Seed banking and breeding
Photo: Department of Conservation
Scoping a resistance breeding programme: Strategy pathways for implementation
Seedbanking and germplasm research strategy
Scoping a resistance breeding programme: Strategy pathways for implementation
It’s likely that myrtle rust will have significant impact on New Zealand myrtles, including species extinction. Breeding approaches can reduce the negative impacts of the disease and help maintain healthy New Zealand myrtle populations.
This research helps inform people about what breeding approaches to take and what species to target in their response to myrtle rust.
Researchers developed a high-level resistance breeding strategy to maintain healthy New Zealand myrtle populations. It includes a decision framework to help prioritise different breeding responses to native myrtle species and the many non-native myrtles.
Strategies include seed collections to preserve genetic diversity, selection for enhanced resistance, and conservation plantings.
Seed collections are recommended for highly susceptible, already threatened species, taonga species or trees, and conservation plantings for high priority species. A prioritisation list of important New Zealand myrtle species was developed.
The importance of ongoing consultation with Māori and co-developing culturally appropriate breeding programmes for selected species is stressed.
Download the report: Scoping a resistance breeding programme: Strategy patheways for implementation
Seedbanking and germplasm research strategy
All New Zealand native myrtles are classified as nationally threatened, however they haven’t received a lot of attention in terms of long-term conservation outside their natural habitats, for example seed banking.
Researchers assessed the optimum conservation strategies for some New Zealand myrtle plants.
They investigated options for storing seeds from myrtle plants, including assessing tolerance to desiccation (drying); establishment of tissue culture (e.g. plant cuttings) storage; development of cryopreservation (freezing) techniques.
What they found and what it means
- Seeds of some myrtle species are considered orthodox and can be stored relatively easily in conventional seed banks.
- However not all myrtle species seeds are desiccation tolerant and therefore can’t be stored in typical seedbank conditions. One of these is Swamp marie; it’s a recalcitrant (difficult) myrtle species when it comes to conventional seed storage, and therefore requires cryopreservation of isolated embryos.
- Bartlett’s rata is highly critically threatened and needs an immediate conservation action plan.
- Seed quality varies – we need to ensure high quality seeds are collected for conservation.
- Seeds collected from different populations behave differently. An informed technical guide/advice on when and where to collect is needed.
- Seed storage alone isn’t the solution – an integrated conservation approach is required.
- Researchers urge that having identified the optimum storage conditions, the germplasm of at risk species need to be conserved immediately. This requires conservation facilities and physical resources. This study also identified the importance of a centralised management and curation system for collected germplasm resources. (Note: The Myrtle Rust Strategic Science Advisory Group is looking at ways to progress this. Read more).
Download the report: Seedbanking and germplasm research strategy (This report is also a chapter in the Myrtle rust research programme 2017-2019: understanding the pathogen, hosts, and environmental influences).
New research Integrated ex situ conservation strategies for endangered New Zealand Myrtaceae species builds on this strategy and was published in the New Zealand Journal of Botany in May 2020. Read more.