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The benefits of sex-free agriculture

With crop breeding by apomixes, seed-saving could change up the seed industry

Apomixis is a disruptive technology.”

These was the oft-repeated phrase of Tim Sharbel, Global Institute for Food Security (GIFS) research chair in Seed Biology, at the recent Canadian Farm Writers’ Federation annual conference in Saskatoon.

Sharbel was speaking on the topic “Eliminating sex from agriculture to feed the world,” an overview of his research at GIFS, which focuses on apomixis, or asexual seed formation in plants.

Citing familiar statistics on the world’s growing population and the need to “feed the world” via increased productivity in agricultural systems, Sharbel presented an overview of his work on apomixis, arguing that asexual seed formation could offer a way around the expensive, inefficient annual development of hybrids via inbred lines and artificial pollination.

Apomixis could fix hybrid genotypes in crop plants, said Sharbel, leading to so-called “virgin births” in farmers’ fields. Apomictic hybrids would not require fertilization, and farmers could save apomictic seed for replanting year to year.

In a word, apomixis is truly disruptive, and would change the entire structure of the seed trade in Canada.

But Sharbel believaes apomixis would benefit agribusiness as well as farmers and consumers by radically reducing the time and resources it takes to develop new inbred lines, thereby opening the door to localized niche breeding and the use of natural biodiversity in field crop breeding programs.

“One potential application of this is that if you can turn sex off in that first generation hybrid, the plant will produce genetically identical offspring from then on,” said Sharbel in a telephone interview. “That sounds bad for the company — farmers never buying seed again — but it would enable companies to generate much more variability in the crops they’re producing using that extra time and money.”

Most of Sharbel’s work these days focuses on plants in the genus Boechera (rock cress), a wild relative of canola that reproduce apomictically. Sharbel’s lab has identified two candidate genes that are potentially responsible for apomixis, and is attempting to use them to “turn off” sexual reproduction in Arabidopsis, maize and canola.

Sharbel doesn’t have results yet, but they’re in the works, he says. “We could have proof of concept in three months, which would mean immediately trying to get partners to put this in canola or maize. It could take five or 10 years (before successful application in field crops),” he says.

“But it’s such a potentially important technology, kind of like finding a cure for cancer because it has so many positive implications.”

Sharbel has been awarded $7 million dollars in funding from GIFS, $369,000 in funding from the Agricultural Development Fund, as well as an additional $47,150 from Sask Canola.

Breeding “hurdles”

According to Habibur Rahman, a canola breeder at the University of Alberta, apomixis is mostly found in polyploid species (plants that receive more than one set of chromosomes from parent plants) but not diploid species (plants that receive only one set of chromosomes from parent plants), like canola.

“This is a long way from plant breeding,” says Rahman. “Apomixis has been found in other species, but the gene has to be brought into canola to see if it works. I don’t anticipate that we’ll see this in breeding programs for a long time.

“It’s a long-term project but it has major benefits if the work pays off, if we can bring it into canola.”

Rob Duncan, a canola breeder at the University of Manitoba, says plant breeders have been working on apomixis for more than 100 years. “There are major hurdles to overcome,” he says. “But it would be an amazing development to be able to utilize apomixis. If you could produce seed asexually costs would go down, and the whole hybrid production scheme would change.”

Like Rahman, Duncan foresees difficulties in application. “The reason we haven’t made great progress on it over the past century is that (apomixis) can be difficult to work with. They’ve worked with it for decades in corn,” he says.

One challenge for hybrid seed production, Duncan says, is that breeders would also need a mechanism to turn apomixis on and off in a plant.

“You’d want to take traits from one parent and combine them with another parent, but then once you’ve made that cross and brought in the variation, you’d want to turn back on the apomixis so that the new genotype could produce asexually,” he explains.

Breeders would also have to maintain agronomic traits in new genotypes, while removing negative “linkage drag” that might come along with apomictic traits.

Sharbel’s lab has a patent on one of its candidate genes and is working on a patent for the second. He says patenting allows GIFS to protect the technology so that his team can move forward with their ideas and ensure the technology isn’t “wasted.” His goal is to avoid exclusively licensing the technology to just one company.

“This has to come out for the benefit of humanity,” he says. “Single generation hybrids are a dream but you have to aim for a dream.”

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Julienne Isaacs

Julienne Isaacs is a Winnipeg-based freelance writer and editor. Contact her at [email protected]

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