Last fall, when agronomist Maxime Côté heard from one of his clients, an agricultural producer based near Ottawa, a pleasant surprise awaited him. The experiment conducted on his soybean field — divided in two, each half planted with a different variety of soybean — had crowned winning genetics.
“The yield difference was incredible,” says Côté. Yield per hectare was about 15% higher for one of the soybean varieties. “I was very surprised! he exclaims.
Phytophthora rot of soybeans, a very widespread disease in the country, would have caused much of the breakup of the less productive half of the field, according to the agronomist. It is estimated that, each year, this fungal disease causes $50 million in damage in Canada.
While most soybean cultivar selection is “blind,” a new diagnostic test allows farmers to choose the variety most resistant to Phytophthora root rot. Since dozens of different strains of the pathogen exist in North America, choosing the most suitable soybean cultivar varies from field to field.
“Using the variety that has the right gene is the best way to protect yourself,” explains Geneviève Arsenault-Labrecque, CEO. and head of research and development at Ayos Diagnostic, a start-up established in Quebec offering a unique molecular test in the world, and which collaborates with Maxime Côté.
Like a COVID test
During his doctorate in plant biology with the professor of plant science at Laval University Richard R. Bélanger, Mme Arsenault-Labrecque participated in the development of a nucleic acid amplification test — better known by the English acronym PCR — capable of identifying the phytophthora disease variant. “It’s really like a test for COVID,” she explains.
This information allows the following season to choose the soybean cultivar with the right genes to resist the variant hiding in the soil of the field. Seed companies already offer soybeans with any of the five known “resistance” genes to Phytophthora Soyaethe pathogen responsible for phytophthora root rot.
Maxime Côté, who offers his services to producers in the Laurentians, Outaouais and eastern Ontario, has been working since 2020 with Mme Arsenault-Labrecque and his team. Two years ago, soil samples were taken from five of his clients growing soybeans. The tests revealed the presence of resistant variants of Phytophthora Soyae in four of them.
Even among producers, Phytophthora rot remains “unrecognized,” warns Mr. Côté. This disease attacks the plants in a subtle way, and the damage is not always easily visible. “In most cases, we will have stunted plants, and the base of the stems can turn brown, explains the agronomist. In extreme cases, the plant may completely dry out, but it will retain its dead leaves. »
Reduce the use of fungicides
At the Cumberland, Ontario grower, who had split his field in two, Ayos’ molecular testing detected the presence of two pesky genetic variations in the local strain of Phytophthora Soyae. Unsurprisingly, half of the field that won the yield race had the right cultivar to ward off this variant of the pathogen. This spring, only this soybean variety was planted.
For Mr. Côté, the molecular diagnostic test is one more tool for improving soybean yields, but also for reducing the amount of fungicide used. Since its customers mainly grow soybeans for human consumption, this aspect is essential.
“We also need to educate producers about improving crop rotations,” he says. Alternating between different crops — wheat, corn and soybeans, for example — radically curbs the proliferation of diseases, he recalls.
From their laboratory of Professor Bélanger at Laval University, Geneviève Arsenault-Labrecque and her associates are preparing to deploy their technology on the Canadian market. After years of research, in 2022, they want to “prove the concept in the field” to convince growers and agronomists to join their services.
The young entrepreneur, whose technology was patented by her university in 2018, believes that changes are needed in the world of soybeans. For decades, the massive use of the same genetic varieties of this legume has favored the emergence of resistant strains of Phytophthora root rot, due to natural selection.
“When a new variety [de soya] is put on the market, it is used massively: it generates resistance [chez l’agent pathogène] “, explains M.me Arsenault-Labrecque. A more enlightened use would make it possible to avoid “burning” varieties developed at the cost of patient hybridization efforts by seed producers. “Now would be a good time to change our ways,” she says.