higher vitamin A content.[93] Sweet potatoes are widely eaten boiled as a favored snack.

In South Africa, sweet potatoes are often eaten as a side dish such as soetpatats.

Asia

[edit]

In East Asia, roasted sweet potatoes are popular street food. In China, sweet potatoes, typically yellow cultivars, are baked in a large iron drum and sold as street food during winter. In Korea, sweet potatoes, known as goguma, are roasted in a drum can, baked in foil or on an open fire, typically during winter. In Japan, a dish similar to the Korean preparation is called yaki-imo (roasted sweet potato), which typically uses either the yellow-fleshed "Japanese sweet potato" or the purple-fleshed "Okinawan sweet potato", which is known as beni-imo.

Sweet potato soup, served during winter, consists of sweet potato boiled in water with rock sugar and ginger. In Fujian cuisine and Taiwanese cuisine, sweet potato is often cooked with rice to make congee. Steamed and dried sweet potato is a specialty of Liancheng County. Sweet potato greens are a common side dish in Taiwanese cuisine, often boiled or sautéed and served with a garlic and soy sauce mixture, or simply salted before serving. They, as well as dishes featuring the sweet potato root, are commonly found at bento (Pe̍h-ōe-jī: piān-tong) restaurants. In northeastern Chinese cuisine, sweet potatoes are often cut into chunks and fried, before being drenched into a pan of boiling syrup.[94]

In some regions of India, sweet potato is roasted slowly over kitchen coals at night and eaten with some dressing, while the easier way in the south is simply boiling or pressure cooking before peeling, cubing and seasoning for a vegetable dish as part of the meal. In the Indian state of Tamil Nadu, it is known as sakkara valli kilangu. It is boiled and consumed as an evening snack. In some parts of India, fresh sweet potato is chipped, dried and then ground into flour; this is then mixed with wheat flour and baked into chapatti (bread). Between 15 and 20 percent of the sweet potato harvest is converted by some Indian communities into pickles and snack chips. A part of the tuber harvest is used in India as cattle fodder.[10]

In Pakistan, sweet potato is known as shakarqandi and is cooked as a vegetable dish and also with meat dishes (chicken, mutton or beef). The ash-roasted sweet potatoes are sold as a snack and street food in Pakistani bazaars especially during the winter months.[95]

In Sri Lanka, it is called bathala, and tubers are used mainly for breakfast (boiled sweet potato is commonly served with sambal or grated coconut) or as a supplementary curry dish for rice.

The tubers of this plant, known as kattala in Dhivehi, have been used in the traditional diet of the Maldives. The leaves were finely chopped and used in dishes such as mas huni.[96]

Hoshi-imo, or Japanese dried sweet potatoes, a specialty of Ibaraki Prefecture, drying in Ōarai City

In Japan, both sweet potatoes (called satsuma-imo) and true purple yams (called daijo or beni-imo) are grown. Boiling, roasting and steaming are the most common cooking methods. Also, the use in vegetable tempura is common. Daigaku-imo (ja:大学芋) is a baked and caramel-syruped sweet potato dessert. As it is sweet and starchy, it is used in imo-kinton and some other traditional sweets, such as ofukuimo. What is commonly called "sweet potato" (ja:スイートポテト) in Japan is a cake made by baking mashed sweet potatoes. Shōchū, a Japanese spirit normally made from the fermentation of rice, can also be made from sweet potato, in which case it is called imo-jōchū. Imo-gohan, sweet potato cooked with rice, is popular in Guangdong, Taiwan and Japan. It is also served in nimono or nitsuke, boiled and typically flavored with soy sauce, mirin and dashi.

Korean japchae, or stir-fried cellophane noodles made of sweet potato starch

In Korean cuisine, sweet potato starch is used to produce dangmyeon (cellophane noodles). Sweet potatoes are also boiled, steamed, or roasted, and young stems are eaten as namul. Pizza restaurants such as Pizza Hut and Domino's in Korea are using sweet potatoes as a popular topping. Sweet potatoes are also used in the distillation of a variety of Soju. A popular Korean side dish or snack, goguma-mattang, also known as Korean candied sweet potato, is made by deep-frying sweet potatoes that were cut into big chunks and coating them with caramelized sugar.

In Malaysia and Singapore, sweet potato is often cut into small cubes and cooked with taro and coconut milk (santan) to make a sweet dessert called bubur cha cha. A favorite way of cooking sweet potato is deep-frying slices of sweet potato in batter, served as a tea-time snack. In homes, sweet potatoes are usually boiled. The leaves of sweet potatoes are usually stir-fried with only garlic or with sambal belacan and dried shrimp by Malaysians.

In the Philippines, sweet potatoes (locally known as camote or kamote) are an important food crop in rural areas. They are often a staple among impoverished families in provinces, as they are easier to cultivate and cost less than rice.[97] The tubers are boiled or baked in coals and may be dipped in sugar or syrup. Young leaves and shoots (locally known as talbos ng kamote or camote tops) are eaten fresh in salads with shrimp paste (bagoong alamang) or fish sauce. They can be cooked in vinegar and soy sauce and served with fried fish (a dish known as adobong talbos ng kamote), or with recipes such as sinigang.[97] The stew obtained from boiling camote tops is purple-colored, and is often mixed with lemon as juice. Sweet potatoes are also sold as street food in suburban and rural areas. Fried sweet potatoes coated with caramelized sugar and served in skewers (camote cue) or as French fries are popular afternoon snacks.[98] Sweet potatoes are also used in a variant of halo-halo called ginatan, where they are cooked in coconut milk and sugar and mixed with a variety of rootcrops, sago, jackfruit, and bilu-bilo (glutinous rice balls).[99] Bread made from sweet potato flour is also gaining popularity. Sweet potato is relatively easy to propagate, and in rural areas can be seen abundantly at canals and dikes. The uncultivated plant is usually fed to pigs.

In Indonesia, sweet potatoes are locally known as ubi jalar (lit: "spreading tuber") or simply ubi and are frequently fried with batter and served as snacks with spicy condiments, along with other kinds of fritters such as fried bananas, tempeh, tahu, breadfruit, or cassava. In the mountainous regions of West Papua, sweet potatoes are the staple food among the natives there. Using the bakar batu method of cooking, rocks that have been burned in a nearby bonfire are thrown into a pit lined with leaves. Layers of sweet potatoes, an assortment of vegetables, and pork are piled on top of the rocks. The top of the pile is then insulated with more leaves, creating a pressure of heat and steam inside which cooks all food within the pile after several hours.

In Vietnamese cuisine sweet potatoes are known as khoai lang and they are commonly cooked with a sweetener such as corn syrup, honey, sugar, or molasses.[100]

Young sweet potato leaves are also used as baby food, particularly in Southeast Asia and East Asia.[101][102] Mashed sweet potato tubers are used similarly throughout the world.[103]

United States

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Sweet potato fries with a vegetarian burger

Candied sweet potatoes are a side dish consisting mainly of sweet potatoes prepared with brown sugar, marshmallows, maple syrup, molasses, orange juice, marron glacé, or other sweet ingredients. It is often served in the US on Thanksgiving. Sweet potato casserole is a side dish of mashed sweet potatoes in a casserole dish, topped with a brown sugar and pecan topping.[104]

The sweet potato became a favorite food item of the French and Spanish settlers, thus beginning a long history of cultivation in Louisiana.[105] Sweet potatoes are recognized as the state vegetable of Alabama,[106] Louisiana,[107] and North Carolina.[108] Sweet potato pie is also a traditional favorite dish in Southern U.S. cuisine. Another variation on the typical sweet potato pie is the Okinawan sweet potato haupia pie, which is made with purple sweet potatoes.

Sweet potato fries served at a McDonald's restaurant

The fried sweet potatoes tradition dates to the early nineteenth century in the United States.[109][better source needed] Sweet potato fries or chips are a common preparation and are made by julienning and deep-frying sweet potatoes in the fashion of French fried potatoes. Roasting sliced or chopped sweet potatoes lightly coated in animal or vegetable oil at high heat became common in the United States at the start of the 21st century, a dish called "sweet potato fries". Sweet potato mash is served as a side dish, often at Thanksgiving dinner or with barbecue.

John Bettencourt Avila is called the "father of the sweet potato industry" in North America.[110][111]

Oceania

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Māori grew several varieties of small, yellow-skinned, finger-sized kūmara (with names including taputini,[112] taroamahoe, pehu, hutihuti, and rekamaroa[113]) that they had brought with them from east Polynesia. Modern trials have shown that these smaller varieties were capable of producing well,[114] but when American whalers, sealers and trading vessels introduced larger cultivars in the early 19th century, they quickly predominated.[115][116][117][118]

Prior to 2021, archaeologists believed that the sweet potato failed to flourish in New Zealand south of Christchurch due to the colder climate, forcing Māori in those latitudes to become (along with the Moriori of the Chatham Islands) the only Polynesian people who subsisted solely on hunting and gathering. However, a 2021 analysis of material excavated from a site near Dunedin, some 250 km (160 mi) further south, revealed that sweet potatoes were grown and stored there during the 15th century, before the industry was disrupted by factors speculated to be due to the Little Ice Age.[34]

Māori traditionally cooked kūmara in a hāngī (earth oven). This is still a common practice when there are large gatherings on marae.

In 1947, black rot (Ceratocystis fimbriata) appeared in kūmara around Auckland and increased in severity through the 1950s.[119] A disease-free strain was developed by Joe and Fay Gock. They gave the strain to the nation, earning them the Bledisloe Cup in 2013.[120][121]

There are three main cultivars of kūmara sold in New Zealand: 'Owairaka Red' ("red"), 'Toka Toka Gold' ("gold"), and 'Beauregard' ("orange"). The country grows around 24,000 metric tons of kūmara annually,[122] with nearly all of it (97%) grown in the Northland Region.[123] Kūmara are widely available throughout New Zealand year-round, where they are a popular alternative to potatoes.[124]

Kūmara are often included in roast meals, and served with sour cream and sweet chili sauce.[citation needed] They are served alongside such vegetables as potatoes and pumpkin and as such, are generally prepared in a savory manner. They are ubiquitous in supermarkets, roast meal takeaway shops and hāngī.

Drying sweet potatoes (Ribera Alta, 1951)

Among the Urapmin people of Papua New Guinea, taro (known in Urap as ima) and the sweet potato (Urap: wan) are the main sources of sustenance, and in fact the word for 'food' in Urap is a compound of these two words.[125]

Europe

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In the Veneto (northeast Italy), sweet potato is known as patata mericana in the Venetian language (patata americana in Italian, meaning "American potato"), and it is cultivated above all in the southern area of the region;.[126][127]

In Spain, sweet potato is called boniato. On the evening of All Souls' Day, in Catalonia (northeastern Spain) it is traditional to serve roasted sweet potato and chestnuts, panellets and sweet wine. The occasion is called La Castanyada.[128][129] As of 2023 Spain is the largest sweet potato producer in Europe.[130]

South America

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In Peru, sweet potatoes are called camote and are frequently served alongside ceviche. Sweet potato chips are also a commonly sold snack, be it on the street or in packaged foods.[citation needed]

Dulce de batata is a traditional Argentine, Paraguayan and Uruguayan dessert, which is made of sweet potatoes. It is a sweet jelly, which resembles a marmalade because of its color and sweetness but it has a harder texture, and has to be sliced into thin portions with a knife as if it were a pie.

Globally

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Globally, sweet potatoes are now a staple ingredient of modern sushi cuisine, specifically used in maki rolls. The advent of sweet potato as a sushi ingredient is credited to chef Bun Lai of Miya's Sushi, who first introduced sweet potato rolls in the 1990s as a plant-based alternative to traditional fish-based sushi rolls.[131][132][133]

Molecular gastronomy

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Freezing a sweet potato until solid, baking at a low temperature, then increasing to a high temperature brings out the sweetness by caramelizing converted sugars.[134][135][136][137]

Ceramics

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Sweet potato, Moche culture, 300 CE, Larco Museum Collection

Ceramics modeled after sweet potatoes or camotes are often found in the Moche culture.[138]

Dyes

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In South America, the juice of red sweet potatoes is combined with lime juice to make a dye for cloth. By varying the proportions of the juices, every shade from pink to black can be obtained.[139] Purple sweet potato color is also used as a natural food coloring.[140]

Aquariums

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Cuttings of sweet potato vine, either edible or ornamental cultivars, will rapidly form roots in water and will grow in it, indefinitely, in good lighting with a steady supply of nutrients. For this reason, sweet potato vine is ideal for use in home aquariums, trailing out of the water with its roots submerged, as its rapid growth is fueled by toxic ammonia and nitrates, a waste product of aquatic life, which it removes from the water. This improves the living conditions for fish, which also find refuge in the extensive root systems.[citation needed]

Ornamentals

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An ornamental sweet potato flower

Ornamental sweet potatoes are popular landscape, container, and bedding plants. Grown as an annual in zones up to USDA hardiness Zone 9, they grow rapidly and spread quickly. Cultivars are available in many colors, such as green, yellow, and purple.[141] Some ornamental varieties, like 'Blackie', flower more than others.[142] These ornamental cultivars are not poisonous, and although the leaves are edible, the tubers do not have a good taste.[143][144]

See also

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Notes

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References

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Revisions and contributorsEdit on WikipediaRead on Wikipedia
from Grokipedia
The sweet potato (Ipomoea batatas (L.) Lam.) is a dicotyledonous plant in the () family, native to tropical regions of Central and , where archaeological evidence indicates cultivation dating back at least 5,000 years. It produces enlarged storage roots—often mistakenly called tubers—that vary in flesh color from orange and to , , and purple, and are valued for their sweet taste when cooked. These roots, along with the plant's leaves and shoots, provide essential nutrition, including complex carbohydrates, , vitamins A and C, beta-carotene, anthocyanins, and minerals such as and . Originating in the Americas, the sweet potato spread through Polynesian voyagers to the Pacific Islands and was introduced to Europe and Asia following Christopher Columbus's voyages in the late 15th century, eventually becoming a global staple. Today, it ranks as the world's seventh most important food crop by production volume, with approximately 86 million metric tons harvested in 2022 (though production has been declining slightly in recent years due to reduced acreage in major producers like China), led by China (accounting for about 54% of the total), followed by significant outputs in Africa and other Asian countries. The crop's adaptability to diverse climates—from sea level to 2,500 meters in altitude—and its ability to yield more edible biomass and nutrients per hectare than any other major food crop without synthetic fertilizers or irrigation make it vital for food security, especially in developing regions. Approximately 95% of production occurs in low- and middle-income countries, where it addresses malnutrition through its high content of provitamin A and other micronutrients. Botanically, sweet potatoes are propagated vegetatively from vine cuttings or slips rather than seeds, thriving in warm, frost-free environments with well-drained sandy loam soils and a growing season of 90–150 days. The plant features heart-shaped leaves, trailing vines up to 4 meters long, and rare, trumpet-shaped lavender or white flowers that appear under short-day conditions. Varieties are classified by root color and shape, with orange-fleshed types prized for beta-carotene (a precursor to vitamin A) and purple-fleshed ones for anthocyanins, which exhibit antioxidant, anti-inflammatory, and potential anti-cancer properties. Beyond human consumption in forms like boiled, baked, or fried dishes, about 50% of the crop is used for animal feed, while processed products include starch, flour, ethanol, and even textiles from the fibers. Nutritionally superior to many cereals, a medium-sized baked sweet potato (about 114 grams) delivers over 400% of the daily recommended vitamin A, substantial vitamin C, and B vitamins, along with resistant starch that supports gut health and blood sugar regulation. Its phytochemicals, including flavonoids and phenolic acids, contribute to bioactive effects such as neuroprotection and hepatoprotection, positioning it as a key crop for combating vitamin A deficiency in vulnerable populations. Despite challenges like viral diseases and climate variability, ongoing breeding efforts focus on enhancing yield, disease resistance, and nutritional profiles to sustain its role in global agriculture.

Description and Taxonomy

Botanical Description

The sweet potato (Ipomoea batatas) is a herbaceous belonging to the , often cultivated as an in temperate climates due to its sensitivity to . It displays a vigorous, trailing or twining growth habit, with robust stems that can extend up to 16 feet (5 meters) in length, spreading rapidly to form dense ground cover or climbing supports. The leaves are alternate, cordate (heart-shaped), and typically measure 2 to 6 inches long, with entire margins; coloration varies from green to purple or variegated among cultivars, contributing to its ornamental appeal in some varieties. The defining feature of the plant is its underground storage roots, commonly referred to as tubers, which function as reservoirs and the primary component. These tubers exhibit diverse morphologies, ranging from cylindrical to irregular or lobed shapes, with average lengths of 4 to 6 inches and diameters of 1 to 3 inches, though larger specimens up to 24 inches long can occur depending on and growing conditions. Skin colors span white, yellow, red, and , while internal flesh varies from white and yellow to orange and , influencing culinary uses and nutritional profiles. Unlike the tubers of common potatoes (Solanum tuberosum), which are modified (stolons), sweet potato tubers are true adventitious roots developed from the plant's . Flowering in sweet potato is infrequent under cultivation, particularly in commercial settings where environmental conditions favor vegetative growth over reproduction. When produced, the flowers are funnel-shaped, akin to those of other in the , measuring 1 to 3 inches across and displaying colors from lavender or to or ; they typically emerge in spring or summer but rarely set viable seed. Propagation occurs almost exclusively through vegetative means, using slips—sprouted vine cuttings or shoots from mature tubers—planted directly into , ensuring genetic uniformity and high yields without reliance on . As a dicotyledonous , the sweet potato is botanically distinct from true potatoes in the family and from true yams (Dioscorea species), which are monocots in the Dioscoreaceae family native to Africa and Asia; sweet potato tubers are root tubers with smoother, thinner skin and sweeter, moister flesh that can be orange, white, or purple, whereas true yams are stem tubers with rough, scaly, bark-like skin and starchy, drier, less sweet flesh usually white or yellowish, capable of growing much larger up to several feet long and over 100 pounds, and primarily cultivated in tropical regions like Africa while sweet potatoes, originating from Central and South America, are more widely grown globally including in the United States. Its root-based tubers and vining habit underscore its evolutionary adaptation for tropical and subtropical environments, where it thrives in full sun and well-drained soils.

and

The sweet potato, scientifically classified as Ipomoea batatas (L.) Lam., belongs to the genus within the family , order , class Magnoliopsida, phylum Tracheophyta, and kingdom . It is a hexaploid with 90 chromosomes (2n = 6x = 90), a level that contributes to its genetic complexity and adaptability. Earlier models suggested an autopolyploid origin from the diploid species Ipomoea trifida, native to , but a 2025 phased chromosome-level assembly indicates a segmental allopolyploid resulting from hybridization among multiple wild tetraploid ancestors. This hybrid structure, with approximately one-third derived from a related to the wild tetraploid I. aequatoriensis and significant portions from unidentified , including one related to the wild tetraploid I. batatas from , arose through natural genomic merging and recombination, enhancing traits like disease resistance and environmental adaptability. This segmental allopolyploid structure features intertwined sequences from different wild species along the chromosomes, rather than distinct subgenomes, challenging earlier models of a single autopolyploid origin. The genus Ipomoea encompasses over 500 species, many of which serve as wild relatives for sweet potato breeding programs. Key species include I. trifida and the recently identified tetraploid I. aequatoriensis, which are used to introgress traits such as and resilience to arid conditions into cultivated varieties. Other relatives like I. triloba also show potential for enhancing in breeding efforts. Due to its natural hexaploidy, the sweet potato exhibits inherent genetic robustness, but breeding challenges persist from its complex and . Research has explored genetically modified varieties for traits like resistance, with successful transgenic lines developed against sweet potato chlorotic stunt and other pathogens, yet no widespread commercial transgenic cultivars exist as of 2025, owing to regulatory hurdles and reliance on conventional breeding. Emerging precision breeding techniques, such as cisgenics, are under investigation to introduce resistance without foreign DNA, potentially accelerating future improvements.

History and Cultivation

Origins and Dispersal

The sweet potato (Ipomoea batatas) originated in , particularly in the Mesoamerican region, where it was domesticated by approximately 5,000 to 8,000 years ago. Archaeological evidence, including carbonized remains and tuber fragments, from sites in and coastal , with the earliest remains dating to around 8000 BCE (though possibly from wild plants), indicates early cultivation and domestication approximately 5,000 years ago as humans selected for larger, sweeter tubers from wild ancestors like Ipomoea trifida. Prior to European contact, the crop dispersed across the Pacific to through pre-Columbian voyages by ancient seafarers, possibly as early as 1000 CE. This transoceanic spread is supported by archaeological finds of sweet potato remains in sites like Island (dated to AD 1200–1300) and Hawai'i, genetic analyses showing shared lineages between South American and Polynesian cultivars, and linguistic evidence such as the cognate term kumara (or variants like kumala) linking Quechua names from the to across islands from to [Easter Island](/page/Easter Island). Following Christopher Columbus's voyages, the sweet potato was introduced to in 1492, when his expedition returned from the with tubers misidentified as a type of yam by Spanish explorers. From Iberian ports, it rapidly spread to and via colonial trade networks and the transatlantic slave trade between the 16th and 18th centuries, with Portuguese traders facilitating its establishment in and the Manila galleons carrying it to the and by the early 1600s. In the , the sweet potato gained prominence for enhancing global , notably during 18th-century famines in , where its introduction via Southeast Asian routes in the late allowed widespread adoption on marginal lands, averting widespread and contributing to population stabilization amid environmental stresses like droughts.

Cultivation Practices

Sweet potatoes are primarily a tropical and subtropical , thriving in warm climates with optimal daytime temperatures of 25–30°C and nighttime temperatures of 15–20°C for formation and overall growth. The plant requires a frost-free period of 90–120 days and is highly sensitive to frost, with physiological processes halting below 10°C, while temperatures must exceed 18°C (65°F) for successful establishment. Although drought-tolerant once rooted, it benefits from relative around 80% and consistent during the 60–120-day growth cycle to maximize yields. For , well-drained, friable sandy loams or similar textures deeper than 25 cm are ideal, with a pH of 5.5–6.5 to support root expansion and prevent nutrient lockup. Heavier clay soils can be used if amended for drainage, but alkaline or waterlogged conditions hinder performance. Propagation occurs vegetatively through slips or vine cuttings, as the crop does not produce viable true seeds for farming. Cuttings of 25–30 cm with 4–6 nodes are sourced from disease-free mother vines and planted at a depth of 7–10 cm in ridges, mounds, or furrows to elevate roots above water levels and facilitate harvest. Recommended spacing is 22–30 cm between plants within rows and 70–90 cm between rows, achieving densities of about 37,000 plants per hectare for balanced yield. Planting timing aligns with warm soil conditions, typically in late spring for temperate zones or year-round in equatorial regions, with maturity reached in 3–5 months depending on cultivar and environment. Crop management emphasizes balanced inputs to sustain while minimizing environmental impact. is prepared by deep tilling and testing to guide fertilization, which prioritizes (e.g., 200 kg K₂O/ha) for tuber bulking, supplemented by moderate and based on site needs. is essential immediately after to reduce stand losses, delivering 200–250 m³/ha every 7–10 days during vegetative growth and ceasing 15 days pre-harvest to toughen skins. Rotation with non-related crops every 3–4 years combats depletion and accumulation, while at 25–30 days aids suppression and protection through manual or mechanical means. Sustainability practices leverage the crop's low external input needs, positioning it as resilient for small-scale and resource-poor farming systems. with nitrogen-fixing like pigeonpea improves , enhances water retention, and boosts tuber yields in rainfed setups. Amid challenges such as erratic rainfall and rising temperatures, breeding efforts target - and heat-tolerant varieties to maintain production stability in vulnerable regions.

Varieties and Breeding

Sweet potato cultivars exhibit significant diversity, primarily categorized by the color of their flesh, which influences both culinary uses and nutritional profiles. Common flesh colors include white, yellow, orange, and purple, with each type adapted to various growing regions and consumer preferences. White-fleshed varieties, such as those prevalent in , offer a mild flavor and firm texture, while yellow-fleshed ones provide a slightly sweeter . Orange-fleshed cultivars, rich in beta-carotene, dominate commercial production and parts of , and purple-fleshed types, valued for their content, are popular in and . Prominent examples include Beauregard, a widely grown orange-fleshed variety in the , developed by for its high yield, uniform shape, and resistance to internal cork virus. Covington, another U.S. staple released by , features orange flesh with excellent storage qualities and blocky roots suitable for mechanical harvest. The Okinawan, also known as Hawaiian purple, is a purple-fleshed originating from but adapted in , noted for its moist texture and properties. Local naming conventions for sweet potatoes vary widely by region, reflecting historical and cultural influences. In , particularly and , the term "camote" is commonly used, derived from origins and spread via Spanish colonization. In , including and Polynesian islands, "kumara" serves as the traditional name, tied to Maori heritage and pre-colonial introductions. These names often coexist with scientific but highlight regional adaptations and dispersal patterns. Breeding programs for sweet potatoes prioritize traits that enhance productivity and resilience, given the crop's hexaploid genome, which complicates traditional selection. Key objectives include increasing yield and root size for commercial viability, improving resistance to diseases like sweetpotato virus disease and Alternaria stem blight, and developing weevil tolerance to reduce post-harvest losses. Nutritional enhancement is a major focus, particularly breeding orange-fleshed varieties to boost beta-carotene levels for vitamin A fortification in vitamin-deficient regions. Climate-resilient traits, such as drought tolerance, are increasingly targeted to support smallholder farmers in arid areas of sub-Saharan Africa and Asia. Recent advances in sweet potato breeding leverage genomic tools to accelerate variety development amid challenges. In 2024, the LSU AgCenter released Avoyelles, an early-maturing orange-fleshed variety with superior disease resistance and yield potential tailored for the U.S. , discovered in Avoyelles Parish fields. The International Potato Center (CIP) has advanced climate-smart lines through the RTB Breeding Network, developing drought-tolerant, biofortified varieties for and , integrating enhancement with heat and water stress resilience. As of 2024, CIP and partners have released over 80 biofortified varieties in , enhancing and resilience for smallholder farmers. Polyploid breeding strategies, accounting for the crop's six sets of chromosomes, combined with using SNP platforms, enable precise trait stacking for yield, , and tolerance.

Production

Global Production Statistics

In 2023, global sweet potato production reached approximately 94 million metric tons, reflecting a key staple in many regions. Projections indicate an increase to around 95 million metric tons by 2025, driven by a (CAGR) of about 3%, primarily fueled by rising demand in and for food security and nutritional needs. Average yields worldwide range from 20 to 25 tons per , though intensive farming systems can achieve higher outputs, such as over 30 tons per in . These yields underscore the crop's efficiency in diverse agroecological zones, contributing to its role in global agriculture. The economic value of the global sweet potato market is estimated at $51.7 billion in 2025, with major drivers including enhanced initiatives and expanding export markets; for instance, U.S. exports reached approximately $213 million in 2023. This valuation highlights the crop's growing commercial significance beyond subsistence farming. Recent trends show a slight decline in production during 2023, attributed to adverse weather conditions in key growing areas, while output is rising in due to expanded cultivation efforts. Looking ahead, climate change is projected to reduce yields by 12-18% in the U.S. South by 2060, posing challenges to sustained growth.

Major Producing Regions

China dominates global sweet potato production, accounting for approximately 55% of the world's output with over 50 million metric tons harvested in 2023. This intensive farming in , particularly in 's subtropical and temperate regions, relies on high-yield varieties and mechanized practices suited to the crop's adaptability to diverse soils and climates. In , production is concentrated in across countries like , , and , contributing over 25% of global totals through smallholder farms that emphasize drought-tolerant varieties for . Orange-fleshed sweet potatoes (OFSP) have been widely adopted in these regions to combat deficiencies, with ongoing breeding for nutritional enhancement. In the Americas, the produces around 1.25 million metric tons annually, primarily in , where export-oriented cultivation focuses on orange and white-fleshed varieties for fresh markets. , a key player in , has shifted toward export-focused production, harvesting varieties adapted to arid conditions for . Trade dynamics highlight significant flows from these regions: the US and export substantial volumes to , with shipping 149,551 metric tons to the in 2024 alone, while African exports overall grew by about 11% post-2023 amid rising demand. The relies heavily on imports, with as the leading intra-regional producer but importing from and the US to meet consumption needs. Regional vulnerabilities persist, notably the 2023-2024 El Niño event, which induced droughts in parts of , reducing yields in and through erratic rainfall and heat stress. In , similar climate pressures have prompted adaptations like resilient varieties, though subsistence farmers face ongoing risks to output stability.

Pests and Diseases

Sweetpotato crops face significant biotic threats from insect pests and pathogens, which can reduce yields and . Major pests include sweetpotato weevils (Cylas spp.), which bore into roots and vines, leading to tunneling damage and secondary infections, with reported yield losses ranging from 5% to 97% in infested areas. Wireworms, the larvae of click beetles (Elateridae family), feed on roots and tubers, creating shallow to deep holes that lower marketability, contributing to overall pest-related losses of up to 40% in affected fields. Root-knot nematodes () form on roots, impairing uptake and causing severe reductions in storage root and , with even low populations leading to up to 50% loss in marketable tubers. Key diseases are primarily viral and fungal. Sweet potato virus disease (SPVD) results from the synergistic interaction of sweet potato feathery mottle virus (SPFMV) and (SPCSV), causing , leaf , and yield reductions of 50-90% in co-infected plants. Sweet potato leaf curl virus (SPLCV), transmitted by (Bemisia tabaci), induces leaf curling, puckering, and reduced foliage, spreading rapidly in warm conditions and exacerbating yield losses. Emerging post-2023 threats include variants of caused by , which leads to vascular discoloration and plant collapse, and postharvest rots from , resulting in surface lesions and decay during storage. Management strategies emphasize (IPM), combining cultural, biological, and host resistance approaches due to limited efficacy and regulatory restrictions on chemical controls. Resistant varieties, such as those bred for tolerance to weevils and nematodes, are widely recommended to minimize damage without heavy reliance on pesticides. Recent 2024-2025 research has advanced virus detection using AI-based imaging and models to identify SPVD and SPLCV symptoms in field images, enabling early intervention and reducing spread. Emerging threats are amplified by , with warmer soils promoting reproduction and range expansion, potentially increasing root-knot damage in previously unaffected regions. SPVD incidence reaches up to 90% in African sweetpotato fields, where rising temperatures facilitate vector proliferation and persistence.

Nutritional Profile

Composition and Nutrients

The raw tuber of the sweet potato (Ipomoea batatas) consists primarily of , accounting for about 77% of its weight per 100 g serving, with the remaining composition dominated by carbohydrates. It provides approximately 86 kcal of energy, including 20.1 g of carbohydrates (of which 4.2 g are sugars and 3 g ). The primary source of sugars in sweet potatoes is starch, which is converted to maltose and sucrose through saccharification by endogenous enzymes such as β-amylase, particularly during cooking or storage, contributing to their characteristic sweetness. 1.6 g of protein, and a negligible amount of at 0.1 g. Sweet potatoes often labeled as "yams" (especially orange-fleshed varieties) provide approximately 86-90 kcal per 100 g, lower than true yams in the Dioscorea genus. Sweet potatoes are particularly rich in certain vitamins and minerals, varying by flesh color. Orange-fleshed varieties contain high levels of , primarily in the form of beta-carotene, providing around 14,187 IU (709 µg retinol activity equivalents, or 79% of the Daily Value) per 100 g. They also supply at 19.7 mg (about 22% of the daily value), low sodium at approximately 55 mg (about 2% of the daily value), and at 337 mg (7% of the daily value) per 100 g raw, with the potassium content higher in baked sweet potatoes (approximately 475 mg per 100 g) due to moisture loss during cooking. Other notable micronutrients include (0.26 mg, 11% daily value) and smaller amounts of like B6 (0.209 mg, 12% daily value). Bioactive compounds contribute significantly to the nutritional profile, with concentrations influenced by variety. , especially beta-carotene, are abundant in orange-fleshed sweet potatoes (OFSP), reaching up to 8.5 mg per 100 g, while white-fleshed types contain far less, often less than 0.1 mg—making OFSP up to 85 times richer in provitamin A , though specific breeding lines may show 8-fold differences. Purple-fleshed varieties are distinguished by anthocyanins, water-soluble pigments with properties, typically ranging from 50–300 mg per 100 g fresh weight, alongside polyphenols such as . These bioactives vary widely: for instance, OFSP emphasize , while purple types prioritize anthocyanins, enhancing overall capacity compared to white-fleshed cultivars.
Nutrient (per 100 g raw)Amount% Daily Value*
Water77 g-
86 kcal4%
Protein1.6 g3%
Total Fat0.1 g0%
Carbohydrates20.1 g7%
3 g11%
Sugars4.2 g-
Vitamin A (as beta-carotene, orange variety)14,187 IU79%
19.7 mg22%
337 mg7%
Sodium55 mg2%
*Based on a 2,000-calorie diet; values for orange-fleshed variety where applicable. In comparison to potatoes, sweet potatoes exhibit higher activity due to their and anthocyanins, with total phenolic content often 2–5 times greater in colored varieties. The of sweet potatoes ranges from 44 (boiled) to 94 (baked without skin), influenced by cooking method and variety, generally lower than that of potatoes (around 80 when boiled).

Health Benefits

Sweet potatoes are recommended as a starch source due to their provision of vitamin A (from beta-carotene) supporting vision, dietary fiber aiding digestion and gut health, complex carbohydrates offering slow-release energy for stable blood sugar levels, promotion of satiety for weight management, and naturally sweet flavor as a healthier dessert alternative. Sweet potatoes are rich in bioactive compounds that contribute to various benefits, supported by recent scientific . Their consumption has been associated with reduced and , particularly through anthocyanins found in purple-fleshed varieties. These pigments exhibit potent properties by scavenging free radicals and activating enzymes such as (SOD), catalase (CAT), and glutathione peroxidase (GPx), thereby protecting against cellular damage in organs like the and liver. Furthermore, anthocyanins inhibit pro-inflammatory pathways, including TNF-α, IL-6, and , which helps mitigate chronic linked to metabolic disorders. A 2025 review highlights that daily intake of 100–200 grams of purple sweet potato can enhance these effects, with studies from 2023–2024 demonstrating reduced inflammatory markers in animal models of . Purple sweet potato anthocyanins also show promise in managing by improving and insulin sensitivity. They inhibit enzymes like α-amylase and α-glucosidase, slowing carbohydrate breakdown and postprandial glucose spikes, while upregulating expression for better . In a 2024 study, anthocyanin-rich extracts normalized blood glucose levels and restored balance in mouse models, reducing HbA1c equivalents by up to 20%. These mechanisms underscore the anti-diabetic potential of purple varieties, with human trials indicating improved glycemic control in elderly participants consuming sweet potato formulations. Orange-fleshed sweet potatoes (OFSP) are particularly effective in combating (VAD), a leading cause of preventable child blindness in , where over 48% of preschool children are affected. The high beta-carotene content in OFSP converts to , meeting daily requirements with just 125 grams per serving for young children. Rigorous biomedical research and scaling programs across 20 African countries have shown that OFSP adoption increases serum retinol levels, reducing VAD prevalence and associated blindness risks by addressing dietary shortfalls that contribute to nearly 500,000 annual cases globally. Post-2023 evaluations in and confirm sustained impacts, with over 6.8 million households benefiting from improved status and eye health outcomes. Beyond these, sweet potatoes support gut health through their content, which promotes beneficial and alleviates . Soluble dietary fiber (SDF) from sweet potatoes enhances microbial diversity, boosting populations of and Alloprevotella while suppressing pathogens like , leading to improved bowel regularity and reduced gastrointestinal discomfort. A 2025 study in models found high-dose SDF (1000 mg/kg) increased short-chain fatty acid production, mitigating gut over 10 weeks. The in sweet potatoes aids regulation by counteracting sodium's effects on vascular tension. Sweet potatoes are low in sodium and do not cause sodium retention; the high potassium content helps balance sodium levels, promotes sodium excretion, and supports blood pressure control. Systematic reviews indicate that potassium-rich foods like sweet potatoes contribute to modest reductions in systolic and diastolic pressure, particularly in hypertensive individuals. In healthy individuals, sweet potatoes do not cause harmful potassium retention, but people with kidney disease should monitor their intake to avoid hyperkalemia. Polyphenols in sweet potato extracts exhibit anti-cancer properties by inducing and arrest in breast and lung cancer cells; a 2025 in vitro study reported up to 96% growth inhibition in lines, outperforming standard treatments like in potency. Additionally, 2024–2025 research on selenium-enriched varieties demonstrates boosted immunity through enhanced activity, which strengthens defenses and immune cell function, potentially reducing risks in selenium-deficient populations. Despite these benefits, sweet potatoes carry some risks, particularly for certain individuals. Raw or undercooked forms contain that can bind calcium and promote stone formation, posing concerns for those prone to oxalate-related calculi; is advised, with cooking reducing oxalate levels by up to 50%. Their moderate (around 11–17 per serving) requires portion control for diabetics, as excessive intake may elevate blood glucose, though mitigates this compared to refined starches. In nutritional comparisons, sweet potatoes provide superior equivalents (from beta-carotene) to staples like or , which lack provitamin A , making them a more effective dietary source for deficiency prevention. They offer similar caloric density to white potatoes (about 86–90 kcal per 100g) but with higher content (3g vs. 2.2g per 100g), supporting better and digestive health.

Culinary and Traditional Uses

Preparation and Cooking Methods

Sweet potatoes are versatile tubers that can be prepared using various cooking methods to suit different culinary needs, with each technique influencing texture, flavor, and availability. is a common method that involves submerging whole or sliced tubers in water until tender, typically for 20-30 minutes, which helps retain a high percentage of water-soluble nutrients and results in a soft, moist texture suitable for mashing or pureeing. , on the other hand, cooks the tubers in an at 200-220°C for 45-60 minutes, promoting of natural sugars through the and yielding a sweeter, firmer exterior with a fluffy interior, though it may lead to greater leaching compared to wet methods. , often used to produce chips or fries, entails slicing the tubers thinly and cooking in hot oil at 160-180°C for 3-5 minutes, creating a crispy texture but requiring careful monitoring to avoid excessive browning. Additionally, both the tubers and their vines—prepared as -rich greens by blanching young leaves and tender stems for 1-2 minutes—preserves moisture and minimizes loss, making it ideal for maintaining the vibrant color and tenderness of the foliage. Post-harvest preservation begins with curing, a process where freshly harvested tubers are held at 29-32°C and 85-90% relative for 7-10 days to heal surface wounds, reduce moisture loss, and enhance disease resistance, thereby extending . Following curing, sweet potatoes can be stored for up to 6-8 months in cool conditions of 13-15°C with high (85-90%) and good ventilation to prevent and decay. For longer-term preservation, drying transforms the tubers into by slicing and dehydrating at 60-75°C for several hours, followed by milling, which concentrates nutrients and allows for stable storage in airtight containers for years while facilitating use in and other applications. In modern culinary practices, sweet potato serves as a base for techniques, such as creating foams through aeration with siphons or gels via gelatinization and setting agents, which leverage the starch's high content to form stable, innovative textures in dishes like espumas or spherifications. Emerging trends as of 2025 emphasize selenium-fortified processing, where tubers bred or treated with fertilizers are incorporated into value-added products like flours and purees to boost content, addressing global deficiencies while maintaining processing efficiency. Nutrient retention varies by method, with and pressure cooking maximizing β-carotene retention, while methods like and air lead to greater losses, though all heat treatments enhance overall bioaccessibility. To minimize health risks, overcooking should be avoided, particularly in or , as temperatures above 120°C can promote formation—a potential —reaching levels up to approximately 0.45 µg/g in fried sweet potato products.

Regional Cuisines

In , sweet potatoes are commonly boiled or mashed and incorporated into hearty , providing a starchy base similar to pounded yam in . For instance, a traditional Nigerian sweet potato , prepared as a with spices and , serves as a comforting everyday dish. Orange-fleshed sweet potato (OFSP) varieties have been promoted in child nutrition programs across the continent to combat , often featured in simple boiled or mashed preparations integrated into family meals. In , sweet potatoes feature prominently in diverse fried and sweetened dishes. Japanese cuisine includes sweet potato tempura, where thin slices of the tuber—often purple varieties—are battered and deep-fried for a crispy texture, commonly served as a side or . Imo-kenpi, a popular Japanese treat, consists of sweet potato sticks deep-fried and coated in sugar syrup for a caramelized crunch. In , candied sweet potatoes are stir-fried with sugar until glazed, offering a street food staple with a sticky, sweet finish. Indian curries frequently use purple-fleshed sweet potatoes for their vibrant color and earthy flavor, simmered with spices like and in vegetarian dishes. Across the Americas, sweet potatoes anchor both savory and dessert traditions. In the United States, sweet potato pie—made with mashed tubers blended into a filling and baked in a crust—remains a essential, tracing roots to African American culinary influences. Candied yams, involving baked or boiled sweet potatoes glazed with and , are a synonymous holiday side dish in Southern cooking. In , camote con leche transforms boiled sweet potatoes into a creamy pudding-like by mixing them with , , and sugar, evoking comforting family recipes. Brazilian purée de batata-doce mashes boiled sweet potatoes with and seasonings, often served as a simple accompaniment to meats. In and , sweet potatoes adapt to local roasting and steaming methods. In the , roasted sweet potatoes are increasingly used as a healthier alternative to white potatoes, sliced and baked with herbs for a caramelized . In , kumara (the term for sweet potato) is traditionally cooked in a hangi, an method where tubers are steamed underground with meats and during communal gatherings. Spanish torrijas, a soaked in sweetened milk, occasionally incorporates mashed sweet potatoes for added moisture and flavor in regional variations. Globally, sweet potato fusion dishes blend traditions, such as incorporating the into lattes for a creamy, spiced beverage in coffee shops. As of 2025, sweet potatoes are increasingly featured in plant-based products like patties and milks, driven by demand for nutritious, versatile ingredients.

Cultural Significance

In ancient , the sweet potato was a foundational staple , domesticated in the Andean around 2500–1850 BCE and integral to systems that supported large populations. Varieties such as "cush-cush" were cultivated extensively, symbolizing sustenance and resilience in high-altitude environments where the crop's adaptability made it essential for . Polynesian oral traditions further elevate the sweet potato's symbolic status, portraying it as a divine gift from gods like , the deity of , who is said to have introduced it to island communities around 1000 AD, underscoring its role in myths of creation and migration. In the context of 19th-century history, sweet potatoes became emblematic of survival among enslaved in the South, where they formed a dietary mainstay on plantations, often grown and harvested under harsh conditions that highlighted themes of endurance and cultural adaptation. Today, the sweet potato is internationally acclaimed as a icon, with organizations affiliated to the , such as , promoting it through programs that address and in vulnerable regions. In the United States, November is observed as National Sweet Potato Month, a designation that honors the crop's historical and contemporary contributions to American agriculture and festivities. Biofortified orange-fleshed varieties have gained prominence in anti-hunger campaigns across , where initiatives in 2024 by the International Potato Center (CIP) distributed these nutrient-enhanced cultivars to combat , impacting millions in countries like and . The sweet potato's economic and cultural impact is deeply intertwined with indigenous practices and social structures. The International Potato Center (CIP) maintains a genebank with over 5,500 sweetpotato accessions, many originating from Andean indigenous communities that preserve of numerous landraces, passed down through generations, which preserves and reinforces tied to ancestral farming techniques. In , women predominantly handle sweet potato farming tasks, from planting to processing, shaping gender roles that emphasize their pivotal contributions to household and community economies, as evidenced in breeding programs in and . A landmark 2025 genome sequencing study revealed the sweet potato's hybrid origins from multiple wild ancestors, providing insights into its evolutionary history that foster greater heritage pride among indigenous cultivators in and beyond. Representations of the sweet potato in art and media highlight its narrative depth. In African folktales, such as West African stories like "The Talking Sweet Potatoes," the crop often symbolizes cleverness or communal sharing, embedding moral lessons in traditions. Its presence in broader , including works exploring colonial and post-colonial themes, underscores themes of and resistance. The sweet potato emoji (🍠), introduced in Unicode 10.0 in 2017, has become a staple in digital branding for campaigns and cultural , evoking harvest celebrations and nutritional advocacy worldwide.

Other Uses

Industrial Applications

Sweet potato anthocyanins, particularly from purple-fleshed varieties, are extracted for use as natural pigments in industrial applications such as and dyeing. These water-soluble compounds exhibit high stability in acidic environments, maintaining color integrity at pH levels of 3 to 5, which makes them suitable for products requiring resistance to degradation under mildly acidic conditions. In textile processing, extracts from purple sweet potatoes have been applied as dyes for , with mordanting agents like enhancing uptake and color fastness. The starch content of sweet potatoes supports various industrial bindings and energy production processes. Sweet potato starch serves as a binder in adhesives due to its strong adhesive properties and ability to form stable gels upon heating, providing an eco-friendly alternative in manufacturing. It has also been investigated for use in ceramics to enhance processing characteristics. In biofuel production, sweet potatoes are fermented to yield , with industrial varieties achieving approximately 160 liters per ton of fresh tubers through and processes. Recent research has also explored production from sweet potato vines via , yielding methane-rich gas suitable for , with studies demonstrating improved efficiency when co-digested with animal . Additional industrial uses include textile sizing, where sweet potato starch improves yarn strength and reduces breakage during weaving. In pharmaceuticals, sweet potato-derived trypsin and amylase inhibitors exhibit potential as enzyme modulators, with compounds like the 33 kDa trypsin inhibitor showing antioxidant activity relevant to drug development. Extracts from sweet potato roots have strong antioxidant properties and are used in cosmetics for skin health benefits, including moisturizing and protection against oxidative damage. Sustainability efforts leverage sweet potato processing waste, such as peels, which are utilized as due to their high and content, reducing disposal and supporting . Emerging applications in 2025 involve selenium of sweet potatoes, enhancing their use in nutritional supplements to address deficiencies through increased organic accumulation in tubers.

Ornamental and Non-Food Uses

Sweet potato vines (Ipomoea batatas) are widely utilized in ornamental for their vibrant foliage and trailing growth habit, serving as effective ground covers that suppress weeds while adding color to landscapes. These vines thrive in full sun or partial shade and can spread rapidly, making them ideal for covering bare soil in gardens or as accents in mixed borders. Gardeners often train them on trellises to create vertical interest, guiding the stems upward to prevent sprawling and enhance aesthetic appeal in container arrangements or hanging baskets. Their heart-shaped leaves in , , or variegated patterns provide lush, low-maintenance coverage, particularly suited for summer displays. The vines and leaves serve as a supplementary food source for herbivorous fish such as plecos, which graze on the tender growth, providing nutritional benefits while promoting in the aquatic environment. Beyond aesthetics and , sweet potato vines are valued as high-protein animal , containing 20-30% crude protein on a basis, which supports in tropical regions. They are commonly fed to and , either fresh or ensiled, to supplement diets during dry seasons and enhance or production. In crafting, dried slices of sweet potato tubers are employed to create rustic garlands and wreaths, often spiced with for a primitive, fall-inspired decor that evokes traditional homestead . Scientific studies have demonstrated the wound healing activity of sweet potato tubers and peels, attributed to their properties that aid skin recovery. Such uses persist in some rural settings for minor inflammations, though they are not a primary therapeutic approach. Amid the surge in hobby gardening, sweet potato vines have emerged as favored low-maintenance houseplants, easily propagated from kitchen scraps in or to yield trailing greenery for indoor spaces. Their resilience and minimal care needs align with trends toward sustainable, beginner-friendly urban cultivation.

References

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