Climate change has made the need for climate resilient crops urgent. An article in the journal Nature reports that “Old-fashioned breeding techniques seem to be leading genetic modification in a race to develop crops that can withstand drought and poor soils”. The Drought Tolerant Maize for Africa project has conventionally bred 153 drought-tolerant varieties that outperform non-tolerant maize varieties by up to 30% in drought conditions.
Dr. Doug Gurian-Sherman, Senior Scientist at the Center for Food Safety in the U.S., contrasts this with Monsanto’s genetically engineered (GE) drought-tolerant seeds, which have shown only about 5-6% yield increases in the U.S. The Nature article states, “Drought tolerance is a complex trait that involves multiple genes. Transgenic techniques, which target one gene at a time, have not been as quick to manipulate it.”
Another programme in Africa has used plant breeding in developing 21 nitrogen-use efficient maize varieties which have increased yields by 20-50% in nitrogen-poor soils in Sub-Saharan Africa. Nature reports that the project researchers are however “at least 10 years from developing a comparable GM variety”.
Dr. Gurian-Sherman points out that conventional breeding has also produced drought-tolerant staple crops such as millet, cassava, rice, and wheat which have no GE counterparts, and that it has proven cheaper and more effective.
He lays out certain principles that must be followed if conventional plant breeding is to bring maximum benefit: (1) it must be coupled with organic and “agroecological” farming systems which are inherently more resilient, (2) it must include meaningful participation of farmers, and (3) public breeding programmes must supply peasant farmers with free or inexpensive seed, which they must be able to save and further improve for local conditions.
Genetically engineered (GE) seeds are often sold to farmers and the public on the grounds that they are the wave of the future, taking over where conventional plant breeding left off by improving productivity and sustainability. But that might be changing.
Last month, the highly respected science journal Nature published a news article reporting that conventional breeding substantially out-performs genetic engineering for several very important traits—drought tolerance and the ability of crops to use nitrogen (e.g., from fertilizer or manure) more efficiently.
It’s unusual to see the two methods compared. Science journals have presented advances in breeding for drought tolerance. But none have been bold enough to say what has been obvious for several years—that conventional breeding is working considerably better than genetically engineered seeds for this trait.
As the Nature article points out: “Transgenic techniques, which target one gene at a time, have not been as quick [as conventional breeding] to manipulate [drought tolerance].” For those who want more detailed information on this topic, I analyzed and compared genetic engineering and traditional breeding for drought tolerance and nitrogen use efficiency in reports published in 2012 and 2009, respectively. I came to very similar conclusions as the Nature article.
The article also notes that while Monsanto hopes to get a transgenic drought tolerant seed trait to Africa “by 2016 at the earliest,” there are already about 153 varieties of conventionally-bred corn currently in trials for drought tolerance. And conventional seeds have been shown to improve yields–a scientific term for the actual amount of corn harvested–by as much as 30 percent higher than non-tolerant varieties during drought. Many other non-GMO drought-tolerant varieties are already deployed to several million farmers with yield improvements reported to be about 20-30 percent compared to previous varieties.
By comparison, Monsanto’s drought tolerant seeds provide only about 5 or 6 percent yield increase in the U.S., and only under moderate drought conditions. Comparisons are somewhat tricky, but there is little doubt that conventional breeding is outperforming GE for improving drought tolerance.
Nature doesn’t mention that conventional breeding has also been making important staple crops popular in the developing world–such as sorghum, millet, cassava, rice, and wheat–much more drought tolerant. There are no available GE seeds for any of these crops.
The Nature article discusses another important genetically complex trait—nitrogen use efficiency (NUE), or the amount of grain produced for a given amount of nitrogen fertilizer. This trait is important in Africa because crops often do not get enough of this crucial nutrient for optimum production. Fertilizer is also scarce and very expensive there. As with drought tolerance, conventional breeding is making inroads—21 varieties with improvements of about 1 tonne per hectare in trials (in much of Sub Saharan Africa, this would amount to about 20 to 50 percent yield increase), with GE traits “at least 10 years away,” says Nature. In developed countries, improved NUE is important because inefficient fertilizer use is the main culprit in over 400 coastal dead zones, where it is harming fisheries. It is also the main contributor of the potent global warming gas, nitrous oxide.
Other important crop traits, such as increased yield potential, are also genetically complex. This has led some scientists to realize that the success of the few available GE traits is due in part to their exceptional simplicity. In other words, drought tolerance is controlled by many genes, which each tend to contribute only a small benefit. Genetic engineering can manipulate only a few genes at a time, but it is hard to find a small number of genes that provide substantial drought tolerance on their own. By contrast, the few engineered genes that have been successful happen to have big effects. But this is often the exception, rather than the rule.
Major Goodman of North Carolina State University, a highly respected corn geneticist and member of the National Academy of Sciences, put this succinctly in testimony before the National Research Council recently. He noted that some have pointed out that the current GE seeds provide solutions to problems that are “low-hanging fruit.” Goodman corrected this perception: They were not low-hanging, he said. They were “on the ground.”
The potential of conventional breeding is largely untapped, as the authors of another Nature article noted last year. Ironically, experimental techniques from the science that genetic engineers also use (molecular biology), has helped conventional breeders better understand the genetics of conventionally-bred crops and related plants.
Some academic scientists claim that GE seeds would be more successful if it weren’t for expensive safety regulations. They claim that the high cost of complying with regulations is a big barrier to getting approval for their genes. But this is not necessarily the reason these crops are not making it to the marketplace. Engineered seeds that would produce drought tolerant plants, or improve yield potential in major crops like corn, soybeans, and rice have huge potential markets, which more than offset any regulatory costs. So these genes are of great interest to big companies with very deep pockets, not just “poor” academic scientists. These companies also have huge research budgets and access to university research; they have been trying to improve these and other traits using GE for many years. Despite all this, the virtual lack of commercial products suggests limitations of the technology.
In severalpapers, Goodman points to other factors that hamper the development of GE seeds. He notes that conventional breeding typically costs about a million dollars per trait, compared to hundreds of millions for genetic engineering. An industry-supported report puts the average cost at $136 million per GE trait, with the large majority of the cost going to research and development and the like, not regulatory expenses. Goodman also explains that genetic engineering is not faster than most types of breeding in producing successful traits, contrary to popular myth.
As I have written elsewhere, genetic engineering may make some contributions to improving agriculture. But since conventional breeding is cheaper and more effective, it should get a much bigger share of public research funding and policy support. Instead, only a small fraction of the U.S. Department of Agriculture research budget supports breeding and agroecology, while Farm Bill policies subsidize and favor a few commodity crops. And due to this lack of support, there are fewer public breeders at land grant universities over the past several decades.
Conventional plant breeding is no panacea. As with genetic engineering, traits that look promising initially can, with further work, reveal problems like lowered yield (or “yield drag”). Breeding for industrial agriculture systems is also a problem. This has led to such dubious projects as tomatoes that are hardy enough to be harvested by machines, but taste like wax, and “green revolution” crops overly-reliant on irrigation, fertilizer, and pesticides, to the detriment of the environment, public health, and often small-scale farmers. But conventional breeding has also shown that it can be of great benefit if certain principles are followed.
First, it must be coupled with organic and “agroecological” farming systems, which rely on long crop rotations, cover crops, mulches, manure, and so on. Second, it must include meaningful participation from farmers. Breeders need to work with farmers on a continuing basis. Farmers know what their challenges are, and what crop characteristics are important to their communities.
Finally, good public breeding must supply poor and peasant farmers with free or inexpensive seed, and farmers must be able to save it and further improve it for local conditions. Agroecology is place-based, meaning that how it is used is based on local conditions such as pests, soils, and climate. This often makes it inherently more resilient than industrial agriculture, which largely ignores these factors, or tries to beat them into submission with expensive chemicals. Farmers, such as small-holders in developing countries also are responsive to local conditions, and maintain vital crop genetic diversity that is needed for continuing improvements. Breeding that respects and supports these farmers is critical.
If done right, conventional breeding and agroeocology can both improve agriculture in many ways. But achieving this potential means getting our priorities straight and seeing beyond silver-bullet solutions. The latest Nature article demonstrates a step in the right direction in recognizing one piece of this puzzle.