- Broccoli’s goodies engineered into tobacco. Jeremy comments: “Let them eat broccoli”.
- Australians discover diversity: livestock graze grain (plants)!
- Unidentified blight strikes Malagasy vanilla: lack of diversity to blame.
Over-utilized crops?
Thinking about biofortification, I imagined a world that relies on fewer and fewer over-utilized crops. When will 95% of our food come from two or three of them? Perhaps a maize-arabidobsis hybrid, a cassava wunderroot, and super-rice? Shouldn’t we rather buck that trend and diversify agriculture? That message comes from several corners, like this one: “a food system that is good for us, our communities and the planet is small-scale, diversified agriculture.”
I checked 1 the FAO statistics to see how bad things are going. How quickly are we un-diversifying agriculture? If you consider the fraction of crop land planted to different crops, it appears that — at the global scale — the opposite of what I expected is happening. Between 1961 and 2007, maize and soybean area went up, but that was countered by the decline in the area planted with wheat and barley. 2 It is a story of both winners and losers, and — overall — an increase in diversity.
Global crop diversity, expressed as the relative amount of land planted to different crops, did not change much between 1961 and 1980, but is has increased since. Between 1980 and 2007, the Shannon index of diversity went up from 3.14 to 3.34.
Do tell me why I am wrong. Is it a matter of scale? Global level diversification of crops while these crops are increasingly geographically concentrated? Could be. Is the diversity index too sensitive to the relative decline in wheat? Perhaps. Or are we really in a phase of (re-) diversification, at least in terms of the relative amount of land planted to different crop species? 3 I cannot dismiss that possibility. For example, I have heard several people speak about on-going diversification (away from rice) in India and China. Has anyone looked at this, and related global consumption patterns, in detail?
Nibbles: mtDNA, Bison, Crises
- mtDNA inheritance not so straightforward after all. Everybody panic.
- Some bison herds more diverse than others. Care needed in genetic management of species. Well I never.
- It’s not a food crisis, it’s a crop diversity crisis.
Go forth and grow halophytes
That seems to be the plea Jelte Rozema and Timothy Flowers make in a Science paper that’s just out. 4 But, frankly, I found the paper disappointing, not least because it is short on clear recommendations. For example, what is one to make of this?
Because salt resistance has already evolved in halophytes, domestication of these plants is an approach that should be considered. However, as occurred with traditional crops such as rice, wheat, corn, and potatoes, domestication of wild halophytic plant species is needed to convert them into viable crops with high yields. Such a process can begin by screening collections for the most productive genotypes.
Are they telling us that domestication of new species is a more profitable approach than trying to breed salinity-tolerance into existing crops? I think so, in which case it would be an interesting view, but I’m not altogether sure that’s in fact the point they’re making. It could have been better phrased. I mean those first two sentences could be summarized as
Domestication of halophytes should be considered. However, domestication of wild halophytes is needed.
Not sure how the editors at Science let that one by. There was also no explicit reference in the paper to the International Centre for Biosaline Agriculture and its genebank. Or to the possible role of crop wild relatives in breeding for salinity tolerance. All around, an opportunity missed.
Great Expectations
Nature has a (behind paywall) feature on Five crop researchers who could change the world. Rather than celebrating those who have arrived, Emma Marris highlights the work of five researchers who still have some way to go before reaching the Food Hall of Fame.
These are her picks.
Peter Dodds (CSIRO, Australia) works on the fundamentals of wheat stem rust. He investigates the substances that the rust fungus excretes, and the plant could use to trigger a defense reaction. He hopes to engineer new and more complex resistance, that the rust might not be able to break. Seems particularly relevant in the light of the UG99 scare.
Jerry Glover is a crop perennializer at the Land Institute, in Kansas, USA. The folks at the Land Institute want us to move from annual to perennial crops. That would be better for the soil and would take much less energy (nitrogen) to produce. They are clearly in it for the long run, but here’s a short and palatable piece about it.
Zhang Jinghua (Hong Kong Baptist University) works on deficit irrigation. The theory is that under modest water stress plants shift all their resources to reproduction and hence grain yield can increase. One trick in his book, and that of Australian grape growers, is ‘partial root zone drying’. Some roots are dry, and signal the need to fill the seeds, while other roots can access the water that is needed to keep producing. Water saving is particularly important in increasingly water scarce Northern China.
Richard Sayre, the director of the Institute for Renewable Fuels, Missouri, USA, was selected because he heads the BioCassava Plus collaboration. They are hoping to develop genetically modified cassava of which 500 g contains the daily requirements of protein, vitamin A and E, iron and zinc 5. They have succeeded in transformations for individual traits, now they have to figure out how to artificially transfer 15 genes into a single variety.
Julian Hibberd (U. of Cambridge) studies photosynthesis. He is one of the brains in the C4 rice consortium led by IRRI. They are trying to create rice plants with C4 rather than C3 photosynthesis. C4 photosynthesis is more efficient at high temperature, and it could be the next big thing (after short straw) to radically elevate rice yield potential — “by a whopping 50%” 6, thinks Hibberd. Seems far fetched, but C4-ness has independently evolved in many plant families, so why not another time, with a little help?
An interesting group, but did Nature miss anyone? Perhaps in branches of research less dominated by biotech? Let us know.