This experiment aimed to evaluate the effects of irrigation regimes based on potential evapotranspiration (100 %, 60 %, and 40 % PET) and doses of nitrogenous fertil- izers (0, 40, and 80 kg ha-1) on the performance of safflower in Qazvin, Iran. Three fractions of potential evapotranspiration: 100 %, 60 %, and 40 % PET are considered as full irrigation (FI), mild deficit irrigation (MDI) and severe deficit irrigation (SDI), respectively. Results revealed that the effectiveness of nitrogen fertilizers was discernable under FI and MDI conditions, how- ever, under SDI, the application of nitrogen fertilizers did not have any improvement effects on evaluated traits. The highest seed yield was recorded in FI + N80 (1253 kg ha-1) and the seed yield of MDI + N80 (1121 kg ha-1) was in the second place with a difference of 132 kg ha-1. However, the best seed qual- ity in terms of protein percentage was related to plants grown under SDI + N80 (23.44 %), which was 43 % higher than FI + N0 (16.45 %). The plants grown under FI + N80 and SDI + N80 conditions showed the highest seed oil content with 28 % and 27.1 %, respectively. The obtained results showed that MDI can be used as a strategy to improve the efficiency of water con- sumption under water scarcity conditions in the semi-arid re- gion.
