Screening large numbers of genotypes for salinity
tolerance in the field is difficult, due to spatial heterogeneity
of soil chemical and physical properties,
and to seasonal fluctations in rainfall. A field study
in Syria using ICARDA’s advanced durum breeding
lines indicated that significant genetic variation for salt
tolerance might exist, but the confounding presence
of drought stress made it difficult to identify genotypes
with salt tolerance (Srivastava and Jana, 1984).
They conclude that ‘the lack of reliable large-scale
field screening techniques still seems to be the biggest
problem in genetic improvement of salt and drought
tolerance of crop plants’. Screening techniques that
can be carried out under controlled environments have
therefore often been used