The Why Files The Why Files --

Lessons from the green revolution


Learning from the green revolution
As the world faces major food shortages, we wonder what we can learn from the green revolution -- the international effort to improve productivity, starting with corn, wheat and rice. Starting around 1960, and spearheaded by the International Center for Corn and Wheat Improvement (CIMMYT) in Mexico, and the International Rice Research Center (IRRI), in the Philippines, the revolution was funded by the Rockefeller and Ford foundations.

Three men in swaddled  headgear lean over green rice stalks in a large research plot
Researchers at the International Rice Research Institute in the Philippines transfer a gene to give rice resistance to a disease called blast.  Photo: Ariel Javellana, IRRI

The green revolution centers developed and distributed high-yield varieties to poor countries, starting in South Asia and Latin America. For his leadership, Norman Borlaug, a wheat breeder at CIMMYT, earned the 1970 Nobel Peace Prize. The system is called, clunkily, the Consultative Group on International Agricultural Research, or CGIAR. The core mission is simple to encapsulate: breed and distribute better seeds, but the reality is more complex. Plant breeding takes years, and after the basic breeding work is done, the CGIAR centers try to transfer improved seeds to national agricultural centers, for tailoring to local conditions.

Older man in white lab coat and khaki hat stands among a group of researchers in frong of a jeep and a cornfield
In 2006, green-revolution pioneer Norman Borlaug (second from left) talks with Kenyan and CIMMYT leaders at an experimental farm in Kenya. Photo: USDA

Which can be problematic. Local conditions are constantly changing. And while the national research centers in a few developing nations, especially China, India and Brazil, are so proficient that they no longer need much help from the CG system, many nations are poor and/or chaotic, and their agricultural research centers barely function. At the same time, the local varieties and crop relatives that are needed for breeding are under threat as farmers replace them with modern varieties.

 Four lines jaggedly descend in a similar path on a graph
One sign of the decline in farm research appears in funding levels for scientists in Africa, home to the worst agricultural-productivity problems. Graph: IFPRI (see #4 in the bibliography).

Agriculture research works, but it’s a slow, steady process
So what has the CG system done for us? The best evidence -- which, admittedly, comes from within the CG system -- appears in periodic “impact assessments,” which seek to measure how many farmers are using CG seeds, and how the new varieties affect yields. A major assessment, published in 2003, found that the green revolution has had revolutionary results. “The overall impact of the international research centers over their 40-year history has been huge,” says study co-author Doug Gollin of Williams College. “I don’t think that was a surprise, anyone who looked at world agriculture would have recognized the influence of the international scientific community and of plant breeding. The surprise was how widespread the successes were, and how much they included crops and regions where the green revolution was not imagined to have had much impact.”

graph of contrbutions of modern varieties
Yields have steadily risen in Latin America and Asia, the original beneficiaries of the green revolution. But in Africa and the Middle East, the benefits largely began in 1980. Notice that the rate of increase picked up during the second period in all regions. The green revolution was a process, not a one-time jackpot, and persistence pays. Data from #6 (see bibliography).

Generally, after the first victories in rice, wheat and corn production, the green revolution was more or less taken for granted, and assumed to have benefited only those three crops, Gollin says. But he argues that the overall impact was much broader. “In contrast to the popular perception … it was surprising to find impacts in other crops, other parts of the world.”

The green revolution did not “occur at a historical moment,” Gollin adds. “We found that it was a process. The application of scientific methods to agricultural problems of the developing world was something that resulted in a sustained, long-term increase. Instead of a one-time jump, we saw an increase in the growth rate as this scientific tool kit came to the developing world.”

Stay focused on the core mission
After the successes of the green revolution, the CG system expanded to new crops and then to concerns beyond farming, notes Gregory Traxler, professor of agriculture economics and rural sociology at Auburn University. “They started out with four centers, to a large extent they were crop-improvement centers, with a relatively confined research agenda.” These centers cover rice (IRRI), corn and wheat (CIMMYT), and the tropics (the International Center for Tropical Agriculture and International Institute for Tropical Agriculture).

“I don’t know if any other agricultural research activity has had more impact than the crop improvement of those four centers,” says Traxler. “The huge impacts have been documented time and time again, and yet funding for those activities, the core activities of the core centers, has been declining over time” in favor of CG centers devoted to forestry, water management and fisheries, where, Traxler says, “there is not documented evidence for success.”

The core CGIAR centers remain critical to helping the poor feed themselves, Traxler insists. “Having a strong, centralized place where you can do pre-breeding, maintain the genetic reserves … has proven to be a very efficient model, more efficient than people expected. There will be a permanent need for someone to take leadership of that crop-breeding activity.”

Don’t take agriculture research for granted
The plant-breeding techniques of the green revolution were largely imported from developed countries, which, ironically, now seem less than fascinated with ag research, says Tracy. “People in the industrial countries have been taking agriculture research for granted for 40 to 50 years, and … in many Two men stand in greenhouse, appraising tall green bean plantcases, we don’t have the infrastructure to do the research that we need to do.”

Robin Buruchara and Suleiman Sebulliba in the bean research greenhouse at the Kawanda Agricultural Research Institute in Uganda. Photo:

Seed companies, he points out, “are telling universities they are going to need 1,000 PhD plant breeders in the next 10 years, and there is no way we have the capacity to train them.” For decades, biologists have been fascinated with reading and manipulating genes, but corn breeder William Tracy hopes the “whole-plant” approach may be edging back into fashion. The ability to read and manipulate genes, he says, can now be used to “understand how the whole plant actually works,” but to assess drought resistance, you will “not get the whole picture if you work entirely at the cellular level. We need people who are able to go out in the field and understand drought resistance at the field level.”

The question of soil fertility
The green revolution was most effective in places with good moisture (from rain or irrigation) and soil that was either fertile or could be amended with fertilizers. These factors help explain why the revolution came “too little and too late” to Africa, where vast areas are short on water and key plant nutrients.

Plant breeders have struggled to create varieties that thrive in poor, dry soils, and here’s a promising new tactic: Breed plants by emphasizing the efficient root structure that can extract scarce water and nutrients. Jonathan Lynch, a professor of plant nutrition at Penn State, notes that 85 percent of the land that could grow common beans (including string beans and soybeans) in southern Africa is deficient in the critical nutrient phosphorus.

In these areas, poor roads and poor farmers derail the “truck-in-the-fertilizer” solution.

Roots extract moisture and nutrients from the soil, and their environment is much more complex than that of the better-studied leaf. “Every leaf is going to experience the same carbon dioxide level, the same temperature,” Lynch says, but for roots, soil temperature, chemistry and presence of helpful or harmful microbes can vary inch by inch.

Roots are difficult to study, as Lynch observes. “For many years, people did not know how to evaluate roots … you might have to destroy the plant to see them, and once you pull them up, they look like spaghetti. Everybody knew roots are important for drought tolerance, tolerance of low soil fertility, but no-one knew what to look for.”

In breeding crops for unfertile soil, Lynch prefers to avoid starting with modern, highly productive varieties, which are bred for good soils, where an extensive root system would Graph has four pairs of bars, the right bar is consistently lower than the right bar in each pair sap too much energy from aboveground parts of the plant. Instead, Lynch starts with “land races,” locally adapted strains that farmers have developed over the centuries. With experience, Lynch says, good roots can often be distinguished by eye, within a few days of sprouting, which trims the long breeding timeline.

Carioca is a variety of the common bean ( Phaseolus vulgaris) that yields well on fertile soil, but takes a big hit when phosphorus is low. Screening for better roots identified three locally adapted beans that excel in low-phosphorus soils, without sacrificing too much productivity on good soil. Data from Steve Beebe, CIAT (see #3 in the bibliography).

The beans that have emerged from the roots-first approach, Lynch says, have “dramatically improved productivity” in low-phosphorus soils. “Good root traits can improve growth by 200 to 300 percent, and the yields may be double or triple. We have successfully developed a new soybean genotype that is grown by 10 million small farmers in the low-phosphorus soil of Southern China. It is yielding significantly more, without fertilizer, or with limited fertilizer applications” (see #7 in the bibliography).

Technology is helpful. Is tech the whole answer?

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