Salt tolerant wheat could boost yields by 25%

Technology and tradition have come together to produce a new variety of salt tolerant wheat that may help farmers in Australia and worldwide adapt to saline soils and respond to climate change.

The new variety of wheat was produced not through genetic recombination, as is characteristic of most genetic modification, but through the old school technique of cross breeding.

The study, led by Matthew Gilliham from the Waite Research Institute at the University of Adelaide, focuses on a trait called Na+ exclusion, which refers to the plant’s ability to maintain low sodium (Na) concentrations, thus improving its tolerance of more saline soils.

Modern durum wheat (Triticum turgidum ssp. durum) has been bred and hybridised so many times over the millennia that it has lost this trait, making it more sensitive to saline soils than other varieties of wheat, including bread wheat (Triticum aestivum).

The researchers then turned to an ancestral wheat relative, Triticum monococcum, which has greater Na+ exclusion thanks to its genetic makeup. However, even though T. monococcum was cross bred with durum wheat in the past, it didn’t pass over the crucial genes that lent salt tolerance.

After screening the genes that contributed to salt tolerance in T. monococcum, the researchers narrowed down on one particular gene, TmHKT1;5-A, which they found to play a significant role in removing sodium from the plant’s roots.

They then proceeded to cross breed the wheat varieties to impart the gene to durum wheat and then test the effect of the gene in field conditions

Happily, they found that in saline soils durum wheat with TmHKT1;5-A had a yield as much as 25 per cent higher than conventional durum wheat.

And because the gene was introduced through cross breeding, any durum wheat containing TmHKT1;5-A will not be labelled as genetically modified or transgeneic wheat.

The Australian Durum Wheat Improvement Program (ADWIP) will be assessing the impact of this new variety of wheat, which might lead to it being rolled out as a commercial variety in areas with highly saline soil.

The study was published today in Nature Biotechnology.