AgBioResearch

Long before people started keeping agricultural records, they were growing soybeans. Archaeological digs in East Asia have revealed that domestication of the crop stretches back almost 9,000 years. Since then, soybean cultivation has expanded to nearly every corner of the globe.

Though raw soybeans are toxic to most mammals, including humans, cooked soybeans are an excellent source of essential nutrients such as protein, dietary fiber, iron, manganese, phosphorus and vitamin B.

Soybean oil plays an important role in cooking, baking and food processing, as well as in biodiesel production and other industrial applications. Soymeal – the plant matter left over once the oil has been extracted – is a reliable source of livestock feed throughout the world. Like other legumes, soybeans also function as nitrogen-fixers, improving soil health by restoring the nitrogen lost during the cultivation of other major crops such as corn.

Phinehas Tukamuhabwa, director of the Makerere University Agricultural Research Institute in Uganda, has been studying and breeding soybean varieties that meet Ugandan farmers’ needs since 1990.

“When I was in graduate school, I read a great deal about the potential soybeans held for economic development,” said Tukamuhabwa, who is also associate professor in the Department of Agricultural Production at the university. “It was a relatively unexplored crop in Uganda back then, but it has become very important for our farmers.”

Soybeans reached Africa in 1858, when they were first cultivated in Egypt. Today soybeans are grown in 47 of the 54 nations in Africa, including Uganda.

Ugandan farmers first began growing soybeans in 1913. Throughout the 1920s and 1930s, scientists developed soybean varieties tailored to Uganda’s specific climate conditions. Production flourished through World War II, when soybeans were an important source of protein and edible oils for the Allies. Soybean production declined with the war’s end, but ramped up again in the 1970s, driven by renewed interest in staple crops. A push for serious soybean research to develop modern cultivars and crop management systems began then.

Soybean yields in Uganda have more than tripled since the end of World War II according to the United Nations Food and Agriculture Organization. Today the crop contributes about $45 million to the nation’s economy. Processing facilities have been built to turn raw soybeans into soybean oil, soy cake, livestock feed and other products.

Ensuring that Ugandan farmers can successfully grow soybeans is an ongoing challenge for researchers. As diseases like soybean rust threaten the crop, the work of conventional breeding of disease-resistant cultivars becomes more urgent. Diseases, however, are not the only challenge that farmers face in their fields.

Tukamuhabwa estimates that nearly 50 percent of the cost of soybean production in Uganda is incurred in weeding and seedbed preparation. Done primarily by hand, this difficult, expensive and time-consuming labor limits the profitability of Uganda’s farmers, many of whom are smallholders without access to the advanced equipment and extensive fields available in more developed nations.

New technology, new possibilities

In 2015, Tukamuhabwa attended a workshop in Brazil for African scientists and policymakers. The gathering was coordinated by the African Biosafety Network of Expertise, a network launched in 2008 through a partnership between Michigan State University (MSU) and the New Partnership for Africa’s Development. The network works to help African nations improve their decision-making capacity on biosafety and biotechnology topics.

While in Brazil, Tukamuhabwa observed genetically modified soybeans growing in the field. During a subsequent visit to MSU, he met Karim Maredia, professor in the MSU Department of Entomology and director of the World Technology Access Program, or WorldTAP.

“Karim and I discussed soybeans and issues farmers in Uganda face while growing them,” Tukamuhabwa explained. “He put me in touch with the researchers at MSU, and through them we were able to acquire new soybean varieties with traits that could make a tremendous impact on our soybean industry.”

Through Maredia, Tukamuhabwa met MSU AgBioResearch soybean geneticist Dechun Wang, who used soybeans featuring a genetically modified trait that rendered them resistant to glyphosate herbicides, namely Roundup, in his soybean breeding program. Common in agriculture in the United States, glyphosate-resistant soybeans allow farmers to spray their fields with highly effective glyphosate herbicides, wiping out weeds quickly, efficiently and cost-effectively, without damaging their crops.

“A broad-spectrum herbicide, like glyphosate, makes plant production much lower in cost,” Wang, professor in the MSU Department of Plant, Soil and Microbial Sciences, said. “The glyphosate-resistance trait makes weed control much easier than traditional herbicides; it’s very convenient for farmers and reduces both the cost of weed management and the number of sprays they need to apply.”

Glyphosate is regarded as one of the safest, most effective herbicides available to farmers. It requires few applications to control a wide range of weeds and, once applied, breaks down very quickly in the environment, leaving little in the way of potentially harmful residue.

While Uganda’s government has authorized the testing of several genetically modified crops, including bananas, cassava, corn and sweet potatoes, introducing new biotechnology requires careful vetting by the country’s biosafety committee. Ruth Mbabazi, research assistant professor with WorldTAP and a Makerere University alumna, helped shepherd Wang’s soybean lines through the Ugandan regulatory process.

Highlighting his partnership with MSU’s scientists became a key element of the information package Tukamuhabwa assembled for the biosafety committee on the work he hoped to accomplish.

“The committee knows that there are limits to scientific knowledge in the developing world,” said Mbabazi, who worked with regulatory agencies in Uganda for 12 years before coming to MSU. “They want to know that experts like the ones here at MSU are willing to help their scientists learn how to use these new technologies.”

Planting the future

In 2017, two years after first meeting Maredia and Wang, Tukamuhabwa was finally able to begin growing the genetically modified soybeans in a greenhouse at the Makerere University Agricultural Research Institute.

Developed for cultivation in Michigan, the crops would mature much too quickly if planted in Uganda’s climate. Consequently, the plants would produce far fewer soybean pods, resulting in a yield too small to be of value. So the first task was crossbreeding the glyphosate-resistance trait from Wang’s varieties into soybeans better suited for Uganda.

“The major challenge we face right now is getting the glyphosate-resistance trait from the U.S. varieties into the soybeans suited for our own environment,” Tukamuhabwa said. “By backcrossing the MSU varieties with our own, we can ensure we have the best of both worlds.”

The team has already completed two backcrosses, with a third in progress. Once that is completed, he anticipates moving the plants out of the greenhouse and into a confined field trial.

Crops grown in greenhouse trials don’t perform the same as they would under normal agricultural conditions. They don’t reach their natural height, nor do they experience the stresses brought on by pests, diseases and fluctuating weather conditions. Seeing how the new cultivars perform under field conditions is an essential test to ensure their utility to farmers. Tukamuhabwa estimates it will take about four years to complete all of the necessary trials.

Helping educate the public about his research with genetically modified crops is also key to Tukamuhabwa’s work. As in much of the rest of the world, genetically modified organisms, or GMOs, remain a contentious issue, and Tukamuhabwa wants to make sure farmers who use GMOs understand them.

“We need to give people all the information we can, so they can see for themselves that this technology is safe, both for them and for their farms,” Tukamuhabwa said. “That means showing them this has been deemed safe in the other countries that have used it, as well as conducting our own safety studies.”

For Tukamuhabwa, his work is about helping farmers improve their livelihoods and helping consumers gain access to better, healthier food.

“If the plants I develop are resistant to diseases, allow for clean, weed-free fields and produce a good yield for farmers, I feel very good about that,” Tukamuhabwa said. “Having soybeans that perform well in the field and make a difference in farmers’ lives is why I do this, and these glyphosate-resistance varieties may help accomplish that.”

For Maredia, this represents yet another productive relationship between MSU and its partners abroad.

“This is a very good case study that shows what we are working on here in Michigan can also help the world without investing a great deal more money into it,” Maredia said. “We already had this technology developed for our farmers here, but at the same time we were able to use it to help farmers in developing countries. That’s part of MSU’s mission, reaching out to the world.”