JUST where would researchers look for valuable genetics to improve wheat? Ultra-modern germplasm? Ancient drought tolerance traits from obscure central Asian wild relatives? The more prosaic answer comes from its frequent neighbour in Australian paddocks, barley.
Traits have been found by CSIRO’s high performance crop team that will hopefully help provide growers with plants with increased vigour, which in turn leads to better water use efficiency and increased grain yields, along with reducing weeds, due to the plant outcompeting them and an increase in nutrient uptake.
Dr Richard Richards, leader of CSIRO’s high performance crops program said the group had produced some ‘super wheats’ by combining different vigour traits from varieties found in Australia and across the globe.
And the key to unlocking this new vigour in wheat was barley.
Dr Richards said he observed barley growing side by side with wheat and noted barley was more vigorous with extra tillers and was better yielding than wheat in dry environments.
He said he believed the resulting ‘super wheats’ that were developed as a result differed to other varieties anywhere else in the world, having deeper, more extensive root systems and more extensive branching.
With an increasing emphasis on water use efficiency in an Australian cropping environment constantly being confronted by drought, Dr Richards claims that crop vigour is one of the best drivers of efficient use of moisture.
He said in many years in southern Australia, only half of the rainfall received in the growing season is used by the crop, meaning the other half is wasted.
To counter this, the focus of the breeding group has been on increasing crop vigour to ensure more rainfall is used by the plant and less evaporates from the soil surface.
Dr Richards believes varietal choice will be increasingly important for growers, saying that the ‘super wheats’ will not necessarily outyield conventional cultivars, with much contingent on the season.
In dry years, he said the super vigorous wheats under development could yield less than current conventional varieties if sown in mid May, however if sown later, they are likely to yield better than current varieties.
This equation changes in an average season, when the research found the super vigorous wheats would be expected to perform better than current varieties.
Along with the work on vigour, 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 says there are two mechanisms in varieties for improving P use efficiency. However, they are not currently found in any of the wheats grown in Australia. The key is in developing wheats with these mechanisms so they can solubilise the large bank of soil P that is currently unavailable to plants.
While it is early days, the team has discovered the P solubilising mechanism in varieties from Brazil. One gene solubilises P using an organic acid secreted from the roots and a second gene is associated with larger root hairs, which make soil bind to the roots. Adhesion of soil particles to roots makes P more available to the plant.
The team is aiming to have elite germplasm into field testing in breeding programs in three years’ time. They have already started crossing varieties and hope to breed 2-3 generations per year, instead of one.
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