Recently in GMOs/transgenic crops Category

That's the title of my latest paper, now online at Field Crops Research. It will eventually be part of a special issue on yield potential.

There's some overlap with my previous publications arguing that many of the "improvements" proposed by biotechnology folks would duplicate traits that have arisen repeatedly in the past and have been repeatedly "rejected by natural selection" due to various tradeoffs. That doesn't necessarily mean those traits can't be useful in today's agriculture.

New material includes an assessment of the extent to which traditional breeding or biotechnology have improved tolerance to cold, flooding, or drought. Although crops probably pollinate their wild relatives more often than the other way around (because crops are more abundant), genes for stress tolerance mostly seem to move in the other direction. For example, high-altitude maize in Mexico has gained cold tolerance from teosinte, not the other way around. This and similar results suggest that natural selection is often better at solving tough problems than humans are. There are still plenty of opportunities for improvement through plant breeding or biotechnology, though. We just need to identify cases where past natural selection has worked against our current interests, and reverse the process. Shorter wheat and rice, less-bitter cucumbers, and thornless berries are a few examples.

That's the topic of a thoughtful essay by Nathanael Johnson on the Grist website. He gives a reasonable summary of my argument that many hoped-for improvements either involve tradeoffs (some of them acceptable) or radical enough changes that their effects will be hard to predict.

He also cites my colleague Jonathan Foley's suggestion that "we" should "Reduce food waste, eat less meat, and make fertilizer and irrigation available to the farmers that need it."

OK, but who's "we"? Any "solution" that requires billions of people to change what they're doing -- because they read Foley's article in Science? -- will be a long time coming. For example, a few million rich consumers eating less meat -- this would lower the demand for meat so that meat prices decrease so that slightly-less-rich consumers eat more meat, but let's pretend total meat consumption goes down a few percent -- would not have much effect on global greenhouse gas production or food security for the billion or two in greatest need. Similarly, if a couple billion consumers wasted less food, that would free up some resources. But if you and a few friends reduce your waste, it's a drop in the ocean.

Reducing pre-consumer food waste has more potential. Because reducing pre-consumer waste could mean larger profits for farmers, food companies, etc., near-universal adoption of practical waste-reducing methods is at least conceivable. Motivation linked to higher profits also means, however, that the obvious improvements have already been made. Less-obvious improvements are already a major research focus, but more likely to be invented by engineers than ecologists.

Expanding access to irrigation might greatly increase food security, but it would be a big project, perhaps costing a significant fraction of what we spend on war or video games. So I'm not holding my breath.

Increasing access to fertilizer can start small and scale up -- avoiding over-fertilization -- so that's an area where contributions from a few million people (or a handful of rich people) could really make a difference. But I worry about solutions that require on-going subsidies.

And then there's plant breeding. Develop a cultivar that out-performs what's available now, and watch it spread.

Carl Zimmer, author of several evolution-themed books and an interesting blog, published an article on weed evolution in Tuesday's New York Times. He used one of my favorite examples of rapid evolution of complex traits (flooding tolerance and crop mimicry in Echinochloa barnyardgrass/watergrass in <1000 years) to make the point that evolution of herbicide resistance (a much-simpler trait) in only a few years shouldn't have been a surprise. For example, glyphosate-resistant weeds are becoming increasingly common, just before the expiration of Monsanto's patent on Roundup-Ready soybeans.

What does the US Constitution say about patents?

"The Congress shall have Power To...promote the Progress of Science and useful Arts, by securing for limited Times to Authors and Inventors the exclusive Right to their respective Writings and Discoveries...."
If the original intent was to give inventors short-term monopolies, in exchange for long-term benefits to society, should the duration of patent protection be shorter for inventions whose useful life is likely to be limited by evolution? For example, 17 years with a really good resistance-management plan, 5 years with no resistance-management plan.... Of course, the Patent Office might need to hire an evolutionary biologist or two.

I agree with the statement from David Mortensen, in the New York Times article that adding another resistance gene to glyphosate-resistant crops, and spraying with both herbicides, will be only "a short-lived solution," although it might last long enough to be worth patenting. If they had put two different herbicide-resistant genes into soybean from the start, and if evolution of resistance requires two or more independent mutations -- this isn't always true -- and if farmers growing that herbicide-resistant crop were somehow required to use both herbicides, evolution of resistance might have taken much longer.

Zimnmer quoted me and mentioned my book on Darwinian Agriculture, depleting Amazon's stock, though they still have a few copies left. You could try your favorite independent bookstore or library.
Under selection pressure imposed by farmers with hoes, Echinochloa watergrass evolved to resemble rice more than it resembles its own recent ancestor, barnyardgrass (Barrett, 1983).

I discussed this example near the end of this lecture at the International Rice Research Institute.

All five of my Darwinian Agriculture lectures at the International Rice Research Institute are now available on YouTube. My talks were prepared in advance, so I was only able to incorporate a small fraction of the interesting things I learned during my visit.

My last talk discussed the tendency (not necessarily by scientists themselves) to exaggerate research progress. For example:

"The researchers have already... successfully introduced 10 out of the 13 genes needed for C4 rice." -- Rice Today, January-March 2013, p. 5

Wheat, rice, soybean and tomato use C3 photosynthesis, named for the number of carbon atoms in the first product of photosynthesis. Maize ("corn" in the US) and sugar-cane use C4 photosynthesis. In hot climates, C4 photosynthesis can support higher rates of crop growth, using less water.

My book (p. 62) uses C4 photosynthesis as an example of "something that may have been easy for natural selection (given millions of years) [but] extremely difficult for humans." So I was surprised to learn, before arriving at IRRI, that C4 photosynthesis only needs 13 genes and that they have already transferred 10 of them. Maybe "skeptical" would be a better word.

I should have asked about this when I met with Paul Quick, who is leading the C4 rice project at IRRI. I'm guessing that he told the magazine that they've identified 13 key genes so far, and transferred 10 of them. My impression, from our discussions, is that they don't yet know the total number of genes they will need to transfer.

They have a lot of smart people, at IRRI and around the world, collaborating on C4 research. C4 rice will need :

* Some way to pump CO2 into bundle sheath cells around the leaf veins, from adjacent mesophyll cells.

* A diffusion barrier around the bundle sheath cells to keep the CO2 from leaking out again.

* More photosynthetic chloroplasts in the bundle sheath cells than rice has now.

* Ideally, closer vein spacing. The assumption is that CO2 can't be pumped very far, so if veins are widely spaced, only a fraction of the leaf will have C4 photosynthesis. But Paul Quick told me that corn husks have C4 photosynthesis throughout the leaf, despite widely-spaced veins. Interesting.

They seem to have made considerable progress on most of the above. I don't think he mentioned any progress on the diffusion barrier, though, which seems more critical than vein spacing, at least to me.
One of the clever approaches they are using is to knock out genes in a C4 plant, at random, to see which of them are essential to C4 photosynthesis. How do they tell if they've knocked out C4? Because of their CO2-concentrating mechanism, C4 plants can survive at much lower CO2 concentrations than C3 plants can. So they grow the random-knockout plant population at 15 ppm CO2 -- the atmosphere is 390 ppm and rising -- and look for plants that don't grow. Sounds like cruelty to plants, but they rescue them before they die, by transferring them to a high-CO2 tent. They're also drawing on IRRI's huge (100,000 genotype) collection of rice varieties and rice's wild relatives.

I don't know if they'll succeed, but this seems like a reasonable test of our current ability to improve complex traits in crops. At a minimum, they should get a lot of useful information about photosynthesis, leaf structure, the evolution of complex traits, etc. This information could have applications beyond improving photosynthesis. For example, the ability to develop crops with wider or narrower vein spacing would have applications in developing more-digestible crop leaves (for cows or for biofuel production). Vein spacing may also affect drought tolerance. Whether spending the same amount of money on other kinds of agricultural research would make more sense is a more-complex question. But the Gates Foundation is funding this "high-risk, high-potential-reward" research, so it doesn't come at the expense of their other work.

For more information, see IRRI's C4 rice page. For an interesting history of the project, see this video interview with John Sheehy, former head of the C4 rice project, who back visiting IRRI the same week I was there talking about Darwinian Agriculture.

Evolution deniers often claim "I used to believe in evolution... until I looked into the science." Many of them are lying, especially about the science part, but what if some of them really did change their minds?

So what? If one of your friends jumped off a bridge...
The evidence for evolution isn't diminished by one person changing his mind.

Similarly, one environmentalist (Mark Lynas) changing his mind about transgenic crops isn't evidence, one way or the other, that they are safe or useful. I don't have much to add to what Chris Smaje and John Vandermeer have written about this high-profile "defection."

My own guess is that the risks of current transgenic crops are less than many environmentalists fear, but the benefits (and potential benefits, at least within the next decade or two) are less than GMO supporters promise.

But, you may ask, as long as investing in biotechnology research will provide some net benefit, shouldn't we do it? As usual, an analogy based on rhizobia may be useful.

How should we view a rhizobial strain that provides some nitrogen to its legume host, but occupies a root nodule that would otherwise have been occupied by a more-beneficial strain? Wouldn't we be better off if the less-beneficial strain were less abundant in soil? Similarly, if some of the money invested in biotechnology would otherwise have been invested in more-beneficial ways, such as developing agricultural methods informed by ecology and evolutionary biology, wouldn't we be better off investing less (but not zero) in biotechnology?