Determination cardinal temperatures seeds germination of two lentil genotype (Lens culinaris Medik) under various priming

In order to determine the cardinal temperatures for seed germination of two lentil cultivars(Robat and Calposh) a factorial experimental were conducted base on completely randomized design with four replications. Germination temperatures includes 0, 5, 10, 15, 20, 25, 30 and 35°C and different priming includes: control(non-priming), Gibberellic Acid(C19H22O6) 100 mg.l-1, Potassium Nitrate(KNO3) 500 mg.l-1, Zinc Sulfate(ZnSO4)100 mg.l-1, Dayan Seed Solution four ml.l-1 and Hydroperiming. The cumulative germination percentage and 50% germination rate were calculated and cardinal temperature diagrams of seed germination of two lentil varieties were plotted based on three regression models(Intersected line, Quadratic Plynomial and Dent- Like). The results showed that cumulative germination percentage and 50% germination rate were significantly affected by priming, cultivar, priming time, interaction of priming and cultivar, priming and time. The highest percentage of cumulative germination was obtained in interaction of Robat cultivar at 10°C. The highest germination rate of 50% was obtained in the interaction between Calposh cultivar and Gibberellic Acid. Among the models, the dent-like model had higher correlation coefficient in priming treatments. According to this model, the base temperature, lower optimum temperature, optimum upper and maximum values for Robat cultivar were 0.46, 23.82, 30.50 and 36.98, respectively, and for Calposh cultivar 1.44, 23.46, 30.30 and 36.87 °C. In generally, Robat cultivar is more cold tolerance than the Calposh cultivar and has a lower base temperature and Robat cultivar had higher vigor seed. Finally, the priming could reduce the cardinal temperatures of both cultivars and increase their germination ability at the lower temperatures.