| An anonymous pro-GMO troll on Twitter recently tweeted, "There’s plenty of studies coming out showing GMO crops are increasing yield now. In the beginning they were breeding for resistance." He ended with a finger-wagging admonition to GMWatch over our stance that GM does not increase yields: "Maybe be a little more informed".
The troll tweets under a fake identity, using the name of Venezuela's mustachioed president Nicolas Maduro and the Twitter handle @madurosmustache. He supplied several links to back up his case. Could he be right?
Widely respected authorities have said that GM doesn't increase yields.
A 2013 peer-reviewed paper looked at crop production data from the United Nations’ Food and Agriculture Organisation (FAO) and found that for staple crops, Western Europe’s almost entirely non-GM agriculture outyielded North America’s GM agriculture, with less pesticide use.
In 2016 the journalist Danny Hakim updated the exercise for the New York Times, looking at more recent FAO data. He found that “genetic modification in the United States and Canada has not accelerated increases in crop yields or led to an overall reduction in the use of chemical pesticides”.
In the same year, the US National Academy of Sciences, an organisation that is broadly – some say excessively – supportive of GM crops, published a report stating that “there was little evidence” that the introduction of GM crops in the United States had led to yield gains beyond those seen in conventional crops.
But maybe things have changed in the years since those reports came out, or maybe there are data out there that these authors weren’t aware of. Have genetic engineers finally managed to crack the code for yield and is GM now delivering whopper supercrops? GMWatch looked into the mustachioed one's evidence.
Forget feeding the world – feed cars
The mustache's first link was to a study titled, "Genetically modified sugarcane for bioenergy generation". The study isn't about feeding the world, but feeding cars – with ethanol, a biofuel that could be produced from sugarcane.
But petrolheads shouldn't get too excited. It turns out that the GM sugarcane is still very much in the experimental phase, with the study's author admitting that "transgene stability is still a challenge since transgene silencing seems to occur in a large proportion of genetically modified sugarcane plants".
List of search results
Another of the mustache's links doesn't point to a study, but a list of search results of studies. They include many dated ones, with some being two decades old.
To be fair to the mustache, it's necessary to dig into these studies to see what they say. Following is a random selection.
GM soy “yield drag”
One study cited by the mustache is titled, "Quality of the 2000 soybean crop in the United States". Table 5 shows a comparison in yield between GM Roundup Ready and non-GM soybeans in 1998 and 1999. Unfortunately for the mustache, in both years, the non-GM soy out-yielded the GM. The "Roundup Ready yield drag" in soy and the generally unimpressive yield performance of GM crops have been well documented.
Detection method
Another study that turns up in the mustache’s search results isn't about GM crop yields at all, but describes a method to detect GMO DNA in genetically modified soybeans, with the aim of alleviating "social concern" about GMOs.
Outdated data
A study by Elisa Pellegrino and colleagues is cited by the mustache and others as an example of higher yields from GM crops. It looked at "21 years of field data" on GM maize, including yield impacts. It found higher yields in GM maize compared with the non-GM parent plants.
However, much of the data are drawn from the early years of GM maize cultivation, before the target insect pests became resistant to the Bt toxins in the crops.
In addition, the GM maize was not compared with the highest yielding non-GM varieties that are likely to be grown by farmers, but the non-GM parent varieties – which are seldom the highest performing varieties.
And what the experiments were testing is not the intrinsic yield potential of GM vs non-GM maize, but any improvements in operational yield (the yield that is left after pest and climate stresses have taken their toll) due to the insect-killing ability of the Bt toxins in the GM crop. The supplementary data for the study shows that many of the tested crops were subjected to high or moderate pest pressure and insecticides were often not sprayed. This means that these non-GM crops didn't receive any pest control measures, whereas the GM Bt crops had their built-in insecticide.
GM Bt crops set to become “redundant”
In the early days of GM Bt maize, the Bt insecticidal toxins worked in cases of heavy pest pressure to produce a marginally improved operational yield. In cases of low to moderate pest infestation, Bt maize offered little or no yield advantage.
However, now pests have evolved resistance, so any operational yield advantage has disappeared, even under heavy pest pressure. So serious has been the drop in effectiveness of GM Bt crops that regulators at the US EPA are recommending that many such crops are withdrawn from the market and scientists are recommending restrictions on their planting in a desperate attempt to delay – not prevent – pest resistance.
One paper reports, "the development of resistance to Bt toxins in many pest insects threatens to make transgenic Bt crops redundant". It has also made Pellegrino and colleagues' study redundant.
There is, of course, a better way. Dr Doug Gurian-Sherman of Strategic Expansion and Trainings, LLC has pointed out that the Western corn rootworm pest that was targeted by Bt toxins only became a problem in the first place due to the destructive methods of industrial agriculture. If agroecological methods had been followed, he explains, the pest could never have built up to damaging levels.
Experimental soy crop
The mustache cites a study by Korean researchers that found a higher yield with GM soybeans than non-GM. But the crop was still in the experimental stage at the time of the paper's publication (2017).
Thousands of greenhouse and field trials have been done with experimental GM crops and have claimed success in highly controlled environments such as greenhouses and field trials. But these crops are not able to translate into real farming conditions, where they are exposed to multiple stresses at the same time. In fact, after a quarter of a century of GM, just two simple traits dominate: herbicide tolerance and insecticide-expressing. And even these have failed in real farm conditions under the onslaught of herbicide-resistant superweeds and – as we have seen – insecticide-resistant pests.
In the Korean study reporting the higher GM yield, it's not clear if the non-GM soybeans used as the control were a high yielding variety popular with farmers, or a "dud" variety that yields poorly. And the study is strangely silent on what matters to farmers – yield per hectare. So it's not clear if the GM soybeans would actually produce high yields in real farmers' fields, or if they were just the "least bad" option out of two unimpressive varieties. Indeed, the authors admit, "It may be too early to say the positive effect of those genes in the yield components of soybean with our limited results."
They recommend ongoing research.
GM process fraught with difficulties
Apparently the Korean soybean researchers did get to extend their research, as two years later in 2019 they published a followup paper. Oddly enough, the mustache doesn't reference this one, and the detail of the scientists' findings may indicate why.
The researchers were trying to increase yield by using GM to force overexpression of the ATPG8 and ATPG10 genes, which produce a certain type of protein (AT-hook proteins) associated with increased seed yield and delayed senescence (ageing).
The authors again report increased yield from the GM lines. But their attempts to obtain viable GM lines were fraught with difficulties. Attempts at GM transformation with the ATPG8 gene only succeeded 1% of the time. That's an awful lot of wasted effort.
Also, they had to add various chemicals to the cultivation medium to prevent browning and cell death in the plant cells "wounded" by the Agrobacterium GM transformation method.
The researchers ran into another problem – obtaining the desired level of expression of the AT-hook protein genes, since too-high expression "causes many troubles such as growth retardation, stay-green phenotype, no bolting, or yield decrease". They explain that senescence in plants has dual features: a low level of senescence will delay ageing and extend photosynthesis and cellular activity, increasing growth and/or yield, but a higher level of senescence will only cause abnormal greening in the plant. They conclude, "delicate manipulation of gene expression is needed because of complexity of senescence".
Needless to say, there is no sign of this fragile GMO in the marketplace.
GM: Worst tool in the toolbox?
We are used to hearing GM crop promoters argue that we need “all tools in the toolbox” to survive the challenges of climate change and rising populations. But the experience of the Korean researchers suggests that GM is the worst "tool in the toolbox" for achieving desirable complex genetic traits, such as yield, disease resistance, or resilience to climate impacts, because these traits are the product of many genes acting together.
Thanks to the biological reality known as "omnigenics", we know that genes operate not as isolated entities but in networks. So if genetic engineers manipulate one or a few genes, they will affect many traits and end up with unintended outcomes, as the Korean researchers found.
The best way to achieve desirable complex traits is conventional breeding, sometimes helped by marker assisted selection, a safe biotechnology that enables breeders to identify genes of interest more precisely. Conventional breeding has consistently proven successful in producing numerous non-GM supercrops.
Brookes and Barfoot: Biotech boosters
Another link provided by the mustache as evidence of GM’s superior yields goes to a press release announcing a report by PG Economics, a consultancy firm run by Graham Brookes and Peter Barfoot.
PG Economics does made-to-measure studies for the biotech industry. Some are published in a journal edited by C.S. Prakash, who also works hand-in-glove with the industry, as George Monbiot has shown.
These conflicts of interest mean that PG Economics' reports largely consist of the GMO lobby referencing itself. The report linked to by the mustache relies heavily on reports and data generated by Brookes and Barfoot themselves, as well as Monsanto, the Argentine no-till GM crop farming association AAPRESID (which has links to agribusiness), and the biotech industry association ISAAA.
Experimental GM rice
The mustache is especially proud of a study reporting "enhanced yield performance" of a GM Bt insecticidal rice in saline-alkaline soil.
But a closer look at the study shows that not only is this yet another unproven experimental GM crop, but there are already serious questions over its effectiveness and safety.
The researchers found that in farmland soil and without target insect pest pressure, the GM rice had significantly weaker vegetative and reproductive growth (including grain number and weight, and seed setting rate), with higher fitness costs than those of its non-GM parent. In contrast, in saline-alkaline soil, the GM rice showed weaker vegetative growth and stronger reproductive abilities than those of non-GM parent, and thus greater fitness.
According to the researchers, previous studies have shown that total yield and seed-setting rate of the GM rice lines were significantly lower than those of the parental non-GM rice under farmland with low insect pressure. They write that GM "Bt genes usually had an obvious vegetative and reproductive growth disadvantage compared with the non-GM parental rice line" under field or greenhouse conditions with low insect pressure or absence of insect pressure. A possible explanation, they suggest, is that the low expression of the Bt insecticidal protein and thus less energy consumption leads to a negligible fitness effect on the reproductive ability of the GM rice in saline-alkaline soil.
Vulnerability to pests?
These results suggest that the GM Bt rice has a stronger reproductive ability than the non-GM parent rice line. The authors speculate – but cannot prove in this study – that this might reduce the yield loss caused by target insects, leading to a higher yield advantage compared with that of the non-GM parent rice in saline-alkaline soil.
But this yield advantage is highly precarious. That’s because the researchers found that expression of the Bt insecticidal protein Cry1C in the GM rice was lower in the saline-alkaline soil than farmland soil and that it decreased further as the plants matured.
This raises the question of whether such a low expression of Bt toxin would leave the crop vulnerable to the insect pests it is designed to kill. Pests have already begun developing resistance to the Cry1C toxin in experimental Bt rice in China.
It seems that genetic engineers and their troll followers forget that energy cannot be created; it can only be changed from one form to another. If plants use more energy to grow and reproduce, such as the GM rice in saline-alkaline soil, they have less energy to devote another activity, such as producing insecticidal toxins.
Rice researchers warn of long-term "risks"
To their credit, the saline-tolerant rice researchers are more cautious than their mustachioed cheerleader. They stress that their data were obtained over one year from saline-alkaline areas with no target insect pressure. They point out that in natural ecosystems, stresses don't occur in isolation (e.g. just saline-alkaline soil), but in multitudes. Therefore they say, "In the future, we plan to conduct the tests of three stress factors, including saline-alkali, target insect, or saline-drought with weed competition for more than 2 years."
So there’s a very long way to go.
In addition, the authors recognise that the increased reproductive fitness of the GM rice in saline-alkaline soil raises biosafety questions over "the long-term natural ecological risks" of planting such rice – and that these must be investigated. They add that they also need to look for unintended effects in the GM rice plants arising from mutations caused by the GM transformation process and tissue culture steps of development.
Approaches that work
The GMO sector, supported by the mustache, is promoting a sticking plaster approach to solving the problem of saline soils, in attempting to change the genes of plants to make them adapted to poor soil.
To address the problem at its roots, the only sustainable approach is to improve the quality of the soil.
Adding organic matter to saline soil has been found to dramatically increase plant growth.
In addition, the system of rice intensification (SRI) has been found to increase rice productivity in saline soil. SRI consists of agroecological approaches such as using wider planting spacings, adding organic matter to soil and aerating it, and using intermittent irrigation rather than continuous flooding.
Experiments with SRI in Indonesia found that the system reduced the use of synthetic fertilizers by 40%, reduced variable costs by 8.35%, and increased the benefits/cost ratio by 95% and crop productivity by 76% compared to control methods. It also increased the benefits/cost ratio by 161% and crop productivity by 133% compared to conventional methods.
Insofar as salinity problems can be overcome with genetics, conventional breeding is light years ahead of GM in developing saline-tolerant rice varieties, among other crops. Indeed, many such salt-tolerant seeds already exist and were distributed to farmers in India by Dr Vandana Shiva's Navdanya organisation, after a tsunami devastated soils.
Red herring
Finally, when it comes to feeding the world, yield is a red herring. There is no shortage of food production, even in countries where hunger is common. Hunger is a product of poverty: Poor people can’t afford to buy the food that is available in the marketplaces of even the least affluent countries. GM crops cannot provide a solution to this problem. Indeed, GM agriculture often displaces the type of agriculture that currently feeds 70% of the world’s population and produces the most food per hectare – peasant farming.
What emerges from the above “evidence” is the lamentable performance of the GMO food venture in spite of millions of dollars of investment over 25 years. It’s not surprising that the GMO lobby’s latest adherent maintains his anonymity by hiding behind a large mustache.
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