Artificial Selection in Plants

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Types of corn. US Department of Agriculture

In the 1800s, Charles Darwin, with some help from Alfred Russel Wallace, first came up with his Theory of Evolution. In this theory, for the first time that had been published, Darwin proposed an actual mechanism for how species changed over time. He called this idea natural selection.

Basically, natural selection means individuals with the favorable adaptations for their environments would survive long enough to reproduce and pass down those desirable traits to their offspring. Eventually, the unfavorable characteristics would no longer exist after many generations and only the new, favorable adaptation would survive in the gene pool. This process, Darwin hypothesized, would take very long periods of time and several generations of offspring in nature.

When Darwin returned from his voyage on the HMS Beagle where he first developed his theory, he wanted to test his new hypothesis and turned to artificial selection to gather that data. Artificial selection is very similar to natural selection since its aim is to accumulate favorable adaptations to create a more desirable species. However, instead of letting nature take its course, evolution is helped along by humans who choose the traits that are desirable and breed individuals possessing those characteristics to create offspring that have those traits.

Charles Darwin worked with breeding birds and could artificially select various characteristics such as beak size and shape and color. He showed that he could change the visible features of the birds to show certain traits, much like natural selection would do over many generations in the wild. Artificial selection does not only work with animals, however. There is also a great demand for artificial selection in plants in the present time.

Perhaps the most famous artificial selection of plants in biology is the origin of Genetics when Austrian monk Gregor Mendel bred pea plants in his monastery’s garden to collect all of the data that began the entire field of Genetics. Mendel was able to cross-pollinate the pea plants or let them self-pollinate depending on what traits he wished to see in the offspring generation. By doing an artificial selection of his pea plants, he was able to figure out many of the laws that govern the genetics of sexually reproducing organisms.

For centuries, humans have been using artificial selection to manipulate the phenotypes of plants. Most of the time, these manipulations are meant to produce some sort of aesthetic change in the plant that is pleasing to look at for their tastes. For instance, flower color is a large portion of artificially selecting for the plant’s traits. Brides planning their wedding day have a special color scheme in mind and flowers that match that scheme are important to bringing their imagination to life. Florists and flower producers can use artificial selection to create blends of colors, different color patterns, and even leaf coloring patterns on their stems to get the desired results.

Around Christmas time, poinsettia plants are popular decorations. The colors of poinsettias can range from a deep red or burgundy to a more traditional bright red for Christmas, to white, or a mixture of any of those. The colored part of the poinsettia is actually a leaf and not a flower, but artificial selection is still used to get the desired color for any given plant.

Artificial selection in plants is not just for pleasing colors, however. Over the last century, artificial selection has been used to create new hybrids of crops and fruit. For instance, corn can be bred to be larger and thicker in the cobs to increase grain yield from a single plant. Other notable crosses include broccoflower (a cross between broccoli and cauliflower) and a tangelo (the hybrid of a tangerine and a grapefruit). The new crosses create a distinctive flavor of the vegetable or fruit that combines properties of their parents.