Tomato

The tomato (US: /təˈmeɪtoʊ/, UK: /təˈmɑːtoʊ/; Solanum lycopersicum) is a plant whose fruit is an edible berry that people often eat as a vegetable. It belongs to the nightshade family, which also includes tobacco, the potato, and chili peppers. The tomato originally came from western South America and was later introduced to other parts of the world by the Spanish during the Columbian exchange in the 16th century.

Tomato plants grow as vines and usually live for one year. They can be sensitive to cold weather but sometimes survive longer when grown in greenhouses. These plants produce flowers that can pollinate themselves. Today, many types of tomatoes exist, differing in size, color, shape, and taste.

Tomatoes are loved around the world for their savory flavor and are used in many dishes. They are a key ingredient in sauces for pasta and pizza, soups like gazpacho and tomato soup, salads, and condiments such as salsa and ketchup. People also enjoy tomatoes as juice and in drinks like the Bloody Mary cocktail.

Naming

The word tomato comes from the Spanish tomate, which itself comes from the Nahuatl word tomatl. The scientific name lycopersicum, meaning 'wolf peach', was used by the ancient doctor Galen for a different plant, but it later became the name used for tomatoes in science.

People say tomato in different ways depending on where they live. In North American English, it is often said /təˈmeɪtoʊ/, while in British English, it is often /təˈmɑːtoʊ/. This difference in pronunciation was even made famous in a song by Ira and George Gershwin in 1937.

History

The tomato likely started as a wild plant in western South America. It was later grown by people in places like Mexico and Central America. The Spanish brought tomatoes to Europe in the 1500s, where they were first thought to be just for decoration because they looked like nightshades, which some people thought were poisonous.

In Mexico, tomatoes were an important part of the diet for the Aztecs, who called them xitomatl. The Spanish shared tomatoes with many parts of the world, including Asia and the Middle East. In Italy, tomatoes were first grown as pretty plants before they became a key part of cooking, especially in places like Naples. Over time, many different kinds of tomatoes were created for different uses, like making sauces or drying.

Tomatoes finally became popular in Britain and the United States after people learned they were safe to eat. Today, places like California and Florida grow lots of tomatoes for fresh eating and processing.

Botany

Tomato plants grow as vines and can reach up to 3 meters tall, though smaller bush types stay around 100 centimeters. These plants are usually grown each year, even though they can live longer.

Tomato plants have branching stems with a growing tip. When this tip stops, new branches take over. The leaves are long with many small parts, and they often have fine hairs. The flowers are yellow and can grow by themselves without help from bees. The fruit, which we call a tomato, comes from the flower and contains seeds.

Tomatoes belong to the nightshade family, which also includes potatoes and tobacco. Scientists often study tomato plants to learn about plant relationships.

Plant breeding

Genetics

Researchers from 10 countries started studying the tomato’s DNA in 2004. A early version of the tomato’s DNA map was shared in 2009, and the full DNA map for a special tomato type called Heinz 1706 was published in 2012. The most recent DNA map from 2021 shows it has 799 MB of information and can make about 34,384 different proteins.

The first food changed by scientists to have special DNA was a tomato named Flavr Savr. It was made to stay fresh longer. This let it ripen naturally while still staying fresh, which was thought to make it taste better. But it didn’t stay firmer than regular tomatoes, which disappointed the scientists. Because of this and other issues, it was only sold until 1997.

When people first began growing tomatoes, they picked ones that were less bitter. This change happened because a special part of the tomato changed during ripening, turning a bitter substance into something not bitter.

Commercial breeding

Modern tomatoes often don’t taste as sweet because they were bred to all turn red at the same time. This began in the middle of the last century when a special type of tomato was found that all ripened to red without a green ring around the stem. Before this, tomatoes had more sugar when they ripened, making them sweeter and tastier.

When tomatoes ripen, their green parts can make sugar through sunlight. But a special change in tomatoes makes these green parts less dense, which lowers the sugar by about 10–15%. During ripening, these green parts turn into parts that make important nutrients like lycopene.

Growers work to make tomatoes better, like making them bigger, keeping them fresh longer, and helping them resist sickness. But sometimes, these changes can make the tomatoes taste worse or have less nutrition.

To improve tomatoes, growers sometimes use wild tomato plants that have good traits, like more sugar or resistance to diseases. But using these wild traits can sometimes hurt other good qualities, like how much fruit the plant makes.

Cultivation

The tomato is grown all over the world for its edible fruits, and there are thousands of different types.

Tomatoes can be grown in greenhouses, which helps produce them during times when they cannot be grown outside. Smaller tomatoes like cherry and grape tomatoes are popular in big greenhouses, while larger varieties are often grown by smaller growers. Tomatoes can also be grown using a method called hydroponics, where they are grown without soil.

To make transportation easier, tomatoes are often picked before they are fully ripe and then allowed to ripen later. In large factories, machines are used to pick tomatoes, which cut the whole plant and sort out the ripe tomatoes for use.

In 2023, the world produced 192 million tonnes of tomatoes, with China making up the largest share, followed by India, Turkey, and the United States.

Pests and diseases

Pests

Tomatoes can be bothered by several small creatures, such as the tomato bug, stink bugs, cutworms, tomato hornworms, and tobacco hornworms. Other pests include aphids, cabbage loopers, whiteflies, tomato fruitworms, flea beetles, red spider mite, Tuta absoluta (tomato leafminer), slugs, and Colorado potato beetles. The tomato russet mite, Aculops lycopersici, can damage leaves, flowers, and fruit, sometimes harming the whole plant.

When attacked by insects, tomato plants make special chemicals to defend themselves. These chemicals can slow down the growth of the pests.

Diseases

Different types of tomatoes have different abilities to fight off diseases. Some common tomato diseases include tobacco mosaic virus, which can spread from handling cigarettes or other tobacco products. Another serious disease is curly top, carried by the beet leafhopper, which makes the top leaves of the plant grow in odd, wrinkled ways. Bacterial wilt is also a common problem.

As food

Culinary

Further information: List of tomato dishes

Tomatoes are loved around the world because of their special flavor. They are a big part of Mediterranean cuisine, like in pizza and pasta sauces. In Spain, people enjoy tomatoes in gazpacho soup and a special dish called pa amb tomàquet. In Middle Eastern cuisine, tomatoes are used fresh in salads, grilled with kebabs, and in sauces.

Tomatoes were brought to India by Europeans and are now used in many curries, like Kashmiri rogan josh and the British tikka masala.

• Tomato soup with croutons
• Rogan josh, a curry often made with tomatoes
• Bloody Mary, a tomato cocktail
• Pa amb tomàquet, Catalan tomato bread
• Tomatoes stuffed with egg and Parmesan cheese

Storage

Tomatoes stay fresh best when kept unwashed at room temperature away from sunlight. Placing them stem down can help them last longer. Unripe tomatoes can be kept in a paper bag to help them ripen. Tomatoes can also be kept long-term by canning, freezing, drying, or cooking them into a paste.

Nutrition

A raw tomato is mostly water—about 95%—with a little bit of carbohydrates, fat, and protein. One tomato has only about 18 calories and gives a good amount of vitamin C, but it doesn’t have many other nutrients.

Effects on health

Experts have found that eating tomatoes does not lower the chance of getting certain illnesses.

Toxins

The leaves, stem, and green parts of unripe tomatoes have small amounts of natural toxins. These can be harmful to pets like dogs if they eat a lot of them. But small parts of tomato leaves or green tomatoes can be used in cooking, like in fried green tomatoes.

Salmonella outbreaks

Sometimes, tomatoes have been linked to illnesses caused by a germ called Salmonella. One big case happened in 2008, and more happened in 2022 and 2023 in the US and some European countries.

In popular culture

Celebrations

In the Walt Disney World Resort in Lake Buena Vista, Florida, there was a very large tomato plant that grew over 32,000 tomatoes weighing 522 kg (1,151 lb).

The town of Buñol in Spain holds an annual festival called La Tomatina, where people throw tomatoes at each other. In 2007, around 40,000 people joined in and threw 115,000 kg (254,000 lb) of tomatoes.

Some U.S. states have made the tomato their official fruit or vegetable. Arkansas chose the South Arkansas Vine Ripe Pink Tomato as both its state fruit and vegetable. Ohio made the tomato its state fruit in 2009, and tomato juice has been its official beverage since 1965. The town of Reynoldsburg holds a yearly Tomato Festival, calling itself "The Birthplace of the Tomato." Finland has an annual event called Tomatkarnevalen in the town of Närpes.

Fruit or vegetable

See also: Vegetable § Terminology

Even though we cook and eat tomatoes like vegetables, scientifically they are fruits. This caused a legal debate in the United States. In 1893, the U.S. Supreme Court decided that for tax purposes, the tomato would be considered a vegetable because that’s how most people use it — as part of a main meal and not a dessert.