Saturday, May 13, 2017

Reinventing Rice for a World Transformed by Climate Change

UC Davis plant geneticist Pamela Ronald wants to create rice varieties that can survive in harsher conditions, including more frequent droughts.

Plant geneticist Pamela Ronald in her lab’s greenhouse at UC Davis. (Credit: Molly Matalon) Click to Enlarge.
Pamela Ronald stands in front of two rows of rice plants, sprouting from black plastic pots, in a stifling greenhouse on the edge of the University of California, Davis, campus.

Researchers in Ronald's plant genetics lab starved the grasses of water for more than a week.  The ones on the right, the control in the ongoing experiment, are yellowing and collapsing.  The leaves in the adjacent plants, equipped with an added gene, are thick, tall, and green.

The hope is that these or similar genetic alterations could help rice and other crops survive devastating droughts, preventing food shortages in some of the poorest parts of the world. ...
She has spent the last three decades working to make rice, a food staple for more than half of the world's population, more resistant to environmental stress.  She was a central player in one the greatest recent success stories in plant genetics, isolating a gene that allows rice to survive extended periods of flooding.  It’s a huge challenge in low-lying parts of Asia, wiping out around four million tons of rice each year in India and Bangladesh alone.  A decade after her lab’s discovery, more than five million farmers grow rice varieties engineered with the so-called Sub1 gene, covering more than two million hectares across Asia.

The latest research could be even more significant, as climate change ratchets up the frequency and intensity of droughts across large swaths of the Earth, threatening the food security and stability of entire nations.  The number of extreme droughts could double by the end of the century, devastating fields and farmers across South Asia and sub-Saharan Africa.

Ronald's work provides a powerful statement for the potential of modern genetic tools to preserve livelihoods and lives, offering a counter narrative to the widespread fears and distortions surrounding genetically modified crops (see Why We Will Need Genetically Modified Foods). “This focus on genes in our food is a distraction from the really, really important issues,” she says.  “How can we reduce the use of toxic inputs?  How can we feed the poor and malnourished?  How can we be sure that farmers have access to seeds, and that consumers can afford the food that’s produced?” 
Under a high greenhouse gas emissions scenario, rice yields would be nearly 15 percent lower than otherwise expected at midcentury, and prices would be 30 percent higher, according to a 2015 report in Environmental Research Letters.

Shifting farming practices and the fertilizing effect of increased carbon dioxide could offset some of these climate impacts.  But it’s going to become much harder and more expensive to maintain yields in many areas, and rich nations will have far greater capabilities than poor ones to make the necessary changes, says Keith Wiebe, senior research fellow at the International Food Policy Research Institute.

Crops altered to survive harsher environmental conditions will be a crucial tool for helping “small farmers who produce in the more tropical environments, who will be the most exposed to climate shocks,” says Alain de Janvry, a UC Berkeley economist.

The work at Ronald’s lab on drought-tolerant rice varieties is in an early phase.  She declines to discuss details, including the basic approach, until they’ve conducted additional experiments to verify the initial results and published their findings.

Other scientists around the world are also racing to develop drought-resistant crops, and have already achieved some advances, including sprays, hybrids, and genetic alterations that help crops switch into water-preserving modes at earlier signs of trouble, or otherwise enable plants to get by with less moisture.

But greater advances will be required to confront the growing challenges ahead, and drought tolerance is a tricky problem.  The trait generally involves various genes and cellular communication pathways.  It’s crucial that any improvements not come at the expense of yield, taste, and other qualities important to farmers and consumers.  And there would seem to be hard limits on how much can ever be achieved, as all plants need water.

Read more at Reinventing Rice for a World Transformed by Climate Change

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