Most studies evaluating genetic variation in salt resistance in crop plants have been performed in controlled or semi-controlled environments at a single level of salt stress with no validation of the results under field conditions. Furthermore, studies under controlled conditions generally involve imposing salinization on seedlings over a relatively short period (often 1–2 d) whereas the salinity stress in the field may show a greater level of spatial and temporal variationใ The variation in salt stress in the field also means that plants can be exposed to a range of salt concentrations at different growth stages, but it is not clear which is the most appropriate salinity level for screening and what stage of development best relates to genetic differences expressed in the field. This information is necessary to develop efficient breeding and selection methods for salt tolerance in crops, and it needs to be compared with the results of studies carried out in naturally saline field environments