Indigo Rose tomato. Photo courtesy of Oregon State University.

If you’re interested in growing unusual fruits and vegetables, you’ve probably been intrigued by the gorgeous dark purple hues of the Indigo series of tomatoes. Developed by Oregon State University, the Indigo Rose variety was the first truly purple tomato. Today, gardeners can choose from other “Indigo” varieties, including Indigo Apple, Indigo Kumquat and Indigo Ruby. You may be wondering if Indigo tomatoes are genetically modified organisms, or GMOs.  The short answer is no. According to scientists at OSU, the Indigo tomatoes were developed using conventional crossing and selection techniques.

What gives purple tomatoes their color?

So what give these purple tomatoes their distinctive color? It’s a class of compounds called anthocyanins. Not surprisingly, anthocyanins are also found in blueberries, cranberries and blackberries. When it comes to tomatoes, anthocyanins only develop on the parts of the fruit that are exposed to sunlight.

Benefits of anthocyanins

According to an article published in the Annual Review of Food, Science and Technology, “it has been suggested that anthocyanins possess anti-inflammatory and anti-carcinogenic activity, cardiovascular disease prevention, obesity control, and diabetes alleviation properties.” Many researchers believe that anthicyanins act as powerful antioxidants.

Other purple tomatoes

While the Indigo series of tomatoes have been produced using traditional selective breeding techniques, other researchers have resorted to genetic engineering to produce blue and purple tomatoes. Researchers at the John Innes Centre in the UK have combined genetic material from snapdragons with tomatoes.

Some heirloom varieties, such as Cherokee Purple (my favorite tomato!) and Black Krim also exhibit purple color characteristics, but it’s not a true, deep purple.


For more on the Indigo tomatoes from Oregon State University, check out the FAQ here: