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Apomixis 101

Apomixis could be called the Holy Grail of plant breeding. According to Rob Duncan, a canola breeder at the University of Manitoba, scientists have been working on it since the 1840s. Even Gregor Mendel, the father of modern genetics, caught the apomixis bug, analyzing the apomictic properties of hawkweed species in the 1860s.

What is apomixis, exactly? According to Ross Bicknell and Anna Koltunow, authors of a review of apomixis in The Plant Cell, “Apomixis in flowering plants is defined as the asexual formation of a seed from the maternal tissues of the ovule, avoiding the processes of meiosis and fertilization, leading to embryo development.”

Apomixis was discovered in 1841, write Bicknell and Koltunow, when it was observed that a lone plant from Australia continued to form seeds when planted in Northern England’s Kew Gardens.

It isn’t a “freak of nature,” however — apomixis has been observed in at least 40 flowering plant families, though few crop plants are apomictic (exceptions include some fruit trees).

What’s the appeal of apomixis to plant breeders? There’s a grab-bag of responses to this question — individual plants with desirable characteristics could be propagated as exact clones through their seed; wild genetics could be more easily integrated into breeding programs; and the development of new cultivars could speed up dramatically.

Tim Sharbel, Global Institute for Food Security (GIFS) research chair in seed biology, says apomixis would allow companies to quickly introduce new varieties of field crops.

“It would rapidly speed up the breeding process. If you can do single generation hybrids you can bring breeding programs from five to 10 years to two to three years. It’s not at all stopping the evolutionary potential, it’s enabling us to harness much more evolutionary potential,” says Sharbel.

Apomictic plants, he says, could be developed using biotechnological or gene editing tools; they’d still have to go through regulatory process, but the development process would be more efficient, and the end result would satisfy everyone.

“What the farmers want is quality, and quality is defined by the purity of your seed. What apomixis would do is produce genotypes with high purity,” he says.

How long it will take for breeders to successfully apply apomixis in field crops, nobody knows. But the dream is as alive now as it was in the 1800s, and better funded. If the GIFS’ massive investment in apomixis pays off, it remains to be seen who will benefit most from this “disruptive” technology. Like most questions about apomixis, the answer to this last question is not straightforward. “

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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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