Category: Breeding

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Breeders not so bad after all

ResearchBlogging.orgSpeaking of evil plant breeders:

It is generally thought that continuous selection among crosses of genetically related cultivars has led to a narrowing of the genetic base of the crops on which modern agriculture is based, contributing to the genetic erosion of the crop gene pools on which breeding is based.

But this may be another faulty meta-narrative. At least that’s what a group of researchers from the Dutch genebank say, as a result of a meta-analysis of 44 genetic diversity studies of the varieties of 8 crops released in successive decades. ((Wouw, M., Hintum, T., Kik, C., Treuren, R., & Visser, B. (2010). Genetic diversity trends in twentieth century crop cultivars: a meta analysis Theoretical and Applied Genetics DOI: 10.1007/s00122-009-1252-6)) This is the result:

trend

The meta analysis demonstrated that overall in the long run no substantial reduction in the regional diversity of crop varieties released by plant breeders has taken place.

Of course, that says nothing about the relative frequency at which these varieties have been grown by farmers, also an important aspect of overall diversity, along with how different the varieties are. Anyway, that decrease in the 60’s was only about 6%, and that has been reversed since then. How? Because of genebanks, say the authors.

In the 1960s and 1970s the introduction of the new Green Revolution-type cultivars for the major staple crops led to concerns on the disappearance of the world’s varietal wealth of crop plants. The widely shared concerns ultimately resulted in the establishment of a worldwide network of international genebanks hosted by the CGIAR research centres. The seed samples stored in these genebanks facilitated access of the world’s crop diversity to plant breeders world wide. It seems likely that the easy access to crop diversity provided by the genebanks, improved communication among breeders and easier exchange of seeds were factors contributing to the reversal of the initial trend in diversity reduction as observed in this meta analysis. Also the increased use of crop wild relatives for breeding and in recent years the use of synthetic wheats will have contributed to the observed diversity increase.

Well, it will be interesting to see, in due course, whether the restrictions on access which followed the Convention on Biological Diversity, had an effect, and whether the International Treaty on PGRFA eventually set the world to rights. As it was designed to do.

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Do we dislike genetic engineers and plant breeders?

James, of the Giant Corn, asks an interesting question:

Do most people who work in the agricultural biodiversity field not like genetic engineering (and even plant breeders)?

This is prompted by his reading of Gary Nabhan’s Where our food comes from, which is about Vavilov and crop diversity and much else besides. James, who is studying for a PhD in plant biology at UC Berkeley, seems to think that the world — or at least Gary Nabhan — has it in for plant breeders and even more so for genetic engineers. I think it is salutary that a plant scientist, someone who has worked on teosinte and it’s more selected form, maize, had barely heard of Vavilov in all his training, and I’m really glad that he has now discovered Nabhan’s book (no matter what he thinks of it) and, more importantly, Vavilov. Here’s part of how I answered his question, in haste:

[T]he greater one’s awareness of agricultural biodiversity, the stronger is the impression that single “breeding” solutions, especially in relation to pest and disease resistance, are inevitably overtaken by the much more rapid evolutionary turnover of pests and diseases. Genetic engineering is even more simple minded than classical plant breeding, transferring just one or a few genes, and is thus even more prone to being overtaken by evolution on the part of the pest or disease. And for nutritional changes, dietary diversity delivers so many additional benefits compared to biofortified staples, that we find it odd that so much money and effort goes into the former and so little into the latter.

In his reply, James talked about stacking resistance genes and high vitA corn (maize) and conceded that both were a lot more work than genetic engineering, especially without molecular markers. My own view, for what it is worth, is that genetic engineering only seems faster. To truly have an impact, the constructs really ought to be put into a wide range of varieties that will thrive in a wide range of conditions. That takes time. So does clearing the regulatory hurdles. And in the end, at least so far, the bottom-line yield gains have hardly been worth sharpening a pencil to write home about.

I am definitely not against plant breeding, nor am I against genetic engineering per se. I do think that genetic engineering has been appallingly managed, has yet to deliver anything of interest to the people who actually have to eat its products (apart from the first ever cleared product, GE tomato paste), and has sucked vast gobs of cash and a few good minds from more interesting and more (intellectually) rewarding science. Other than that, I personally have nothing against it.

In other news: The Scientist Gardener reports that Monsanto’s patent on its first generation herbicide resistant Roundup Ready soybean is about to expire! and suggests that “[w]e’d be even better off (more competition, more disruptive technologies) if we loosened up genetic engineering regulation and let the small guys play”.

Now there’s a thought.

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Nary a drop to drink

The BBC had an interesting series of maps in December last year on the effects of climate change, economic and population growth on per-capita water availability, based on the work of Martina Floerke and colleagues at the University of Kassel in Germany. Here’s the picture for 1961-90. Red is bad.

1961

And here is the 2070s. Click to enlarge.

2070s

Doesn’t look good, particularly for Central and West Asia, and both southern and North Africa. That’s where your drought tolerant crop varieties are going to come in useful, I guess. And not just that. But I don’t understand how Australia gets away with it so lightly.