A Matter of Selection

The brassica oleracea plants exhibit change through many different phenotypes such as color, length, width, height, and thickness. One characteristic of the Brassica oleracea that showed most variation was color. All the plants expressed some shade of green but some also had what looked like purple veins coursing through the stem and leaves. According to a color chart I found via google images the shades of green that the plants have are shamrock, sage, fern, and olive. These shades of green are very mild and some shades like sage have undertones of grey and brown in them.

The colors are very noticeable but there are things that are not as obvious when looking at the plant. When we observe the plant we usually are standing and looking down at it. From this angle we can see the shape, size, and color of the leaves and depending on where we are looking from we can see bits of the stem. These are factors that are the most noticeable but what’s under the leaves? While looking at the stem of some of the brassica oleracea I noticed something intriguing that is probably overlooked by most people. Coming down from the stem on one of the plants I noticed a base or a bulb where the stem met the ground. This base was about two to three inches in diameter while other plants where the stem met the ground were smaller than that.

These brassica oleracea are all different because there of geographic isolation. They all came from a common ancestor but they were separated so they adapted to different environments. Natural selection comes into play and alleles change to see the perfect combination of genes for these plants. For example some of the plants are huge and perhaps they’ve developed that size so that they can get more energy from the sun and eliminate competition with other plants by creating less space for them to live in and taking nutrients and resources. Now humans have been caring for the genetics of the plants so they can make money selling them. If the plant turns out weak and scrawny customers will not want to buy it so people use artificial selection to only breed a select few of the plants that are superb so their offspring will most likely be genetically superior and people will want to buy more of it.

No matter where the plants grow there will always be traits that the different types of brassica oleracea share. One of these traits that are very common are the leaves. The leaves of the different types of plants are all similar to each other in size and shape. The leaves grow an average of eight to ten inches long depending on the plant and they all have the same shape. The shape of the leaves are long, not that wide, and the edges of the leaves are curvy. I think the reason why they are so long is so that they could obtain more sunlight, and the edges are curvy so they are aerodynamic so if the wind is strong the leaves won’t be damaged.

To change the shape and size of the leaves the breeder would obviously have to breed the plant with a bigger or smaller plant depending on what is being requested. If someone wants a plant to have smaller leaves then they would take a plant from that type with the smallest leaves and breed it with another plant that has small leaves until the small leaf gene is a common allele. If desired the plants leaves could be bigger too by taking a plant with bigger than the average size leaves and take another plant similar to that until the allele for that trait becomes frequent.