Brendon Cant brendon at iinet.net.au
Thu Mar 16 19:58:15 EST 2006

Crop Doctor



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Frost damage last spring cut about 700,000 tonnes from WA's 2005/06-harvest.


Wheat varieties Wyalkatchem and Carnamah were the most frequently frosted.


Grains Research and Development Corporation (GRDC) supported researcher,
Garren Knell of ConsultAg, explains that this is primarily because they are
the most widely adopted varieties and growers frequently sow them too early
in the season, especially in frost prone paddocks or regions.


Sowing long season wheat varieties later in a seeding program on frost prone
paddocks greatly reduces the likelihood of frost damage.


Frost prone soils, due to their better water holding capacity, usually have
less yield penalty from delaying seeding than soils higher in the landscape.


Shorter season varieties have other traits making them more frost prone. 


Wyalkatchem and Carnamah have more plasticity in flowering time than other
varieties, because their development is triggered by cumulative degree days,
making flowering time hard to predict.


This characteristic enables the plant to respond to the season and flower
earlier or later, depending on conditions. 


Under moisture stress, or a warm, mild winter, they will flower earlier. Or,
if there is a late rain, they will flower longer. This characteristic
increases yields in the absence of frost, but can devastate yields in a
frost year.


Frost damage to longer season varieties Yitpi, Stiletto and Calingiri, also
widely grown in WA, is much less common. 


Longer season varieties use day length to trigger ear emergence, making
flowering time much more predictable and allowing growers to calculate it.


This means growers can plant these varieties so that they flower later in
the season, when there is a lower chance of a frost.


By planting longer season varieties later on frost prone paddocks, growers
can minimise their risk of yield losses due to frost.


The Crop Doctor is GRDC Managing Director, Peter Reading, Tel 02 6272 5525

Further Information: Garren Knell, Tel 08 9881 5551

GRDC REF: CDFeb064/CAG00002/Blumenthal

Brendon Cant & Associates
Public Relations & Marketing 
Suite 5
4 Gugeri St
Claremont WA 6010
Tel 08 9384 1122


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