Effect of Seed Priming on Seedling Characteristics, Root Growth, and Phenology of Rice under Direct ‎Seeding

To investigate the effect of seed priming on emergence characteristics, root morphological growth, and phenological trends of rice in direct seeding, an experiment has been conducted in Sari Agricultural Sciences and Natural Resources University within 2019. The study is conducted as factorial in a randomized complete block design with three replications. The factors include Tarom Hashemi and Shiroudi cultivars and priming at five levels, namely hydropriming (for 48 hours), calcium chloride, and potassium chloride priming (Ψs -1.25 MPa), ascorbate acid (10 mg l-1), and control (no priming). The effect of priming on emergence percentage shows that the highest amount of this trait belongs to 90% in priming with calcium chloride, which is not significantly different from priming with potassium chloride and water. The rate of emergence of priming with calcium chloride, potassium chloride, and water has increased by 50%, 36%, and 29%, respectively. Results show that priming with calcium chloride, potassium chloride, ascorbate acid, and water has increased by 55%, 50%, 33%, and 38% of the plant height and by 48%, 29%, 12%, and 25% of plant dry weight, respectively. In Shiroudi and Tarom Hashemi cultivars, the time required for the onset of tillering has been 27.40 and 24.53 days; panicle appearance, 90.4 and 53.87 days; flowering, 100.53 and 70.87 days; and maturity 132.26 and 94.61 days, respectively. The least time required for panicle appearance and flowering is observed in priming with calcium chloride, although this has not been significantly different from other priming, and decreased by 11.17 and 7.5 days to the control, respectively.