Bt Corn Maize - Transgenic Corn
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BREAKING: Study Shows GM Corn Cause Massive Tumors in Lab Rats

Eating genetically modified corn (GM corn) and consuming trace levels of Monsanto's Roundup chemical fertilizer caused rats to develop horrifying tumors, wid...
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Crop Science: Transgenic Corn Rootworm Protection Increases Grain Yield and Nitrogen Use of Maize

Crop Science: Transgenic Corn Rootworm Protection Increases Grain Yield and Nitrogen Use of Maize | Bt Corn Maize - Transgenic Corn | Scoop.it

Engineered to produce the bacterial toxin, Bt, "Bt corn" resists attack by corn rootworm, a pest that feeds on roots and can cause annual losses of up to $1 billion. But besides merely protecting against these losses, the Bt trait has also boosted corn yields, in some cases beyond normal expectations. So what makes it so successful?


Via CIMMYT, Int.
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Transgenic Corn Rootworm Protection Increases Grain Yield and Nitrogen Use of Maize

Maize (Zea mays L.) hybrids expressing Bacillus thuringiensis (Bt) derived resistance to corn rootworm (Diabrotica spp.) are widely grown. Our hypothesis was that Bt hybrids exhibit increased N uptake, resulting in greater grain yield and N use efficiency (NUE) relative to their nonprotected counterparts. In 2008 and 2009, two transgenic corn rootworm resistant (Bt) hybrids with VT3 (YieldGard VT Triple) technology along with their near-isogenic non-Bt Roundup Ready Corn 2 (RR2) counterparts were evaluated at Champaign, IL, with supplemental N of 0, 67, 134, 201 or 268 kg N ha−1. Despite minimal corn rootworm feeding pressure on roots, the Bt hybrids produced an average of nearly 1.1 Mg ha−1 more grain than their RR2 counterparts. In the comparison of DKC61-72 RR2 and DKC61-69 VT3, Bt protection promoted increased grain yield at low N (+1.0 Mg ha−1; P ≤ 0.01) and a 31% greater response to fertilizer N. With adequate N, grain yields of the comparison DKC63-45 RR2 and DKC63-42 VT3 did not differ; however, the latter maximized its yield with an average of 38% less fertilizer N. Increases in NUE (+80%; P ≤ 0.10) and N uptake efficiency (NUpE) (+31%; P ≤ 0.10) at the N rates required to optimize grain yield of Bt hybrids were detected in 2008, but NUE and NUpE were not significantly different between isolines in 2009. We conclude that transgenic corn rootworm protection has supplemental agronomic benefits, with greater N uptake and NUE in some environments.


Via Jean-Pierre Zryd
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Detection of Transgenic and Endogenous Plant DNA Fragments and Proteins in the Digesta, Blood, Tissues, and Eggs of Laying Hens Fed with Phytase Transgenic Corn - Ma &al (2013) - PLoS One

Detection of Transgenic and Endogenous Plant DNA Fragments and Proteins in the Digesta, Blood, Tissues, and Eggs of Laying Hens Fed with Phytase Transgenic Corn - Ma &al (2013) - PLoS One | Bt Corn Maize - Transgenic Corn | Scoop.it

The trials were conducted to assess the effects of long-term feeding with phytase transgenic corn (PTC) to hens on laying performance and egg quality, and investigate the fate of transgenic DNA and protein in digesta, blood, tissues, and eggs. Fifty-week old laying hens (n = 144) were fed with a diet containing 62.4% PTC or non-transgenic isogenic control corn (CC) for 16 weeks. We observed that feeding PTC to laying hens had no adverse effect on laying performance or egg quality (P>0.05) except on yolk color (P<0.05).

 

Transgenic phyA2 gene and protein were rapidly degraded in the digestive tract and were not detected in blood, heart, liver, spleen, kidney, breast muscle, and eggs of laying hens fed with diet containing PTC. It was concluded that performance of hens fed diets containing PTC, as measured by egg production and egg quality, was similar to that of hens fed diets formulated with CC. There was no evidence of phyA2 gene or protein translocation to the blood, tissues, and eggs of laying hens.


Via Alexander J. Stein
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The Realized Yield Effect of Genetically Engineered Crops: U.S. Maize and Soybean - Xu &al (2013) - Crop Science

The Realized Yield Effect of Genetically Engineered Crops: U.S. Maize and Soybean - Xu &al (2013) - Crop Science | Bt Corn Maize - Transgenic Corn | Scoop.it

Yield improvements are critical to ensuring food security for a growing world population especially in view of the increasing potential for use of land in biofuel production. Efforts to sustain the impressive rate of past productivity gains, epitomized by such successes as the Green Revolution, are bound to rely on biotechnology innovations such as those responsible for the development of genetically engineered (GE) crops.

 

Some argue that the use of biotechnology can substantially improve yields relative to the trajectory established by traditional breeding in the 20th century. Because U.S. adoption of GE varieties has been very strong since their introduction in the late 1990s, we investigated empirically whether and to what extent the GE technology has improved realized yields.

 

We study this question for nonirrigated U.S. maize... and soybean... yields over 1964 through 2010, having controlled for local effects, weather, fertilization, and the preexisting (non-GE) crop improvement trend. For maize we find that GE varieties have increased realized yields, with a stronger gain in the Central Corn Belt (CCB). For soybeans, GE varieties appear to have slightly reduced yields.

 

For both crops we find a strong trend in yield growth, which may have accelerated in recent years within the CCB. However, the combined effects of yield trend and GE adoption are predicted to fall short of the growth rate envisioned by industry projections.


Via Alexander J. Stein
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Alexander J. Stein's curator insight, May 1, 2013 10:45 PM

While Bt maize can reduce losses from insect attacks (i.e. increase net yields), herbicide-tolerant soybeans can facilitate weed management (i.e. not necessarily increase yields).

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When bad science makes good headlines: Bt maize and regulatory bans - Romeis &al (2013) - Nature Biotechnol

The safety of transgenic crops and derived foods continues to be a contentious issue of public and political debate. The debate is confounded when poorly designed studies that report unusual and controversial results receive a disproportionate amount of attention in the scientific and lay press, which in turn, influences both public policy and perceptions about agbiotech...

 

Numerous laboratory toxicity studies and field experiments, as well as years of field observations in countries where Bt maize is cultivated, have provided evidence that the Cry1Ab protein expressed in Bt maize does not cause adverse effects on arthropods outside the order Lepidoptera... Supporting data have been analyzed in reviews and meta-analyses.

 

Despite this preponderance of evidence, a few outlier studies claiming adverse effects of Cry1Ab to nonlepidopteran species have been the subject of persistent media coverage and often undue consideration by regulators. The potential of such studies to inform the risk assessment of Bt crops depends on... whether they are caused by other confounding factors associated with the design of the study... This requires a careful evaluation of the underlying test protocol... 

 

Environmental risk assessment of transgenic crops should be a scientifically defensible approach to ensuring that environmental protection goals are appropriately considered... However, the regulation of transgenic crops continues to be highly politicized and so it is essential that... evaluation should include both the quality of the study itself as well as its relevance to the risk assessment process...

 

The consequences of a poorly informed decision can be substantial, resulting in the deployment of transgenic plants that may be harmful to the receiving environment. More likely, ill-informed decisions lead to the rejection of potentially useful transgenic plants, impeding access to environmental and/or financial benefits by farmers, product developers and other participants in the agricultural production and value chains.

 

The illegitimate use of science to further political agendas (or capture media attention)... is certainly not unique to agbiotech... This perpetuates unfounded concerns about approved GE crops, leads to overly precautious and expensive regulations, and limits opportunities to access and apply genetic engineering to address pressing food security, social, economic and environmental challenges.


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East African researchers collaborate to fight maize disease

East African researchers collaborate to fight maize disease | Bt Corn Maize - Transgenic Corn | Scoop.it

“Last season some portions of my maize crop grew to knee high, the leaves turned yellow and those that grew produced very little grain,” says Wambui. Indeed farmers in Kenya, Uganda and Tanzania last year recorded losses of about 50-100percent on their total maize yields following the outbreak of a new maize disease known as Maize Lethal Necrosis Disease –MLND.


Via CIMMYT, Int.
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Genome-wide transcript analysis of early maize leaf development reveals gene cohorts associated with the differentiation of C4 Kranz anatomy - Wang - The Plant Journal - Wiley Online Library

Genome-wide transcript analysis of early maize leaf development reveals gene cohorts associated with the differentiation of C4 Kranz anatomy - Wang - The Plant Journal - Wiley Online Library | Bt Corn Maize - Transgenic Corn | Scoop.it

Photosynthesis underpins the viability of most ecosystems, with C4 plants that exhibit 'Kranz' anatomy being the most efficient primary producers. Kranz anatomy is characterized by closely spaced veins that are encircled by two morphologically distinct photosynthetic cell-types. Although Kranz evolved multiple times, the underlying genetic mechanisms remain largely elusive, with only the maize scarecrow gene thus far implicated in Kranz patterning. To provide a broader oversight into the regulation of Kranz differentiation, we carried out a genome wide comparative analysis of developmental trajectories in Kranz (foliar leaf blade) and non-Kranz (husk leaf sheath) leaves of the C4 plant maize. Using profile classification of gene expression in early leaf primordia, we identified cohorts of genes associated with procambium initiation and vascular patterning. In addition, we used supervised classification criteria inferred from anatomical and developmental analyses of five developmental stages, to identify candidate regulators of cell-type specification. Our analysis supports the suggestion that Kranz anatomy is patterned, at least in part, by a SCARECROW/SHORTROOT regulatory network and elucidates likely components of that network. Furthermore, the data infer a role for additional pathways in the development of Kranz leaves. This article is protected by copyright. All rights reserved.


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Monsanto and other GM firms are winning in the US – and globally - The Guardian

Monsanto and other GM firms are winning in the US – and globally - The Guardian | Bt Corn Maize - Transgenic Corn | Scoop.it
The Guardian Monsanto and other GM firms are winning in the US – and globally The Guardian If you have a feeling that genetically modified (GM) foods are being forced upon the population by a handful of business interests and vociferously defended...
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Study Finds Brazilian Biotech Offers Significant Grower Benefits - Farm Futures (2013)

Study Finds Brazilian Biotech Offers Significant Grower Benefits - Farm Futures (2013) | Bt Corn Maize - Transgenic Corn | Scoop.it

The Brazilian Association of Seeds and Seedlings, ABRASEM, on Tuesday released the sixth edition of studies on the economic and social-environmental impacts of the adoption of biotechnology on Brazilian crops. According to the analysis, ... the grower of a crop of 50 hectares (about 123 acres) of insect-resistant corn has already earned an additional return of up to $100,400 since this technology was commercialized in Brazil. The projection is that over the next ten years, this same grower will see an increase of $324,100 in earnings, chiefly due to the increase of productivity that the technology provides.

 

Evaluating the overall picture for biotechnology in Brazil, taking into account the three crops with transgenic varieties that have already been approved and are in commercial production – corn, soybeans and cotton – the results are also significant. With the prospect of the approval of new technologies, greater adoption by growers and enhancements of the existing technology, the total economic benefit from the adoption of transgenics in the next ten years should come to $118.2 billion, with 82% of this amount going to the grower.

 

Another highlight of the study is gains in productivity, which turned out to be the key factor in economic benefits generated for growers, surpassing the reduction of production costs, a dominant factor in earlier studies. This change could also be attributed to the good results for agriculture accruing from the adoption of transgenic corn... 

 

The study also presents the benefits of biotechnology for the environment and the sustainability of Brazilian agribusiness over the past 16 years – since the arrival of the first genetically modified seeds in Brazil – as well as for the next ten years, taking into consideration factors such as water use, diesel consumption, carbon emissions and the use of pesticides... 

 

Also at: http://www.prnewswire.com/news-releases/biotechnology-guaranteed-us-100-k-to-average-brazilian-corn-growers-in-four-years-according-to-abrasem-187893531.html


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Transgenic Corn Rootworm Protection Increases Grain Yield and Nitrogen Use of Maize - Haegele & Below (2013) - Crop Sci

Transgenic Corn Rootworm Protection Increases Grain Yield and Nitrogen Use of Maize - Haegele & Below (2013) - Crop Sci | Bt Corn Maize - Transgenic Corn | Scoop.it

Engineered to produce the bacterial toxin, Bt, "Bt corn" resists attack by corn rootworm, a pest that feeds on roots and can cause annual losses of up to $1 billion. But besides merely protecting against these losses, the Bt trait has also boosted corn yields, in some cases beyond normal expectations. So what makes it so successful?

 

Fred Below and Jason Haegele of the University of Illinois at Urbana-Champaign set out to answer that question by determining how Bt corn uses nitrogen in the soil. Nitrogen is an important nutrient for corn, and with better root systems, it's possible that Bt corn uses nitrogen differently than non-resistant strains, ... affecting corn production. The study... showed just that -- Bt corn had higher yields and used nitrogen more efficiently than non-resistant corn.

 

With its resistance to corn rootworm, Below explains, Bt corn has healthier and more active roots than corn without the resistance trait. And a better root system can lead to improved function for the plant as a whole. "If you can protect the investment the plants made in the root system," explains Below, "you can realize everything that roots do like take up nutrients and water and provide anchorage."

 

The researchers conducted experiments over two years, growing resistant and non-resistant crops and applying five different amounts of nitrogen. The resistant corn had higher yields than the non-resistant crops (nearly 21 bushels per acre) and more easily tolerated low nitrogen levels. More efficient use of nitrogen in the soil would be especially beneficial in areas where nitrogen is lost through heavy precipitation or erosion. Additionally, Bt corn would fare better at current levels of nitrogen use in the United States...

 

The healthy roots and efficient nutrient use of Bt corn could lead to changes in management practices that would further increase production. Banded or placed fertility, a method by which a farmer can place fertilizer where the roots are likely to be, would be more effective when used on the robust root system. Additionally, increasing plant populations could further increase yield. "When you have a higher population of plants, each individual plant has a smaller root system, so that made it difficult to increase plant population when you had insects chewing on the roots," explains Below. "With the Bt corn, though, you can protect the root system and grow more plants" ... 

 

http://www.sciencedaily.com/releases/2013/02/130206110920.htm

 

Abstract: 

 

Maize... hybrids expressing Bacillus thuringiensis (Bt) derived resistance to corn rootworm... are widely grown. Our hypothesis was that Bt hybrids exhibit increased N uptake, resulting in greater grain yield and N use efficiency (NUE) relative to their nonprotected counterparts. In 2008 and 2009, two transgenic corn rootworm resistant (Bt) hybrids with VT3... technology along with their near-isogenic non-Bt Roundup Ready Corn 2 (RR2) counterparts were evaluated at Champaign, IL, with supplemental N of 0, 67, 134, 201 or 268 kg N ha−1. Despite minimal corn rootworm feeding pressure on roots, the Bt hybrids produced an average of nearly 1.1 Mg ha−1 more grain than their RR2 counterparts. In the comparison... Bt protection promoted increased grain yield at low N... and a 31% greater response to fertilizer N. With adequate N, grain yields of the comparison... did not differ; however, the latter maximized its yield with an average of 38% less fertilizer N. Increases in NUE... and N uptake efficiency (NUpE)... at the N rates required to optimize grain yield of Bt hybrids were detected in 2008, but NUE and NUpE were not significantly different between isolines in 2009. We conclude that transgenic corn rootworm protection has supplemental agronomic benefits, with greater N uptake and NUE in some environments.

 

http://dx.doi.org/10.2135/cropsci2012.06.0348

 


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Vip3Aa and Cry1Ab proteins in maize reduce Fusarium ear rot and fumonisins by deterring kernel injury from multiple Lepidopteran pests - Bowers &al (2013) - World Mycotox J

Vip3Aa and Cry1Ab proteins in maize reduce Fusarium ear rot and fumonisins by deterring kernel injury from multiple Lepidopteran pests - Bowers &al (2013) - World Mycotox J | Bt Corn Maize - Transgenic Corn | Scoop.it

Field trials were conducted in 2008, 2009 and 2011 to assess fumonisin contamination in transgenic (Bt) and non-Bt maize hybrids infested with European corn borer, corn earworm, and Western bean cutworm. Comparisons were made among maize hybrids expressing two transgenic insect resistance proteins (Cry1Ab × Vip3Aa), a single resistance protein (Cry1Ab), or no insect resistance. The field design was a randomised complete block design with four replicates of each hybrid × insect combination. 

Kernel injury, Fusarium ear rot, and fumonisins (FB1+FB2+FB3) in maize grain were measured. These measurements differed significantly among years of the study. In all years, significant positive correlations were present between insect injury and Fusarium ear rot, insect injury and grain fumonisin levels, and Fusarium ear rot and grain fumonisin levels. 

Under all insect infestation treatments, Cry1Ab × Vip3Aa hybrids were the most resistant of the hybrids with regard to any of the grain quality measurements. Averaged over all insect infestations and years, insect injury, Fusarium ear rot, and grain fumonisin levels were all low in Cry1Ab × Vip3Aa (0.1% and 2.2% of total kernels, and 0.56 mg/kg, respectively). The highest average levels of insect injury, Fusarium ear rot, and grain fumonisin contamination (3.3% and 7.2% of total kernels, and 5.47 mg/kg, respectively) were found in the non-Bt hybrids. 

The presence of transgenic insect protection (Cry1Ab × Vip3Aa or Cry1Ab) resulted in significant reductions in all grain quality measurements as compared with the non-Bt hybrids. Only grain obtained from Cry1Ab × Vip3Aa hybrids consistently had acceptable fumonisin content according to both US guidance levels and EU regulatory limits. These results indicate that Cry1Ab × Vip3Aa maize hybrids are more likely to yield high quality, low-fumonisin grain compared to hybrids expressing only Cry1Ab or lacking insect resistance.


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Case studies: A hard look at GM crops - Nature.com

Case studies: A hard look at GM crops - Nature.com | Bt Corn Maize - Transgenic Corn | Scoop.it
Nature.com
Case studies: A hard look at GM crops
Nature.com
In the pitched debate over genetically modified (GM) foods and crops, it can be hard to see where scientific evidence ends and dogma and speculation begin.
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PLOS Genetics: The Genomic Signature of Crop-Wild Introgression in Maize

PLOS Genetics: The Genomic Signature of Crop-Wild Introgression in Maize | Bt Corn Maize - Transgenic Corn | Scoop.it

From the abstract... "We found evidence suggestive of the incorporation of adaptive Zea mays ssp mexicana [aka teosinte] alleles into maize during its expansion to the highlands of central Mexico. In contrast, very little evidence was found for adaptive introgression from maize to mexicana."


Via Mary Williams
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Mary Williams's curator insight, May 10, 2013 4:33 AM

Very nice study of gene flow between a domesticated crop and its wild, conspecific relative, and its evolutionary and ecological implications.

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GE Crop Risk Assessment Challenges: An Overview

GE Crop Risk Assessment Challenges: An Overview | Bt Corn Maize - Transgenic Corn | Scoop.it
There have been dramatic changes in the transgenic composition of GE corn a&#110 (There have been dramatic changes in the transgenic composition of GE corn and soybeans over ...
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BMC Genomics | Abstract | Meta-analyses of QTL for grain yield and anthesis silking interval in 18 maize populations evaluated under water-stressed and well-watered environments

Background: Identification of QTL with large phenotypic effects conserved across genetic backgrounds and environments is one of the prerequisites for crop improvement using marker assisted selection (MAS). The objectives of this study were to identify meta-QTL (mQTL) for grain yield (GY) and anthesis silking interval (ASI) across 18 bi-parental maize populations evaluated in the same conditions across 2-4 managed water stressed and 3-4 well watered environments. Results: The meta-analyses identified 68 mQTL (9 QTL specific to ASI, 15 specific to GY, and 44 for both GY and ASI). Mean phenotypic variance explained by each mQTL varied from 1.2 to 13.1% and the overall average was 6.5%. Few QTL were detected under both environmental treatments and/or multiple (>4 populations) genetic backgrounds. The number and 95% genetic and physical confidence intervals of the mQTL were highly reduced compared to the QTL identified in the original studies. Each physical interval of the mQTL consisted of 5 to 926 candidate genes. Conclusions: Meta-analyses reduced the number of QTL by 68% and narrowed the confidence intervals up to 12-fold. At least the 4 mQTL (mQTL2.2, mQTL6.1, mQTL7.5 and mQTL9.2) associated with GY under both water-stressed and well-watered environments and detected up to 6 populations may be considered for fine mapping and validation to confirm effects in different genetic backgrounds and pyramid them into new drought resistant breeding lines. This is the first extensive report on meta-analysis of data from over 3100 individuals genotyped using the same SNP platform and evaluated in the same conditions across a wide range of managed water-stressed and well-watered environments.


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India: New hybrid maize seed developed for Gujarat

India: New hybrid maize seed developed for Gujarat | Bt Corn Maize - Transgenic Corn | Scoop.it
The variety is rich in Lysine (an essential amino acid) and is touted to be a source of rich protein diet for the tribals, who are its major consumers.

Via CIMMYT, Int.
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Neurotoxin: Mining The Clostridium Botulinum Genome

Neurotoxin: Mining The Clostridium Botulinum Genome | Bt Corn Maize - Transgenic Corn | Scoop.it
The toxin that causes botulism is the most potent that we know of - just 1/1,000th the weight of a grain of salt can be fatal, which is why so much effort has been put into keeping Clostridium botulinum, which produces the toxin, out of our food.
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