Elsa A. Cousins | March 5th, 2017

Did you know that all of those popular cruciferous green vegetables, such as kale, broccoli and collard greens, are all the same species? It all started with wild cabbage, the source of all these vegetables rich in vitamin C, fiber, and other essential nutrients [1]. Wild cabbage belongs to the mustard family and has been cultivated by humans for thousands of years. This cultivation has altered the natural course of evolution – resulting in a plethora of physically different vegetables that are technically all the same species! Kale, cauliflower, broccoli, cabbage, kohlrabi and many more commonly consumed foods seen all over the vegetable aisle are all this same species. 

Fig 1.  An example of the many different versions of Brassica oleracea. Source.

Farmers are agricultural magicians, with generations of growing crops creating so much variety in the vegetable aisle! The establishment of distinct versions of the same species, such as kale and broccoli, is an everyday example of how evolution works. Crossing vegetables to promote certain traits, such as leafiness in kale and many edible flower buds in broccoli, has led to many distinct vegetables that we have named and consume on a regular basis.  

Fig. 2 Fields of cabbage at the US Vegetable Laboratory in Charleston, SC. Source.

One particularly long-term example of this is broccoli. Thousands of years ago, broccoli was cultivated in Italy in ancient Roman times [2]. Today, 90% of the crop that is produced in the US is currently grown in California, but California has been experiencing incredible drought, negatively impacting vegetable production. To make up for the depleting production of broccoli in California, the US Vegetable Laboratory in Charleston, SC, is developing broccoli that can grow in South Carolina [3]. Combining tried and true agricultural techniques with new and improving genetic technology, they are altering broccoli to be grown in different places and environments while still producing the same distinct vegetable we know and love.

Fig 3. The US Vegetable laboratory in Charleston, SC. Source.

US agricultural scientisats do this in much the same way that farmers developed the distinct vegetables originally, but with the addition of current technological advancements and genetic discoveries. By growing broccoli in the field and looking for plants that succeed in the higher temperatures of South Carolina, they breed broccoli that can grow in a different environment than where it has historically been produced. This field work is combined with cutting edge genetic work, manipulating the plants to succeed in a new environment. They also work to increase the health benefits of these crops, determining mineral content of different versions of the plants [4]. This genetic enhancement research is also being conducted with other leafy versions of the species, including kale and cabbage. All sorts of vegetables that we all eat have been genetically modified by people, for as long as we have been growing them! 

Literature Cited

[1] Cruciferous vegetables. Wikipedia. https://en.wikipedia.org/wiki/Cruciferous_vegetables

[2] M.D. Orzolek, W.J. Lamont Jr., L.F. Kime, and J.K. Harper. Broccoli Production. Ag Alternatives, Pen State Extension.

[3] United States Department of Agriculture. Agricultural Research Service. Charleston SC. https://www.ars.usda.gov/southeast-area/charleston-sc/vegetable-research/

[4] S. Durham. USDA Research Explores Mineral Content of Broccoli Varieties. 2011. Agricultural Research Service.