Posts Tagged ‘Matthew Reynolds’

Warmer night temperatures reduce wheat yields in Mexico, scientists say

International gathering highlights cutting edge efforts to improve yields, nutrition, and climate change resilience of a globally vital staple food 

by Julie Mollins

A view from the Norman E. Borlaug Experiment Station, Ciudad Obregón, Sonora, Mexico. Photo: M. Ellis/CIMMYT.

As many regions worldwide baked under some of the most persistent heatwaves on record, scientists at a major conference in Canada shared data on the impact of spiraling temperatures on wheat.

In the Sonora desert in northwestern Mexico, nighttime temperatures varied 4.4 degrees Celsius between 1981 and 2018, research from the International Maize and Wheat Improvement Center (CIMMYT) shows. Across the world in Siberia, nighttime temperatures rose 2 degrees Celsius between 1988 and 2015, according to Vladimir Shamanin, a professor at Russia’s Omsk State Agrarian University who conducts research with the Kazakhstan-Siberia Network on Spring Wheat Improvement.

“Although field trials across some of the hottest wheat growing environments worldwide have demonstrated that yield losses are in general associated with an increase in average temperatures, minimum temperatures at night – not maximum daytime temperatures –are actually determining the yield loss,” said Gemma Molero, the wheat physiologist at CIMMYT who conducted the research in Sonora, in collaboration with colleague Ivan Ortiz-Monasterio.

“Of the water taken up by the roots, 95% is lost from leaves via transpiration and from this, an average of 12% of the water is lost during the night. One focus of genetic improvement for yield and water-use efficiency for the plant should be to identify traits for adaptation to higher night temperatures,” Molero said, adding that nocturnal transpiration may lead to reductions of up to 50% of available soil moisture in some regions.

Climate challenge

Saskatchewan farmer Brian Rugg in his wheat fields. Photo: Marcia MacNeil/CIMMYT

The Intergovernmental Panel on Climate Change (IPCC) reported in October that temperatures may become an average of 1.5 degrees Celsius warmer in the next 11 years. A new IPCC analysis on climate change and land use due for release this week, urges a shift toward reducing meat in diets to help reduce agriculture-related emissions from livestock. Diets could be built around coarse grains, pulses, nuts and seeds instead.

Scientists attending the International Wheat Congress in Saskatoon, the city at the heart of Canada’s western wheat growing province of Saskatchewan, agreed that a major challenge is to develop more nutritious wheat varieties that can produce bigger yields in hotter temperatures.

As a staple crop, wheat provides 20% of all human calories consumed worldwide. It is the main source of protein for 2.5 billion people in the Global South. Crop system modeler Senthold Asseng, a professor at the University of Florida and a member of the International Wheat Yield Partnership, was involved in an extensive study  in China, India, France, Russia and the United States, which demonstrated that for each degree Celsius in temperature increase, yields decline by 6%, putting food security at risk.

Wheat yields in South Asia could be cut in half due to chronically high temperatures, Molero said. Research conducted by the University of New South Wales, published in Environmental Research Letters also demonstrates that changes in climate accounted for 20 to 49% of yield fluctuations in various crops, including spring wheat. Hot and cold temperature extremes, drought and heavy precipitation accounted for 18 to 4% of the variations.

CIMMYT wheat physiologist Gemma Molero shares her findings with IWC attendees. Photo: Marcia MacNeil/CIMMYT

At CIMMYT, wheat breeders advocate a comprehensive approach that combines conventional, physiological and molecular breeding techniques, as well as good crop management practices that can ameliorate heat shocks. New breeding technologies are making use of wheat landraces and wild grass relatives to add stress adaptive traits into modern wheat – innovative approaches that have led to new heat tolerant varieties being grown by farmers in warmer regions of Pakistan, for example.

Collaborative effort

Matthew Reynolds, a distinguished scientist at CIMMYT, is joint founder of the Heat and Drought Wheat Improvement Consortium (HeDWIC), a coalition of hundreds of scientists and stakeholders from over 30 countries.

“HeDWIC is a pre-breeding program that aims to deliver genetically diverse advanced lines through use of shared germplasm and other technologies,” Reynolds said in Saskatoon. “It’s a knowledge-sharing and training mechanism, and a platform to deliver proofs of concept related to new technologies for adapting wheat to a range of heat and drought stress profiles.”

Aims include reaching agreement across borders and institutions on the most promising research areas to achieve climate resilience, arranging trait research into a rational framework, facilitating translational research and developing a bioinformatics cyber-infrastructure, he said, adding that attracting multi-year funding for international collaborations remains a challenge.

Nitrogen traits

Another area of climate research at CIMMYT involves the development of an affordable alternative to the use of nitrogen fertilizers to reduce planet-warming greenhouse gas emissions. In certain plants, a trait known as biological nitrification inhibition (BNI) allows them to suppress the loss of nitrogen from the soil, improving the efficiency of nitrogen uptake and use by themselves and other plants.

Victor Kommerell, program manager for the CGIAR Research Program on Wheat and Tim Searchinger, senior fellow at the World Resources Institute, answer media questions. Photo: Marcia MacNeil/CIMMYT

Scientists with the BNI research consortium, which includes Japan’s International Research Center for Agricultural Sciences (JIRCAS), propose transferring the BNI trait from those plants to critical food and feed crops, such as wheat, sorghum and Brachiaria range grasses.

“Every year, nearly a fifth of the world’s fertilizer is used to grow wheat, yet the crop only uses about 30% of the nitrogen applied, in terms of biomass and harvested grains,” said Victor Kommerell, program manager for the multi-partner CGIAR Research Programs (CRP) on Wheat and Maize led by the International Maize and Wheat Improvement Center.

“BNI has the potential to turn wheat into a highly nitrogen-efficient crop: farmers could save money on fertilizers, and nitrous oxide emissions from wheat farming could be reduced by 30%.”

Excluding changes in land use such as deforestation, annual greenhouse gas emissions from agriculture each year are equivalent to 11% of all emissions from human activities. About 70% of nitrogen applied to crops in fertilizers is either washed away or becomes nitrous oxide, a greenhouse gas 300 times more potent than carbon dioxide, according to Guntur Subbarao, a principal scientist with JIRCAS.

Although ruminant livestock are responsible for generating roughly half of all agricultural production emissions, BNI offers potential for reducing overall emissions, said Tim Searchinger, senior fellow at the World Resources Institute and technical director of a new report titled “Creating a Sustainable Food Future: A Menu of Solutions to Feed Nearly 10 Billion People by 2050.”

To exploit this roots-based characteristic, breeders would have to breed this trait into plants, said Searchinger, who presented key findings of the report in Saskatoon, adding that governments and research agencies should increase research funding.

CGIAR Research Program on Wheat Director Hans Braun (Photo: Marcia MacNeil/CIMMYT)

Other climate change mitigation efforts must include revitalizing degraded soils, which affect about a quarter of the planet’s cropland, to help boost crop yields. Conservation agriculture techniques involve retaining crop residues on fields instead of burning and clearing. Direct seeding into soil-with-residue and agroforestry also can play a key role.

Modern wheat breeding benefits high- and low-input farmers, study shows

Study results underscore the value of CIMMYT’s breeding programs.

Farmer Gashu Lema’s son harvests improved variety “Kubsa” wheat, Gadulla village, Mojo Ethiopia 2015. Photo: CIMMYT/P. Lowe

This story by Marcia MacNeil was originally posted on CIMMYT.org.

A recent article in the journal Nature Plants validates the work of wheat breeders who produce yield-boosting varieties for farmers across a range of incomes and environments. 

Based on a rigorous large-scale study spanning five decades of wheat breeding progress under cropping systems with low, medium and high fertilizer and chemical plant protection usage, the authors conclude that modern wheat breeding practices aimed at high-input farming systems have promoted genetic gains and yield stability across a wide range of environments and management conditions.

In other words, wheat breeding benefits not only large-scale and high-input farmers but also resource-poor, smallholder farmers who do not use large amounts of fertilizer, fungicide, and other inputs. 

This finding underscores the efficiency of a centralized breeding effort to improve livelihoods across the globe – the philosophy behind the breeding programs of the International Maize and Wheat Improvement Center (CIMMYT) over the past 50 years.

It also contradicts a commonly held belief that breeding for intensive systems is detrimental to performance under more marginal growing environments, and refutes an argument by Green Revolution critics that breeding should be targeted to resource-poor farmers.

In a commentary published in the same Nature Plants issue, two CIMMYT scientists — Hans Braun, director of CIMMYT’s global wheat program and the CGIAR Research Program on Wheat and Matthew Reynolds, CIMMYT wheat physiologist – note the significance of the study.

“Given that wheat is the most widely grown crop in the world, sown annually on around 220 million ha and providing approximately 20% of human calories and protein, the social and economic implications are large,“ they state.

Among other implications,

  • The study found that modern breeding has reduced groups of genes (haplotypes) with negative or neutral effects – a finding which will help breeders combine positive haplotypes in the future, including for hybrid breeding.
  • The study demonstrates the benefits of breeding for overall yield potential, which — given that wheat is grown over a wider range of environments, altitudes and latitudes than any other crop, with widely ranging agronomic inputs – has significant cost-saving implications.

Braun and Reynolds acknowledge that the longstanding beliefs challenged by this study have a range of influences, from concern about rural livelihoods, to the role of corporate agribusiness and the capacity of Earth’s natural resources to sustain 10 billion people. 

While they welcome the conclusions as a validation of their work, they warn against seeing the study as “a rubber stamp for all things ‘high-input’” and encourage openness to new ideas as the need arises.

“If the climate worsens, as it seems destined to, we must certainly be open to new ways of doing business in crop improvement, while having the common sense to embrace proven technologies, ” they conclude.   

Past, present and future of crop modelling for food security

This new publication summary was originally posted on the CIMMYT blog

Resource-poor farmers worldwide stand to gain from developments in the field of crop modelling. Photo: H. De Groote/CIMMYT.

“Crop modelling has the potential to significantly contribute to global food and nutrition security,” claim the authors of a recently published paper on the role of modelling in international crop research. “Millions of farmers, and the societies that depend on their production, are relying on us to step up to the plate.”

Among other uses, crop modelling allows for foresight analysis of agricultural systems under global change scenarios and the prediction of potential consequences of food system shocks. New technologies and conceptual breakthroughs have also allowed modelling to contribute to a better understanding of crop performance and yield gaps, improved predictions of pest outbreaks, more efficient irrigation systems and the optimization of planting dates.

While renewed interest in the topic has led in recent years to the development of collaborative initiatives such as the Agricultural Model Intercomparison and Improvement Project (AgMIP) and the CGIAR Platform for Big Data in Agriculture, further investment is needed in order to improve the collection of open access, easy-to-use data available for crop modelling purposes. Strong impact on a global scale will require a wide range of stakeholders – from academia to the private sector – to contribute to the development of large, multi-location datasets.

In “Role of Modelling in International Crop Research: Overview and Some Case Studies,” CGIAR researchers, including CIMMYT wheat physiologist Matthew Reynolds,  outline the history and basic principles of crop modelling, and describe major theoretical advances and their practical applications by international crop research centers. They also highlight the importance of agri-food systems, which they view as key to meeting global development challenges. “The renewed focus on the systems-level has created significant opportunities for modelers to participant in enhancing the impact of science on developments. However, a coherent approach based on principles of transparency, cooperation and innovation is essential to achieving this.”

The authors call for closer interdisciplinary collaboration to better serve the crop research and development communities through the provision of model-based recommendations which could range from government-level policy development to direct crop management support for resource-poor farmers.

Read the full article in Agronomy 2018, Volume 8 (12).