The effect of culture media type and species on embryogenic tissue induction in somatic embryogenesis of pine genus

Nowadays, plantlet production via somatic embryogenesis is considered as an efficient technique in clonal propagation of selected genotypes and breeding programs of conifers. Although it is in the phase of research in our country, but it is expected that traditional methods will be replaced by this technique soon. The main purpose of this survey is determination of suitable culture medium and selection of superior species with respect to embryogenic tissue production. The possibility of somatic embryogenesis has been studied in five different pine species, using two different culture mediums. The embryogenic tissue induction phase was performed using mature zygotic embryo explant and culture mediums DCR and HLM-1 in species Pinus eldarica, P. brutia, P. nigra, P. radiata and P. sylvestris. Cross section of embryogenic tissue was measured in two phase 3 and 6 weeks after the initial culture. The obtained results showed a significant effect of culture medium type and species on the amount of embryogenic tissue induction and the best results was obtained from P. eldarica in DCR medium. In order to proliferation of embryogenic tissues, subculture of tissues was performed every two weeks in new culture medium for ten weeks. Then, embryogenic tissues were exposed to two pretreatments of culture medium without growth regulator and culture medium with growth regulators BA and 2,4-D. Finally, in order to maturation of somatic embryo from embryogenic tissue, the segments of embryogenic tissue with an approximate weight of 75-100 mg were transferred to DCR culture medium containing 25 mg/l of ABA, 60 g/l of sucrose and 4 g/l of gelrite. The DCR culture medium with the same combination but without ABA was considered as control. In spite of pre-embryonic structures in embryogenic tissue, transformation of pre-embryo to the complete embryo did not accomplished and just in a small number of P. eldarica tissues, unnatural embryonic structures (long and vitreous) were observed.