Salinity effect on plant growth at the seedling stage of durum wheat (Triticum durum Desf.)

Soil salinity is a serious threat in many parts of the world in general and of Tunisia in particular, which negatively affects plant production. In this experiment, response of durum wheat to salinity in seven genotypes namely; four local cultivars (Azizi, Jenah Khotifa, Hmira and Swebâa Eljia), two improved varieties (Karim and Om Rabia) and an algerian cultivar (Oued Zeneti)] to salinity (0 and 100 mM of NaCl) was investigated in hydroponic conditions. Salinity induced no effects in all genotypes on the maximal efficiency of PSII (Fv/Fm) photochemistry. The Fv/Fm showed that Jenah Khotifa and Karim were the most tolerant genotypes under saline conditions (100 mM of NaCl). This may be associated with higher chlorophyll (a and b) contents. Results also depicted that all genotypes showed higher content proline as well as lower sodium content as compared with Jenah Khotifa with a reduction of 68.53% under 100 mM NaCl. It was concluded that high chlorophyll content and the proline accumulation in plant will improve the salt tolerance of wheat genotypes in breeding programs.   Key words: Durum wheat, salt stress, genotypic variation, seedling stage.