To prevent lodging, Borlaug would have to modify his wheat by breeding it with wheat varieties that had stalks—“straw,” in the jargon—short and rigid enough to support the increased grain. Breeding for shortness, in fact, might be a double win. It would protect the grain that his varieties were already producing from lodging. But it could also mean that the plants would spend less energy producing inedible straw. Short plants would take in just as much energy from the sun as tall plants, but they could channel more of that energy into creating grain. A field of short plants might feed more people than a field of tall plants.
Unfortunately, viable short plants would not be easy to find. Taller plants are more likely to see the sun, and thus more likely to grow and reproduce. Genes for shortness, conversely, put plants at an evolutionary disadvantage, and so are discouraged. In breeding for shortness, Borlaug would be fighting natural selection.
Compounding the difficulty was the second problem: a powerful new variety of P. graminis had shown up in the United States. Since the First World War, Stakman had cultivated a network of farmers who sent him samples of the rust growing in their fields. Much as medical researchers today monitor the development of new strains of influenza, Stakman was looking for the onset of new strains of stem rust. His Minnesota students would test each sample against a cluster of twelve standard wheat varieties, comparing its effects to those from other known varieties. In 1938 a farmer had sent Stakman a rust sample from a barberry bush in New York that had escaped the anti-barberry crusade. In tests, the New York rust rapidly killed all twelve standard wheat varieties. U.S. Department of Agriculture (USDA) researchers conducted their own experiments and “established beyond a doubt that every commercial variety of wheat then grown in the United States and Canada was susceptible.” So were all of Borlaug’s varieties in Mexico.
Luckily for farmers, the new rust strain—15B in Stakman’s catalogue of stem-rust “races”—didn’t seem to spread easily. It was deadly, but not especially contagious. Stakman watched 15B for more than a decade as it confined itself to a few areas around remnant barberry bushes. He worried that it would suddenly become more virulent. Exactly this came to pass in 1950; 15B exploded across the entire U.S. wheat belt in a matter of weeks. Nobody could account for the change. A mutation, a buildup of critical mass, favorable weather conditions—whatever the reason, decades of progress against stem rust were about to be wiped out.
Alarmed, Stakman and his USDA counterparts convened the first-ever international stem-rust conference in November. Borlaug attended and gave a report on Mexico. The attendees decided to establish in seven nations rust-monitoring programs that in years to come would prove a valuable tool for rust-fighting. But that tool would do nothing in the short term. Even as the researchers met, 15B was racing south on the Puccinia highway, crossing the Rio Grande. Borlaug knew that the Bajío, already plagued by rust, would soon be hit harder; Sonora, now thriving, would be flattened. In the affluent United States, 15B would lead to reduced harvests and hardship for farmers; in poor rural Mexico, it would lead to malnutrition and ruin.
In April 1951 race 15B was detected in Mexico for the first time; by summer it was charging through the Bajío. Seeking to avoid calamity, Borlaug set up four large nurseries in central Mexico and tested 15B against sixty-six thousand wheat varieties: sixty thousand from his own work, five thousand from a USDA collection of world wheats, and a thousand other lines from various parts of the Americas. This was a huge task, though he now had more help; over the years, the Mexican Agricultural Program had trained more than five hundred young researchers, of whom it had hired more than a dozen. Despite the assistance, the results were disturbing. Of the mass of wheat varieties, only four survived 15B, most of them relatives of the Kenyan types Borlaug was already using. And none of the four helped him with his other problem—they weren’t short. A few of the sixty-six thousand varieties had short straw, but the rest of the plant was small, too, including the cluster of grain-bearing spikelets at the top. Miniature plants, miniature harvests. And in any case all the short plants were susceptible to rust.
The following summer Borlaug both examined the candidates from the previous year more carefully and tested all of the thirty thousand varieties in the USDA wheat collection. The task was even larger, but it met with even less success. Every single one of the USDA wheats fell to 15B, including all the varieties with short straw; at one growth stage or another, so did almost all of the potential rust-resisters from the previous year. Borlaug’s team had now exposed tens of thousands of lines of wheat to 15B. Only two varieties had survived, both descended from the four original survivors: Kentana 48 and Lerma 50 (the numbers represent the year each variety was first produced). Lerma 50 was highly resistant but made terrible bread. Until it could be crossed with wheat with better baking characteristics, Mexican farmers would have to plant Kentana 48—what choice did they have? It would keep the rust away, keep the harvests growing. But a single variety for an entire nation—it was not a situation that could endure for long.
Astonishing in retrospect, Harrar and the Rockefeller Foundation leaders in Manhattan chose this moment to expand the Mexican Agricultural Program. Wellhausen, the maize breeder, had resuscitated Rockefeller’s maize venture by establishing high-tech facilities to breed U.S.-style hybrid maize for Mexican conditions—exactly the sort of effort Carl Sauer had warned about, exactly the sort of effort Mexican researchers and politicians had wanted. But the project flagship had become Borlaug’s wheat. Harrar, once skeptical, had become an enthusiast. Ignoring the new varieties’ susceptibility to rust, Harrar seized on the early signs of success to argue that the Mexican Agricultural Program should be expanded to other nations, even other continents. The foundation agreed and promoted him to program director.
To begin the expansion, Harrar went to India; Joe Rupert, Borlaug’s former housemate, traveled to Colombia. Borlaug was sent to Argentina. Accompanying him was USDA researcher Burton B. Bayles. Arriving in November 1952, the two men discovered, quickly and unhappily, that rust afflicted Argentina, too. Borlaug was in a grim mood. Bad enough that his tests had generated just two potential candidates that resisted 15B, he told Bayles. But a second new strain of P. graminis—race 49 in Stakman’s stem-rust catalogue—had shown up in the Bajío that spring. By August it had become clear that both Kentana 48 and Lerma 50 were susceptible to 49, Kentana perhaps a little less than Lerma. Now Borlaug did not have a single variety that could withstand attack. And he still had not found a single plant with both a short stem and a normal cluster of spikelets. Despite more than a decade of drudgery, Borlaug’s program was tottering.
A prerequisite for a successful scientific career is an enthusiastic willingness to pore through the minutiae of subjects that 99.9 percent of Earth’s population find screamingly dull. Bayles and Borlaug ruminated about the quirks of Puccinia graminis as they toured the pampas, running through one possibility after another. The basic problem had been understood for decades: wheat that fended off one rust race could always be susceptible to another. Borlaug asked if it would be possible to create a “composite” wheat—a variety with many types of resistance. What if he found a line of wheat that was immune to 15B and crossed it with a line immune to 49 and then crossed the result with other lines immune to other races? Bayles told him that the standard answer was that wheat was simply too complex. Each time he crossed one line with another, there was a chance that the genetic reshuffling would bury the desirable traits he had elicited in previous crosses. The likelihood skyrocketed if the breeder was crossing many lines at once. Every throw of the darts threatened to undo the results of the previous throws. Borlaug asked if the odds could be overcome by running truly massive trials—tens of thousands of crosses, year after year, a staggering amount of work—with high selectivity. “You might just get away with it,” Bayles said, in Borlaug’s recollection.
Along the way, Bayles told Borlaug that a colleague, Orville Vogel of Washington State University, was
also experimenting with a variety of short wheat. Known as Norin 10, it had been sent to Vogel by a U.S. agricultural researcher in postwar Japan. Ordinary wheat was almost the height of a tall man; Norin 10 plants barely reached to the knee, dwarfs “so damn short,” the researcher wrote to Vogel, “they’re pretty much underground!” After returning from Argentina, Borlaug wrote to Vogel. Cheerful and generous, a tinkerer known as much for his farm-equipment inventions as his plant breeding, Vogel was happy to share this odd Japanese wheat. A carefully packed envelope arrived in Mexico the following summer. Inside were eighty seeds: sixty of the original Norin 10, twenty from Vogel’s own experimental crosses.
In November 1953 Borlaug planted the Norin 10 at Sonora. As Vogel had said, Norin 10 had short straw and normal-sized cluster of spikelets, exactly the architecture he was looking for. But the dwarfs proved quiveringly vulnerable to 15B. The new race of P. graminis consumed them like so many sticks of kindling in a fire, felling each and every plant before it produced a single kernel of wheat. Borlage’s supply of Norin 10 vanished, and with it his only source of genes for the right kind of shortness. Meanwhile, none of the thousands of other crosses he had performed grew up short.
Outside the experimental station, Kentana was still keeping 15B at bay. In an inexplicable bit of luck, race 49 had been mostly quiescent that year. Up north, 15B was causing the worst catastrophe to hit midwestern wheat farmers since the Dust Bowl. Sooner or later, both would arrive in Sonora. Borlaug had limited time to get ready, and he had just lost a breeding season—and all of his Norin 10—with nothing to show for it.
Borlaug returned to Mexico City and his family the following spring. Dourly he went to Chapingo to make the next big round of crosses. By this time the Rockefeller Foundation had built a new building for the work; the tarpaper shack, still in use, slumped against it. When he went inside the shack, he came across Vogel’s envelope of seeds, thumbtacked to a wall with scores of others. To Borlaug’s surprise, eight kernels of Norin 10 were still inside.
Eight seeds! He still had a chance to grow plants with short straw—if he could keep them away from rust. Working with exquisite care, he sowed the seeds in individual pots under grow lights in the basement of the new building. Each pot was wrapped in fine gauze that would block rust spores. Visiting his eight plants daily, he watched them sprout and grow—but only to two feet. By controlling the lights, he was able to induce the dwarfs to flower at the same time as his other varieties. He crossed them with the newest versions of his most resistant wheat varieties, Kentana and Lerma, which he had also grown in gauze-wrapped pots in the basement. At the end of the summer, he harvested about a thousand seeds from the crosses.
Packed in bags, the seed went with him to Sonora, where he planted it in the open. No grow lights, no gauze wrapping, just a thousand plants, crosses of Kentana and Lerma with Norin 10, on a plot tucked away in the rear of the experimental station. Most of the plants were short—the dwarfing gene was dominant, as geneticists say. But rust quickly killed hundreds of them. Worse, many of the survivors were sterile. Still, about fifty of the plants fended off 15B, barely reached Borlaug’s thighs, and produced grain. And these plants looked good in so many other ways. Each plant not only produced more grain heads than typical varieties—they “tillered profusely,” as farmers say—but each head had more and bigger spikelets than typical varieties.
After so much failure, things were abruptly going right. Chance, finally, had favored him: he had hit a clutch of bull’s-eyes at once, success quick and unpredictable as failure. The fifty short plants provided a few thousand seeds—just enough for the next generation of crosses. Wary of setbacks, Borlaug said nothing to his superiors about what he was doing. He went to Chapingo, planted these seeds, and bred them to other plants with multiple strains of resistance to P. graminis—15B, 49, and every other weapon in rust’s arsenal. Then back to Sonora to do it again. Now test for milling quality. With the predictable perversity of nature, the dwarfs—so superior in so many ways—had soft, shriveled, low-protein seed that made terrible flour. So he had to breed in milling quality, too. Then taste, and maybe color. The process took another five years, but the plants stayed short, and they kept tillering profusely and not lodging, and the grain was plentiful, and beginning to be usable.
The difference between the dwarf and ordinary wheat was striking, as shown in this photograph, taken in Sonora in 1957, of two plots of wheat planted side by side at the same time. Credit 31
By 1960 Borlaug and his team were ready to show off the new varieties. Every April, just before harvest, the Sonora station had a field day, where local farmers could see what the scientists were doing. Tractors pulled wagonloads of visitors through the fields, stopping at a dozen stations where researchers and staff standing by chartboards would explain their work. The dwarf varieties, grown in plots that couldn’t be seen by visitors from the road, would be a surprise. Borlaug knew that farmers plagued by lodging would understand instantly the implications of dwarf wheat. But he didn’t want them simply to grab the seed—the new varieties still didn’t produce grain that could be easily milled. To keep farmers out of the field, Alfredo García, the young Mexican agronomist at that station, instructed the tractor drivers not to let visitors off the wagons when they stopped by. On field day, Borlaug later recalled,
I stood off at a distance and watched what happened when these first wagons pulled up. As the first one pulled up—there were about six of them—[García] motioned to the tractor driver to move that one up further so he could bring another three in, and then he was going to tell them not to get off the wagons. But after he had finished talking to the tractor driver, he looked around, and I’ll bet there were 50 farmers in these plots [of dwarf wheat], pulling out the heads and showing this and showing that. From then on, it was chaos. [García] lost his temper. He lost control. He started to curse. It was a real show. And then some of these wheats got away right there.
The seed, Borlaug knew, would be impossible to retrieve. It would be planted the next season and taken to the mill. If the mill owners rejected the grain because it didn’t make good flour, that would be a disaster for the Mexican Agricultural Program. He was pretty sure that he was just a year or two away from wheat that would make excellent flour. The key, he thought, was to convince the mills to take the grain, even if it was not yet ready. By this time, Borlaug had gained some credibility and had some support in the capital. He had learned to speak rough Spanish and had a forceful manner when needed—he was not above jabbing a finger into a man’s chest and leaning close to make a point. He called on the mills and told their owners that next harvest they would be getting batches of poor-quality grain from Sonora and they should—they would—buy it anyway, because it would be good for the country, absorbing the losses was their patriotic duty, and it would be only one or two seasons because he would fix the dwarf strains in the interim. (He was right; the better varieties were released in 1962.)
At the same time, he was exultant—García’s bellowing, impotent fury on field day was the soundtrack of success. In the ass-end of nowhere Borlaug and his Mexican team had created something new to the world: an all-purpose wheat. Short, fecund, and disease-resistant, it could be sown in soil rich or poor anywhere in Mexico and produce well. As long as farmers provided water and fertilizer, the plant would thrive and the harvest would be large. The fertilizer could be cow manure or bird guano or bags of chemicals made in factories. The water could be from rain or concrete irrigation channels. It didn’t matter: pile on the inputs and the grain would grow in quantities greater than ever before, he thought, cascades of wheat that would banish hunger for millions.
The new wheat varieties were not a permanent solution to farmers’ problems. Driven by the inexorable forces of evolution, new variants of stem rust and other pests would emerge. Wheat breeders would have to create new varieties to combat them. Hidden inside the genes of the new varieties were now-unknown negative traits that sooner or later would show up i
n the field (scientists call this “residual heterozygosity”). Breeders would have to figure out how to eliminate their effects. And there were places where the new varieties wouldn’t prosper: farms in unusually hot places, unusually wet places, or places with soil contaminated by metal or salt. Breeders would need to develop special strains for them. Still, Borlaug and his team had created something new.
Later Borlaug would think of these new, high-yielding seeds as part of a package, the other pieces being adequate nutrients (which meant, mostly, plentiful fertilization) and water management (which meant, mostly, careful irrigation). The package—seeds, fertilizer, water—was like one of the antibiotic pills that had, astonishingly, come into doctors’ offices after the war: an entity, the product of faraway scientists, which could work its magic anywhere, at any time, as good at wiping out bacteria in Ireland as it was in Indonesia. Borlaug could take the wheat package to any part of the globe. The seeds and fertilizers and water practices would have to be adjusted to local conditions, much as pharmaceutical companies packaged their universal antibiotics into shots or pills or liquids or nasal sprays according to local preferences. But the idea was that the guts of the package would work anywhere.
The package was a turnkey, ready for use. Switch it on, and yields would skyrocket. No longer did farmers have to worry much about local varieties or particular soil conditions or (if they had irrigation) even the weather. Just follow the instructions, same here as anywhere else; the package was good for everyone. It freed farmers from the land—or, anyway, took a giant step toward that goal.