12 | New Scientist | 7 December 2019
SEEDS from hundreds of wild
relatives of food crops such
as bananas and rice have been
collected to save their valuable
genetic diversity before it is lost.
This could be crucial for feeding
the world as the climate changes.
“It was a massive effort,” says
Hannes Dempewolf at the Crop
Trust in Bonn, Germany, which led
the 10-year project. The next step
is to use the wild plants to breed
new crop varieties with traits such
as resistance to drought or disease.
That is important because
we know that if farmers keep
cultivating the same varieties
in the same way, crop yields can
plummet as pests and diseases
evolve and spread.
What is more, climate change is
now also hitting food production,
by making floods and droughts
more extreme. “You have to walk
faster to stand still,” says Alisdair
Fernie of the Max Planck Institute
for Molecular Plant Physiology
in Germany, who wasn’t involved
in the project.
This is why the Crop Trust set
out to save the genetic diversity
present in wild plants. “Since 2013,more than 12 million seeds have
been collected,” says Chris Cockel,
at Kew’s Millennium Seed Bank in
the UK, who also worked on the
project. These come from about
5000 locations and represent
400 relatives of food crops.
Plants sampled include a type
of wild carrot that grows in salty
water, an oat relative resistant
to the powdery mildew that
devastates normal oats, and a
kind of bean that tolerates high
temperatures and drought.The seeds are now being sent to
non-profit breeding organisations
around the world. Some will also
be stored in seed banks.
In some cases, the collectors
arrived in the nick of time. In
Ethiopia, samples from multiple
species were taken from a region
that will soon be flooded by a dam.
In Chile, they found only one sitewhere a wild barley was still
growing after a massive fire
devastated its habitat.
Sometimes they were too
late. In Costa Rica, collectors
found only sugar cane
plantations and urban sprawl
where a wild rice used to grow.
“We have made incredible
progress,” Marie Haga, director of
the Crop Trust, said in a statement.
“But there is more to be done,
and as threats to the world’s
biodiversity mount, this work
is more urgent than ever.”
As well as improving existing
crops in this way, we should also
be conserving and domesticating
wild plants that are rarely grown
and eaten, says Fernie. At present
the world is over-reliant on a
handful of crops, some of which
are grown in locations where
conditions aren’t ideal.
In these places, domesticating
local plants – which can now be
done very rapidly – could allow
more food to be grown in a more
sustainable way. But for farmers
to diversify the plants they grow,
consumers will have to diversify
their diets. ❚RUSSIAN interference in
democratic debate on social
media might not actually be that
effective. That is the conclusion
of one of the first major studies
to look at how such campaigns
affect public opinion.
Sunshine Hillygus at Duke
University in North Carolina and
her colleagues tracked more than
1200 politically partisan Twitter
users on the social network, withSeeds of Pterocarpus
rotundifolius trees
stored in the UKSocial mediaBiodiversityMichael Le PageANDREWM
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Race to find wild relatives of crops
to help secure world food supplies
Russia’s ‘troll
factory’ has little
real impact
their permission, during October
and November 2017. The goal
was to see how interaction with
other people on Twitter affected
their attitudes to politics.
Then Twitter released the names
of more than 4000 accounts linked
to the Internet Research Agency
(IRA), a firm in Saint Petersburg that
allegedly delivers disinformation on
behalf of the Russian government.
Hillygus and her colleagues realised
that the Twitter users they were
following may have interacted
with the IRA accounts.
“We were able to figure out
within our sample who wasexposed to those trolls in that
window between us measuring
their attitudes at two different
times,” she says. One in five of the
people that the team monitored
interacted with IRA accounts.
Each person in the study was
measured on six political attitudes
and behaviours, including where
they placed themselves on the
political spectrum, and how they
would feel if a family member“ Tweets posted by the
accounts accounted for
only 0.1 per cent of their
Twitter interactions”married someone politically opposed
to them. Contrary to fears expressed
in the media, people remained
steadfast in their opinions, even
after being targeted by IRA accounts
(PNAS, doi.org/df8c).
“Interaction with IRA accounts
didn’t change people’s attitudes
or behaviours,” says Hillygus.
Saif Shahin at American University
in Washington DC says he isn’t
surprised by the results, as tweets
posted by IRA accounts represented
0.1 per cent of all the liking,
retweeting and responding that the
study’s participants did on Twitter. ❚
Chris Stokel-Walker