Plant breeding companies and growers will have access to wheat lines with improved tolerance to sodic, magnesic and dispersive soils thanks to a GRDC investment.

The investment 'Improving wheat yields on sodic, magnesic and dispersive soils' is bringing together soil scientists, plant breeders, plant physiologists, agronomists and crop geneticists.

They are developing pre-breeding wheat lines with improved tolerance to a number of stresses associated with sodic soils. Sodic, or dispersive, soils occur across about 68 per cent of cropping land in Australia.

Project leader and University of Adelaide Associate Professor, Glenn McDonald, says sodic soils can cause a number of issues, including chemical and physical constraints which can hamper root growth, water use and ultimately yield.

"We are looking to combine tolerances to multiple stresses which can improve adaptation to hostile conditions associated with sodic soils, such as high boron, high soil pH, waterlogging, high aluminium and high soil strength," he says.

"There are wheat varieties that have tolerances to one or two of these traits, but as far as we know there is no variety with tolerance to them all."

The investment is a national collaboration between the:

• University of Adelaide;
• Department of Primary Industries and Regional Development (DPIRD) in Western Australia;
• Department of Jobs, Precincts and Regions in Victoria;
• NSW Department of Primary Industries (NSW DPI); and
• University of Queensland.

University of Adelaide postdoctoral fellow, Dr Rhiannon Schilling says 50 varieties of Australian wheat have been screened for their tolerances to different constraints.

"Out of the 50 varieties, we know where they sit in their tolerances for individual constraints," Dr Schilling says.

"We want to 'pyramid' tolerance to multiple sodic soil constraints into these elite wheat varieties."

Dr Schilling says analysis of field trials has shown that varieties with multiple tolerances achieve a better yield in low-rainfall environments of up to five per cent.

“But in higher-yielding environments, that advantage is not apparent,” she says.

"Using the Focused Identification of Germplasm Strategy (FIGS), we identified lines which have been able to maintain root growth in soils with a pH of up to 9.5.

“As a result of this, we have also been developing new germplasm to incorporate this trait into elite wheat cultivars.

"Trials have involved screening more than 200 wheat breeding lines from around the world specifically collected for tolerance to constraints associated with sodic soils.

"All germplasm with promising tolerances will be released to breeders to incorporate in their own breeding programs."

Dr McDonald says another important finding from the project has been a better understanding of root growth.

"The assumption is that these improved tolerances result in better root growth deep in the soil, which allows for better water extraction," he says.

"This has given us the opportunity to use root DNA technology to measure the distribution of roots within the soils and how that relates to water use.

"We can then link that back to their overall tolerances to multiple constraints."

More information: Dr Glenn McDonald, 08 8313 7358, glenn.mcdonald@adelaide.edu.au; Dr Rhiannon Schilling, 08 8313 7398, rhiannon.schilling@adelaide.edu.au