De-Domesticated Weedy Rice Is Unintended Legacy of Green Revolution

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By Washington University In St. Louis
March 25, 2020

Biologist Kenneth Olsen Tending Rice

Biologist Kenneth M. Olsen has a tendency rice within the Jeanette Goldfarb Plant Growth Facility at Washington University in St. Louis. Credit: Joe Angeles/Washington University

A brand new world learn about finds the level to which high-yielding rice sorts preferred within the a long time because the “Green Revolution” will be apt to head feral, turning a staple meals crop right into a weedy scourge.

Weedy rice is a de-domesticated shape of rice that infests paddies international and aggressively outcompetes cultivated sorts. A brand new learn about led by means of biologists at Washington University in St. Louis presentations that weed populations have advanced a couple of instances from cultivated rice, and a strikingly excessive percentage of recent Asian weed lines will also be traced to a couple of Green Revolution cultivars that had been broadly grown within the overdue 20th century.

The scientists imagine {that a} common procedure is at paintings, performing at a genomic and molecular stage to permit fast adaptation to weediness. The new learn about is printed March 26, 2020, within the magazine Genome Biology.

“One of the hallmarks of the Green Revolution was the use of cross-breeding to create high-yielding cultivars,” mentioned Kenneth M. Olsen, professor of biology in Arts & Sciences. “For rice and many other crops, this involved hybridizing traditional varieties to combine their best traits. This type of rice breeding was very different from traditional rice farming, where varieties aren’t cross-bred and farmers replant seed from their own harvests.”

The Green Revolution was once an generation of era switch that introduced high-yield sorts of rice, maize, and wheat to the creating global, greater than doubling the cereal manufacturing in creating nations from 1961 to 1985. Changes in irrigation, fertilizer and seed construction led to outstanding productiveness positive factors.

But there have been different much less predictable results.

“Once you start hybridizing different varieties, you can wind up with all kinds of new traits, including some that are unexpected and undesirable,” Olsen mentioned. “What we learned from our study is that one of those unexpected side effects was a propensity of the elite cultivars to go feral and emerge as agricultural weeds.”

Olsen and his collaborators used complete genome sequencing to inspect the foundation and adaptation of 524 world weedy rice samples representing all main areas of rice cultivation.

Much like a circle of relatives tree, the brand new genomic research presentations relationships amongst weedy rice lines and demonstrates the level to which the similar genes are concerned every time a brand new weed pressure evolves.

This is the primary such learn about to incorporate weedy rice lines from in every single place the sector in one research.

“One of the huge advantages of being able to sequence entire genomes nowadays is that we can achieve very high-level resolution in figuring out who is related to whom,” Olsen mentioned. “This same approach is being used now with the novel coronavirus to track the sources of new infections as they show up in new locations.”

“For weedy rice, we were able to infer that a lot of the weed strains that are now widespread in Asia are very closely related to rice cultivars that were first developed during the Green Revolution.”

Olsen is a countrywide knowledgeable in weedy rice. The National Science Foundation not too long ago awarded $2.6 million to Olsen and collaborators to resolve what makes weedy rice one of these fierce competitor.

“Although the genetic mechanism isn’t especially surprising, what did really surprise me was what a high proportion of weedy rice in Asia originated this way,” Olsen mentioned. “We estimated that over a 3rd of the weed lines now infesting some areas of China most likely advanced from elite cultivars.

“From our previous studies in other regions, we knew that some weedy rice strains have likely been around since the earliest days of agriculture,” Olsen mentioned. “What’s now clear is that weedy rice has probably been emerging repeatedly throughout the 10,000-year history of rice cultivation — right up to the present day.”

Reference 26 March 2020, Genome Biology.DOI: 10.1186/s13059-020-01980-x

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