Once you entered the greenhouse compound at Oregon State University they weren’t hard to spot. Amid the broccoli and beans, purple tomatoes stand out.
There were only a few plants left from this year’s tomato crop, a couple of Indigo Rose and a couple of the new Midnight Roma varietal. Indigo Rose came out in 2011, with the just-released Midnight Roma the latest concoction in the vegetable breeding and genetics career of OSU Professor Jim Myers.
“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.”
Myers says the Midnight Roma has more flavor than its predecessor, the Indigo Rose.
"It's not going to compare with a sweet cherry or a succulent slicer, but it really excels in making sauces and cooked dishes," he said.
The Midnight Roma, which is available only online from the Row 7 Seed Co. in Tarrytown, N.Y., also is chock-full of anthocyanins, the same healthy antioxidants found in blueberries. And it’s the purple skins that contain the anthocyanins, which makes the Midnight Roma better for uses that don’t call for peeling the tomato.
It was 10 years after the development of the Indigo Rose that Myers finally found what he wanted in the Midnight Roma, after painstaking experimentation with cross-breeding the Indigo Rose with the Oregon Star tomato varieties.
“We did a series of self-pollinations that took the plants out seven generations,” said Myers on Wednesday from the OSU west greenhouses. “Then you start looking for consistency. If you still are seeing variations, you need to keep going.”
Myers estimates it took hundreds of plants to get to where he wanted with the Midnight Roma. Beans can require tens of thousands of plants to get to a desired genetic variation, with soybeans and corn in the hundreds of thousands, Myers said.
When asked to compare the earlier Indigo Rose to the Midnight Roma, Myers said:
“They are similar in color and plant characteristics but differ in fruit type. Indigo Rose is a saladette type most suitable for using fresh. Midnight Roma has thick, fleshy walls and a relatively small seed cavity typical of tomatoes used for cooking and making sauces. Chefs tell me that they like it because Midnight Roma rapidly cooks down to a very thick sauce that has a deep burgundy red color.”
The purple color can be a challenge to some consumers, Myers said.
“What I’ve found over the years is that people’s reaction to these tomatoes is very polar — they either love it or hate it,” he said. “Some folks like novelty, whereas other don’t think vegetables should venture outside of traditional norms. I think that over time, Indigo tomatoes are becoming accepted more widely.”
Indigo Rose, which is now in its 10th year, has been licensed in Europe, Japan, Canada and South Africa.
“My expectation is that Indigo tomatoes will remain a niche market (overall),” Myers said. “I think that there is potential for the processing market to be much larger for Indigo tomatoes as they enhance the color of processed products.”