Grains Research and Development

Date: 01.06.1999

Yields soar as wheats are matched to environments

The Australian National University and CSIRO team that extracted top yields from the Centre's Plant Growth and Performance Program. From left: Richard Richards, Tony Condon, Vicki Fischer, Graham Farquhar, Greg Rebetzke

The Australian wheat industry is set to reap many hundreds of millions of dollars as new high-yielding varieties from the Centre's wheat research projects are commercialised.

Closest to commercialisation are new water-use efficient wheat lines being developed for the northern wheatbelt. This means more growth from the water available to the crop and a way to cope with the 'dry finishes' common to the north.

In Queensland the most promising new lines have out-yielded the parent Hartog by as much as 15 per cent and could be released commercially within about three years.

Getting the coleoptiles out

Another major breakthrough has been the identification of new dwarfing genes that allow for greater coleoptile length and seedling vigour.

"Dwarfing genes in current varieties produce short coleoptiles that reduce emergence if sowing deep or under conservation farming practices," said project scientist Greg Rebetzke. "The new dwarfing genes can be combined with genes for greater coleoptile length to offer much more consistent emergence than is possible with current varieties."

The Centre's third research focus for higher wheat yields has been to improve early vigour. The three projects promise novel germplasm and management strategies to farmers around Australia. More than 1,000 advanced wheat lines are being grown by breeders in all states.

Maximising water-use efficiency

All three projects have involved collaborative research between groups led by Richard Richards and Tony Condon at CSIRO Plant Industry and Graham Farquhar at the Research School of Biological Sciences, ANU.

Much of the research innovation comes from fundamental discoveries by the two groups about the way plants trade water for carbon dioxide during the photosynthetic process, and the importance of early growth vigour in minimising soil water loss.

"The advantage of the water-use efficiency trait on increasing grain yield is most evident in the lower-yielding Australian environments where water is less plentiful, which is about 97 per cent of the Australian wheatbelt," said Dr Rebetzke.

Early vigour

He said said the group also worked on greater early vigour of wheats to make them more like higher-yielding barley and triticale crops of southern Australia. These cereals produce greater leaf area and dry matter early in the season to shade the soil surface. The shading reduces water loss through soil evaporation, keeping water for later use in photosynthesis.

"We've started breeding a number of overseas wheats that produce greater early vigour than current Australian varieties with the local varieties," said Dr Rebetzke.

"Early results are encouraging with high-vigour wheats producing up to 10 per cent greater yield than commercial parents when evaluated in some environments."

Given that a 1 per cent improvement in wheat yield across Australia is expected to be worth about $30-40 million every year, the Centre investment should reap rich rewards for Australia.

Region North