Maintaining a Conservation Collection

  • Harrisia simpsonii seedlings

    Harrisia simpsonii seedlings growing at Fairchild Tropical Botanic Garden greenhouse. Photo credit: Tighe Shomer.

  • Quercus havardii seedlings growing

    Quercus havardii seedlings growing in the greenhouse at the Morton Arboretum. Photo credit: Sean Hoban.

  • Photo of key tree cactus

    Key tree cactus (Pilosocereus robinii) seedlings growing for experiment in Fairchild Tropical Botanic Garden nursery. Photo credit: Joyce Maschinski.

  • Photo of Amorpha georgiana var. georgiana

    Amorpha georgiana var. georgiana growing in nursery at North Carolina Botanical Garden. Photo credit: Mike Kunz.

  • Photo of experiment with Key tree cactus

    Experiment with Key tree cactus (Pilosocereus robinii) to test growth across salinity gradient. Photo credit: Joyce Maschinski.

  • Photo of seed germination trials of Harrisia aboriginum

    Seed germination trials of Harrisia aboriginum growing in Fairchild Tropical Botanic Garden nursery.

  • Photo of San Diego Zoo Global Nursery

    San Diego Zoo Global Nursery. Photo credit: Ken Bohn.

  • Photo of Pilosocereus robinii seedlings

    Pilosocereus robinii seedlings growing in Fairchild Tropical Botanic Garden. Photo credit: D Powell.

  • Quercus havardii seedlings growing in the greenhouse at the Morton Arboretum. Photo credit: Sean Hoban.

  • Harrisia simpsonii seedlings growing at Fairchild Tropical Botanic Garden greenhouse. Photo credit: Tighe Shomer.

  • Acanthominta ilicifolia, San Diego Zoo Global Nursery. Photo credit: Ken Bohn.

Summary

  • While the conservation collection grows in the nursery, take care to maintain genetic diversity.
  • Keeping records and labels on maternal lines will help track the potential genetic diversity represented in the collection and can be used to equalize family lines for reintroductions or other conservation translocations.
  • If maintaining more than one population or related species, take care to avoid unintended cross-pollination.

Minimize artificial selection and genetic drift.

Maximizing germination of a seed accession may require using varying conditions and allowing enough time.

  • Within a single accession, seeds may have variable germination rates or some seeds may have dormancy, while others do not. Planning to encompass this variation when doing germination trials will help ensure genetic diversity of seedlings.
  • Labeling germination trials by maternal lines allows practitioner to track diversity and ensure equal representation in subsequent research or reintroduction trials.

Maintain material across maternal lines.

  • Consciously maintain material across maternal lines to capture diverse growth rates, flower production, and presumably genetic diversity.
  • Monitor the survivorship and health of the clearly labeled maternal lines represented in the accession.
  • Maintain accurate records of the number of surviving individuals and total maternal lines to approximate the genetic representation of the collection. Note that genetic studies would be required to know the true genetic diversity in the collection.
  • Avoid artificial selection. When trying to increase numbers of an accession, it is easy to choose the best and most fecund to replicate. It is important to have and maintain all maternal lines in the living collection whether they be on display in the garden, in a tissue culture lab, or in the nursery.
  • If mortality occurs excessively for one maternal line, consider replanting to refresh the diversity represented.

Maintaining accessions offsite for generations requires periodic immigration from wild sources.

  • If an accession must be maintained offsite as whole plants for a number of generations, maintain as large a population as possible and provide periodic immigration from a wild source population of approximately five migrants per generation and increase (triple, if possible) the sample size each generation (Havens et al. 2004).

Minimize unintended hybridization.

  • Use knowledge of breeding system and wild population dynamics to inform these actions.
  • Grow seeds from different populations at different times.
  • If growing seeds from more than one population simultaneously, physically separate them or place them under netted cages to avoid pollen transfer.
  • Note that there may be compelling reasons to cross-pollinate populations, such as one population consists of a single self-incompatible clone (Menges et al. 2016).
  • Because genetic loss and change can occur during a single generation, best practice is to grow plants from wild-collected seeds (Basey et al. 2015) and preferably use F1 or F2 seeds for conservation introductions whenever possible. Seeds produced in a cultivated condition may have attributes that are disadvantageous in the wild, yet many conservation introductions must rely on seeds generated in a nursery in order to have adequate numbers to reintroduce to the wild. (See Part 1E, “Curating Small Samples: Increasing the Number of Seeds for Storage and Restoration.”)

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Suggested Citation

Center for Plant Conservation. Maintaining a Conservation Collection in CPC Best Plant Conservation Practices to Support Species Survival in the Wild. Web Version. https://plantnucleus.com/best-practices/maintaining-conservation-collection Accessed: 09/28/2020 - 2:17pm