Dr Jack Christopher from Queensland DAFF discusses stay green wheat at a field study day in Gatton on the Darling Downs, Queensland.
Winter cereals research on the Darling Downs was the focus of a recent field day in Gatton. The event gave researchers, plant breeders, agronomists and growers the opportunity to see firsthand the research being carried out in the region.
Researchers from the Queensland Alliance for Agriculture and Food Innovation (QAAFI), the University of Queensland, and the Queensland Department of Agriculture, Fisheries and Forestry (DAFF) talked about their work on pre-breeding, disease resistance and frost tolerance in wheat and barley.
Dr Lee Hickey explains how researchers are mapping complex genetic traits in Gatton, Queensland.
PHOTOS: Tom Dixon
Barley pre-breeding is focused on bringing together all genes for resistance to the key foliar diseases: net form net blotch, spot form net blotch, spot blotch, leaf rust and powdery mildew.
The importance of selecting varieties with resistance to major foliar diseases, such as leaf rust and net form net blotch in barley, and stripe rust and yellow spot in wheat, was highlighted by Queensland DAFF pathologist Greg Platz.
Gatton is home to a rust-screening nursery, which forms part of the GRDC-funded National Variety Trials (NVT) to evaluate new and existing varieties. The trials provide growers with information to help choose the most appropriate variety for their area. Information is available online (www.nvtonline.com.au).
Frost has caused widespread damage to cereal crops in the north this season. Queensland DAFF researcher Dr Troy Frederiks says that “counterintuitively” frost is a real problem in subtropical areas, such as the Darling Downs, where delayed sowing to reduce frost risk then reduces yield because of late season heat and drought stress.
“For individual growers, major frost losses may only occur one year in every 10, but the damage can be catastrophic, with almost total crop losses,” he says.
“Screening trials at Wellcamp allow us to identify sources of improved genetic frost resistance, evaluate the impacts of frost damage on wheat and barley lines for the northern region, and provide growers with advice on the best lines for their region.”
Researchers Dr Mark Dieters at the University of Queensland and Dr Stephen Neate at Queensland DAFF are researching better crown rot tolerance in wheat by integrating tolerance genes into elite wheat varieties. “We are currently testing advanced lines in yield-loss trials to study the effect of the genes on these elite varieties,” Dr Neate says.
Dr Dieters says speed-breeding technology allows researchers to breed up to five generations a year and test the effect of the genes from eight different crown rot donor lines. Derived lines will be released to breeding companies for further evaluation next year.
Root lesion nematodes
Two species of root lesion nematodes (RLN) occur in the northern grains region. Researchers are looking at the combined effects of both species on crop growth in field trials at Formartin and Kindon, Queensland.
“Screening of nematode resistance is done using high quality glasshouse tests to determine rates of reproduction in the plant roots,” says Queensland DAFF researcher Dr John Thompson.
“We are also developing DNA markers in collaboration with the Australian Wheat and Barley Molecular Marker Program, at the University of Adelaide, to be used as tools to breed wheat varieties with greater resistance to infection.”
RLNs cause plant damage and yield loss costing growers about $47 million in the northern region alone, Dr Thompson says. “While tolerant wheat grows and yields well under high RLN conditions, resistant wheat prevents the build-up of RLNs in the paddock, and is better in the long term for future crop rotations.”
QAAFI plant physiologist Dr Jack Christopher is leading a GRDC-funded ‘stay-green’ drought-tolerance project in wheat. Incorporation of stay-green into new wheat varieties may improve drought tolerance.
Dr Christopher says stay-green wheat lines such as SeriM82 also have a narrow root angle. This enables them to access more water from deeper in the soil profile and maintain yield under water stress during the grain-fill period.
These traits are being combined during development of a new mapping population. QAAFI researcher Dr Lee Hickey is developing a new type of mapping population that allows researchers to dissect complex genetic traits in wheat for the first time.
“These populations have been useful in sorghum pre-breeding to unravel complex traits such as stay-green, root angle and heat stress tolerance,” Dr Hickey says. “We’re hoping to be able to use them to solve these problems in wheat too.”
Mapping populations will be tested in 2014.
Dr Lee Hickey,
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GRDC Project Code
DAQ00167, DAW00206, UQ00049 (crown rot), UQ00068 (stay-green)