By Dr Ananya Mandal, MD
Australian researchers have crossed a modern wheat variety with a wild ancestral cousin to produce a high-yielding salt-tolerant plant that will help tackle world food shortages due to soil salinity.
Matthew Gilliham, of the University of Adelaide, said the new variety of durum wheat would be made freely available to publicly funded breeding programs overseas. Field trials in Moree and at other sites across southern Australia have shown that the new variety has a grain yield in salty soil of up to 25 per cent higher than that of the standard variety.
Dr Gilliham said that this was the first study in the world to demonstrate on a farm, not just in the laboratory or greenhouse, that a new salt-tolerant wheat had improved yield. “This is why this work is particularly important, we think,” he said. The results of the fifteen years of efforts are published in the Nature Biotechnology journal today.
The team first identified a gene in an ancestral salt-tolerant relative of commercial durum wheat that removes sodium from water as it is transported from the roots to the leaves. Gilliham said when salt accumulates under in the leaves of wheat, it becomes toxic and reduces the plant yield. “We have identified a gene from an ancestor of modern wheat that when inserted into a modern commercial variety of wheat improves its salinity tolerance in the field in terms of grain yield by up to 25 per cent…This gene functions by preventing the salt from the soil getting up into the leaves of the plant,” he said.
Dr Gilliham said their challenge was then to develop a new cross-breed which had this gene, without reducing the crop yield. Field tests showed the new hybrid performed the same under normal conditions as the commercial wheat without the gene, but outperformed it under salty conditions.