The path for growing winter and slow-developing spring wheat varieties in the low- and medium-rainfall zones of the southern region is becoming clearer following the first year of in-paddock trials of a range of commercially available cultivars.
Interim results from the three-year trial has fast developing winter cultivar Longsword achieving optimal flowering dates and competitive yields in the low-rainfall zone, while Kittyhawk, ADV11.9419 and other pre-release cultivars performed well for the medium-rainfall zone.
La Trobe University senior lecturer and project lead Dr James Hunt says while the project is still in its early stages, these results were promising and farmers could look to use these slower developing varieties, including the line V019150-01 which will be released in 2018. This line has achieved Australian Prime Hard quality in the south eastern classification zone (southern New South Wales), but is yet to be classified in the southern region (South Australia and Victoria).
“At the end of this project we aim to give farmers a clear indication of when they can sow the slower developing cultivars on the market, how much plant available water is required at sowing and what other management is required,” he says.
“Winter wheat cultivars can potentially allow wheat growers in the southern region to sow much earlier than currently practiced, allowing a greater proportion of farm area to be sown on time.”
Inspecting the winter and slow-developing spring wheat trials at Booleroo, South Australia is Hart Field Site Group’s Dylan Bruce, left, and Sarah Noack with South Australian Research and Development Institute (SARDI) research scientist Kenton Porker.
In order to determine these factors, South Australian Research and Development Institute (SARDI*), Hart Field Site Group, Moodie Agronomy, Birchip Cropping Group, Agriculture Victoria, FAR Australia, Mallee Sustainable Farming have conducted three different experiments in the southern region.
Experiment one
- Target sowing dates: 15 March, 1 April, 15 April and 1 May.
- Eight cultivars: ADV08.0008, ADV11.9419, Cutlass, Kittyhawk, LPB14-0392, Longsword, Scepter, Longreach Trojan and V096150-01.
- Locations: SA - Minnipa, Booleroo Centre, Loxton, Hart. Victoria - Mildura, Horsham, Birchip and Yarrawonga.
- Management factors examined: Testing which wheat cultivar performs best in which environment and when they should be sown.
Experiment two
- Sowing dates: 15 March, 1 April, 15 April and 1 May.
- Cultivars: Longsword, Kittyhawk and ADV11.9419.
- Irrigation: 10 millimetres, 25mm and 50mm applied at sowing.
- Management factors examined: Quantifying how much stored soil water and breaking rain is required for successful establishment of early sown wheat without yield penalty.
Experiment three
- Sowing date: 15 April.
- Cultivars: Longsword, Kittyhawk and ADV11.9419.
- Management factors examined: Nitrogen at sowing, nitrogen at early stem elongation, defoliation to simulate grazing, plant density 50 plants/m2, plant density 150 plants/m2; determining impacts of management factors other than sowing time to maximise yields.
While experiment one and two will need further seasons to reveal useful research trends, Dr Hunt says the early outcomes from experiment one had take-home messages for farmers.
“In this experiment the best winter cultivars sown in March or April were able to match but not exceed yields of elite spring cultivars sown in early May,” he says.
“The best performing winter cultivar changed with environment, being Longsword in yield environments of below 3 t/ha and ADV11.9419 in yields environments above 3t/ha.
“In both environments yield of winter cultivars was very stable across all times of sowing, but tended to be highest when sown in mid-April.”
Part of the winter and slow-developing wheat variety work is determining impacts of management factors other than sowing times to maximise yields such as these grazing treatments to simulate defoliation applied to the Yarrawonga, Victoria site.
Interestingly, the experiment found Longsword to experience 30 per cent sterility in cooler and high-rainfall sites in yield environments greater than 3t/ha. Dr Hunt says this rules out Longsword for many farmers, particularly as it failed to receive milling quality classification last year.
“People are certainly preferring to sow earlier and while they should be changing cultivars to do this, they’re pretty limited in the cultivars they have available, particularly in the low-rainfall regions,” he says.
“We were hoping Longsword would be it, but given its quality and sterility problem we’re still searching for the cultivar to recommend.
“Our network of trials has a low-rainfall emphasis and we hope to find an option here.”
Dr Hunt says pre-release cultivar ADV11.9419 is well-suited to medium-high rainfall sites achieving optimum flowering times from a broad range of sowing dates and will become a commercial option after official launch at the end of this year. He says Kittyhawk is the best cultivar currently on the market for medium rainfall zones at this stage.
The second year of trials are underway with sowing now complete.
“We’re likely to learn a lot more in a different way this year because we’ve had the warmest, driest autumn on record so things have been pushed to the limit a lot more,” Dr Hunt says.
“I think we will learn about minimum amounts of rain for establishment.
“The autumn rainfall decline is a real trend and this is a year that is a classic case, so there are lessons to learn when it comes to early sowing and slow developing wheat responses.”
*SARDI is a division of Primary Industries and Regions SA
GRDC Research Code 917069
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