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The dwindling European corn borer, GM maize & soybeans, and the effects of global warming on wheat

By Maggie Hennessy

- Last updated on GMT

Related tags: Maize, Us

Shrinking populations of a historically damaging corn pest could mean significant savings for Eastern US farmers, a genetically engineered grain cell wall invertase could significantly improve grain yield and quality, the EFSA GMO panel deems a GM soybean safe for food and feed use, and charting the effect global warming may have already had on winter wheat in China.

Corn pest decline could save farmers money

Falling populations of the European corn borer (ECB) pest in the Eastern US suggests that use of costly genetically modified ECB-resistant corn hybrids may be unnecessary in some areas, according to Penn State researchers.

ECB, which was introduced to North America from Europe in the 1900s, used to cause annual crop losses of about $1 billion nationwide. To kill these worms, farmers began growing a genetically modified type of corn that expresses insecticidal toxins, which were isolated from the bacterium Bacillusthuringiensis. The downside of the Bt corn hybrids, widely adopted for their exceptional ability to manage ECB (they kill 99.9% of larvae), is the high cost of purchasing the seeds.

The researchers assessed larval damage in Bt and non-Bt corn hybrids at 29 sites across Pennsylvania over three years (2010-2012). During September of each season, they assessed corn borer damage on 400 random plants at each site, recording ECB tunnels and larvae per stalk and evaluating corn ears for ECB damage.

According to the results, the Eastern US is experiencing widespread population declines of ECB. “With less ECB damage around, non-Bt hybrids in our tests yielded just as well as Bt hybrids, so the decline in ECB populations provides an opportunity for growers to generate greater profits by planting high-yielding non-Bt seed, which is much cheaper than Bt seed. Secondarily, planting more non-Bt corn will reduce the potential for ECB to develop resistance to Bt toxins as corn rootworms have done in about a dozen states so far,”​ said Eric Bohnenblust, graduate student in entomology. 

Source: Pest Management Science
DOI: 10.1002/ps.3712
“Current European Corn Borer, Ostrinia nubilalis, Injury Levels in the Northeastern US and the Value of Bt Field Corn”
Authors:Eric W. Bohnenblust, James A. Breining, John A. Shaffer, Shelby J. Fleischer, Gregory W. Roth and John F. Tooker

GE cell wall enzyme can improve grain yield and quality

The cell wall invertase gene can be genetically engineered to improve both grain yield and grain quality in crop plants, according to research published in the Plant Biotechnology Journal​.

Grain size, number and starch content are important determinants of grain yield and quality. One of the most important biological processes that determine these components is the carbon partitioning during the early grain filling, which requires the function of cell wall invertase.

For the study, the researchers found that expressing the cell wall invertase-encoding gene from Arabidopsis, rice (Oryza sativa) or maize (Zea mays), driven by the cauliflower mosaic virus (CaMV) 35S promoter, all increased cell wall invertase activities in different tissues and organs, including leaves and developing seeds. As a result, grain yield was improved up to 145.3% in transgenic maize plants as compared to the wild-type plants. The researchers reproduced this effect in two-year field trials at multiple locations.

The dramatically increased grain yield is due to the enlarged ears with both enhanced grain size and grain number. Constitutive expression (a permanently active state) of the invertase-encoding gene also increased total starch content up to 20% in the transgenic kernels.

Source: Plant Biotechnology Journal
DOI: 10.1111/pbi.12102
“Constitutive expression of cell wall invertase genes increases grain yield and starch content in maize”
Authors: Bei Li, Hua Liu, Yue Zhang, Tao Kang, Li Zhang, Jianhua Tong, Langtao Xiao, Hongxia Zhang

EFSA GMO panel calls GMO soybean safe for human, animal consumption

A European Food Safety Authority (EFSA) GMO panel has deemed herbicide-tolerant soybean BPS-CV127-9 as safe and nutritious as non-GM soybean varieties.

In a review following an application to commercialize the GM soybean for food and feed use, the panel determined the GM soybean and its derived products are “unlikely to have adverse effects on human and animal health, in the context of its intended uses.”

A safety assessment identified no concerns regarding the potential toxicity and allergenicity of the newly expressed proteins or soybean BPS-CV127-9. A feeding study with broiler chickens confirmed that the nutritional properties of soybean BPS-CV127-9 seeds are not different from those of its conventional counterpart and commercial non-GM soybean varieties.

The panel couldn’t identify any differences in seed composition that would require further safety assessment. Though the panel identified a difference in seed weight for the GMO soybean, such a difference doesn’t impact its overall safety. The EFSA GMO panel draw conclusion on its forage composition, though soybean forage isn’t expected to be imported in significant amount for feed use.

Source: EFSA Journal
doi:10.2903/j.efsa.2014.3505
“Scientific Opinion on application (EFSA-GMO-NL-2009-64) for the placing on the market of herbicide-tolerant genetically modified soybean BPS-CV127-9 for food and feed uses, import and processing under Regulation (EC) No 1829/2003 from BASF Plant Science”
Panel: Salvatore Arpaia, Andrew Nicholas Edmund Birch, Andrew Chesson, Patrick du Jardin, Achim Gathmann, Jürgen Gropp, Lieve Herman, Hilde-Gunn Hoen-Sorteberg, Huw Jones, József Kiss, Gijs Kleter, Martinus Løvik, Antoine Messéan, Hanspeter Naegeli, Kaare Magne Nielsen, Jaroslava Ovesná, Joe Perry and Nils Rostoks. 

Climate change linked to lower historic wheat yields in China?

Increasing average temperature may have impacted wheat production during the last 50 years, according to a new study published in Global Change Biology​.

Because wheat is particularly sensitive to high temperatures and previous studies have mainly focused on heat stress in crops under future​ climate change, the researchers sought to characterize heat stress and its changes during the past 50 years and its effect on the wheat grain yield in China.

Using a multiple linear regression model, the researchers evaluated the impact of heat stress and average temperature between heading and maturity at farm-scale on wheat yields, finding that both explained approximately 29% of the observed grain yield variability of winter wheat in China from 1960 to 2009.

Despite uncertainties associated with limited sample sizes and the correlation of heat stress with average temperature, a significant negative impact of heat stress on wheat yields was observed in the entire production region and in most subregions. These results indicate that the historical increase of heat stress between heading and maturity in most of wheat-producing regions may have resulted in wheat yield reduction in China.

Source: Global Change Biology
Article first published online Nov. 20, 2013, DOI: 10.1111/gcb.12442
Authors: Bing Liu, Leilei Liu, Liying Tian, Weixing Cao, Yan Zhu and Senthold Asseng

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