Effect of Pre-treatments of Gibberellic Acid and Freezing on some Seed Germination Traits of Two Wild Almond Species under in vitro and in vivo Conditions

Three experiments were carried out under in vivo and in vitro conditions to evaluate the effects of gibberellic acid (GA3) and freezing on germination and growth of Prunus scoparia (Badam Kohi) and Prunus elaeagnifolia (Arjan) species. In the first experiment, treatments were 4 concentrations of GA3 (0, 50, 100 and 150 mg/L) and two soaking duration time (12 and 24 h). In the second and third experiments, the effects of different temperatures (18 and -16 °C) on the germination and growth of different species in soil and on tissue culture MS (Murashig and Skoog) media were investigated. The results showed that both seed germination percentage and germination rate increased significantly using GA3 and freezing temperature. The highest shoot length (4.48 cm) and root length (20.5 cm) were obtained in P. scoparia in 150 mg L-1 GA3 and duration time of 24 and 12 h, respectively. In freezing conditions (-16 °C) and in soil medium, although the highest germination percentage (92%) was related to Badam Kohi, but it did not show any significant difference with other treatments in freezing and MS medium. Shoot length of both P. scoparia and P. elaeagnifolia species increased with freezing pretreatment, but this increase was not significant under in vitro condition. The results of this study make it possible to use freezing treatment in soil conditions to produce seedling rootstocks of P. scoparia and P. elaeagnifolia in the nursery with shorter duration time and lower cost than other methods.