"Green Revolution" fix for wheat may be coming un-done.
March 25, 1999
Wheat Disease Resistance Weakening
Filed at 8:19 p.m. EST
By The Associated Press
MEXICO CITY (AP) -- Genetic resistance bred into wheat crops 40 years
ago has begun to break down, resurrecting the threat of crop plagues not
seen since the last major outbreak in the United States in the 1950s, a
nonprofit wheat group said Thursday.
A new, mutated form of the stem-rust fungus -- a disease that virtually
disappeared from the face of the Earth after destroying as much as half of
wheat yields decades ago -- reappeared several weeks ago at an experimental
farm in the rainy highlands of Uganda.
The reappearance of the wind-borne spores, which corrode the plants' stems,
threatens a genetic fix introduced during the ''Green Revolution'' in the late
1950s and early 1960s, scientists from the Mexico City-based International
Wheat and Maize Improvement Center said. The nonprofit group discovered
the fungus.
They made the announcement as U.S. Agriculture Secretary Dan Glickman
prepared to unveil the U.S. Plan for Food Security on Friday, and said they
plan to ask U.S. aid officials to help fund an emergency monitoring and
research program.
''The resurgence of stem rust in Uganda is alarming because it signals the
breakdown of a resistance gene that protects wheat in many countries,'' said
Timothy Reeves, the center's director.
Most affected would be eastern and southern Africa, where many crops
depend solely on the sr-31 resistance gene.
But the sr-2 gene complex, used throughout much of the rest of the world
and which is still able to prevent the fungus, may not work as effectively
against the mutated spores.
The last major outbreak, which occurred in the United States in the
mid-1950s, destroyed up to 50 percent of wheat crops on many U.S. farms.
Reeves said research is needed using new biotechnology methods, like
molecular marking, to understand the sr-2 resistance and possibly develop
more defenses against crop diseases like stem rust, leaf rust and yellow rust.
One thing is sure: The spores won't stay on the African savanna where they
first appeared. ''It'll move,'' Reeves said. ''It will travel.''
Copyright 1999 The New York Times Company |
