By Andrew Pollack

To satisfy the world's growing demand for food, scientists are trying to
pull off a genetic trick that nature itself has had trouble accomplishing in
millions of years of evolution.
They want to create varieties of corn, wheat and other crops that can thrive
with little water.

As the world's population expands and global warming alters weather
patterns, water shortages are expected to hold back efforts to grow more
food. People drink only a quart or two of water every day, but the food they
eat in a typical day, including plants and meat, requires 2,000 to 3,000
quarts to produce.

For companies that manage to get "more crop per drop," the payoff could be
huge, and scientists at many of the biggest agricultural companies are busy
tweaking plant genes in search of the winning formula.

Monsanto, the biggest crop biotechnology company, says its first
drought-tolerant corn will reach farmers in four years and will provide a 10
percent increase in yields in states like Nebraska and Kansas that tend to
get less rainfall than eastern parts of the Corn Belt.

At a recent farm show here called Husker Harvest Days, a few thousand
farmers were guided past a small plot on which Monsanto had grown its
drought-tolerant corn next to a similar variety without the "drought gene."
A transparent tent had shielded the plants from any rain through the hot
Nebraska summer.

The results were, to be sure, less than miraculous. Both the
drought-tolerant and the comparison plants were turning brown and
shriveling, and they were about 3 feet shorter than the lush green irrigated
corn growing nearby. But the drought-tolerant plants, which also contained a
second gene to protect their roots from a pest, were a little greener and a
few inches taller than the comparison plants, and their cobs were missing
fewer kernels.

Monsanto said the improvement was significant. And the Nebraska and Kansas
farmers who toured Monsanto's plot, many of them facing water-use
restrictions and soaring pumping costs for irrigation, said any improvement
would be welcome.

"We pump water like there's no end, and that's not going to last forever,"
said Tom Schuele, a farmer in Cedar Rapids, Neb. Monsanto's competitors,
including DuPont's Pioneer Hi-Bred unit and Syngenta, say they also plan to
introduce water-efficient corn in a few years. And companies are working on
plants that can stand up to heat, cold, salty soils and other tough
environments.

A small California company called Arcadia Biosciences is trying to develop
crops that need only half as much nitrogen fertilizer as a conventional
plant. Fertilizer is crucial to modern food production, but the large
quantities used today damage the environment. And because fertilizer is made
from natural gas, its costs have soared along with other energy costs.

Public sector scientists are also on the hunt. Researchers at the University
of California and the International Rice Research Institute in the
Philippines are developing rice that can survive flooding, which causes
major crop losses for poor farmers in the lowlands of India and other
countries. While rice is typically grown in standing water, the plants will
die if submerged for more than a few days.

Many of these advanced crops are being developed using genetic engineering.
The technology, already used to make crops that can resist weeds and
insects, has spurred worldwide controversy. But in an era in which people
are marching in the streets of many countries to demand more food at lower
prices, low-water crops might win over areas that now shun biotech crops,
such as most of Africa.

"Drought tolerance to me is the most critical entry point," said Calestous
Juma, a professor of international development at Harvard who has advised
African governments on biotechnology. "This is kind of reopening the window
for genetic modification."

Critics accuse the biotechnology industry and its backers of exploiting the
recent global food crisis to push a technology that has been oversold and
that could have unanticipated health and environmental effects.

Indeed, many past predictions of how biotechnology would create novel crops
have not come to fruition. And some experts say Monsanto and its peers have
not published enough information to prove they can make drought-tolerant
crops.

"I want to see more, I guess, from the Monsanto work before I'd be convinced
they've got it," said John S. Boyer, an emeritus professor at the University
of Delaware.

Safety questions must also be answered. Changing the water needs of a plant
requires a more fundamental alteration of its metabolism than adding a gene
to make the plant resistant to insects. "The potential for unintended side
effects is greater, so the testing has to be greater," said David A.
Lightfoot, a professor of genetics and genomics at Southern Illinois
University.

How much could be gained by use of these new crops is not yet clear. A
report in 2007 by the International Water Management Institute, which is
part of an international network of agricultural research centers, concluded
that genetic improvements would have only a "moderate" impact over the next
15 to 20 years in making crops more efficient in using water.

"Greater, easier and less contentious gains," it said, could come from
better managing water supplies, rather than trying to develop crops that can
flourish with less water.

But many experts say the situation is grave enough that all approaches must
be tried simultaneously.

Poor growing conditions can reduce crop yields by 70 percent or more below
their potential. American farmers, for instance, average about 150 bushels
of corn an acre. But David K. Hula of Charles City, Va., won a competition
last year by harvesting nearly 386 bushels an acre, a measure of what modern
crop varieties can achieve under optimal conditions.

No single approach is likely to suffice for all types of dry conditions.
"Probably no one has found the magic gene yet," said Jian-Kang Zhu, a
professor of plant biology at the University of California, Riverside.
"Probably there is no magic gene."
www.checkbiotech.org