Australia
November 25, 2011

New research results have given grain growers hope that partial resistance to the damaging disease crown rot may be around the corner for durum wheat.

Durum, the main pasta wheat grown in Australia, is notoriously susceptible to crown rot.

The pathogen costs the Australian grains industry $ 79 million or $6.63 per hectare per year, according to Grains Research and Development Corporation (GRDC) analysis.

The figures are reported in the GRDC publication, The Current and Potential Costs from Diseases of Wheat in Australia, which also details estimates that if current control measures weren’t in place crown rot would cost the industry $36.44/ha or $434 million per year.

Dr Steven Simpfendorfer, NSW Department of Primary Industries (NSW DPI), Tamworth plant pathologist says a GRDC-supported research project demonstrated that partial crown rot resistance present in hexaploid wheat lines could be transferred into durum wheats.

“A number of back crosses of hexaploid x durum lines have been produced which show levels of partial resistance equal to or better than that of the hexaploid parent Sunco ,” Dr Simpfendorfer said.

“The incorporation of partial resistance to crown rot will provide growers with increased durum yields, better quality and greater confidence to reduce tillage and retain stubble to derive benefits of decreased soil erosion and increased moisture retention.

“The deployment of partially resistant durum varieties coupled with farming system solutions will ultimately reduce the importance of crown rot as a major impediment to the expansion and viability of the durum industry in Australia.”

Dr Simpfendofer said genetic resistance was not a magic bullet for managing crown rot losses and needed to be used in an integrated approach to disease management.

“There is no resistance to infection by the crown rot fungus in durum or other cereals,” he said.

“The genes involved infer partial resistance which appears to slow the rate of spread through tissue.

“Incorporating genetic resistance into varieties, especially durum wheat which is highly susceptible to crown rot, is valuable in reducing losses by growers but on its own will not provide complete control of this disease.”

Dr Simpfendorfer said commercial varieties, near release varieties and reselected varieties should be evaluated for partial resistance/tolerance to crown using an inoculated versus uninoculated trial design across environments in northern NSW to provide a more robust rating. This is equally relevant for crown rot ratings in bread wheat and barley varieties, he said.

“Inherent yield potential across environments needs to be an important consideration when incorporating sources of partial resistance into durum backgrounds as this can allow for greater compensation of yield loss associated with crown rot infection.

He said all crown rot breeding efforts (bread wheat, durum and barley) needed to have a greater focus on ensuring they were also improving levels of tolerance (yield in the presence of crown rot) under field conditions.

For more information, visit www.grdc.com.au/diseaselinks.
 

Website: http://www.grdc.com.au

Published: November 25, 2011