Hopes grow for climate-proof beans

A breakthrough in the development of temperature-resilient beans could help sustain a vital source of protein for millions of people around the globe, the BBC reports.

The news offers a glimmer of hope for many farmers in developing nations.

Climate projections suggest that 50% of the countries' bean production will be lost by 2050 if farmers do not have access to the new variety of bean.

The discovery was made by plant breeders at CGIAR, a global agricultural research group.

One of the plant breeders involved in the research, Steve Beebe - a senior bean researcher at the International Center for Tropical Agriculture (CIAT) - explained that bean plants were, as a rule, very sensitive to excessive heat.

"Typically, beans are not grown in environments where the night temperature is above 18C (64F) or 19C," he told BBC News.

"Night temperatures are especially critical because the bean flower pollinates itself during night hours and the pollination process is very sensitive to temperature.

"When we talk about heat tolerance, we are especially concerned about the night-time temperatures."

Dr Beebe said the team wanted to see if there were varieties that displayed a trait of coping with night-time temperatures in the region of 23C.

"We gathered up the lines that we had in our breeding programme - lines that had been selected for other traits such as drought tolerance, which has been a high priority as well.

"We also pulled some lines off the shelf that were the result of a crossing programme about 12-15 years ago between our common bean and a tepary bean.

He explained that the tepary bean was a neglected crop, grown by native Americans in the southwest US and Mexico in very hot and dry environments.

"We first started evaluating them for drought tolerance but when we decided to go into temperature evaluations, we selected these along with a much larger line of beans selected for drought or disease resistance," he recalled.

"We looked for varieties that were able to set pods and produce seeds in those conditions. We selected about 30 materials that were promising. That meant it was about 3% of our material that was of any interest at all.

"When we looked at what we had selected, the vast majority went back to the crosses that we had made 12-15 years ago."

Dr Beebe said the tepary bean as a food crop was not a popular cultivar.

"The grain type is very unusual, it is very small - only about half the size you are probably accustomed to.

The plant type is not agronomically acceptable because it is very low growing and spreads," he said.

"But it has some very interest traits of heat tolerance and drought tolerance."

The beans, nicknamed heat-beaters, could help maintain a valuable source of protein and iron for almost half a billion people as the world warms, if researchers are able to get seeds to farmers.