Plant tissue culture targeting germplasm conservation

The management and protection of wild species and domesticated crops are essential for the maintenance of plant biodiversity. Plant tissue culture-based in vitro culture technique provides an alternative and valuable option for multiplication and conservation of a wide range of plant species, especially vegetatively propagated plants, plants having recalcitrant seeds, and plant species at risk of extinction. The plant tissue culture technique allows for propagating such plant species with high multiplication rates and conservation for short to medium term or long term. The slow growth culture technique is used to achieve short- to medium-term preservation of plant germplasm under growth-limiting conditions, which allow the storage of germplasm from a few months to 1–2 years by extending subculture intervals. The strategies adopted for the storage of plant germplasm under slow growth storage include the incubation of cultures at low temperature, minimal growth medium by minimizing nutrient components in the medium, or applying growth retardants or osmoticum for limiting the growth of cultures. Cryopreservation is an ideal and most viable technique for the long-term conservation of plant genetic resources. Refinement in technology mainly, newly developed droplet-vitrification and cryo-plate methods increased the applicability of cryopreservation for long-term preservation of plant genetic resources. Instead of several limitations, both slow growth storage and cryopreservation methods are now routinely used to conserve a wide range of plant species. This chapter briefly presents the recent progress on short- to medium- and long-term conservation of plant germplasms by slow growth storage and cryopreservation. The role of in vitro culture technique and their applications and limitations in the conservation of plant biodiversity is also discussed.