Response of winter rapeseed (Brassica napus L.) cultivars to salt priming of seeds

Laboratory tests and a field experiment were carried out to evaluate the effects of salt priming (0.8% NaCl with electrical conductivity of 15.3 dsm-1 and 0.8% KNO3 with electrical conductivity of 12.5 dsm-1 for 8 h at 20 ± 1°C) on seed invigoration and field performance of three winter rapeseed cultivars (Okapi, Opera and Talayeh). The field experiment was arranged as split plot factorial based on RCB design in three replicates, with irrigation regimes (I1, I2 and I3: irrigation after 80, 120 and 160 mm evaporation from class A pan) in main plots and cultivars and salt priming treatments in sub-plots. Salt priming, particularly KNO3 priming, decreased mean germination time and increased seedling size, compared with non-primed seeds. Irrigation treatments had no significant effect on yield and yield components of rapeseed cultivars in the field, suggesting that this crop was well-performed even under the limited irrigation regimes. Although response to salt priming varied among rapeseed cultivars, seed priming generally increased grain yield per unit area through enhancing rate and percentage of seedling establishment, pods per plant and grains per plant. The highest improvement in grain yield per unit area was observed for seeds primed with KNO3 (31.5%) followed by those primed with NaCl (22.5%).