The plant is a semi-determinate variety, meaning the tomatoes tend to ripen at about the same time, making it timely for preserving.
The new Oregon State University-developed tomato Midnight Roma follows in the steps of 10-year-old Indigo Rose, the first antioxidant-rich purple tomato available on the market.
Indigo Rose was bred by Jim Myers, vegetable breeder and professor in the OSU College of Agricultural Sciences. Midnight Roma is the result of crossing Oregon Star, a big, fleshy tomato good for slicing or paste with excellent flavour, and Indigo Rose, a dark purple tomato that contains anthocyanins, the same healthy antioxidants found in blueberries. Both varieties were also developed at OSU.
“We were selecting for a really dark Indigo-type processing tomato,” Myers said. “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.”
For Midnight Roma, Myers concentrated on flavour and disease resistance, coming up with a better-tasting tomato than many other paste tomatoes. It also is resistant to verticillium wilt. The plant is a semi-determinate variety, meaning the tomatoes tend to ripen at about the same time, making it timely for preserving. The anthocyanins are contained in the dark skin. So, to keep the antioxidants, the skin must be included in processing. Myers suggests running the sauce in a blender or food processor and then pressing it through a sieve, which he has done with success.
Midnight Roma darkens in the same way, and sunlight is key to getting purple skin, which contains the anthocyanins, Myers said. To achieve the highest level of antioxidants, use a trellis and prune excess leaves to allow the maximum amount of sun to reach the tomatoes.
“One of the parents for Indigo Rose that led to its purple, anthocyanin-rich skin was an experimental variety with wild tomato genes discovered by Carl Jones, a then OSU graduate student who was examining plants in a special collection at the University of California, Davis, that is part of the U.S. Department of Agriculture’s National Plant Germplasm System. At that point, the health benefits of antioxidants weren’t commonly known and other breeders weren’t working on a marketable purple tomato”, Myers said.
