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Breeding Aluminum Tolerance into
Wheat By Linda
December 27, 2001
Increasing wheat yields at the present rates, on the
worlds richest soil, may not be enough to provide adequate nourishment to
people in countries with rapidly growing populations, according to an
Agricultural Research Service geneticist
in Columbia, Mo.
The worlds less productive soils must also produce much
higher wheat yields to feed the world population, projected by the United
Nations to hit 9 billion people in 2040, according to
Gustafson at the ARS
Research Unit in Columbia. Increasing dependence will be placed on acidic,
Aluminum, found mostly just below the topsoil, impairs plant
growth on nearly 2.5 billion of the worlds 8 billion acres of cropland,
including 86 million U.S. acres.
When soils are acidic, more aluminum is available in the soil
and plant growth is restricted. Gustafson wants to help plant breeders develop
new wheat varieties with genes enabling plants to yield abundantly on this type
of soil. Another way to increase yields, beside breeding, is to add lime to
deacidify soils, but hauling lime long distances is expensive.
In researching ways to tap into genetic resources for improving
aluminum tolerance, Gustafson and colleagues have identified a major wheat gene
for aluminum tolerance, found between two closely situated marker genes. Wheat
breeders can now select breeding lines that have these markers in order to
breed for aluminum tolerance. This marker-assisted selection may halve the
current 10 to 15 years it takes to develop a new variety.
Also, borrowing genes from another cereal, rye, may be
wheats best hope for surviving on acidic, high-aluminum soils. The
research on mapping rye genes may help breeders place desirable rye genes into
wheat-rye crosses without sacrificing wheats desirable agronomic and food
qualities. Gustafson has found molecular markers in rye that are closely linked
to the aluminum tolerance genes and can help transfer desirable rye genes into
detailed story on the research is in the
December issue of
ARS is the U.S. Department of
Agricultures chief scientific research agency.