Work starts to fast-track marker delivery

By Helen Olsen

The Australian Winter Cereals Molecular Marker Program has entered the second phase of its operation - to increase breeders" and researchers" access to new markers.

The program, to use advanced molecular marker technology to improve wheat and barley germplasm, is now two years old. Phase one involved the identification of stable genetic markers for marker-assisted breeding. These included the development of markers for traits such as protein quality and disease resistance.

The focus now is to close the gap between the technology and its application. One of the first steps in phase two will be to reduce the costs of using markers, and to simplify access by breeders and researchers.

Research fellow at the University of Adelaide, Dr Matthew Hayden, who heads the project, says cost is the biggest hurdle for using the markers that have been developed.

"High costs can occur through having to use a specialist laboratory to carry out assays, and in the length of time waiting for results," he says.

According to Dr Hayden, the current system also involves multiple assays that can be expensive in terms of consumables as well as time. Also, some current marker assays are either not reliable, or allow only a few markers to be tested at a time.

"The aims of this project are to develop a standard assay to test for all markers and to create a system where breeders and researchers can assay for the markers of interest in their own laboratories," he says.

Making the testing of markers more uniform means that breeders and researchers will be able to assay for any one of 1000 markers each for barley and wheat far more cheaply and quickly than is currently possible.

"Ultimately we"re planning to provide breeders and researchers with a marker database, complete with instructions on how to use it, and primer aliquots (samples) at cost, which will greatly reduce expenses," Dr Hayden says.

The primer aliquots contain one of the main ingredients for the assays, known as polymerase chain reaction (PCR) assays, which only require a tiny amount of genetic material from each sample plant.

The technology allows for multiple genes to be introduced into a wheat or barley breeding line, and quickly tested for by the polymerase chain reaction. This can be particularly useful for a disease such as rust.

"Rust pathogens can easily overcome rust resistance if the resistance is conferred by one gene," Dr Hayden explains.

"However, if multiple rust resistance genes are transferred to a plant, the pathogens find the resistance conferred by them much harder to overcome. Molecular marker techniques allow quick testing to see whether all the genes have been successfully transferred to the plant. Without the techniques, that would be virtually impossible."

Along with disease and pest resistance, genes coding for quality traits such as grain hardness and agronomic characteristics can be added to a plant and tested for.

For more information:
Dr Matthew Hayden, 08 8303 7158,
GRDC Research Code: UA00072, program 1