In these volcanic valleys of central Mexico, on the Canadian prairie, across India's northern plain, they sow and they reap the golden grain that has fed us since the distant dawn of farming. But along with the wheat these days comes a harvest of worry.
Yields aren't keeping up with a world growing hungrier. Crops are stunted in a world grown warmer. A devastating fungus, a wheat "rust," is spreading out of Africa, a grave threat to the food plant that covers more of the planet's surface than any other.
In Chicago, London and other money centers, the wheat market is so roiled by bad news and speculators that rising prices may put bread out of reach for millions more of the world's poor.
As he tended his 2 kilometer-high (mile-high) field here, where ripening grain nodded in the wind, Jose Emiglio Taboada was troubled — about a changing climate, about crop diseases, about "really, really expensive" fuel and fertilizer.
"I like growing wheat, very much. It's a beautiful thing to do," said this farmer and son of farmers. "But for our children to be interested in growing wheat, it has to be profitable."
Far to the north, Rolf Penner is growing less interested.
On his 770 Manitoba hectares (1,900 acres), "I probably had 50 percent less in wheat this year than I used to," the Canadian said. "Wheat hasn't had the productivity gains other crops have."
On the other side of the world, on the Punjab Plain, Indian grower Ramanjit Singh Mansaia had little choice as he readied for November's planting. Government marketing is heavily geared toward wheat — for the naan, chapati and other bread staples of the Indian diet.
Mansaia is unhappy. "Global warming is increasing," he said by cellphone from his village, Safipur Kalan.
"I used to have a very, very bumper crop, a healthy crop. Now I'm getting very, very poor performance" — 20 percent less grain, he said, as the wheat matures too quickly in rising temperatures.
The future of wheat — in many ways the future of food — was the subject of an emergency meeting of agricultural officials who flew to Rome from around the world in late September, concerned over skyrocketing prices.
Since July, when traders saw a historic heat wave devastating Russia's crop, prices on the world's wheat exchanges have shot up 50 percent. Corn and other grains rose in lockstep.
Then Mozambique was rocked by riots over rising bread prices, and 2010 began to look like 2008, when an even bigger spike in cereal prices touched off violence worldwide.
After its Sept. 24 session, the Intergovernmental Group on Grain, sponsored by the U.N.'s Food and Agriculture Organization (FAO), said the role of outside speculators in grain markets should be examined. But the specialists said they saw no repeat of 2008's crisis on the immediate horizon.
That same day, however, the FAO warned that big wheat-importing countries such as Egypt, half of whose 80 million people rely on government-subsidized bread, would be hard hit by billions of dollars added to their import bills.
"You will probably have a longer period of high prices, a feature we should get used to," FAO economist Abdolreza Abbassian, secretary of the grain group, told The Associated Press.
Will wheat prices ever settle back to the low, steadier levels of 2005 and earlier? "No," he replied. "We've ruled out that possibility."
Since 2005, the FAO's cereals price index has doubled. Meanwhile, the number of chronically undernourished in the world has swelled, standing today at an FAO-estimated 925 million — one-seventh of humanity.
Feeding the world, 9 billion people by 2050, will mean boosting food output globally by 70 percent over 40 years, the FAO says. But wheat, the biggest source of protein in poorer countries, is falling behind: As global population grows 1.5 percent a year, the growth in wheat yields — the amount of grain produced per hectare — has slipped below 1 percent a year. In the U.S., yields generally peaked in the 1990s.
In the face of leapfrogging prices, stagnating yields and shifting climate zones, wheat cannot be counted on to fill mankind's stomach in the future as it has since at least 7000 B.C. And affordable substitutes are often unavailable in places like India and Egypt.
"Humanity faces tremendous challenges to food security," the world's top wheat researchers conclude in a blueprint for a stepped-up strategy to produce more of the grain.
Across the 4,100-meter-high (13,500-foot-high) Tlaloc sierra from Taboada's farm — the mountain where Aztec farmers prayed to their rain god — these researchers search for more scientific ways to boost crop yields at CIMMYT, Spanish-language acronym for the International Maize and Wheat Improvement Center, whose $60 million budget and global staff of 700 are supported by governments and foundations worldwide.
The most urgent task facing CIMMYT is to stop the spread of the virulent wheat stem rust, first identified in Uganda in 1999 and dubbed Ug99.
"You're talking about a nasty rust strain being at the doors of a country like Pakistan, which grows 9 million hectares of wheat. And you have India next door," said Etienne Duveiller, CIMMYT's head wheat pathologist. "You need to make sure you don't come up with a disaster."
Stem rust, most feared of wheat scourges, was thought largely defeated after the late American agronomist Norman Borlaug and other CIMMYT pioneers crossbred high-yielding, rust-resistant wheat varieties in the 1960s. But the resurgent rust has overcome those old resistance genes.
Its spores, billions carried on the winds, land on wheat plants, germinate and send threadlike tentacles into the stem, sucking up nutrients and growing into reddish-brown, blister-like pustules that kill the plant.
From Uganda, the rust spread into Kenya, wiping out most of the crop in recent years, and on to Ethiopia and Sudan, across the Red Sea to Yemen and, most recently, to Iran. Millions of farmers in its path cannot afford mass fungicide applications.
Scientists believe Ug99 will inevitably reach the breadbaskets of south Asia, and beyond. U.S. soldiers returning from the region might unwittingly bring home spores in their clothing or gear.
"Probably the biggest concern right now is of transport by people," said Les Szabo, a rust researcher at the U.S. Agriculture Department's Cereal Disease Laboratory in St. Paul, Minnesota.
A stem rust outbreak in 1953-54 wiped out almost half the wheat in Minnesota and the Dakotas. Today, said Szabo, "approximately 80 percent of the wheat currently grown in the U.S. is susceptible."
His team, working with Ug99 kept in high-security storage, is studying its molecular structure for quicker detection and crossbreeding wheat in search of resistant varieties.
Duveiller and other CIMMYT researchers, meanwhile, lead the hunt for defenses in developing countries, drawing on 150,000 wheat types preserved in a refrigerated, earthquake-proof seed bank, and on the test fields in CIMMYT's 40-hectare (100-acre) complex.
Rather than look for a single "silver bullet" resistant wheat gene, one a sudden fungal mutation might overcome, they seek arrays of traits in wheat plants that complicate the rust's development, by killing wheat cells near the spore, for example, to stall its spread.
Developing these multiple "minor gene" defenses is a slow process, requiring crossbreeding and growth of generations of new varieties, to inbreed traits and test them.
Since research intensified in the mid-2000s, thousands of varieties have been flown from Mexico and elsewhere to Kenya, to be tested against the endemic Ug99 itself at Njoro, in the highlands north of Nairobi. Nine new CIMMYT wheat types proved promising and have been sent to countries in the Ug99 front line.
Eventually, however, researchers must find lines to replace almost all the thousands of wheat varieties grown worldwide, and that could take another five to 10 years, Duveiller said, calling it a global "race against time."
"I believe in science, so I believe we can address even big challenges," the Belgian scientist said. "But let's cross our fingers."
The biggest challenges may come from climate change. Although wheat might first flourish, it would eventually suffer in a warmer world.
More carbon dioxide in the atmosphere, the chief global warming gas, should help plant growth. Rising temperatures should open more of Canada and Siberia to wheat. Scientists find that slight warming helps wheat yields in temperate zones.
But if temperatures rise more sharply, as climatologists predict, the yield begins to plummet. Warming will change precipitation patterns that generations of farmers have relied on, and evaporate water more quickly. And climate change will upset other natural balances.
"The evolution of pests and diseases is very much a function of climate," said Matthew Reynolds, CIMMYT's chief of wheat physiology.
"If the climate is changing, then new races can spring up in a very unpredictable fashion. It could be seen as the greatest threat of climate change to agriculture."
Even moderate temperature rises, meanwhile, are shrinking crops in regions already at a heat threshold for wheat, like north India, as farmer Mansaia and Indian agronomists report.
"We estimate that for every degree increase, the yield may be decreased by 10 percent," said Hans-Joachim Braun, head of CIMMYT's wheat program.
Researchers warn of trouble spots: Warming is expected to reduce Nile River water flows by 40 percent, imperiling Egypt's already inadequate wheat crop; the Beijing government's climate assessment says warming could cut China's wheat and rice output by up to 37 percent.
And the American breadbasket is not immune, noted analyst Lester Brown of Washington's Earth Policy Institute, who has long foreseen global food shortages.
"What if the heat wave centered in Moscow this summer, what if that heat wave had been centered in Chicago?" Brown asked. "And we lost 40 percent of the grain crop, 160 million tons of grain? There would be chaos in the world grain market right now."
In these volcano-rimmed valleys of Tlaxcala state, farmers sense the change scientists measure.
"Extreme drought. Then this year too much rain," Taboada recalled.
CIMMYT's Reynolds elaborated: "This year in central Mexico we had the wettest summer on record, and last year we had the driest. This typifies the kind of risk we're going to face with climate change."
Taboada is adapting, switching to a furrowing method that holds water better, building his own furrowing-seeding-fertilizing machine to cut fuel use by doing more with each pass over his fields.
In the marketplace, meanwhile, he feels less uncertainty, since local farmers the past two years could enter into futures contracts for their crops for the first time.
"It protects farmers against price fluctuations," he said.
If he looked across the northern border, however, he might wonder about the future of futures.
With such contracts, farmers establish a guaranteed floor price for a set amount of wheat to deliver months down the road. Historically, this was a way to steer prices into a range relatively predictable for everyone in the market, from farmer to baker.
But the U.S. in the 1990s began loosening regulation of oil, grain and other commodity futures. Investment banks created index funds based on these futures prices, and by the mid-2000s billions were pouring into the new vehicles, from pension funds and others seeking diversification.
The speculative holdings, especially on the Chicago grain exchange, exploded from $15 billion in 2003 to $200 billion in 2008, U.S. Senate investigators report. And grain futures prices leaped with them, from about $3 a bushel of wheat in mid-2006 to more than $11 in early 2008, before falling back as overextended banks and investors sold off.
Crisis and riots followed in grain-importing countries worldwide as the street prices for bread doubled and tripled. The U.N. estimated 40 million more people were pushed over the hunger line.
The gains, meanwhile, did not always reach farmers, since the here-and-now cash price they were getting lagged the wildly traded futures. And sharply higher fuel and fertilizer costs cut into their margins.
Not everyone sees a major cause-effect link between market speculation and the 2008 food price crisis.
"Everybody wants a simple answer, and there is no such simplistic answer. Markets are complex," said Layne Carlson, secretary of the Minneapolis Grain Exchange.
Other factors were in play: Weather problems with harvests; a growing appetite for meat, and hence feed grains, in China and India; rising demand for corn for ethanol. But Senate investigators last year found "significant and persuasive evidence" that commodity index traders were a major cause of the price spike, and Congress has taken action.
Under this year's Dodd-Frank financial reform law, the Commodity Futures Trading Commission (CFTC) in 2011 will rein in speculation by imposing limits on how many futures contracts individual firms can hold.
Such tightening up will work better if Europe's commodity exchanges, centered in London, are similarly tightened, closing off loopholes for global traders. But the European Union has no CFTC-style commodities regulator.
"The French government has proposed creating one. I think it's absolutely essential," said analyst Steve Suppan of the Institute for Agriculture and Trade Policy, a Minneapolis think tank.
The EU's internal markets chief, Michel Barnier of France, wants action, calling speculative bets on food "a scandal." But he may face British opposition.
As lawyers and economists on two continents work to make wheat more affordable via the markets, scientists in Mexican test fields, Minnesota greenhouses and elsewhere will work to make wheat more productive — for the pasta and naan, the Wheaties and Chinese dumplings, the Egyptian pita of the future.
They have big plans: A year-old global research consortium has set a goal of boosting wheat yields by 50 percent in 20 to 25 years. It will mean "redesigning" the wheat plant. They're consulting structural engineers, for example, about how a stem can support a fatter head of grain.
Getting that fatter head may require genetic modification, the engineering of life forms that still arouses public opposition, slowing current research on "GM wheat."
Such opposition is "self-delusion," said Thomas A. Lumpkin, CIMMYT's director-general. "GM is necessary."
Wheat physiologist Reynolds envisions, for example, possibly transferring a gene from rice to give wheat more heat tolerance.
What's also necessary, Lumpkin said, are large boosts in government funding for agricultural research, after a period of "short-term thinking and complacency about global food security," leading up to the 2008 crisis.
The American agronomist worries, however, that CIMMYT's longtime supporters, including the U.S., may pull back.
"With the financial crisis, people and countries are becoming more selfish and shortsighted," he said. "We're very fearful about our future with these traditional donors.
"And the consequences are in the future — when food becomes scarce."