Penn State root research results in breeding of improved bean plants for Africa

Farmers in Angonia, Mozambique, happy with the performance of new varieties of common bean developed by an international partnership of plant scientists that included researchers in Penn State's College of Agricultural Sciences, pose among plants in a bean field. Plant breeding field trials have been conducted with bean growers in multiple regions of the country in southeast Africa. - Image: Jimmy Burridge

In the culmination of more than a decade of research on root traits conducted by Penn State plant scientists, about three tons of seed for common bean plants specifically bred to thrive in the barren soils of Mozambique will be distributed there Dec. 11.

Farmers, nongovernmental organizations and seed companies in eight villages across the central region of the country in southeast Africa will receive seed for bean plants that possess an enhanced ability to acquire the essential nutrient phosphorus. The distribution is a joint event led by the Mozambican Institute of Agrarian Research (IIAM), with support from Penn State, the International Center for Tropical Agriculture (CIAT), the McKnight Foundation and the U.S. Agency for International Development.

"This is an important milestone, the product of many years of effort here at Penn State in collaboration with our international partners, especially in Mozambique," said lead researcher Jonathan Lynch, distinguished professor of plant nutrition. "With long-term support from our sponsors, we were able to translate scientific discoveries to the practical impact of new bean lines with better stress tolerance."

Because planting season in Mozambique is January and February, the December distribution of seed for more productive bean plants is perfectly timed. Common beans are extremely important as a protein source for smallholder farmers and people living in lower socioeconomic circumstances around the developing world, particularly in southeast Africa, where beans are the primary protein source.

Common beans are extremely important as a protein source for smallholder farmers and people living in lower socioeconomic circumstances around the developing world, particularly in southeast Africa, where beans are the primary protein source. - IMAGE: Neil Palmer/CIAT

Most soils in Mozambique — one of the poorest nations in Africa, where farmers cannot afford to buy fertilizer if it is even available — are extremely deficient in phosphorus. So developing plants more efficient at taking up the scant available phosphorus is critical. For 11 years or so, Lynch's research group in the College of Agricultural Sciences has focused on developing bean plants more adept at taking up phosphorus.

Research has revealed that long and dense root hairs are associated with much more efficient phosphorus uptake, noted Jimmy Burridge, a senior postdoctoral researcher in the Lynch laboratory. And acquiring more phosphorus enables a plant to be more robust and to grow longer roots to follow water down the soil profile.

"For years we have worked to identify traits or characteristics associated with root systems that are related to better performance, and we have passed our findings on to plant breeders, who use them to integrate those root characteristics into new lines," he said. "They have created crosses between varieties with long, dense root hairs and varieties that grow best in Mozambique's harsh conditions."

Studies have shown that bean plants with long, dense root hairs have increased disease tolerance just because they are healthier, Burridge explained. With better nutrition, plants are more energetic — able to grow faster and be more productive.

Penn State research has revealed that long and dense root hairs are associated with much more efficient phosphorus uptake. Acquiring more phosphorus enables a plant to be healthier, more robust and to grow longer roots to follow water down the soil profile, resulting in it being more productive. - IMAGE: Jonathan Lynch Research Group/Penn State

Penn State's contribution to improving southeast Africa's food-security prospects will endure well beyond the release and distribution of these new bean lines, Lynch pointed out.

"When we began our work in Mozambique many years ago, there were few trained colleagues in the country, so we first engaged in training several Mozambican scientists, who returned to their posts and are now our partners there," he said.

One, Celestina Jochua, who earned her doctoral degree from Penn State and was advised by Lynch a few years ago, now is working as a plant breeder with IIAM. She spearheaded the effort to develop the new bean lines.

The initiative is one of very few cases in which selection for root traits has been used to improve yield, according to Lynch. There has been considerable scientific interest in deploying root traits in crop breeding because roots are so important for plant growth where drought and low soil fertility are common, but there are few success stories because root biology is complex and challenging.

The new bean lines will have much better yields in Mozambique's barren soils and stressful growing conditions than the best lines previously available, researchers say, so families and communities will have more food security and income. - IMAGE: Jimmy Burridge

"The success of this effort shows the way for others to develop more stress-tolerant crops, which are urgently needed in developing countries for food security," Lynch said. "And it's also strategically important for the sustainability and resilience of agriculture in America and other wealthy nations, which confront increasing drought and heat stress from global climate change."

But for now in Mozambique, the new bean lines will have much better yields in stressful conditions than the best lines previously available, so families and communities will have more food security and income, Lynch said.

"This breakthrough shows the value of agricultural research in enabling new technologies that will help us overcome the grand challenge of the 21st century — how to sustain 10 billion people in a degrading environment."