Category: Breeding

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Maize and genetic engineering: why bother?

I was talking to Greg Edmeades tonight. Our conversation coalesced on the topics of the recent posts on maize water stress tolerance and on the usefulness of engineering purple tomatoes.

For many years, Greg led the maize crop physiology group at CIMMYT. He says that one of the main reasons for their success with drought tolerance is their long term institutional commitment to it: 35 years and counting. A particularly impressive feat is the widespread adoption of their maize varieties in southern Africa. For example, ZM623, selected from South African parents by Marianna Bänziger, is grown on about a million ha, says Edmeades.

His take on biotech for drought tolerance is, sure, “use whatever works, but if you are an African agricultural research institute, then, why bother?” Monsanto is reporting 10-15% yield increase under drought stress, and says it will make their technology freely available for use in Africa. Edmeades reckons that you can get a similar yield increase in about 7 years of conventional breeding and selection. And less when using molecular markers. If that is the case, it may not be worth it to deal with the complexities of genetic engineering.

Unless, perhaps, the approaches are entirely additive and you get a combined yield benefit of 30%. I think that’s unlikely. Drought tolerance is about making best use of the available water. It does not increase the amount of water.

Later:
Greg told me that I had been a little harsh in suggesting that he would not advise national programs in Africa to use a transgenic approach to drought tolerance. He would only advice against transgenes if “they had access to a steady stream of good germplasm improved for drought tolerance, and there was no regulatory framework for transgenes in place in that country. If regulatory frameworks exist, and there is no facility of improving their own varieties (or newly released commercial varieties) for drought tolerance in a systematic way, then certainly I’d take the transgenic option, especially since it is being offered on a royalty free basis.”

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Purple tomatoes for longer life — if you’re a mouse

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I was going to do an in-depth analysis of a paper in tonight’s Nature Biotechnology, but it’s been a busy weekend and there are two press releases out there that do enough of a job on it for my purposes. From one:

Scientists have expressed genes from snapdragon in tomatoes to grow purple tomatoes high in health-protecting anthocyanins. … The scientists tested whether these elevated levels actually had an effect on health. In a pilot test, the lifespan of cancer-susceptible mice was significantly extended when their diet was supplemented with the purple tomatoes compared to supplementation with normal red tomatoes.

Mice given 10% of their diet in the form of powdered, freeze-dried purple tomato lived an average of 182 days, compared to 142 days for mice fed the same amount of freeze-dried red tomato or no supplement, which did not differ from one another. That’s great. Proof of concept, if you like.

From the other:

“The study” says Cathie Martin, FLORA project coordinator “confirms the latest research trends arguing that we can obtain significant beneficial effects by simple changes in our daily diet. We are not talking of pills or supplements but only food. It is worthy of notice that recommendations by worldwide governments risk to be unaccepted. The 5-a-day program promoted by the American National Cancer Institute 20 years ago does not seem to be very incisive and not just because of the lack of time. Financial crisis is giving an hand to the failure of good intentions mainly due to the expensive costs of fruits and vegetables. Research has to do something, has to find new ways to face the challenge. A solution may rely on concentrating in few but selected products the largest part of nutrients we should intake during the whole day”. ((I think this may have been babelfished a couple of times, but that’s not my responsibility.))

Researchers are clearly working hard to put anthocyanin genes into tomatoes, hoping, I suppose, that eventually people will eat those, or freeze-dried anthocyanin-rich genetically-engineered tomato powder, to ward off cancer. I wonder though, why they didn’t start with a naturally purple tomato and attempt to up-regulate the purple pigment genes. Too difficult? There are many such varieties, and I happen to be sensitized to them right now because in connection with something else I came across the Organic Seed Project, which lists “Improvement of Prudens Purple Tomato” as one of its Participatory Plant Breeding projects. Alas, that’s all it does. List it. Anyone know more?

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The top photograph, from the research scientists, shows their very purple engineered tomato. The lower one, which has a very bluish cast, suggesting an excess of Photoshopping zeal, shows Prudens Purple in the centre and Black from Tula, a Russian variety, on the right. I’m not aware of any thorough measurements of anthocyanins in tomato varieties, though there is a wild relative with a gene that produces anthocyanin fruit. What is more, it has been conventionally-bred into domesticated tomatoes. We blogged it almost two years ago. ((Although the link that points to is dead and gone.)) I wonder why we have heard no more about it.

My point is not that there’s anything wrong with genetically engineered purple tomatoes. It is that lots of people may think there is. Indeed, and I know I’m going out on a limb here, such a belief may even be more common among those who are most likely to eat food-based dietary supplements to promote good health. So if researchers really want people to eat their tomatoes, why engineer them?

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Single gene looking for water

Drought tolerance is the holy grail in crop improvement these days. We are running out of water; cannot easily expand irrigation; poorer farmers are affected most by it; and climate change will make things worse (etc.).

Breeding for drought tolerance has not been very successful. For lack of trying? Many years of work at CIMMYT seem to be paying off. Or is it just too damn difficult because of the multiple genes involved (from stomatal regulation to root growth), and the multiple droughts (when, how long, how much) to deal with.

Drought tolerant maize compared with local varietyCan biotech come to the rescue? This New York times article suggests that big companies and single genes may do the trick. I have to see it before I believe it, something like this picture, which shows drought-resistant corn on the right, tested next to “traditional” corn plants in Nebraska, USA. I want to see that picture in the fields of African farmers.

Or should farmers who cannot grow maize because of drought start thinking of another crop? Why not grow sorghum?

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Nibbles: Funding, Cow Gods, Ãœber Bee, Rice, Bushmeat, Oaks

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One seed at a time activism

I’ve been having an argy-bargy with Gary of Muck and Mystery over how best to achieve diversity in the seed supply. To polarize, he seems to think that government research in seed breeding for specialized markets, like organic growers, is evil and serves to undermine further the diversity that does exist. I believe that the biggest obstacle is regulation, especially in Europe, where everything not permitted is forbidden. In a recent comment, he said this:

Seed companies do not seek to prevent seed saving. That’s nonsense. Seed companies seek to provide better seed, so good that growers will buy them. This is as true for the smallest independent seed shop as for the huge commercial suppliers. Europe can buy seeds from the world. There’s this thing called the internet to find them and companies that deliver even the smallest packages for decent prices. If that is illegal, then you have identified the problem. The only problem. What’s more. if there are local landraces that those seed companies do not sell, they’d likely be interested in doing so if they had a market for them. Once they are available, growers in other places are sure to try them since their customers would pay for variety. If the people deal with one another without state mediation and control there will be no diversity problem.

There are bits of that I would definitely argue with, but rather than pour fuel on the fire, I’ll simply say that he does have one very good point. In Europe unregistered seeds may not be available locally but “this thing called the internet” does at least offer the opportunity to try things from elsewhere. OK, your package could be confiscated, but it might get through and then you’ve got something new to play with, especially if you know enough to save your own seed in future. There’s also a “Traveller’s Exemption” that allows Europeans returning from abroad to bring back five small packets of seeds unregistered in the EU.

In that spirit, I was happy to see, on the same day as Gary’s advice, a new post at Bishop’s Homegrown. Hip-Gnosis Seed Development List of Available Seed 2009 is just that. A list of the varieties that Alan Bishop is developing and that he’s making available to growers elsewhere. He explains it like this:

We continuously select (year round) for new adaptations, unique colors, and higher nutritional content as well as taste and performance in our seed crops. Many of our seeds are unique breeding lines that will allow the home gardener to select for what they like and need in their own unique micro-climate conditions as well as in taste and color. Hip-Gnosis Seed Development operates now as a unique collective of seed growers and plant breeders working and trading together on the homegrown goodness message board (http://alanbishop.proboards60.com) where many of our varieties can be traded and bartered for (both from us and from other members). As always, all of our seed is public domain property and as such should be traded and allowed to continue its regional expansions into new territories for new selections and strains. We openly encourage everyone to share these special seeds far and wide.

I’m sure he’d welcome some (more?) Europeans in there, to explore and work with Astronomy Domine sweetcorn, Jack White tomato or even Robert Johnson Mississippi Delta Burley Tobacco. ((Can you tell where Alan Bishop is coming from?))

Bishop is just one of the grower enthusiasts at work using ancient and creating modern diversity. There are others like him, not just in the US but in many other parts of the “developed” world. There are even some in Europe.

So yes, go ahead, order seeds over the internet, see what works for you, select and adapt your seeds, and spread them around.

I bet, though, that if Europeans were able to pursue diversity directly instead of through loopholes and over the internet, we would see a lot more of that kind of thing here.