Frost risk – manage wheat variety and sowing time

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Wheat is highly susceptible to frost damage between ear emergence and flowering. Growers have tried to minimise frost damage by delaying sowing so crops flower after the high frost risk period in early spring. But delayed sowing of wheat can incur a yield penalty of 20 kilograms per hectare (kg/ha) per day. Another approach is to manage the ‘flowering window’ across a wheat cropping program. DAFWA's Wheat Agronomy Team has developed Flower Power a tool to help farmers work out the best time to sow to reduce frost risk.

Minimising frost risk

Growers can minimise frost risk by matching wheat variety to sowing time so the variety flowers within the ‘flowering window’. The flowering window is the period between the last frost and the last effective rain.

When managing the flowering window the following points should be considered:

  • Choice of variety and sowing date are key to maximising yield potential. Earlier sowing can lead to better water use efficiencies and higher yields. The risks are weeds, frost and leaf disease.
  • Matching variety to sowing time aims to maximise growth. It aims to also minimise the likelihood of frost at flowering and avoid the incidence of high temperature events during grain fill.
  • Delayed sowing of wheat can avoid frost damage during flowering but a yield penalty of 20 kilograms (kg), per hectare (ha), per day can occur. This penalty in yield is highly variable from season to season.
  • The heat and moisture stress associated with delayed sowing can increase grain protein percentage at the cost of grain yield and can produce higher screenings.

Management options

  • Match varieties maturity to sowing time: choose to sow a variety so it flowers during the flowering window, the period of time when frost risk and terminal drought risk are lower.
  • Spread the flowering time of a variety across your cropping program: sow a mid maturing wheat variety throughout your cropping program but ensure flowering is within the low risk period and before terminal drought stress.
  • Grazing: grazing vegetative crops can delay flowering to some extent, but how long flowering is delayed varies between varieties and the length of the grazing period.

Contact information

Christine Zaicou-Kunesch
+61 (0)8 9956 8549
Brenda Shackley
+61 (0)8 9821 3243
Page last updated: Thursday, 23 June 2016 - 10:42am

Authors

Christine Zaicou-Kunesch
Brenda Shackley
Georgia Trainor