Wild relative gives disease-resistance transplant

Dr Evans Lagudah at Plant Industry shows the difference between a modern wheat cultivar (right) and T. tauschii

A wild relative of bread wheat is helping scientists make healthier wheat varieties. Dr Rudi Appels and Dr Evans Lagudah of the CSIRO Division of Plant Industry in Canberra are pioneering the use of advanced DNA technology to transplant disease resistance genes from wild relatives to modern wheats.

The project is concentrating on a wild wheat species, Triticum tauschii. Many lines of the species have been collected in the Middle East and have been tested for a number of agronomic characters. These include resistance to several rusts mildews and blotches, various insects, cereal cyst nematode and root knot nematode, and tolerance of temperature extremes and salt hardiness; grain qualities ot interest to bakers are also involved

Some of these genes have already been isolated and are being genetically engineered into modem bread wheal. Collaborative research on T tauschii funded by growers through the GRDC is underway between CSIRO and the University of Sydney, the Victorian Institute of Dryland Agriculture at Horsham, the state departments of agriculture.

The use of DNA markers to identify disease-resistant genes, developed in the course of this project, is greatly speeding-up parts of the process of developing new cultivars with resistant characteristics.

"'Wild relatives are part of the secondary gene pool of wheat," said Dr Appels. "Primary gene pools are synonymous with traditional concepts of biological species. In bread wheat, for instance, the primary gene pool consists of five subspecies of Triticum aestivum and all its cultivars.

"Bread wheat has six closely related species of Triticum which constitute its secondary gene pool; these can be crossed with Triticum aestivum with a fair degree of success and are now being sourced for useful genes with which to improve bread wheat quality and disease resistance."