In vitro preservation of somatic seeds and nonencapsulated hemp explants

Somatic seed technology and cold storage are used for rapid clonal propagation of plants and germplasm preservation. These methods provides genetic uniformity, pest and disease-free plants, easy to handle, and transport. The storage at low temperature reduces the metabolic rate, minimizes the risk of somaclonal variation and prolong storage time. The cold storage protocols of somatic seeds for Cannabis sativa L. are scare and limited to drug type chemotypes. The aim of this study was to develop protocols for nonencapsulated shoot tips and for alginate-encapsulated somatic seeds of industrial hemp genotypes. Aseptic axillary shoot tips derived from in vitro grown plants were used as explants and storage up to 6 months at 4 °C in the dark. Somatic seeds were produced in 3% sodium alginate and Murashige and Skoog (MS) medium salts with addition of sucrose or mannitol. Synthetic seeds were stored at 4 °C in the dark up to 6 months. The effect of the bead composition, and the time of storage on plant regeneration was investigated. After 6 months of cold storage the highest regrowth 45% was recorded for the nonencapsulated explants. Recovery of somatic seeds was 90% under the same storage condition after 3 months. Well-developed, rooted plants regenerated from encapsulated, stored explants were successfully acclimatized.