Univrsity of Tehran Press Iranian Journal of Field Crop Science 2008-4811 52 2 2021 06 22 Effects of different treatments on seed dormancy breaking in Syrian Thistle (Notobasis syriaca) as the first report in Iran Effects of different treatments on seed dormancy breaking in Syrian Thistle (Notobasis syriaca) as the first report in Iran 133 144 83814 10.22059/ijfcs.2020.277612.654591 FA Ahmad Zare Plant Production and Genetics Department, Faculty of Agriculture, Agricultural Sciences and Natural Resources University of Khuzestan. Bavi, Mollasani, Iran., Bavi, Mollasani, Iran 0000-0003-2505-6134 Seyed Amir Moosavi Plant Production and Genetics Department, Faculty of Agriculture, Agricultural Sciences and Natural Resources University of Khuzestan. Bavi, Mollasani, Iran., Bavi, Mollasani, Iran 0000-0002-3845-2075 Journal Article 2019 03 10 To evaluate the effects of different treatments on seed dormancy breaking of Notobasis, two separate experiments were conducted at Agricultural Sciences and Natural Resources University of Khuzestan, in 2017 with three replications. The first experiment included nine physical, mechanical and chemical treatments (control, surface scarification, intense scarification, one and two weeks of chilling at 4°C, soaking into hot water for two hours without scarification , soaking in 25°C distilled water for two hours with scarification  and acid treatment for six and 12 minutes) based on completely randomized designs (CRD). The Second experiment was hormone priming arranged as a factorial experiment based on completely randomized design with gibberellin concentrations (0, 200, 400, 600, 800 and 1000 ppm) and priming duration (12 and 24 hour) as the treatments. The highest seed germination (40%) obtained from 12 minutes of acid treatment. Results showed that seed germination reached to 100% after priming seeds with GA3 concentrations for 12 hours. However, increase the priming durations to 24 hours, significantly declined seed germination to 47% in 200 and 400 ppm of GA3 concentrations. The Increase of GA3 concentrations in 12 hours led to a linear reduction of T50 from 31 hours in 200 ppm to 19 hours in 1000 ppm). In 24 hours of priming treatment, T50 followed a Gaussian function and the highest T50 (92 hours) was obtained from 600 ppm. It is recommended to immerse the seeds for 12 minutes in sulfuric acid and prime with 400 ppm GA3 acid for 12 hours to break dormancy and increase the vigor index. To evaluate the effects of different treatments on seed dormancy breaking of Notobasis, two separate experiments were conducted at Agricultural Sciences and Natural Resources University of Khuzestan, in 2017 with three replications. The first experiment included nine physical, mechanical and chemical treatments (control, surface scarification, intense scarification, one and two weeks of chilling at 4°C, soaking into hot water for two hours without scarification , soaking in 25°C distilled water for two hours with scarification  and acid treatment for six and 12 minutes) based on completely randomized designs (CRD). The Second experiment was hormone priming arranged as a factorial experiment based on completely randomized design with gibberellin concentrations (0, 200, 400, 600, 800 and 1000 ppm) and priming duration (12 and 24 hour) as the treatments. The highest seed germination (40%) obtained from 12 minutes of acid treatment. Results showed that seed germination reached to 100% after priming seeds with GA3 concentrations for 12 hours. However, increase the priming durations to 24 hours, significantly declined seed germination to 47% in 200 and 400 ppm of GA3 concentrations. The Increase of GA3 concentrations in 12 hours led to a linear reduction of T50 from 31 hours in 200 ppm to 19 hours in 1000 ppm). In 24 hours of priming treatment, T50 followed a Gaussian function and the highest T50 (92 hours) was obtained from 600 ppm. It is recommended to immerse the seeds for 12 minutes in sulfuric acid and prime with 400 ppm GA3 acid for 12 hours to break dormancy and increase the vigor index. https://ijfcs.ut.ac.ir/article_83814_c4f7a7b77002abf6be113990538502c5.pdf