Partial characterization of the trait for enhanced K(+)-Na (+) discrimination in the D genome of wheat.

The long arm of chromosome 4D of wheat (Triticum aestivum L.) contains a gene (or genes) which influences the ability of wheat plants to discriminate between Na(+) and K(+). This discrimination most obviously affects transport from the roots to the shoots, in which less Na(+) and more K(+) accumulate in those plants which contain the long arm of chromosome 4D. Concentrations of Na(+) and K(+) in the roots, and Cl(-) concentrations in the roots and shoots, are not significantly affected by this trait, but Na(+), K(+) and Cl(-) contents of the grain are reduced. The trait operates over a wide range of salinities and appears to be constitutive. At the moment it is not possible to determine accurately the effect of this trait on growth or grain yield because the aneuploid lines which are available are much less vigorous and less fertile than their euploid parents.