A ten-year retrospective on the efficacy of droplet vitrification for cryobanking of Allium ramosum L. germplasm.

Abstract

Background: Allium ramosum is an important member of the genus Allium, which is commonly known as Chinese chive or fragrant-flowered garlic. Conserving the genetic diversity of different species of Allium is crucial, and cryopreservation has emerged as an important strategy for long-term conservation of alliums.

Objective: To develop a reliable protocol for the cryoconservation of A. ramosum shoot bases.

Materials and methods: Different parameters, viz. (a) cold-hardening (5 degree C for 16/8 h photoperiod), (b) PVS2 dehydration (0, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55 and 60 min), (c) pregrowth medium (MM3: MS + 0.1 mg/L NAA + 0.5 mg/L 2iP + 10 mg/L spermidine + 3% sucrose; MM10: MS + 0.1 mg/L NAA + 0.5 mg/l 2iP + 10 mg/L spermidine + 10% sucrose) and (d) preculture duration (1, 2, 3, 4 and 5 days) were tested using a vitrification technique.

Results: Shoot bases excised from 4-wk old in vitro cultures that had been cold-hardened at 5 degree C (16/8 h photoperiod) and precultured on MM10 with 10% sucrose at 5 degree C for 3 days resulted in highest post-thaw regrowth of 43% after conventional vitrification. However, when droplet-vitrification was used, post-thaw regrowth was increased to 77%. Retesting of shoot bases after 10 years of cryobanking, revealed no significant difference in the post-thaw regrowth of A. ramosum.

Conclusion: This is the first report of the long-term cryopreservation of A. ramosum shoot bases using vitrification and droplet-vitrification techniques. https://doi.org/10.54680/fr25210110512.