In salt tolerance tests at Scottish Crop Research Institute a significant difference has been detected between the shoot sodium content of salt stressed (grown in 150 mol m"3 NaCI) 'Golden Promise1 and its parental line 'Maythorpe1 'Golden Promise' was found to have about 50% of the sodium level in its shoots compared to 'Maythorpe'. Since shoot sodium accumulation is correlated with salt tolerance in the Tnticeae, the results imply that a mutational difference between 'Golden Promise' and 'Maythorpe' is responsible for the increased tolerance to salt. This mutation has important implications for salt tolerance research and crop improvement Current work aims to map the mutant locus to a specific chromosomal region, and to determine if the sodium exclusion character is a pleiotropic effect of the GPert locus or due to some other mutation. Differential screening at the DNA, RNA and protein levels may also be exploited in isolating and characterising the mutant locus