funder_partner: United States Agency for International Development (USAID)

February, 2005

A CIMMYT research team is using an old but effective technique to get a head start on some very advanced crop science. Their aim is to breed high yielding maize that also resists infection by a dangerous fungus. As part of a USAID-funded project, the team uses ultraviolet or black light to identify maize that inhibits Aspergillus flavus, a fungus that produces potent toxins known as aflatoxins.

The fungus is particularly widespread in maize-growing regions of Africa, and the aflatoxins it produces can cause health problems in those who ingest it in high doses. By starting with elite maize varieties, those that already cope well in drought and high temperatures, and that resist damaging insects, the project hopes to produce a “package deal” for farmers: maize lines can survive these conditions and resist Aspergillus flavus.

No continent is immune from the Aspergillus problem. During 1988-1998, losses from aflatoxin damage in the US exceeded USD 1 billion. The United States has set an upper permissible aflatoxin level of 20 parts per billion in food, and the European Union has even stricter tolerances. A carcinogen, aflatoxin was recently linked with the deaths of more than 50 people who consumed contaminated grain in Kenya. A study in West Africa found a strong association between aflatoxin levels in children’s blood and stunted growth. “There is no easy quick-fix to this problem,” says Dan Jeffers, CIMMYT researcher overseeing the project, “but when a solution is found, everyone wins.”

By collaborating with scientists in the US, CIMMYT is better able to accomplish its goal of helping resource-poor farming households who consume their own maize. “We want to combine useful traits that will lessen the incidence of aflatoxin in the crop,” says Jeffers. “By crossing maize varieties that already are drought tolerant with those that resist Aspergillus, commercially viable and attractive lines should emerge.” This holistic approach will provide better varieties to collaborators and eventually to farmers.

The kernels vibrate as they shuffle down the tray of the light box. Healthy kernels appear faded under the black light, but the infected grain glows. Jeffers and his team will use the fluorescence data to choose the maize lines that show the least amount of fungal infection. “The most promising materials will then be used in further studies to look at aflatoxin levels,” Jeffers says.

May, 2005

CIMMYT shows technology to enhance farmer income and reduce ocean pollution

Wheat farmers in the Yaqui Valley of Mexico’s Sonora State will be the first to gain from a new technology developed by CIMMYT researchers with partners from Oklahoma State and Stanford Universities. And while the farmers in Mexico will benefit, CIMMYT believes that farmers and the environment in many developing countries will reap rewards as well.

“I wish I had known about it this season,” said Ruben Luders when he saw the results. He farms 400 hectares of wheat in the Yaqui valley. “It will save me money.”

What Luders and more than twenty-five other farmers saw in a demonstration was an effective and accurate way to determine both the right time and correct amount of nitrogen fertilizer to apply to a growing wheat crop. Wheat needs nitrogen to grow properly, but until now there has been no easy way to know how to apply it in an optimum way. Traditionally farmers in the region fertilize before they plant their seed and then again at the first post-planting irrigation. The new approach, developed in conjunction with Oklahoma State University in the United States, uses an infrared sensor to measure the yield potential of wheat plants as they grow.

“I had been looking for something to determine nitrogen requirements for a long time,” says CIMMYT wheat agronomist, Dr. Ivan Ortiz-Monasterio. “This technology was already being used by CIMMYT scientists for other things, such as estimating the yield of different genotypes. It has taken time to calibrate it, but now we have a useful tool to determine the nitrogen a wheat plant needs.”

The sensor is held above the young, growing wheat plants and measures how much light is reflected in two different colors—red and invisible infrared. In technical terms this is called measuring the Normalized Differential Vegetative Index (NVDI). After much testing, Ortiz-Monasterio and his colleagues from Oklahoma State found they could get a handheld computer to calculate the nitrogen requirement of the plants from the two readings.

The demonstration, conducted in the fields of four different farmer-volunteers, showed they could maintain their yields using far less fertilizer. That is because fertilizer residue from over-applications in past seasons can still be utilized by the new crop.

“We used to feed the soil first, before growing the wheat,” says Luders. “Now we know we should feed the wheat.” He and his friends calculated that with just 80 hectares of wheat the nitrogen sensor, which costs about US $400, could pay for itself in a single season.

The demonstration was made possible because farmers in the Yaqui Valley have consistently supported the research work of CIMMYT and of Mexico’s national agricultural research institute, INIFAP, in the area.

There is much more to this technology than a tool to maximize farm income. A recent Stanford University study published by the prestigious science journal Nature showed that each time farmers irrigate their fields, some of the excess nitrogen fertilizer washes into the nearby Sea of Cortez. The heavy load of nitrogen in the water results in blooms of algae which deplete the oxygen in the water. In other parts of the world such algae blooms can do serious damage to local fisheries. If widely adopted in the Yaqui Valley, the nitrogen-optimizing technology should result in less fertilizer washing into the sea.

Runoff of excess nitrogen fertilizer is a problem that will threaten many more sensitive bodies of water around the world, according to Ortiz-Monasterio. “As farming systems intensify to feed more people, we need to increase production but minimize impact on the environment,” he says. So while farmers in the State of Sonora may be the first to benefit, they certainly will not be the last. Just five days before the demonstration in Ciudad Obregon, the first infrared sensor, a result of a USAID linkage grant with CIMMYT and Oklahoma State, arrived in Pakistan. This way, a technology proven in the field in Mexico will go on to assist farmers in poorer parts of the world and help maintain the health of coastal waters at the same time.

For further information, contact Ivan Ortiz-Monasterio (i.ortiz-monasterio@cgiar.org).

CIMMYT E-News, vol 6 no. 6, October 2009

In 2009, out of a global population of 6.8 billion people, more than 1 billion regularly woke up and went to bed hungry. By 2050 the population is expected to grow to 9.1 billion people, most of whom will be in developing countries. Unless we can increase global food production by 70%, the number of chronically hungry will continue to swell. To help ensure global food security, a new research consortium aims to boost yields of wheat—a major staple food crop.

There is no easy fix for world hunger. Any improvement will require complex collaborative efforts and funding to support them. With this in mind, wheat scientists and agricultural experts from diverse private and public institutions are joining to form a Wheat Yield Potential Consortium (WYC). This group will strive to improve wheat yields, which must increase 1.6% annually to meet a projected demand of 760 million tons by 2020.
The unofficial launch of the WYC happened in November 2009, when over 60 world-renowned experts gathered for a USAID-sponsored symposium at CIMMYT’s Mexico headquarters to integrate various research components into a common breeding platform for improving wheat yields.

“Over the past year we’ve been pulling together experts in photosynthesis who have ideas on how to raise the overall biomass of the crop, as well as other experts in crop adaptation to make sure that increased biomass will also translate into better yields,” says Matthew Reynolds wheat physiologist and initiator of the WYC.

In recent decades, wheat yields have increased nearly 1% each year, but global population is growing roughly 1.5% annually. Climate change, unsustainable cropping practices, and changes in diet preferences further challenge wheat’s ability to meet the demands of a global population that relies on the crop for more than one-fifth of its caloric intake.

Meeting of the minds

“The international wheat community recognizes that each of us has different skills and that, though individually we cannot solve the problem of insufficient wheat yields, collectively we can,” said Richard Richards chief research scientist at Australia’s Commonwealth Scientific and Industrial Research Organization, Plant Industry, who has been commissioned to review a WYC project proposal under development.

The Consortium will pursue advanced approaches to increase wheat yields, including increasing the efficiency of photosynthesis, improving the plant’s adaption to target environments, and using physiological and molecular breeding. To date, selective, conventional breeding has been the main force behind yield improvement. Scientists breed a large number of high-yielding wheat plants, select early generations with good agronomic traits, populate trial fields with the offspring, and move the best forward in the breeding program. The cycle is then repeated. This system has been successful, but precedent suggests it will not be fast enough to overcome the combined challenges of population growth and climate change. “Instead of going straight to the end product —yield—we must look at every yield-determining physiological process and improve the efficiency of the limiting ones,” Richards said.

Powering up photosynthesis

Under favorable conditions, yield is a function of the interception, conversion, and distribution of solar energy. To increase yield, one or more of these components must be improved. Thanks to years of wheat improvement, the efficiency of solar energy intercepted is nearly 90% and energy distribution results in an almost optimal proportion of total biomass to grain, roughly 50%. “This leaves the conversion of sunlight into chemical energy—mainly controlled by photosynthesis—as the main yield component left to improve,” said Xinguang Zhu, group leader of Plant Systems Biology at the CAS-MPG Partner Institute of Computational Biology.

One way to do this is to increase carbon-fixing efficiency during photosynthesis. Plants that thrive at moderate temperatures, like wheat, tend to use C3 carbon fixation, a slow system that accepts both carbon dioxide and oxygen. The fixation of oxygen, called photorespiration, reduces the efficiency of photosynthesis. Plants that inhabit warmer locations, like maize, tend to use C4 carbon fixation, which increases chloroplastic CO2 concentration, reduces photorespiration, and improves energy-use efficiency.

The fact that the C4 system has evolved many times in nature has inspired scientists to look for ways to introduce parts of it into wheat, so that the plant can thrive at relatively high temperatures. This will be essential as temperatures in tropic and subtropic regions continue to climb. Studies show that for every 1°C of warming, wheat yields in these areas will fall 10%. Given that 95% of the world’s malnourished people live in these regions—which also have the highest rates of population growth—high-yielding wheat that can beat the heat could make a world of a difference.
For more information: Matthew Reynolds, wheat physiologist (m.reynolds@cgiar.org).