Developing Wheat Resistant to Leaf Rust

By George Grow

This is the VOA Special English AGRICULTURE REPORT.

American research scientists are using information from genetic material to make wheat more resistant to leaf rust. The researchers have identified small pieces of genetic material in wheat plants that are linked to leaf rust resistance. These markers are made of genetic material called D-N-A. The researchers plan to use these markers to develop wheat with longer-lasting resistance to the disease.

Gina Brown-Guedira of the Agricultural Research Service identified the genetic markers in wheat. Her team in Manhattan, Kansas is collecting the information. Agricultural Research magazine published a report on the project.

Leaf rust is a threat to wheat production in many areas of the United States. More than five percent of all hard winter wheat grown in the north central part of the country was lost to leaf rust during the Nineteen-Nineties. The disease cost farmers about one-hundred-fifty-million dollars in crop losses each year. The disease also seriously affects the quality of products made from wheat flour.

A fungus causes wheat leaf rust. Plants infected with the organism develop small reddish or orange spores on their leaves.

In the past, researchers developed wheat plants with different resistance levels to wheat leaf rust. Such plants had only a single leaf rust resistance gene. The plants usually began to lose their effectiveness against the disease after a few years.

Mizz Brown-Guedira is combining leaf rust resistance found in two ancestors of modern wheat. One plant, known as goatgrass, grows in areas from Afghanistan to Syria. The other comes from Iran, Iraq and Turkey. The researchers hope genes from the two plants can be combined and moved into plant cells. They say such cells could be used to develop wheat resistant to the disease.

Scientists currently must study genetic material in a plant to confirm the presence of more than one resistance gene. Such genetic studies are a slow process, however.

Mizz Brown-Guedira and her team can test a plant for the presence of several D-N-A markers that are linked to the resistance genes. They say their research can speed the work of developing plants with resistance genes.

This VOA Special English AGRICULTURE REPORT was written by George Grow.