An efficient in vitro organogenesis protocol for the endangered relic tree species Bretschneidera sinensis and genetic fidelity assessment using DNA markers

is a monotypic species of rare and tertiary relic trees mainly distributed in China. is a potentially valuable horticultural plant, which has significant ornamental and research value, and is a crucial tool for the study of phylogeography. The artificial cultivation of is of great scientific value and practical significance. In this study, we developed a direct organogenesis process of using mature zygotic embryos as initial materials. The highest sterile germination induction (54.5%) from the mature zygotic embryo was obtained in a Murashige and Skoog (MS) medium with 2.0 mg·L 6-benzylaminopurine (6-BA) and 0.2 mg·L α-naphthaleneacetic acid (NAA). The highest percentage of shoot regeneration (90.37%) was attained using 1.0 mg·L 6-BA and 0.01 mg·L NAA in the MS medium. The Woody Plant Medium (WPM) had the greatest adventitious shoot elongation rate of 93.33%. The most optimized rooting rate was 88.89% in a half-strength MS medium containing 2.0 mg·L indole-3-butyric acid (IBA) and 1.0 mg·L NAA. The genetic fidelity of regenerated plantlets was assessed using inter-simple sequence repeats and random amplified polymorphic DNA molecular markers, confirming the genetic uniformity and stability of regenerated plantlets. Our research presents an effective propagation system for , laying the groundwork for its germplasm conservation and large-scale production while maintaining high genetic integrity.