Perennial wheat on the drawing board
GroundCover™ Issue: 111 | Author: Nicole Baxter
Researchers have raised the potential for perennial wheat that can be grown as a future grain-and-graze option for Australian mixed farms.
In a paper published in the journal Crop & Pasture Science, lead author Dr Philip Larkin, from CSIRO Plant Industry, says perennial wheat could be a viable grain-and-graze crop with further breeding.
Perennial wheat is developed by crossing annual wheat with related perennial grasses.
After testing the best performing genetic material from overseas at the Cowra Agricultural Research and Advisory Station in central New South Wales, Dr Larkin says the most promising perennial donor species is the diploid tall wheatgrass Thinopyrum elongatum.
In trials, supported by the Future Farm Industries Cooperative Research Centre, two lines survived for up to four years and produced grain yields of at least 40 per cent of EGA Wedgetail in the first year and with comparable forage dry matter.
“The fact that grain yields were recorded for four consecutive years is a significant finding and highlights the potential to select promising lines with enhanced longevity,” Dr Larkin says.
Using genetic material sourced from Washington State University and The Land Institute in Kansas, collaborating researcher Matt Newell, from the NSW Department of Primary Industries, says trials showed the experimental perennial wheat lines could be grazed for longer than current grazing wheats and still go on to produce harvestable grain.
While there is concern about the potential disease risks that perennial wheat could pose to annual crops by acting as a green bridge, Mr Newell says the disease resistance of the experimental lines tested was excellent, in part because of strong disease resistance provided by the perennial parent.
“Some experimental lines demonstrated very strong resistance to stripe rust, leaf rust, yellow dwarf virus and wheat streak mosaic virus, which afflict current annual wheat varieties,” he says.
In addition, the lines tested showed suitable milling qualities, with protein content of between 15 and 19 per cent and gluten and dough characteristics suitable for bread flour.
Although the results are encouraging, Mr Newell says the research is still in its early stages and additional work needs to be done to increase the robustness of the experimental lines so more plants survive over successive years.
“After the first year of sowing, we are seeing a decline in plant populations and grain yields,” Mr Newell says. “Further research is needed to increase plant persistence and higher grain yield.
“Our current genetic material is suited to high-rainfall areas (more than 600 millimetres), but in our next experimental phase we are hoping to improve the adaption of the lines for planting in drier areas.”
The local researchers are collaborating nationally and internationally, with seed from the Cowra trial now being tested for yield and longevity at Wagga Wagga, NSW, Toowoomba, Queensland, and Manjimup, Western Australia, as well as in the US, Canada, Italy, Nepal, South Africa, the UK and the Netherlands.
In 2013, trials were initiated to investigate whether growing perennial wheat with subterranean clover would improve agronomic performance.
Mr Newell says planting perennial wheat with subterranean clover should reduce the need for extra nitrogen inputs while also improving the quality of forage for grazing.
Aside from not having to resow each year, Mr Newell sees plenty of other advantages for perennial wheat.
“Perennial wheats have deeper roots than annuals so they are able to access more of the soil for nutrients and moisture,” he says.
“The perennial grass parents used in the hybrid material have demonstrated tolerance to many soil constraints, including acidity and salinity, so when we cross these with annual wheats it is likely these traits are also transferred to the progeny.”
While Mr Newell is excited about the economic prospects of perennial wheat in providing growers with greater flexibility and enterprise diversity, he also sees the crop as a potential winner for the environment.
“Our dependence on annual crops and pastures has changed the hydrology of the landscape, leading to soil acidification, waterlogging, erosion and salinity,” he says.
“Perennial wheat may allow us to restore some of our degraded landscapes while also providing grain at the end of the season, and that’s important for maintaining food security.”
More information:Dr Philip Larkin,
02 6246 5060,
02 6342 3862,
Region National, Overseas, North
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