Imagine it’s 1935, and you’re a Soviet agronomist.

Not just any agronomist, though. You’re the founder and head of the Lenin All-Union Academy of Agricultural Sciences.

And among your many accomplishments, your research had led you to  propose that certain crops… like the rye that helped  feed your fellow comrades… were basically an accident.  Humans didn’t domesticate them. Thanks to evolution, they domesticated themselves. Oh, and your reward for all your hard  work?

You just lost your job. One of your academic rivals  has the ear of Joseph Stalin, and neither of them believe  biology works the way you do. You are Nikolai Ivanovich Vavilov.

And the next eight years of  your life do not get better. But decades after your death, scientists totally got your  back, and proved you were right. [♪INTRO] Let’s turn back the clock just a bit,  and establish Vavilov’s credentials. This was a guy obsessed  with the history of plants.

Or more specifically, the  science of the history of plants. I’m talking stuff like heredity,  genetics, and natural selection. He did a lot of research trying to find where important crops were first domesticated, and what happened as they spread  to other parts of the world.

He also basically invented  the concept of a seed bank, and there is a great story about  the one he founded in Leningrad. But we don’t have time to get to that, today. Domestication is the process of  humans turning wild plants and animals into versions that are useful  to us and that we take care of.

Meanwhile, cultivation is  what we call it when farmers grow and care for those domesticated plants. But for as long as there  have been cultivated crops, there have been weeds, unwanted  plants growing among the crops and competing with them for space and resources. For most of human history, farmers’ approach to weeding was pretty basic.

They looked for plants that didn’t belong and used plows, hoes, or just their hands to yank them out. This means that the weeds that  looked the most like the crops they were infiltrating would  have been the most likely to escape farmers’ notice, survive,  and pass on their genes. That’s right!

Those farmers became the unwitting agents of natural selection. And this brings us to the  concept of Vavilovian mimicry! You may have heard of other types  of mimicry, like Batesian mimicry.

That’s where a tasty or harmless animal copies the appearance of a bad-tasting or dangerous one. But those caterpillars  didn’t just start off looking like tiny snakes by sheer coincidence. It took generations for the  less snake-looking caterpillars to get eaten before they  got to pass on their genes!

Our weeds don’t want to die, either. And the ones more likely to stay  growing in the field are the ones that best resemble the crop  the humans are trying to grow. And in some cases, evolution wound up making a weed that was such a good crop mimic, it wound up making a new crop-quality plant.

This is what Vavilov figured out, based on his years of investigating crop domestication. He traced wheat, which humans domesticated around 10,000 years ago, back to an area of southwestern Asia where it was especially genetically diverse and had a long history of cultivation. And when he was there, he learned that some wheat farmers saw rye as a weed, and made a point of removing stray rye stalks from their fields.

In fact, you can translate  the Turkish common name for “rye” to “the plant that  torments the wheat and barley”! Based on this, Vavilov realized  that early wheat farmers could have accidentally  domesticated rye by nudging it to blend in with wheat  better and better over time. Rye would have developed bigger, easier-to-harvest seeds as it evolved to more closely match wheat.

Because rye is also more cold-  and drought-tolerant than wheat, farmers realized what they had  and started growing it on purpose. The earliest evidence for domesticated rye dates to about 8600 years ago! Now, Vavilov didn’t name all of these weed-to-crop mimics after himself.

He called them secondary crops. And today, we’ve identified a lot  more examples of secondary crops, and even confirmed them with genetics studies. For example, a study published in 2022 backs up Vavilov’s original idea that  rye started out as a weed.

And multiple studies have shown that at least one common variety of oat originated this way! As oats got better at mimicking barley, they evolved bigger seeds that  stayed on the plant until harvest, instead of dropping off as  soon as they were mature. Yet another crop that started out  as a Vavilovian mimic is false flax, an old oilseed crop that’s now seeing a resurgence as a potential biofuel source.

But not every Vavilovian mimic  turns into a useful crop. Sometimes, natural selection  just makes sneakier weeds. For example, some populations  of a weed that grows in Chinese rice paddies have evolved to  look more like baby rice plants.

This makes it harder for farmers  to find and get rid of them… they’re definitely still weeds, though. But Nikolai Vavilov would not live  to see any of these developments. I mean, it would be hard for a man born in 1887 to read a paper published in 2022.

But in the 1930s, the USSR wasn’t really a great place to be a great scientist. For one thing, Vavilov believed  in the importance of collaboration and worked with plant scientists  in other, non-Communist countries. This was at a time when the  Soviet Union was becoming more and more isolationist, so  Vavilov’s connections made some of his fellow Soviets suspicious  that he might be a spy.

Meanwhile, Stalin was more into  pseudosciences that fit with his own worldview than he was the ideas of  legitimate researchers like Vavilov. One of the dictator’s favorite  so-called scientists was a guy named Trofim Lysenko, who rejected what was known about genetics and evolution at the time. Instead, he claimed that  environmental stress could spontaneously transform one  type of crop into another.

This fit well with Communist  ideas about the right environment creating better, tougher  people who could then pass these improvements onto future generations. Meanwhile, the real science  of genetics, which Vavilov was a proponent of, was  actually seen as anticommunist! Somewhere along the way, Lysenko  started badmouthing Vavilov, and even blamed him and other agronomists for his own research failures to  develop new and improved crops.

The USSR went through a really  bad famine in the early 30s, so it makes sense that people  would be wanting solutions fast. But maybe the government shouldn’t have put a guy in charge who believed in utter baloney, and then told an actual expert to work under him. By 1935, Vavilov had been dismissed as head of the academy he founded.

Lynsenko, meanwhile, would be given  the position three years later. Then, in 1940, Vavilov was arrested in Ukraine, while on a collecting expedition. He died of starvation in a Soviet prison in 1943.

And for a while, his contributions  to science were forgotten. Which is a bummer. But things  started turning around in 1955, when Vavliov received a posthumous pardon from Stalin’s successor, Nikita Khrushchev.

The Soviet scientist once accused of failing to feed his country even  got enough of a reputation glow-up to get his face on an 1987 postage stamp. Which I think works as a 100th birthday present. And over the past few decades,  more and more botanists and weed scientists have come to appreciate  Vavilov’s ideas and theories.

Granted, some scientists have  argued that secondary crops aren’t “true” mimics, because of  all the accidental human meddling. But, scientists have been using the term Vavilovian mimicry since at least 1982. And now, what started out  as a quirky idea about weeds domesticating themselves is  a widely accepted theory.

It’s probably even more  important, now, as humans try to develop fancy, high-tech ways to control weeds. For example, today’s agriculture  scientists are working on new ways to use cameras and machine learning to identify individual weeds  for spraying in fields. This could provide a whole new  source of selective pressure, and create a new generation of Vavilovian mimics!

Sunflowers and sugar beets, for example, both already have weedy relatives  that look a little bit like them, and could become even more like them with a nudge from natural selection. So on the one hand, we could  be forcing ourselves into a never-ending arms race  with the weeds in our fields. But on the other, we could stumble  into another way to feed people.

And keeping the world fed is,  objectively, a good thing. So thank you, Nikolai Vavilov. Not only for showing us how  plants can domesticate themselves, but upholding science when forces  around you would rather you not. [♪OUTRO]