Conservation of wild Solanum germplasm based on seed cryopreservation and slow growth conservation

The wild Solanum resources are a key part of Yunnan’s plant genetic diversity, and some of these resources are traditional vegetables for the local Dai and Hani ethnic minorities. However, their genetic diversity has been declining due to rapid urbanization, making conservation urgent. To establish a scientific preservation system, this study selected 15 wild Solanum germplasm resources collected from Dai and Hani-inhabited areas in Yunnan. For 9 cryo-tolerant genotypes, 8%–10% seed moisture content was optimal; preservation duration had negligible effects within the appropriate seed moisture content range, while germplasm traits significantly impacted seed survival and regeneration. Plantlets regenerated from these preserved seeds maintained stable morphological and physiological traits, and the stability of their DNA structures was further verified using 6 primers of ISSR and RAPD markers. A medium-term slow growth conservation system, which was based on the induction of adventitious buds through the cotyledon organogenesis pathway, was developed for 6 cryo-sensitive materials. The medium “MS + 30 g/L sucrose + 7 g/L agar + 2.0 mg/L ZT + 0.1–0.2 mg/L NAA (pH=5.8)” had the highest adventitious bud induction efficiency; “1/4 MS + 60 g/L sucrose + 9 g/L agar + 75–100 mg/L CCC + 0.1 mg/L ABA (pH=5.8)” retarded stem elongation while ensuring survival. Recovered plantlets only had lower root biomass than controls, with no other obvious variation in traits or DNA. This study not only provides technical support for the stable preservation of S. undatum and its relatives but also lays a foundation for safeguarding ethnic vegetable genetic resources and promoting sustainable development of Solanaceae breeding and biodiversity conservation.