Comparative Study of Pinus radiata Plant Production Methods: Classical Seed Germination vs. Somatic Embryogenesis, from Operative to Biochemical Approaches

Because of the effects of climate change, a shortage of seeds from superior mother trees for forestry breeding programmes can occur. While biotechnological tools can help address this challenge, the benefits and drawbacks of each technique need to be evaluated. In this work, a comparative Pinus radiata plantlet production study was performed using two different approaches: seeds versus somatic embryos. For each procedure, the number of plantlets obtained was recorded, and the manual labour time was calculated. The skills and time required were higher for somatic embryogenesis, but so was the number of plantlets obtained: 3660 acclimatized somatic plantlets versus 1124 acclimatized zygotic plantlets. The number of different genotypes obtained was higher when germinating mature seeds, but somatic embryogenesis coupled with cryopreservation offers the advantage of having a backup for field-tested material. Additionally, analyses of carbohydrates, total protein and dry weight of somatic and zygotic embryos were carried out. These analyses revealed considerable differences between somatic and zygotic embryos but underlined the importance of high sucrose levels for germination in both systems. In conclusion, each technique offers advantages and disadvantages, and the choice will depend on the objective, the species and the value of the material to be propagated.