A major breakthrough by bean breeders promises to secure the staple food of hundreds of millions of people around the world, as this vital source of protein comes under threat from rising global temperatures.
For nearly half a billion people – most of them in Latin America and Africa – the humble bean, of which there are many varieties, is the main source of daily protein.
Beans are highly nutritious – not only do they contain protein, but they also add fiber, complex carbohydrates, vitamins and other micronutrients to the diet.
Amid fears that global warming could threaten this important food, bean breeders at CGIAR – a global group dedicated to increasing food security and human health – have created 30 new types of “heat-beater” beans.
Researchers at CGIAR had previously warned that rising global temperatures could threaten bean production in the Latin American countries of Nicaragua, Haiti, Brazil, and Honduras, while in Africa, Malawi and the Democratic Republic of the Congo would be the most vulnerable, followed by Tanzania, Uganda and Kenya.
Many of the new heat-beater beans are crosses between commonly consumed types – such as pinto, white, black and kidney beans – and the heat-tolerant tepary bean, which has been grown as a staple since pre-Columbian times in what is now northern Mexico and the American southwest.
Steve Beebe, a senior CGIAR bean researcher based in Colombia, says:
“This discovery could be a big boon for bean production because we are facing a dire situation where, by 2050, global warming could reduce areas suitable for growing beans by 50%.”
He explains that the heat-tolerant beans they tested may withstand the worst-case scenario – where greenhouse gas build-up leads to an average increase of global temperature of 4 degrees Celsius (about 7.2 degrees Fahrenheit).
“Even if they can only handle a 3-degree rise, that would still limit the bean production area lost to climate change to about 5%,” he notes. “And farmers could potentially make up for that by using these beans to expand their production of the crop in countries like Nicaragua and Malawi, where beans are essential to survival.”
As well as developing the beans to have increased heat tolerance, the researchers are breeding them to contain more iron to enhance their nutritional value.
The researchers tested more than 1,000 bean lines to find the best varieties to breed for heat-tolerance. They were already looking for beans that were tolerant to drought and poor soils.
They tested the beans at facilities on Colombia’s Caribbean coast, where they deliberately exposed the legumes to nighttime temperatures well above those they would normally tolerate.
The beans are most vulnerable to rising temperatures at night, when pollination – which is very temperature sensitive – takes place.
Among the beans they found to be especially tolerant to heat was one recently brought into commercial production in Nicaragua because of its high drought tolerance.
In Costa Rica, tests with the new bean showed it produced double the normal crop yield. Beebe says they now have evidence that this increased yield was not just because of better drought tolerance but also due to heat tolerance:
“What this shows us is that heat may already be hurting bean production in Central America far more than we thought and farmers could benefit from adopting the new heat-beater beans right now.”
Beans do not only provide much-needed protein and nutrients, they also have other health benefits.
For example, Medical News Today recently reported new research that showed a variety of black bean that is commonly consumed in Mexico may help lower blood pressure and also has antioxidant properties. The researchers, from the National School of Biological Sciences of the National Polytechnic Institute in Mexico, also found evidence that proteins in the Jamapa bean can remove heavy metals from the body.