Have a cocktail and beat frost and heat

Mixing wheat varieties can assist with frost and heat shock management

Andrew Fletcher, CSIRO, says a mixture of wheat varieties planted together reduces the risk of crop wipe-out from frost.

Andrew Fletcher, CSIRO, says a mixture of wheat varieties planted together reduces the risk of crop wipe-out from frost.


Trial work in Western Australia has found a mixture of wheat varieties sown together can limit damage from frost and heat.


WORRIED about excessive heat or frost at the pointy end of the growing season?

Relax, kick back and have a cocktail is the message from one WA-based CSIRO researcher.

Unfortunately for those with visions of a nice dry martini, the cocktail in question is a mix of three different wheat varieties.

Presenting at last week’s Agronomy Conference in Ballarat, Andrew Fletcher, cropping systems scientist at CSIRO, said his research had found a mix of two or three varieties with slightly different phenologies was a good risk management tool.

“In particular in frost prone environments you can stabilise yield through multiple flowering times,” Dr Fletcher said.

He said a one-off frost even could cause severe damage in a paddock with uniform flowering times if it hit at the wrong moment.

“If the wheat is all flowering and you get frost or heat it can have a severe impact on yield, obviously if you manage that by having different flowering times the impact on total yield is reduced.”

“You are more likely to get some damage but it will be less severe,” Dr Fletcher said.

He said he foresaw the wheat cocktail as being particularly useful in paddocks with a history of frost issues.

“Perhaps you have a low-lying paddock that always gets frosted, this would be a relevant agronomic option there.”

At present, the wheat shandy approach has its limitations.

Bulk handlers require varietal declarations when wheat is delivered, although unlike barley, wheat varieties can be commingled.

“The marketing side of it isn’t my area of expertise, but I would think you could deliver it as the lowest of the varieties’ classification, if the paddocks were a mix of hard and APW wheat, you’d deliver it as APW.”

Logistically, he said his work had involved varieties with a slight difference in maturities.

“In terms of crop ripeness we did not encounter significant problems with some plants being ready and some not.”

Dr Fletcher said it was difficult at the start of the season to know whether there would be bigger issues with frost, which in general hurt yields on early-maturing lines, or with heat, which knocks around later ripening varieties.

“It’s a bit of a lottery, particularly in Western Australia, and I think by mixing your varieties you get to have your chips on two different spots in the one paddock.”


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