New sources of stem rust and leaf rust resistance from wild oat species for cultivated oats

DOMESTIC MILLERS in the south-eastern region process about 70,000 tonnes of oats worth $11m at the farmgate. Stem rust is currently the greatest yield- and quality-limiting disease of oats in this region. The current milling oat varieties Euro and Echidna are susceptible to stem rust and leaf rust and have suffered grain yield losses of up to 50 per cent, reduced groat percentage and ease of dehulling. Stem rust was widespread in oats in the 2000 growing season, and in many cases neither Euro nor Echidna was accepted for milling grade because of reductions in hectolitre weights. Growers in the south-eastern region have also had to spray oat crops with fungicides at a cost of about $60 per hectare.

Due to the magnitude of damage caused by stem rust in oats, incorporating stem rust resistance in new oat varieties is a priority. However, all known sources of stem rust resistance in cultivated oats have been overcome by the pathogen in Australia. The future of oat stem rust resistance in Australia depends on identifying and introducing new sources of resistance into adapted varieties. The SARDI team, including Pamela Zwer, Sue Hoppo and Phil Davies, are assessing the value of wild oat species obtained from overseas collections for rust resistance and other desirable agronomic traits such as drought and salinity tolerance. Staff of the ACRCP at the Plant Breeding Institute Cobbitty, and Dr Taing Aung, a world-respected Canadian cytogeneticist, are assisting in the project.

Contact: Dr Pamela Zwer 08 8303 9485 email