Maize for dryer, hotter climates

New technologies such as drones are speeding up breeding to provide farmers with maize varieties that stand up to climate change. Despite severe drought in Zimbabwe, new maize varieties bred to withstand heat and drought have yielded twice as much as commercial varieties, helping farmers ensure household food security.

New maize varieties conventionally bred to withstand extreme weather are helping farmers stay one step ahead of climate change in sub-Saharan Africa.

Temperatures are increasing in Africa and the past three decades have been the warmest on record, according to the International Panel on Climate Change.

Farmers are especially feeling the heat in sub-Saharan Africa, where maize is the key staple food crop and nearly all of it is grown with increasingly erratic rainfall, rather than irrigation.

“We are no longer sure when to prepare the land for planting or when to start planting,” said Appollonia Marutsvaka, a 62-year old farmer from Zaka, a rural village in Zimbabwe. “If the situation persists, then most of us who have small farms will sink deeper into poverty.”

Concerned by the expected impact of increasing heat on African maize yields, researchers at the International Maize and Wheat Improvement Center (CIMMYT) began breeding heat tolerance into maize five years ago, crossing their lines with sources of heat tolerance and selecting the best offspring.

In 2016, the new, hardy maize was put to the ultimate test by a severe regional drought, which was brought on by the El Niño weather phenomenon and described by the United Nations as the worst in decades.

“El Niño had a devastating impact on agricultural production in southern Africa and high temperatures have been one of the biggest yield-reducing factors associated with El Niño, in many areas of Zimbabwe,” said Jill Cairns, a senior maize physiologist at CIMMYT.

Zimbabwean farmer Appollonia Marutsvaka displays her heat- and drought-tolerant maize.

Marutsvaka tested CIMMYT’s climate-smart maize and said it worked in her fields. Despite the harsh drought, she was able to harvest enough from the trial plot to round out grain stores in her household.

“In the past, I harvested nothing as my crops were literally burned by the scorching heat,” she said. “During the 2015-2016 growing season, I realized almost 200 kilograms of white grain.”

Overall, the on-farm trials showed that the heat- and drought-tolerant varieties yielded twice as much as current commercial maize varieties in a severe drought, so farmers who grow the new maize can improve their harvests even under difficult conditions.

The value of foresight

New crop varieties take years to develop, and the new heat- and drought-tolerant varieties would not be available if researchers had not started breeding for those traits, based on climate change projections back in 2011.

“If breeding had only started with demand, the first heat-tolerant varieties would not have been ready until 2021 and many more people would have gone hungry,” Cairns said. “This underscores the need for breeding programs and investments to keep pace with the latest climate projections.”

Most maize varieties grown in Africa were bred over 30 years ago for a much cooler climate. CIMMYT’s maize breeders are working to speed up breeding efforts to help farmers stay ahead of climate change.

“It is more than just a single variety, it’s a process,” said Cairns. “Our investments in breeding efficiency through new molecular and phenotyping tools helped us develop heat-tolerant varieties that yielded so well under El Niño in just five years.”

Drones cut the time it takes to monitor crop health from days to minutes.

Traditionally, varieties can take up to 20 years to reach farmers. However, new technologies, such as data from flying drones loaded with cameras and other sensors can cut the time to monitor crop health from days to minutes.

Scientists are also working in public and private partnerships to improve seed systems and speed the deployment of climate-ready varieties to farmers.

The importance of adapting African agriculture to climate change was highlighted at the 2016 Marrakech Climate Change Conference, and the story of heat-tolerant maize in Zimbabwe was shared as an example of how agriculture can adapt to a changing climate.

Maize breeding work in Africa is supported by the U.S. Agency for International Development, the Bill & Melinda Gates Foundation and the CGIAR Research Program on Maize.

Revolutionizing crop observation tools

Focusing on the rapid advance in technologies to observe and record plant growth using technologies such as drones and automated sensors, 200 world-class scientists from over 20 countries gathered at CIMMYT headquarters in Mexico for the 4th International Plant Phenotyping Symposium.

Aiming to make breeding for food crops faster and more effective, experts shared news on the latest tools to measure plant traits and, combined with cutting-edge genetics and statistics, to sharpen their understanding of how crops adapt to the environment– a research area known as “phenotyping.”

In addition to learning from each other’s experiences, a half day was dedicated to drafting position papers on priority areas for future research and a keynote talk and discussion on harmonizing the many phenotyping platforms that have emerged in recent years.

CIMMYT partnered with the International Plant Phenotyping Network to organize the event.

Text: Matthew O'Leary

Contributor: Jill Cairns

Photos: Johnson Siamachira

Graphics: Gerardo Mejía

Editors: Bianca Beks, G. Michael Listman, Julie Mollins, Geneviève Renard

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