The preservation of pear germplasm, like that of other clonal germplasms, is difficult because it requires conservation of whole plants or their tissues. Among the currently available methods for long-term conservation of clonal germplasm, cryopreservation of shoot tips is the most reliable and cost- and space-effective option. Alginate-coated axillary shoot tips from in vitro−grown pear were conserved successfully in liquid nitrogen (LN) following dehydration. Shoot recovery from cryopreserved shoot tips was improved greatly after 8 weeks of cold acclimation, but recovery decreased slightly after then. The highest regeneration rate was observed when in vitro shoot tips were preincubated in MS (Murashige and Skoog) medium with 0.3 M sucrose for 48 h, and when alginate-coated shoot tips were precultured in MS medium with increasing sucrose concentrations (0.5 M and 0.7 M) for 8 and 16 h, respectively. When the encapsulated beads were dehydrated for up to 7 h [25% water content (fresh weight basis)] under laminar flow, the highest regeneration rate was observed in “BaeYun No. 3” (55.7%) and “Whanggeum” (43.3%) after warming from LN. This technique is useful as a practical procedure to cryopreserve plant material that is sensitive to freezing of the surrounding cryoprotectant medium. Therefore, this technique appears to be promising for the cryopreservation of shoot tips from in vitro−grown plantlets of pear germplasm.

Abstract
 Introduction
 Materials and Methods
  Preparation of plant material and cold hardening
  Preincubation, encapsulation, and preculture
  Air desiccation
  Thawing and plant regeneration
  Data analysis and statistical procedures
 Results and Discussion
  Effects of cold hardening on recovery
  Effects of preincubation and preculture on recovery
  Effects of dehydration by air drying on regeneration
 References

• JungYoon Yi(National Agrobiodiversity Center, NIAS, RDA) Corresponding author
• YoungYi Lee(National Agrobiodiversity Center, NIAS, RDA)
• GiAn Lee(National Agrobiodiversity Center, NIAS, RDA)
• EunHo Son(National Agrobiodiversity Center, NIAS, RDA)
• HongJae Park(National Agrobiodiversity Center, NIAS, RDA)