Posts Tagged ‘Maize’

High-protein maize also resistant to parasitic weed

A flowering witchweed (Striga asiatica L. O. Krantz) in a conventionally-ploughed maize field on sandy soils in Madziwa, Zimbabwe. Photo credit Christian Thierfelder, CIMMYT.

The world produces more maize by weight than any other cereal crop. Maize, also known as corn, is a staple food in many countries. But farmers growing corn face many challenges, such as drought, diseases, and pests.

For example, in sub-Saharan Africa, 20 to 80% of maize yields may be lost because of a semi-parasitic plant, Striga. In areas infested with Striga, farmers may even lose their entire crops.

In a new study, researchers from southern Africa identified several varieties of maize resistant or tolerant to Striga. Importantly, these varieties also have improved nutritional content, particularly protein.

The combination of Striga tolerance and improved nutrition is key. Farmers, as well as local populations, will benefit, says Peter Setimela, a study co-author. Setimela is a scientist at the International Maize and Wheat Improvement Center (CIMMYT) in Harare, Zimbabwe.

Striga infestations can force small farmers in sub-Saharan and southern Africa to abandon their farms. “Striga is known to affect fields that have poor soil fertility. Its seeds can stay in the soil for more than 15 years,” says Setimela. “Many small farmers can’t afford to buy chemicals to control Striga. They may also be unable to buy chemical fertilizers.”

Having access to varieties of maize that can tolerate Striga will benefit these farmers. They will be able to continue farming and growing maize in areas with Striga.

The improved nutritional content of these maize varieties will also help. The varieties have a wider variety of amino acids, the building blocks of protein.

“Typically, maize is poor in essential amino acids. Human and animal bodies can’t make these amino acids. They have to be obtained from food,” says Setimela. “Lack of essential amino acids can impair growth and development. It can also weaken the immune system.”

Many rural populations depend on maize as a staple food. “But these populations often have limited access to protein sources, such as eggs, meat, and dairy products,” says Setimela. “If varieties of maize can provide high-quality protein, these populations will benefit.”

Setimela and colleagues tested both typical and high-protein varieties of maize for Striga resistance in the lab and field.

A flowering witch weed (Striga asiatica L. O. Krantz) at Goromonzi district, Zimbabwe in maize field under conservation agriculture. Photo credit Isaiah Nyagumbo, CIMMYT.

Controlled conditions, such as those in the laboratory, allow researchers to conduct tests that may not be possible in the field. But “ultimately, crops will be grown in farmers’ fields,” says Setimela. “We ensured that the results from controlled environments also apply to field conditions.”

Field experiments were carried out in three locations in Zimbabwe with diverse conditions. The researchers tested eight high-protein varieties and four typical varieties of maize. They measured several plant characteristics, including yield, height, vigor, and kernel weight.

Researchers found four varieties of high-protein maize that also showed high levels of Striga tolerance and high yields.

“These varieties will provide options to farmers in areas with Striga,” says Setimela. “They will improve food security and nutrition.”

Read more about this research in Crop Science. The European Union funded this research through Welthungerhilfe (SIMBA Project). The German Academic Exchange Service (DAAD) provided a partial scholarship to the first author. CIMMYT-Zimbabwe and the CGIAR Research Program on Maize (MAIZE) provided scientific support; Seed Co, and Mukushi Seeds provided germplasm.

Tar Spot Complex a potential big black spot on US maize economy

Figure: Maize-producing counties in the USA that are vulnerable to Tar Spot Complex (TSC) of maize, developed based on climate analogue model analysis procedure matching historic climatic data of 13 counties where TSC has been detected.

new study shows that nearly 12 million hectares of the maize-growing USA, approximately 33 percent of the entire maize-growing area of the country, might be vulnerable to a disease called Tar Spot Complex (TSC).

Native to Latin America, one of the two major fungal pathogens involved in TSC of maize was detected for the first time in the United States in 2015. In Latin America, TSC can cause up to 50 percent losses in maize yields, but the impact of one fungal pathogen alone on maize yields unknown. There is a hypothetical likelihood that the second fungal pathogen involved in TSC, could migrate to the US. If this happens, the devastating TSC disease in the US could cause significant economic damages.

Even a one percent loss in maize production caused by the disease in this area could lead to a reduction in maize production of 1.5 million metric tons of grain, or approximately $231.6 million in losses. Such production losses would not only affect the $51.5 billion US maize industry, but also the food security in a number of low-income countries that are heavily dependent on maize imports from the US.

The emergence and spread of new crop diseases or new variants of already established diseases around the globe over the last decades have generated serious threats for food safety and security. Therefore, the improvement of crop disease resistance has become one of the key focus topics of research at the International Maize and Wheat Improvement Center (CIMMYT).

The intent of this study is to raise public awareness regarding potential TSC outbreaks and to develop strategies and action plans for such scenario.

This study was published by an interdisciplinary team of CIMMYT scientists in the journal of Mitigation and Adaptation Strategies for Global Change regarding the potential threats of TSC in the US and its global consequences. Within this article, ex-ante impact assessment techniques were combined with climate analogue analysis to identify the maize growing regions that may be vulnerable to potential TSC outbreaks in the USA.

This work was supported by the CGIAR Research Program on Maize (MAIZE).

Preserving native maize and culture in Mexico

By: Matthew O’Leary

Felipa Martinez shows off some of her family’s maize from last year’s harvest. Photo: Matthew O’Leary

Felipa Martinez, an indigenous Mexican grandmother, grins as she shows off a bag bulging with maize cobs saved from last harvest season. With her family, she managed to farm enough maize for the year despite the increasing pressure brought by climate change.

Felipa’s grin shows satisfaction. Her main concern is her family, the healthy harvest lets her feed them without worry and sell the little left over to cover utilities.

“When our crops produce a good harvest I am happy because we don’t have to spend our money on food. We can make our own tortillas and tostadas,” she said.

Her family belongs to the Chatino indigenous community and lives in the small town of Santiago Yaitepec in humid southern Oaxaca. They are from one of eleven marginalized indigenous communities throughout the state involved in a participatory breeding project with the International Maize and Wheat Improvement (CIMMYT) to naturally improve the quality and preserve the biodiversity of native maize.

These indigenous farmers are custodians of maize biodiversity, growing seeds passed down over generations. Their maize varieties represent a portion of the diversity of the 59 native Mexican races of maize, or landraces, which first developed from wild grasses at the hands of their ancestors. These different races (or types) of maize diversified through generations of selective breeding, adapting to the environment, climate and cultural needs of the different communities.

First zinc-enriched maize in Guatemala to combat malnutrition

By Jennifer Johnson

Tortillas made of zinc-enriched biofortified maize. Photo: HarvestPlus.

The first zinc-enriched maize varieties developed specifically for farmers in Guatemala were released this month as part of efforts to improve food and nutrition security in a country where over 46 percent of children under five suffer from chronic malnutrition.