Screening in hydroponics failed to predict differences in salt tolerance and ion uptake in soil, whether under controlled conditions or in the field. The hydroponic method used—exposing seedlings to short periods of salinity stress—is one commonly used to assess salt tolerance and to examine the mechanisms of salt tolerance among genotypes. Despite the emphasis that has been placed on Na+ and/or Cl– exclusion as a selection criterion for salt tolerance (Munns et al., 2006), no relationship was observed between the level of exclusion and salt tolerance in the genotypes used in hydroponic study based on early growth (Fig. 3). The different rankings in salt tolerance and in the relationships between ion concentration and salt tolerance between soil and hydroponics suggest there are fundamental differences in the nature of the two systems that influences the responses to salinity between the plants grown. This has important implications for the development of salt-tolerant germplasm and for elucidating the relative importance of the mechanisms of salt tolerance in the field.