A BETTER understanding of early barley plant development has led to the breeding of "super vigorous" wheats by the CSIRO.
Increasing plant vigour has the potential to produce greater water-use efficiency and better grain yields in crops.
It can also reduce weeds and increase nutrient uptake.
CSIRO's High Performance Crops Program team leader, Richard Richards, saw barley growing alongside wheat and noted that the barley was more vigorous with extra tillers and was better yielding than wheat in dry environments.
Dr Richards' research team worked out how barley achieved its higher vigour and then set about recreating that in wheat.
The research team has produced unique wheat plants by combining different traits that control vigour from local and international varieties.
Dr Richards said these super-vigorous wheats were different to other varieties and had deeper, more-extensive root systems and more extensive branching.
He said crop vigour was important in making best use of rainfall.
In many years in southern Australia, only half of the rainfall received in the growing season was used by the crop, meaning the other 50 per cent was wasted.
Dr Richards' focus had been on increasing crop vigour to ensure more rainfall was used by the plant and less evaporated.
He said it was a balancing act to choose the right variety of wheat for the range of climate conditions possible during a growing season.
In dry years, the super-vigorous wheats under development could yield less than current conventional varieties if sown in mid-May. However, if sown later, they were likely to yield better than current varieties.
Dr Richards said in average rainfall years, the super-vigorous wheats were expected to perform better than current varieties.
The CSIRO team has also been working on wheats that do not require as much phosphorus, and is leading the world with its results.
Dr Richards said there were two mechanisms in varieties for improving phosphorus-use efficiency.
But he said they were not currently found in any of the wheats grown in Australia.
He said the key was in developing wheats with these mechanisms so they could solubilise the large bank of soil phosphorus currently unavailable to plants.
While it is early days, the team has discovered the phosphorus solubilising mechanism in varieties from Brazil.
One gene solubilises phosphorus using an organic acid secreted from the roots and a second gene is associated with larger root hairs, which makes soil bind to the roots.
Adhesion of soil particles to roots makes phosphorus more available to the plant.
The CSIRO research team is aiming to have elite germplasm into field testing in breeding programs in three years.
Dr Richards said it had started crossing varieties and hoped to breed two or three generations each year, instead of one.
