Central Queensland's sustained spell of extremely cold weather that has persisted throughout August is expected to have inflicted severe frost damage across the region's extensive planting of wheat and chickpeas.
Department of Primary Industries and Fisheries development extension officer Rod Collins said frost had been reported almost daily across the Dawson-Callide and Central Highlands grain-growing belt since August 1.
The 2008 Central Queensland wheat planting was estimated at 160,000 ha whereas the chickpea crop was around 50,000 ha.
Mr Collins said that with the May-planted crops sown using moisture seeking tines, the bulk of these crops would have been flowering in the first two weeks of August.
"Wheat is most vulnerable to frost damage during the flowering stage where the developing seed embryo is killed and the heads fail to fill," Mr Collins said.
Wheat planted in the June rainfall event would have been at the boot stage during the frosts and could also have suffered damage.
Mr Collins said that after inspecting a number of wheat crops in the Dawson-Callide region, he had also found visual evidence of stem frosting which effectively cut off all nutrient flow to the developing seed head.
"Where stem frosting has occurred, the wheat heads have an unhealthy yellow-green colour instead of a bright green," Mr Collins said.
"Frost-damaged heads tend to yellow prematurely and turn white and closer inspection shows there is no seed development in the glumes."
Much of the region's chickpea crop was sown in May and with two major in-crop rainfall events in June and July, the plants have flourished producing vegetative growth to 1 m.
Mr Collins said that while the chickpeas look healthy, there has been very little pod set as the excessive cold weather has caused the flowers to drop off.
"While there is still time for the plants to flower and set pods as the weather warms - provided there is sufficient subsoil moisture - the yield potential has been slashed," Mr Collins said.
Mr Collins said the potential wheat and chickpea frost-damage yield losses could have serious implications for growers who opted to forward sell a portion of the 2008 grain harvest to lock in attractive market prices.
"The message for all growers is to check their crops for damage to enable them to make an informed management decision," Mr Collins said.
DPI&F principal technical officer Peter Keys said a farm walk to inspect the Central Queensland winter cereal trials would be held on September 9 at the Biloela Research Station from 10.30am. All regional growers are welcome.
Mr Keys has a responsibility to supervise the Central Queensland winter cereal trials associated with the new pre-breeding program with an objective to deliver high value agronomic traits to regional grain growers.
Growers joining the farm walk will also have an opportunity to inspect the soon-to-be-released new chickpea variety which is essentially an improved Moti variety but is slightly quicker to flower with higher yield and larger seed.
Following seed multiplication, commercial chickpeas growers will have this new high-yielding variety on their farms to plant for the 2010 winter season available through AWB Seeds which has the commercial marketing rights.