Non-GM breeding outstrips GM on salt tolerance
Non-GM salt-tolerant potato wins award
Traditional breeding has left GM in the dust when it comes to salt-tolerant crops.
There are also non-GM salt-tolerant rice and wheat varieties:
Naturally the long-term solution to salinity is to rebuild soils to make them less saline. There are some resources here:
Humble spud poised to launch a world food revolution
The Guardian, 18 Oct 2014