Unlocking sorghum's gene bank: Adapting agriculture to a changing climate

Jan 03, 2013 by Steven Powell
Unlocking sorghum’s gene bank: Adapting agriculture to a changing climate
Sorghum crop growing in South Carolina. Credit: Nadia Shakoor

(Phys.org)—Climate change poses a major challenge to humanity's ability to feed its growing population. But a new study of sorghum, led by Stephen Kresovich and Geoff Morris of the University of South Carolina, promises to make this crop an invaluable asset in facing that challenge. Just published in the Proceedings of the National Academy of Sciences (PNAS), the paper puts genetic tools into the hands of scientists and plant breeders to help accelerate their ability to adapt sorghum to new conditions.

A hardy cereal crop that was first domesticated in the Horn of Africa some 10,000 years ago, is now cultivated worldwide, from Texas to China. Sorghum is a particularly drought-tolerant grain and an essential part of the diet for 500 million people, chiefly in sub-Saharan Africa and India. In the U.S., where it is primarily grown for , sorghum's climate resilience was highlighted during the devastating summer drought of 2012.

A large international effort decoded the genome of the species cultivated for food, Sorghum bicolor, which was published in the journal Nature in 2009. That genome represents the genetic accounting of a single individual of sorghum. But as individual humans have that underlie physical differences such as eye color, so do individual plants of sorghum. The focus of the current effort was to establish the connections between gene differences and physical differences – a detailed understanding of those connections will constitute a tremendous tool for plant breeders.

The team behind the current PNAS publication – which also included researchers at Cornell University, the International Institute for the Semi-Arid Tropics in India and Niger, the University of Illinois and the U.S. Department of Agriculture – used genotyping-by-sequencing (GBS) to determine the individual of 971 sorghum varieties taken from world-wide seed collections. The scientists identified more than a quarter million single-nucleotide polymorphisms (SNPs); that is, single letters in the genetic code where individual variants of sorghum can differ.

Unlocking sorghum’s gene bank: Adapting agriculture to a changing climate

The results were possible thanks to a tremendous genetic resource that was built over many years, and largely before genotyping was even technically possible. For almost a century, sorghum seeds from a variety of international locations have been stored in seed banks, with dates and geographic origins often noted with each sample.

"We're taking advantage of the incredible diversity found in the gene bank," said Morris, a research assistant professor at USC and lead author on the paper.

One subject of particular scrutiny in the paper was the genetic control of the panicle, the structure on the top of the plant that holds the grains. This feature is an important consideration for successful breeding, particularly when climate is a consideration. Closely packed grains, for example, are preferred for maximum crop yield in dry areas, but in places with abundant rainfall, more spacing is desirable to allow grains dry out more readily and reduce crop losses from moisture-caused disease.

The researchers identified genes that likely contribute to this physical feature, and they also mapped them geographically according to the source of the original seed. The result was insight into how different variants of the genes spread according to regional climates – which varied widely in the study, from the edge of the Sahara to the rainy highlands of east Africa.

The results will "provide resources for everyone around the world who breeds sorghum," Morris said. "The goal is to do it faster than the way it's been done traditionally, which takes years of growing and crossing and testing."

That's particularly important because the semi-arid regions where sorghum is a staple food are predicted to be most adversely affected by . Sorghum varieties that currently thrive there will have to be bred for new conditions, a time-consuming process. "The challenges facing agriculture are getting more severe, so the tools that we have for crop improvement have to keep pace," Morris said.

A further step forward will involve genomic selection, another collaborative effort planned for the coming year that will again involve Kresovich, the SmartState Endowed Chair of Genomics at USC and senior author on the PNAS paper. With that method, in which computers are used to select the most promising candidates to test in the field, "you might be able to take years off the breeding cycle," Morris said. "Instead of having to grow thousands of varieties, you test thousands of varieties 'in silico' and pick a few hundred of the best for growing the next generation."

Explore further: A different kind of green movement: Seedling growth in space

More information: www.pnas.org/content/early/2012/12/19/1215985110

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User comments : 12

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ScooterG
1.3 / 5 (13) Jan 03, 2013
Another AGW money-grab effort.
Shootist
1 / 5 (5) Jan 03, 2013
Another AGW money-grab effort.


But it's for the .
RealScience
4.2 / 5 (5) Jan 03, 2013
Gosh, Scooter, the article doesn't say that climate change is caused by people. Drought-tolerant plants would be useful even if recent droughts had purely natural causes.

It is strange to hear YOU implying that any climate change must be caused by people...
ScooterG
1 / 5 (8) Jan 03, 2013
Gosh, Scooter, the article doesn't say that climate change is caused by people. Drought-tolerant plants would be useful even if recent droughts had purely natural causes.

It is strange to hear YOU implying that any climate change must be caused by people...


Gosh, Real, what would be REALLY strange is to see climate change studies conducted without bias and utilizing generally-accepted scientific protocols.
FrankHerbert
2 / 5 (8) Jan 03, 2013
Because anything that disagrees with you is biased. DUUUUUUUURRRRRRRRR
RealScience
3.5 / 5 (2) Jan 04, 2013
what would be REALLY strange is to see climate change studies conducted without bias and utilizing generally-accepted scientific protocols.
]

That would be great, but we'd need another earth as a control.
And even if we had one, the other earth might object to us dumping a teraton of CO2 into their atmosphere (or tens of gigatons of methane) to see to what extent they cook or drown or are OK.

So we use studies of past climates versus sea levels versus CO2, and try to correlate with solar input (Milankovich).
We then cross-check with climate models that look at known factors (e.g., IR absorption by CO2) and uncertain factors (largely feedbacks like clouds versus temperature, ocean current changes, etc.). And even then the uncertainty is so large that we take dozens of the models that best match history and look at the range of results.

While far from perfect, it is the best we have. And the results so far support AGW, albeit with large uncertainty in the amount of warming.
ValeriaT
3 / 5 (1) Jan 04, 2013
We should protect and conserve the genes of cultural plants against many other catastrophic events, including the spreading of GMO with built in silencer genes into the wild.
RitchieGuy01
2 / 5 (4) Jan 04, 2013
Because anything that disagrees with you is biased. DUUUUUUUURRRRRRRRR
FrankHerbert

TheGhostofOtto1923 is trying to hide from me again in his cockpuppet FrankHerbert.

Blotto, why are you doing this to me, darling. You said that we would get married as soon as same sex marriage became law. But you haven't called me in several weeks and I miss our making love.

I sold my sorghum farm to my brother and his partners and I made lots of money from the sale. As you know, sorghum is good for making food and also biofuel. But I wanted to be with you and live with you, Otto.

Please call me, you great big cockman.
ScooterG
1 / 5 (5) Jan 05, 2013
"That would be great, but we'd need another earth as a control."

Environmentalists have a well deserved bad reputation. The public has been lied to and fleeced too many times. And they (the environmentalists) wonder why there is skepticism? Environmentalists have lost any/all credibility due to their own stupidity/ignorance/radicalism.

Actions have consequences. Enjoy the bed you've made for yourself.
RealScience
4 / 5 (2) Jan 05, 2013
@ScooterG - Most of the lying and fleecing has been by politicians (covering the whole left/right spectrum), followed by corporations (including but not limited to oil/gas/mining).

I do agree that 'humans are evil, technology is evil' environmental radicals are ridiculous and cost credibility.

Overall, however, sensible environmentalists have alerted people to deforestation, soil erosion, chemical waste dumps, acid rain, airborne lead and mercury, ozone depletion, over-fishing, etc. in time to make a difference, and this is continuing with excessive ground-water extraction and climate change.

Where environmentalists typically err is in underestimating the earth's carrying capacity / ability to recover, technology advances (e.g., green revolution), and falling birth rates. This has sometimes caused environmentalists to cry 'crisis' long before something is a true crisis, but even then it has typically still been a future danger that has been misjudged as a present crisis.
Shootist
1 / 5 (4) Jan 05, 2013
Gosh, Scooter, the article doesn't say that climate change is caused by people. Drought-tolerant plants would be useful even if recent droughts had purely natural causes.

It is strange to hear YOU implying that any climate change must be caused by people...


Crops do not need to be adapted to changing climate. I do not mean crops shouldn't be adapted, just that they need not be.

Don't panic.

Farmers have adapted to changing climates by changing what they sow for 10,000 years. I imagine it will remain much the same (tread upon by the heavy foot of government regardless).
Steven_Anderson
2.5 / 5 (4) Jan 06, 2013
Regardless of the cause, man made or not. The environment is changing much more rapidly than at any time in history. Normal Natural evolution of plants and adaptation wont be enough. The vast majority of doubters of man made climate change even admit that climate is changing. So funding research that makes plants able to adapt to it is a good idea for EVERYONE. The alternative is to wait until its too late. When the plants don't grow we starve. When we starve we go extinct.