Unlocking Seed Dormancy and Elucidating Storage Behavior in Morinda royoc (Rubiaceae): Crucial Insights for Propagation and Ex Situ Germplasm Conservation

Morinda royoc L. is a shrub with high pharmacological value due to its antimicrobial and metabolic bioactivity. However, its low germination limits its commercial use and conservation. This study characterized the morphophysiology of its diaspores, evaluated pre-germination treatments (mechanical endocarp removal and GA₃ soaking at 600 and 1200 ppm), and determined its storage behavior. The analyses showed a highly significant effect where manual endocarp removal overcame mechanical restriction and eliminated dormancy, achieving 100% germination within two weeks, whereas the control reached only 51.5% after 23 weeks. Treatments with GA₃ did not improve germination compared to the control, and an inhibitory effect was observed at 1200 ppm, although 100% of the non-germinated embryos remained viable. The seeds maintain viability above 90% after three months of storage at 25, 5, and -20 °C. Our findings suggest that M. royoc seeds exhibit orthodox behavior (tolerant to desiccation and freezing) and non-deep physiological dormancy. This study documents, for the first time, a method for the complete release of dormancy in the species, which is essential for successful propagation. Our results provide a rapid and economical germination method that facilitates mass propagation, establishing the technical basis for the transition toward commercial-scale cultivation and ensuring the effective conservation of M. royoc germplasm.