Maximising the value of seed collections for horticulture and conservation

Myrtaceae in Australia: Use of Cryobiotechnologies for the Conservation of a Significant Plant Family under Threat

“…Increasing threats to this family from land clearing, cataclysmic wildfires, and myrtle rust are increasing the need for human intervention to avert the extinction of individual species [53]. While many dryland species in this family can be conserved by seed banking, the number of species falling in the category of 'exceptional' is growing, as research into seed storage behavior identifies species with recalcitrant, freezingsensitive or short-lived seeds [75][76][77][78], and as myrtle rust reduces the capacity for seed set [59,70,123]. Long-term conservation of these exceptional species will require investment in cryobiotechnologies-in vitro culture, cryopreservation and supporting sciences.…”

“…The remainder of the family falls into the category of 'exceptional' [74], with species that no longer produce seeds due to myrtle rust (e.g., Rhodamnia rubescens and Rhodomyrtus psidioides [70,75]), or that produce seeds that are intolerant of desiccation (e.g., Syzygium spp. [72,76]) or storage at −20 • C (e.g., Backhousia citriodora [77] and Rhodamnia maideniana [78]).…”

“…The 13 known Backhousia species occur on the east coast of Australia, predominantly in Queensland [2]. Backhousia citriodora and B. myrtifolia are perhaps the most well-known species, the former for its value as a commercial species and the latter as a species commonly used in habitat restoration programs [77]. Backhousia spp.…”

“…have been reported to have a range of susceptibility to myrtle rust, from 'low' to 'very high' [81]. Myrtle rust damage can impact conservation research on such species by reducing seed availability, as reported in a study of seed set, characteristics, longevity and germination of B. citriodora (intermediate) and B. myrtifolia (orthodox) [77]. No reports of successful cryopreservation could be found for this genus.…”