- WatermelonsTheories abound concerning where exactly the watermelon originated. Historians only agree that it first grew somewhere in Africa, spread to the Mediterranean, and later popped up in Europe.
Harry Paris, a horticulturalist at the Agricultural Research Organization in Israel, has concluded that the watermelon’s earliest ancestor was first cultivated in Egypt some 4,000 years ago. This ancient fruit was hard, bitter, and pale green in color—a far cry from today’s sweet, fleshy variety.
So why would the ancient Egyptians want to spend time and energy growing something like that?
Paris believes that they were cultivated simply for their water. During the dry season, watermelons stored well and the Egyptians could pound them to a pulp and extract their water content. He also believes that the Egyptians were the ones who began the selective breeding process that ultimately led to watermelon as we know it.
- BananasThe fleshy yellow fruit found all over was first cultivated in Papua New Guinea between 7,000 and 10,000 years ago. The banana is yet another edible plant with several varieties, most of which are found today in Asia.
The long, yellow variety, known as the Cavendish, is the result of centuries of careful breeding by diligent agriculturalists. It descends from two wild banana species: Musa acuminata and Musa balbisiana. The former has flesh that isn’t very tasty when eaten raw, and the latter is a short, stubby little thing with lots of hard, pea-sized seeds in the middle.
Thousands of years ago, banana cultivators discovered that cross-pollinating these two plants sometimes produced a sweet, yellow, seedless fruit that was also rich in nutrients. As this variety is seedless, these bananas must be produced by human-assisted asexual propagation (otherwise known as cloning).
This form of reproduction makes the Cavendish much more susceptible to disease than its hardy ancestor. Since the plants are genetically uniform, a banana-killing pestilence could quickly and easily wipe out whole crops. For this reason, cultivators are careful with their output lest the world experience a banana apocalypse.
- TomatoesWild Tiny Pimp might sound like an unfortunate street name but it’s actually the name of a tomato species. In fact, it’s the tomato species from which all other tomatoes descend. Plant scientists call it Solanum pimpinellifolium, or just “pimp.”
Today, these pea-sized tomatoes grow on scraggly vines found in northern Peru and southern Ecuador. South Americans first domesticated them during the pre-Columbian Then these tomatoes spread to Europe and eventually back to North America.
Today’s wide assortment of domesticated tomatoes all come from the tiny pimp and, interestingly enough, only have five percent genetic variation between them. Crossbreeding modern types with the earlier wild ones, including the pimp, produces a plant that’s hardier and less susceptible to disease.
- CarrotsThe earliest known cultivated carrots were first grown in the 10th century in Asia Minor and Persia. Before it was domesticated, the wild carrot was spread all over the world. Seeds up to 5,000 years old have been discovered in Europe.
The carrot’s original appearance was small and white. It also had more of a forked appearance like a plant root. Most likely, ancient cultures used it as a medicinal plant.
It’s thought that the carrot’s transformation into the orange, sweet, less bitter descendant so popular today took many centuries to breed. Today’s orange carrots are known as Carotene or Western carrots, while their cousins are known as Asiatic or Eastern carrots, which have purple and sometimes yellow roots
- Pawpaw(Papaya)Though Pawpaw is eaten around the world today, it originated in the tropical climate of Latin America. The modern commercial papaya descends from the wild papaya, and they both have very different appearances.
The wild papaya is round and about the size of a plum. Some species even closely resemble a cacao pod. The ancient Maya were the first to cultivate papaya about 4,000 years ago. Growing the fruit is a complicated process because the grower doesn’t know which seeds will produce fruit-bearing plants until after they’ve begun to grow.
- MaizeIt’s hard to imagine a world without this most essential staple crop. Corn was one of the first food plants cultivated at the start of human agriculture some 10,000 years ago in the area that is modern-day Mexico. At one time, ears of corn were very small and gradually became bigger over time thanks to artificial selection.
If we go back even further, we find that corn’s ancient ancestor is a wild grass plant called teosinte. It looks very little like corn, though they both produce kernels. On a genetic level, though, the two plants are quite similar.
Geneticist George Beadle found in his experiments that there were only five chromosomes responsible for the most noticeable differences between the two plants. Teosinte underwent small genetic changes over time that eventually resulted in the appearance of maize.