CORVALLIS, Ore. — Midnight Roma, a tomato developed by Oregon State University and released in 2021, follows in the footsteps of Indigo Rose — the first antioxidant-rich purple tomato available on the market.
Indigo Rose was bred by Jim Myers, the Baggett-Frazier Endowed Chair of Vegetable Breeding and Genetics at Oregon State University. A now-retired professor in the College of Agricultural Sciences, Myers focused his career on improving vegetables for flavor, nutrition and disease resistance using traditional breeding techniques.
"Anybody into home canning would be interested. Chefs like it for making sauces."
Midnight Roma is a result of crossing Oregon Star — a large, fleshy tomato prized for slicing or making paste — with Indigo Rose, a dark purple tomato that contains anthocyanins, the same healthy antioxidants found in blueberries.
Both varieties were developed at Oregon State.
“We were selecting for a really dark Indigo-type processing tomato,” Myers said in 2021. “Ultimately, we got a really nice one. Anybody into home canning would be interested. Chefs like it for making sauces. Right now, Serious Pie in Seattle is using Midnight Roma to make pizza sauce.”
Row 7 Seed Co., based in Tarrytown, New York, holds the exclusive rights to Midnight Roma and is selling seed online.
In developing Midnight Roma, Myers concentrated on flavor and disease resistance, creating a better-tasting paste tomato that also resists verticillium wilt. The plant is a semi-determinate variety, meaning the tomatoes ripen around the same time — ideal for preserving. The anthocyanins are concentrated in the dark skin, so to retain the antioxidants, it’s important to include the skin during processing. Myers recommends blending the sauce and pressing it through a sieve, a method he has used successfully.
Indigo Rose attracted attention when it was released in 2011. At the time, public awareness of antioxidant health benefits was growing, and the introduction of a purple tomato was novel. However, many home gardeners weren’t sure when to harvest it and often picked it too early. Over time, people learned that the tomato ripens when its color shifts from shiny blue-purple to a dull purple-brown and the bottom turns from green to red.
Midnight Roma ripens in the same way. Sunlight exposure is essential for developing the dark purple skin, which holds the anthocyanins. To achieve the highest levels of antioxidants, Myers advises trellising and pruning to allow maximum sun exposure.
In addition to the 'Indigo' series, Myers’ breeding program has released multiple vegetable cultivars, including a green bean variety used by processors on 80% of the acreage in Oregon. His work extends beyond the lab through participatory plant breeding, which involves farmers and chefs in evaluating and selecting new cultivars. This approach helps ensure the varieties developed meet practical needs in the field and the kitchen.
Myers also led the Northern Organic Vegetable Improvement Collaborative (NOVIC), a nationwide project focused on breeding vegetable varieties tailored for organic farming systems.
Other purple tomato varieties
Between the releases of Indigo Rose and Midnight Roma, Myers introduced several other purple tomato cultivars: Indigo Cherry Drops, Indigo Pear Drops, and Indigo Kiwi. All are widely available except Indigo Kiwi.
Breeding these tomatoes involves a meticulous process: transferring pollen from the male stamen to the female style by hand. With each generation, the most promising plants are selected and crossed again until the desired traits are achieved.
One of the parents of Indigo Rose was an experimental tomato with wild genes discovered by Carl Jones, then a graduate student at Oregon State. While examining specimens in a U.S. Department of Agriculture National Plant Germplasm System collection at the University of California, Davis, Jones found a tomato with anthocyanin-rich skin. At that time, the health benefits of antioxidants were not well known, and few breeders were working on purple tomatoes for the market.
Now, Indigo Rose is used to develop new varieties.
“While other fruits, such as blueberries, have higher concentrations of anthocyanins, tomatoes are consumed practically daily in the United States,” Myers said. “The tomato is the nation’s most popular vegetable — unless you count potatoes.”
