Tomato upgrade comes with purple hue

Packed with anthocyans The nutritious purple tomato has been found to have anti-inflammatory properties

RIDGETOWN, Ont. — The search for a healthier processing tomato continues at the University of Guelph’s Ridgetown Campus.

Researcher Steven Loewen told a Vegetable Day held on the campus July 17 that he now has a line of purple-skinned tomatoes.

Unlike heritage tomatoes, which are often more brown than purple, Loewen said his purple tomato has an eggplant-like colour on the outside and is deep red inside.

The purple hue is associated with higher levels of anthocyans, which are reputed to have a wide range of health benefits. Recent research at the U of G and in China has demonstrated an antioxidant effect.

“They applied it to an animal model by feeding those tomatoes to rats,” he said.

“They found it reduced inflammation, and the effect was dose dependent. What we’re trying to do is to take a tomato that’s already very good from a nutritional standpoint and make it even better.”

The purple tomato is just one of Loewen’s many projects. He’s also working with 1,200 breeding lines in a search for better agronomic characteristics, improved yields and greater genetic diversity.

It’s a long-term effort, with another breeder making the initial crosses between wild and commercial lines many years ago.


Loewen has been focusing on the positive traits of poorly adapted material, eliminating line defects through a backcrossing process and then enhancing positive traits.

The results are lines that commercial breeders can use.

An objective that has so far eluded Loewen is the development of tomato lines resistant to bacterial disease. He had been using a horizontal breeding technique to develop multi-gene resistance but later abandoned the effort.

Phil Richards, a tomato grower near Dresden, Ont., said bacterial spot is a significant problem this year. The canopy sags in affected fields as the disease moves from lower leaves upward.

Other work at Ridgetown focuses on pesticide evaluation, the benefit of cover crops and a rotational study.

Trials conducted by Laura Van Eerd show that the long-term use of cover crops in vegetable-production rotations are an economically viable option with improved yields paying for the cover crop and sometimes paying a dividend.

Long-term plots that use the 17-point Cornell Soil Health Test as an evaluation tool have demonstrated that wheat in the rotation benefits soil health in Ontario.


However, while farmers recognize the benefits of rotation, they also pay attention to commodity prices.

As a result, more than 2.5 million acres of soybeans were planted in Ontario this year compared to less than two million acres of corn and 750,000 acres of wheat.

Okra and Asian-type eggplant varieties are being evaluated in Ridgetown for the first time as part of a project led by the Ontario Fruit and Vegetable Growers Association, which sees an opportunity to re-place imports.

For example, Ontario’s okra production meets only five percent of the demand, although field production in the province is limited to mid to late summer.

About 200 acres of okra are now grown in Ontario, said Michael Brownridge of Agriculture Canada.

The crop is handpicked by workers who repeatedly sweep through fields. Much of the okra exported to Canada originates in Central America.

Sweet potatoes, which can be stored for more than a year, also have potential in Ontario. Most of the increased demand has been driven by the popularity of sweet potato fries.