Somatic embryogenesis in slash pine (Pinus elliottii Engelm): improving initiation of embryogenic tissues and maturation of somatic embryos

Slash pine ( Pinus elliottii Engelm.) has strong adaptability, early growth and high turpentine yield, and it is widely planted in southern China. Breeding of disease-resistant varieties is an effective way to prevent and control development of pine needle brown spot on slash pine in China. Plant regeneration by somatic embryogenesis has been achieved for slash pine, but large-scale production of somatic embryos remains restricted by several factors. We tested different embryogenesis conditions from time of initiation to maturation and studied genetic stability at simple sequence repeat (SSR) loci of regenerated plants in slash pine. Immature zygotic embryos of four open-pollinated mother trees were used for initiation of somatic embryogenesis. Seed sources (families) had a significant impact on initiation of embryonal suspensor mass (ESM, p