Demand for plant products has never been greater.
More people, rising affluence, and expanding
biofuels programs are rapidly pushing up the
prices of grain and edible oil. Boosting supply
isn't easy: All the best farm land is already in
use. There's an acute need for another jump in
global agricultural productivity--a second Green
Revolution. Can it happen? Will it happen?
My career has spanned astounding leaps in our
ability to decipher and use genetic information
to understand and improve crop plants. DNA
sequencing methodology was just breaking open
when I was a postdoctoral fellow in the
mid-1970s. I was able to sequence a complete
gene, a goal that had seemed unattainable just a
few years earlier, though today it is a routine
part of a biologist's toolkit. A chance encounter
with the legendary plant geneticist Barbara
McClintock drew me into the wonderful
phenomenology of maize transposons. I decided to
study the molecular behavior of these jumping
genes, although there were doubts that plant DNA
could even be cloned.
The doubts are gone. We've accumulated vast
amounts of plant sequence data, ranging from the
complete genomes of rice and the model plant
Arabidopsis thaliana to extensive collections of
gene and genome sequence data from many
agricultural plants, including maize, wheat, and
soybeans, as well as plants across the plant
kingdom, from mosses to trees. Sequence
information has profoundly transformed plant
genetics and increased its power. Rapid advances
in the ability to add genes to plants have made
it possible to improve and protect plants in very
specific ways. Our growing understanding of how
plants handle such stresses as insufficient water
and too much heat, salt, or toxic metals permits
directed genetic modifications that enhance
plants' ability to remain productive under
adverse environmental conditions.
So the techniques and knowledge for a new Green
Revolution are in hand. The Green Revolution of
the 20th century was driven by genetics
(mutations that changed plant architecture) and
chemistry (fertilizers that increased plants'
ability to make sugar out of air and water). It
was accomplished by just a handful of plant
breeders working on the world's few major grain
crops: corn, wheat, and rice. Perhaps the
agricultural successes, even excesses, of the
past century gave us a false sense of food
security.
Last December, the New York Times quoted a top
United Nations food and agriculture official as
saying that "in an unforeseen and unprecedented
shift, the world food supply is dwindling rapidly
and food prices are soaring to historic levels."
Josette Sheeran, executive director of the World
Food Program, was quoted as saying: "We're
concerned that we are facing the perfect storm
for the world's hungry." She said that poor
people were being "priced out of the food
market." In the months since, there have been
food riots in Africa, Asia, the Middle East, the
former Soviet Union, and Central and South
America.
How did this happen? Genetically modified (GM)
cotton and corn with built-in protection from
boring insects, and herbicide-resistant soybeans,
have been adopted very rapidly in some countries,
particularly the United States and Canada,
increasing yields and decreasing the use of
pesticides and herbicides. But despite a
quarter-century's experience and a billion acres
of GM crops grown worldwide, there are many
nations that remain adamantly opposed to food
from plants modified by molecular techniques.
Others hesitate to adopt them for fear of losing
markets in nations that reject GM technology.
Big grains are only part of the story. There are
many food, beverage, and fiber crops, each with
its characteristic pests and diseases. Moreover,
there are more than 400 million small farms,
primarily in the developing world, growing a
large variety of crop plants on a small scale,
often without the benefit of either genetically
improved seeds or fertilizer. A new Green
Revolution demands a global commitment to
creating a modern agricultural infrastructure
everywhere, adequate investment in training and
modern laboratory facilities, and progress toward
simplified regulatory approaches that are
responsive to accumulating evidence of safety. Do
we have the will and the wisdom to make it happen? |
