Effects of Temperature and Season on In Vitro Establishment and Shoot Multiplication of Picea abies (L.) H. Karst

Plant propagation originated  from the mature tissues is the most desirable method in producing clonal plants, however microbial contamination usually is the main concern during regeneration processes. Moreover, commercial production of plants using clonal propagation is considered as high throughput method due to the   removal of seasonal barriers, lower cost of production with higher yield when compared to the conventional propagation methods. In this research the regulatory roles of 2-iso-pentenyl adenine (2iP) and Zeatin (Z) along with two temperature regimes, 22 and 28 °C, on mature explants of Picea abies (L.) H. Karst was evaluated for adventitious shoot regeneration. Norway spruce micro-cuttings considerably  benefited from Ridomil and Benomyl treatments for fungal decontamination in explants taken in spring or fall. The highest percentage of regenerated explants (68.75%) as well as the highest  numbers of adventitious shoots per explant were obtained in MS media supplemented with 4 µM Z. Furthermore, the highest length of proliferated shoot (1.17 cm) was achieved at 3.2 µM 2iP treatment. However, there were no significant differences in the length of adventitious shoots using different concentrations of 2iP. Incubating explants at 28˚C resulted in null or deformed regeneration in Norway spruce.