Wheat mix tackles frost
No wheat varieties have proved to withstand severe frost events, with trials showing the only difference between wheat varieties occurred during mild frost events above -2C.
That was the message from DAFWA frost expert Ben Biddulph, speaking at a series of pre-seeding frost workshops throughout the Wheatbelt.
Dr Biddulph said one of the only ways to mitigate severe frost risks in these situations was to spread the flowering window of the cropping program over several weeks and with different crops of varying susceptibility.
He said farmers should also consider mixing alternative enterprises and crops in frost prone areas, such as oats, barley and hay.
"In frost events of between -2C and -6C, we have found all wheat varieties are equally susceptible," he said.
But he said trials had shown differences between varieties during less severe frost events, down to -2C, where Wyalkatchem types were more susceptible than other varieties.
Frost trials have been running concurrently in Wickepin, Loxton (South Australia) and Narrabri (NSW) since 2012 with 144 frost events tagged and scored for frost damage.
Mr Biddulph said in Wickepin in 2014, less frost-susceptible varieties yielded 300kg more at the end of the season than more susceptible varieties, after both groups had several frost events before and during flowering.
"Obviously this shows a useful difference in wheat varieties' frost susceptibility" he said.
Dr Biddulph said trials had also shown frost-induced sterility was more prevalent in wheat than barley, particularly for frost occurring during the flowering window.
"Barley appears to hold up a lot better during the flowering stage because it has more of a cover on the head than wheat," he said. "Although our trials have shown that barley can be susceptible during early grain growth."
As a result of screening techniques adopted in the three trials, the GRDC National Frost Initiative plans to release a frost rating on wheat and barley, similar to a disease rating, this season.
Fifty common wheat and 20 commercial barley varieties are likely to be rated for frost susceptibility.
But Dr Biddulph said any frost rating should only be used to fine tune frost risk management after making all other variety selection, rotation and agronomic decisions.
GRDC's National Frost Initiative is a five-year program, beginning last year, which will tackle the issue of frost through genetic research, management practices and environment monitoring.
According to Frost Program knowledge manager Sue Knights, the initiative is unique in bringing together intellectual capital from a number of disciplines.
"It is designed in a way to be flexible and allow new research input during its lifetime for the benefit of growers," she said.
