Salt-tolerant wheat made possible

The Molecular Plant Breeding CRC's Dr Yusuf Genc has found that different varieties of wheat have different ways of dealing with salinity. The research has implications for cereal breeders, who have long sought to breed varieties that are resistant to salinity.

Transient salinity, the seasonal movement of salt in and out of the soil profile, is responsible for losses of up to $1.3 billion per year for the Australian farming economy.

So far, researchers have had limited success into the development of new salt-tolerant varieties. But with new insight into the mechanisms that wheat uses to cope with salt, breeders may soon be able to select for salt tolerance.

According to Genc, keeping the salt out is not the only coping mechanism. Rather, somewhat like a mangrove tree, it seems that some wheat varieties take the salt up into their roots, but are less affected by it than other varieties.

The mechanism, known as 'tissue tolerance', could result in dramatic yield increases for salinity-affected growers if it could be bred into other wheat varieties.

Genc and his team grew two wheat varieties, Berkut and Krichauff, at varying salt concentrations, and evaluated their salt uptake and grain yields.

While both are known to be good salt tolerators, they found that Berkut does not prevent the salt from entering the plant as well as Krichauff. Instead, it takes the salt in but still yields as much as Krichauff, if not more.

"This was at first puzzling, because traditionally researchers thought high salt concentration meant poor ability to withstand the salt," said Genc.

Some varieties had the exclusion ability whereas other varieties had the tissue tolerance ability. Genc is looking to identify DNA markers, a kind of genetic 'fingerprinting', which will allow breeders to screen for salt tolerance.

With field trials planned for later this year, Genc hopes to find the same effect in the field.

"The results from these trials could be a major step forward towards salt-tolerant wheat," Genc said.