Genetic modification in a thirsty world

November 2012

Drought tolerant maize lines at Kiboko, Kenya
Drought-tolerant non-GM maize in Kenya. Photo by CIMMYT on Flickr
In summer 2012, the arrival was announced of “the holy grail of seed companies, drought-tolerant corn,”. Farmers in Iowa, who are suffering their first major water shortage in 24 years, were shown the “latest gee-whiz addition to seed offerings” to help them beat the drought.

Monsanto was plugging its 'DroughtGard' GM corn, which it plans to have on the market by next year. Authorisation has already been given for the GM corn by the US government, but to sell its “exciting technology” on the global market, approval is still needed in several key countries. The Company expects DroughtGard to yield 5 to 10 percent above normal in dry areas.

Earlier in the year, GM-concern group, the Union of Concerned Scientists (UCS), produced a report detailing “Why Genetic Engineering Is Not Solving Agriculture's Drought Problem in a Thirsty World”.

Irrigation for agriculture accounts for 68% of the freshwater Americans extract from their environment: water is limited, even when there isn't an actual drought. The UCS has pointed out that Monsanto's advertising campaign for DroughtGard, in which it touts its intention to develop seeds which yield “more crop per drop”, is misleading. The GM corn performs well under moderate drought conditions, but its water-use efficiency (the water it uses under normal conditions) isn't any better than other crops available. Since drought can't be predicted far in advance, farmers have no way to judge whether it's worthwhile investing in DroughtGard when they're buying seed.

One Wall Street Journal writer criticised the UCS study for having too little faith in the ability of science and technology to find an answer to the world's shortage of water for agriculture. The gist of the article was that, typically, new technologies start slow but then get more effective and less expensive over time. GM 'solutions', it seems, can be expected to follow the same trend.

This seems a rather wild generalisation on which to stake our entire future food supply. For one thing, there are some major examples of technologies which have not shown the expected improvement, notably nuclear power which never did fulfill it's dream of being 'too cheap to meter'. For another thing, technological dead-ends are quickly forgotten.

What the Wall Street Journal ignores is one of the key points made by the UCS: technologies, such as genetic engineering, which involve living organisms are inherently complex and unpredictable. The end-result is that, if any benefits emerge, they may be accompanied by undesirable trade-offs not only in the properties of the crop, but in agricultural, social, environmental and health aspects.

A common refrain from politicians, farmer organisations and GM-lobbyists is that we should use every tool available to us and that GM is simply one such tool. This, in reality, is idealistic nonsense: we do not have the resources to pursue every tool we have.

What we do already have, as the UCS Report explains, are numerous drought-tolerant crops and many ways to substantially address the global food problem, even in a thirsty world.

The means we already have, without GM, to counter water shortages
  • Classical breeding techniques and improved farming practices have been increasing drought tolerance in U.S. corn by an estimated 1% per year for decades; there's no reason to believe this can't continue. Compared with the time needed to develop GM crops, this makes conventional breeding faster.
  • Alongside Monsanto's first demonstration of DroughtGard in Iowa, were, DuPont Pioneer's non-GM drought-tolerant 'Aquamax' corn and Syngenta's non-GM drought-tolerant 'Artesian'. All three crops are expected to yield the same, but the non-GM varieties are available for purchase now.
  • In 2012, the UK Department for International Development won an award for its part in developing and disseminating 34 new, non-GM, drought-tolerant maize varieties to farmers in 13 African countries, benefitting some 2 million small-holder farmers few of whom have irrigation.
  • Agrichemicals require water for their application, and their use reduces soil carbon and water-retention. However, crop management alone can reduce chemical use and increase crop productivity with consequent reduced water needs. A recently published long-term, large-scale study showed how, by simply diversifying crop rotations (up to a 4-year 4-crop cycle) and including animals in the system, ecosystem services could be engaged to displace synthetic inputs. Besides reducing applications of nitrogen fertilizer and herbicides, yields and profits were similar to, or greater than, those of the conventional low- or no-rotation systems. Weeds were suppressed effectively in all systems, but freshwater toxin loads were two orders of magnitude lower than in the conventional sites. (Adam S. Davis et al.) 
  • “Several food and feed crops, such as sorghum or pearl millet, are naturally more drought tolerant than corn. These crops are often less productive than crops more familiar in the United States—probably partly because they have received more limited attention from crop breeders. Many have untapped potential for improved yields and other desirable traits, suggesting opportunities to use them more widely in dry regions around the world.” (UCS High and Dry Report)
A huge number of commodity crops in America are now GM with an added gene for tolerance to the herbicide ‘Roundup’ whose active ingredient is glyphosate.

Not only are glyphosate-tolerant plants ill-equipped to deal with drought, but they become less water-efficient after their treatment with glyphosate. Direct comparison of glyphosate-tolerant GM crops grown side-by-side with high-quality non-GM varieties have shown a far superior yield in the conventional versions (for example, 100-120 bushels per acre for a non-GM corn compared with 8-12 bushels per acre for the GM one).

There are several plausible mechanisms which could give these differences in yield and water use. For example, glyphosate-tolerant plants are deficient in lignin (the stem's main supporting material), and their ability to transport water up from the soil is reduced as a result. Also, glyphosate itself reacts with, and impairs, the uptake of minerals essential to the plant. Both of these side-effects probably contribute to the demonstrated reduction in photosynthesis characteristic of such GM plants.

How long should we flog this particular dead biotech horse waiting for the technology to get better and cheaper before we give up and grow high-quality, robust conventional crops with lower water requirements instead?

The answer is surely that the time to build on our knowledge of proven crops and proven crop-development methods is right now, because any delay or diversion could be catastrophic to our food supplies.

Time and money spent on a long-term GM wish which may never be fulfilled is wasted.


This might leave you with the uncomfortable feeling that drought-tolerant GM plants are being developed to counter the drought-intolerance of the same company’s glyphosate-resistant GM crops. Also, of course, GM drought-tolerant crops will be patented. Ah, more profit!

In the UK our current problem is more one of too much water rather than too little. However, both problems are most easily solved the same way, with robust crop varieties which don't have to cope with the physiological stresses caused by lab-made DNA as well as extreme weathers.

  • Adam S. Davis et al., 2012, Increasing Cropping System Diversity Balances Productivity, Profitability and Environmental Health, PLOS ONE, 7:10
  • Doug Gurian-Sherman, A Less Thirsty Future Through Engineered Crops?, 13.09.12,
  • Dr. Eva Sirinathsinghji, GM Crops Destroyed by US Drought but non-GM Varieties Flourish, Institute of Science in Society Report 9.10 12
  • Hayden Smith, Food prices go up as the rain comes down, Metro, 11.10.12
  • Dan Piller, Drought-tolerant seed entices weary farmers, Des Moines Register, 29.08.12
  • Drought tolerant maize wins 2012 UK Climate Week Award, International Institute of Tropical Agriculture News Release, 13.03.12
  • Monsanto's 'DroughtGard' Corn - Not Much Use in a Drought, Union of Concerned Scientists Report
  • High and Dry - Why genetic engineering is not solving agriculture's drought problem in a thirsty world, Union of Concerned Scientists Report, June 2012

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