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.

Today, the existence of various biotic and abiotic stresses has necessitated research with different rootstocks in different climatic and soil conditions. Thus, the growth trend and some vegetative and reproductive characteristics of Miyagawa Satsuma mandarin on C-35 citrange rootstock in plain and foothills of east Mazandaran were evaluated during 10 years. The trees on this rootstock had medium growth and yield. The canopy volume at the end of the experiment was 13.75 and 5.90 m³ in plain and foothills, respectively. Despite several frost stresses, the survival of trees was 100% in both locations, however, the trees in foothills entered an alternate bearing cycle, and the alternate bearing index reached 0.27 and 0.65 percent in plain and foothills, respectively. Tree yield in plain and foothills was 48 and 35 kg and considering planting distances, the yield was 24 and 18 tons per hectare, respectively. Fruits in foothills had more total soluble solids, titratable acid, and ascorbic acid (24, 72, and 16 percent, respectively) and less harvest index (3.1 units). The best harvest time in plain was late September and in foothills was early October. In general, the plain had higher external quality fruits and a more regular and stable annual yield.