New Canadian roses disease resistant, cold-hardy and low maintenance

A cold tolerant, disease resistant rose variety is the dream of many a landscape gardener in the world’s cooler northern regions.

It may soon be a dream no more.

Dr. Rumen Conev

Dr. Rumen Conev, Vineland’s lead rose breeder

Dr. Rumen Conev is leading a breeding program at the Vineland Research and Innovation Centre that is developing landscape and garden rose varieties that will be resistant to Black Spot, survive frigid Canadian winters, and thrive in our shortened growing season – all while producing plentiful blooms and sporting glossy dark green foliage.

“Hardiness is definitely important, but the number one priority now is to breed for disease resistance,” explains Conev. “You can have a cold-hardy rose with a pretty flower, but if it defoliates, it won’t have consumer appeal.”

Chief culprits are Black Spot and Powdery Mildew, two diseases that cause leaf discoloration and in the case of Black Spot, defoliation – leaves turn undesirable colours before dying and falling off.

Conev’s work now involves breeding specific rose varieties for Black Spot resistance, and from those varieties, he selects cultivars that also show resistance to Powdery Mildew.

The Vineland rose breeding program wasn’t started from scratch, though.

In 2010, the Canadian Nursery Landscape Association (CNLA) obtained the rights to Agriculture and Agri-Food Canada’s hardy rose breeding program which dates back to the 1950s, and struck an agreement with Vineland to have it take over the research program.

“Our work now is a continuation of Agriculture and Agri-Food Canada’s work, continuing the tradition of breeding extremely cold hard roses that can survive -35C to -40C without mulching and protection,” says Conev.

Vineland’s program is the only one of its kind in the world, he adds, so there is a definite market niche for cold hardy, disease resistant roses.

Canadian roses in the past were marketed only in Canada and in very limited amounts in the U.S. With the new cultivars, the goal is to build international markets, particularly in regions with climates similar to Canada’s, such as Scandinavia and Eastern Europe.

Although Canada’s nursery sector generated sales of $637 million in 2013, exports only accounted for $13.5 million of that.

Germany and the United States are currently the world leaders in landscape and nursery rose production.

“The “Knockout” rose series became the best seller in horticulture history in only five years and this is what could happen with our roses too,” says Conev of the market potential. “Not only are they cold-hardy and Black Spot resistant, but they also look good with their dark green and glossy foliage so that consumers enjoy having the plant even when it is not in bloom.”

Vineland’s team carries out over 15,000 controlled crosses every year in an effort to combine traits from hundreds of Canadian and international varieties and lines.

Thousands of controlled crosses are carried out at Vineland every year

Thousands of controlled crosses are carried out at Vineland every year

Between 10,000 and 15,000 seedlings are then planted in the fields at Vineland’s research farm every year.

The best ones – less than one per cent of those initial plants – are selected for commercial testing.

This means they are sent to CNLA-member nurseries across Canada in British Columbia, Alberta, Manitoba, Ontario, Quebec and New Brunswick for further evaluation.

Vineland also has a partnership with the University of Saskatchewan, which operates a test site in one of the coldest areas of urbanized Canada.

“We have test sites from Zone two to Zone eight so we can pinpoint what the cold tolerance limits are of each tested selection,” says Conev, describing how climate zones are rated, with lower numbers being colder and higher numbers representing warmer regions.

Following two to three years of rigorous outdoor testing without fungicide sprays and winter protection, a couple of the best performing cultivars will be selected annually for commercialization.

Conev expects Vineland to start releasing its new roses into the market in the spring of 2018.

It normally takes 10 years or more to bring new varieties to market, but Vineland was able to shorten that pipeline to seven years by doing several activities at the same time, such as identifying winning cultivars and acquiring protection under Plant Breeders’ Rights to begin propagating enough plant material for commercialization.

And soon the process will be shortened even further.

Vineland has just received a $1.4 million research investment from Agriculture and Agri-Food Canada to modernize its rose-breeding program by adding DNA fingerprinting technology.

“If you can identify Black Spot resistance at the molecular level, it makes it easy to select the right varieties in very early stages so we don’t have to go into field trials with 15,000 seedlings. We can narrow it down earlier, which saves money and increases efficiency,” explains Conev.

“Good marketing will sell new cultivar for one year, but good genetics will sell it for 50,” he adds.

Vineland’s rose breeding program is supported by Growing Forward 2 (GF2), a federal-provincial-territorial initiative.

Dr. Conev with rose varieties outside a greenhouse at Vineland

Dr. Conev with rose varieties outside a greenhouse at Vineland