Stop Sprouting In The Ears

Awns are the long spines or 'beard' on the ears of wheat. These channel rainwater on to the ripe grains, causing them to sprout before they are harvested.

Sprouting can affect up to five percent of the wheat crop in Australia, costing the industry hundreds of millions of dollars.

Research at Australia's CSIRO Plant Industry shows that wheat without awns is far less susceptible to sprouting damage than wheat with awns.

The researchers are now working towards breeding awnless varieties that have the same high quality and yields as current bearded varieties.

"This is a real break from the tradition of breeding wheat with awns," says CSIRO's Dr Richard Richards.

"Most Australian wheats are bred from wheats that have awns because it's believed that awns assist the plant during very dry or hot conditions.

"In fact there is very little reliable scientific evidence in support of this and so awns may just be an historic relic of modern wheat breeding."

Dr Richards says his research team has found that varieties of wheat that have awns are 40 percent more likely to experience the problem of sprouting compared to wheat without awns.

"When it rains the awns channel water towards the ripened wheat grain causing more water to get to the grain than if there were no awns," says Dr Richards.

"The more water that reaches the wheat grain the more likely it is to sprout."

Sprouting is particularly prevalent in the states of New South Wales and Queensland where rain is common during harvest but it can occur in southern wheat growing areas as well.

Although there is an obvious benefit in reducing sprouting through the use of awnless varieties, their use has not been widely adopted.

"This is largely because there are so few awnless wheat varieties available to growers. Varieties such as Suneca, Sunlin and Rowan are the best examples of awnless varieties," says Dr Richards.

"Fortunately the absence of awns is a trait that is easily bred into new varieties through traditional breeding. This is what we are doing now by combining the awnless trait with another important trait, long coleoptiles or first shoots.

"Seedlings with long coleoptiles are more likely to emerge successfully, have higher survival rates and are more vigorous."

Dr David Bonnet, who is working under Graingene, a strategic alliance involving the AWB Limited, CSIRO Plant Industry and the Grains Research Development Corporation, is now combining the awnless trait with the long coleoptile trait into high yielding, semi dwarf wheats with excellent grain quality for regions where sprouting frequently occurs.

"By June 2001 we will have established the first field trials of these wheat lines. We expect to be able to release a long coleoptile, awnless wheat variety within four years," says Dr Bonnett.

"We have fast tracked this aspect of our breeding program as we consider it to be very important and we are keen to make our new wheats available to growers as soon as possible."

"Through our breeding program we are creating new wheats with all the existing benefits but also establish better and have a built in capacity to reduce the risk of sprouting," says Dr Richards.

"We might not be able to control the weather but we can help farmers manage its potential negative effect on their crops."