Friends are hard to come by in times of war and when you’re hungry even a single morsel of food can be your best friend. During the 1860s, in the United States, the Civil War put food security to the test. Starvation was threatening but there was one crop which helped save the people of the South. General Robert E. Lee called it “the only unfailing friend the Confederacy ever had.”
Lee called that friend a “cornfield pea.” It’s unclear whether he thought it ironic that the crop which saved so many Confederate lives was brought to the Americas by enslaved African people. Despite the pea’s association with the evils of slavery giving it a sorry reputation, it later became a popular dish all over the South, traditionally eaten on New Year’s Day. It is better known as the cowpea or black-eyed pea and bears the affectionate name of Hoppin’ John. And it continues to save millions of people from starvation.
“The cowpea has nourished people for many centuries,” said Ousmane Boukar, a cowpea breeder working with the International Institute of Tropical Agriculture (IITA) in Nigeria. “But now it needs a hand to ensure it can continue to be an unfailing friend even while the climate crisis is affecting production.” Boukar, a Cameroonian who developed a taste for cowpeas as a child, is leading a project to unite the crop with its distant cousins in the wild to develop climate-smart varieties.
Our Daily Cowpea
Cowpea (Vigna unguiculata) was first domesticated in Africa and is now grown globally. According to the Food and Agriculture Organization (FAO) of the United Nations, however, around 81% of the world’s cowpea crop is still grown in Niger, Nigeria and Burkina Faso, and about 200 million men, women and children in sub-Saharan Africa rely on it for their daily sustenance. It’s the second most widely grown grain legume in Africa after the groundnut, which incidentally moved the other way, from the Americas.
“There are two reasons why cowpea is so widely grown in West Africa,” said Boukar, who conducted his PhD research on cowpea breeding at Purdue University. “It’s packed full of nutrition, and it’s a perfect match for African climates and soils.”
Cowpea is not only rich in protein, but also in essential nutrients and digestible carbohydrates; its energy content nearly equals that of cereal grains. The seeds of some types of cowpeas cook quickly, an important consideration where fuelwood is scarce and expensive.
And it gives back to the land. Like other legumes, cowpea takes nitrogen from the air and produces nutrients that help the crop to grow and compete with other plants.
Cowpea has been adapting to the harsh African conditions for thousands of years. “It can grow in places which receive less than 300 mm of annual rainfall,” said Boukar. “And it can tolerate much higher temperatures than crops like maize.”
Cowpea Under Pressure
But those temperatures are expected to rise even further as our climate changes. There will be more weather extremes and higher incidences of some pests and diseases. Cowpea is very hardy, but even it may struggle under those conditions.
“Cowpea can take the heat, but not if nighttime temperatures reach 35°C,” said Boukar. “At those temperatures, pollen won’t develop, and without pollen we won’t get any seeds.” But distant relatives of cowpea growing in the wild in Africa can take the heat and drought better than their domesticated counterparts.
IITA breeders started looking for sources of genetic diversity in the center’s genebank. There they found 15,000 samples of cowpeas collected from more than 100 countries. “But we were just interested in 1,570 of them,” Boukar said. “Those were the wild cowpeas, and we hoped some of them might have the traits we were looking for.”
Boukar planted 200 carefully selected samples from among those 1,570 and grew them out to see how they would respond to heat and drought conditions.
“Indeed, we found a number of very promising samples,” said Boukar. “Even better, we found samples that could tolerate both heat and drought.”
Using traditional breeding techniques, they then crossed some of these crop wild relatives with high performing cowpeas to produce varieties which deliver better yields even under harsh conditions. They planted these improved plants in Nigeria, Burkina Faso and Niger to evaluate them under different conditions.
The breeders selected the best of the best and have disseminated this material to national partners so it can be used in their cowpea breeding programs.
“Now we have cowpea breeding lines which retain the good attributes of the cultivated lines – like taste, color and yield – but also have drought and heat tolerance from the wild relatives,” said Boukar. “Even a small increase in cowpea yields can benefit millions of people.”
“Cowpea is that trusty but shy friend that’s often overlooked,” said Benjamin Kilian who coordinates the cowpea and other pre-breeding projects at the Crop Trust, a non-profit independent organization based in Bonn, Germany. “This work has increased the base of genetic diversity of cowpea, and that will allow further improvement of the crop by breeders around the world.”
The team at IITA and partners have shown that a bit of attention to a friend – and to its wild relatives – can have significant dividends.
Read the original version of that article here.