research: Genetic resources

The fates of farmers and maize landraces in the central highlands of Mexico hinge on complex interactions between global and local economies

Researchers, the media, and members of civil society organizations from many quarters have expressed a concern for the perceived loss of native Mexican maize diversity, either through its replacement by scientifically improved varieties or simply the out-migration of the peasant farmers who created and often serve as custodians of this diversity. The number of landraces grown has declined as a result of these phenomena, according to CIMMYT research, but native diversity is still valued and conserved by local farmers.

The intertwined fates of farmers and native maize in the Valley of Toluca, in the Central Mexican Highlands, illustrate the complexity of the forces at work. There, challenges of international competition are balanced by specialized opportunities from large urban markets. Surprisingly, the native races sometimes still hold sway over improved maize varieties.

Farmers seek options in a shifting economy

Ricardo Becerril is a relatively young man, but speaks with the quiet authority of an elder. When asked if the maize varieties grown by generations of farmers in the Toluca Valley are in danger of extinction, he furrows his brow and seems to pull the response up from a well of experience on his father’s farm. “No, not here,” he says. “They’ve worked for us, even without being improved—or at least having had only minimal, empirical selection.”

Today Becerril is hosting a group of some 20 farmers from his home community, Taborda, who came to hear a presentation on organic agriculture. Like nearly all Valley farmers, he is continually seeking new and better options, as the Mexican economy and climate around them shift rapidly. These farmers are large-scale and prosperous by developing country standards, with average holdings of 10 hectares or more and the swelling urban markets of Toluca and Mexico City nearby. They express longing for times past, when they could still live off sales of the maize they grew. That livelihood began to fade in 1994, when the North American Free Trade Agreement (NAFTA) opened Mexico’s borders to a flood of subsidized maize from the USA. Now, even with dramatic hikes in maize prices from the biofuels boom, farmers barely cover production costs with grain sales. So, adding value to their traditional skill of maize farming, soon after NAFTA they found a new use for their harvests. “We can’t profitably sell the maize, so we feed it to sheep and cattle,” says Becerril, whose family’s homesteads fatten some 300 to 400 head a year.

When biomass beats grain

Becerril and the other Toluca Valley farmers grow a range of crops, including wheat, oats, and sorghum, but maize is their mainstay. Their local varieties, “criollo blanco” and “criollo amarillo”—essentially, indigenous white and yellow—have previously walked the knife-edge of extinction, according to Dagoberto Flores, research assistant in CIMMYT’s Impacts Targeting and Assessment Unit. “The farmers told me they once replaced their native landraces with improved varieties a number of years ago,” says Flores. “They didn’t like the improved maize, because it was shorter and produced less forage, so they went back to the native varieties. I asked them if they hadn’t lost the seed of the landraces. They said, ‘certainly not—some of the older farmers were still growing the old seed on small plots, so we were able to get it back.’ ”

Flores has talked to farmers in Taborda and other communities in the Toluca Valley as part of CIMMYT studies on the value of maize residues for forage and on local markets for this commodity. The Center is promoting zero-tillage and other resource-conserving practices that normally require farmers to leave stalks and leaves from the previous crop on the soil surface, rather than feeding them all to farm animals. In either case, where forage production brings a premium, a plant type like that of the native maize, with more above-ground biomass, might be advantageous.

Becerril grows an assortment of maize hybrids, but still sows and trusts the native maize. Among other things, he likes the criollos’ yields and the fact that their seed is cheap or free and available locally. “If we can’t make ends meet with our local varieties, how are we going to do it with the hybrids?” he says. “You buy it one year and there’s good seed, and the next year it’s not available. I strongly believe that we should conserve our locals—the hybrids or transgenics will never perform the way as our criollos do.”

The value of diversity

In the maize germplasm bank of CIMMYT, there are 23,000 unique samples of native maize seed, including the Toluca Valley landraces, kept against the day humanity may require it. Much of this maize is no longer grown in farmers’ fields. “Among other things, this diversity represents a hedge against new crop diseases or pests,” explains Suketoshi Taba, head of maize genetic resources at CIMMYT. He cites a recent example of CIMMYT researchers in eastern Africa developing new maize varieties that resist larger grain borer. The pest can chew through a third of a farmer’s grain store in six months. “That resistance came from Caribbean maize seed collected 40 or 50 years ago and enhanced through breeding programs,” Taba says. He and his team also regularly provide researchers or farmers with seed from older collections of native maize to “enhance” the more recent versions, thereby making it more likely that farmers will benefit from growing them.

If farmers stay on the land, so will the maize

Pedro León Peredo’s spry leap from a roaring tractor totally belies his 73 years of age. Native of Los Reyes village in the Toluca Valley, he grows about 20 hectares of maize, oats, and pasture to fatten some 200-300 head of sheep and calves a year. He uses maize hybrids, but also raises considerable stands of the criollo maize. He fertilizes his land with manure, plows in some residues, and rotates crops—especially the local and hybrid maize types: “We’ve tested the hybrids, and after growing them for several seasons in one place, they take up all the nutrients and then don’t grow or yield well,” he says. León also tells Flores of a rainy, windy year where the heavier native maize fell over but the hybrids gave good yields.

Most of the farmers Flores interviewed are 40 years old or more, reflecting the demographics of out-migration. “They are the ones who really appreciate the criollos, saying they make tortillas that are sweeter and store better than those from hybrid grain,” according to Flores. “They say even the animals prefer forage from the native maize.”