Evaluation of salt tolerance of rapeseed (Brassica napus L.) cultivars using physiological markers

For the evaluation of salt tolerance of rapeseed cultivars, an experiment was conducted in the greenhouse at Sari Agricultural Science and Natural Resources University (SANRU). In this experiment, seven rapeseed cultivars were examined under three levels of salt stress (0, 7 and 14 ds.m-1). The experiment was a factorial based on a completely randomized design with four replications. Characteristics such as vegetative growth, shoot Na+ and K+ contents, K+/Na+ ratio and grain yield were measured and the cultivar response to salinity was evaluated using statistical parameters like stress susceptibility index (SSI) and salt tolerance index (STI). In general, tolerant cultivars (LSG2 and LSN) showed higher agronomic performance and presented lower Na+ and higher K+ and K+/Na+ ratio like Sarigol and RGS003. An increase in shoot Na+ content correlated negatively with yield (r = -0.38, p<0.05) and STI (r = -0.39, p<0.01) but in turn positively with SSI (r = 0.40, p<0.01). These two droughts could be considered efficient criteria for screening salt tolerance of rapeseed cultivars.