Assessing the comparative response of wheat and barley genotypes to salinity stress using destructive and non-destructive techniques

Assessing the comparative response of wheat and barley genotypes to salinity stress using destructive and non-destructive techniques

Salinity reduces crop productivity in many agricultural areas, especially in arid and semi-arid regions. Growth is reduced by osmotic effects and ion-specific mechanisms. While Munns et al (1995) proposed a two-phase model of salt injury, where growth is initially reduced by osmotic stress and then by Na+ toxicity, it is currently difficult to assess the relative importance of the two mechanisms to yield reduction because they overlap. The objectives of this experiment were to evaluate the mechanisms of salt tolerance in wheat and barley and to quantify the injury of seedlings suffered under NaCl stress. A factorial experiment examined the effect of NaCl (100 mM),) on the growth of two varieties of bread wheat (Krichauff, Berkut), two varieties of durum wheat (Line 149 and cv Tamaroi) and four varieties of barley (Clipper, Sahara, Mundah and Keel). These varieties were selected because of their differences in salt tolerance. The experiment was a completely randomised design with 8 replicates. Non-destructive and near-real-time measurements of plant growth were made during the experiment using a LemnaTec Scanalyzer®. Destructive harvests at selected time points were used to assess the growth of plants and to measure changes in Na+, K+ and Cl- concentrations and leaf osmotic potentials. Gas exchange studies were made at different times using a LI-COR 6400 portable gas exchange system. Physiological analyses of these traits in relation to the different mechanisms of salt tolerance and their suitability as selection parameter will be discussed.

Poster presentation.