A WHEAT trial at Hines Hill, west of Merredin, has found that a type of Mace which had the long coleoptile gene added was better able to recover from frost by reshooting green heads.
The trial formed part of a Grains Research and Development Corporation (GRDC) project which is attempting to assess where the long coleoptile gene - known at Rht18 - would fit in the farming system.
Breeding companies are now marketing varieties with what is known as 'longer coleoptile' - including Calibre and Valiant - however those varieties don't have the Rht18 gene in them.
Instead they have been bred for yield and the companies have progressed lines that have longer coleoptiles.
On the other hand, Mace 18 - which formed the basis of the Hines Hill trial - has had the gene added.
The trial was sown in April, at both shallow (dry) and deep depths (120 millimetres into moisture), with all varieties with the Rht18 gene and varieties with longer coleoptiles that were sowed deeper into moisture getting a good strike.
The varieties without the Rht18 gene and those varieties with shorter coleoptiles did not germinate until the next rain event several weeks later.
When the trial was frosted at the beginning of September, it was noted that all of the varieties, including standard Mace, Mace 18 and the longer coleoptile types were all affected.
However, according to SLR Agriculture research agronomist Michael Lamond, who is leading the project, the Mace 18 plots and several of the other varieties with the Rht18 gene reshot at the bottom, whereas none of the conventional varieties or those with longer coleoptiles showed any form of recovery.
"We harvested the frosted heads from both crops, then we went back later and harvested the green heads that had re-shot in the Mace 18 once they matured and had got quite a substantial amount of recovery," Mr Lamond said.
"One of the attributes of the Rht18 gene is that it has got bigger and more vigorous cells, meaning it has a better ability to forage for nutrients such as nitrogen and carbon and it is that which the scientists from Canberra have attributed to Mace 18's ability to recover following a frost event.
"While the varieties with the longer coleoptile did emerge well at the beginning of the year due to their deeper sowing, they didn't have the same vigour and didn't recover from the frost in the same way."
For growers in the low rainfall areas who were hit badly by frost, barley seems to have recovered to some extent and there were some green heads, but there were virtually none in the wheat, whereas in this trial, Mace 18 also reshot those green heads and while the recovery may only be half a tonne, it means instead of getting 300-500 kilograms per hectare from a badly frosted paddock, growers might instead get one tonne.
With excitement building around the addition of the Rht18 gene, growers' first opportunity to try it for themselves will be next year in the form of LongReach Plant Breeders' Bale - an awnless wheat that is the first variety with the gene to become commercially available.
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