Abstract
Abstract Lemon myrtle ( Backhousia citriodora , F. Muell.) is a native Australian myrtaceous species, highly valued for its unique, citral-rich essential oil. The development and success of this Australian industry has been in jeopardy since the detection of myrtle rust ( Austropuccinia psidii ) in Australia (April 2010). Since the initial invasion, it has spread across the major lemon myrtle growing regions in New South Wales and Queensland. The main commercial clones are highly susceptible to infection, with plantations experiencing up to 70% production losses. To identify resistance to A. psidii for industry use, disease assessments were conducted on germplasm originating from 13 Queensland provenances, established in two clonal field trials. Newly collected germplasm from the Ubobo provenance was also screened under controlled conditions. Infection caused symptoms ranging from small, restricted sori on a low percentage of leaves, to infection on up to 100% of leaves, with distorted shoots and severe dieback on infected stems. No fully resistant germplasm was identified, but significant differences in observed disease offer opportunities to select more resistant clones than those currently relied on by the industry. Germplasm from Eumundi, Noosa and Woondum (southern Queensland), and Silver Valley (northern Queensland), showed superior resistance to A. psidii across assessments and trial sites. Substantial variation in plant growth traits of importance to commercial production (e.g. canopy structure and foliage density) was observed among the provenances, families, and clones evaluated across the trials, suggesting the need to consider plant growth, biomass yield and essential oil properties when selecting industry-suitable germplasm. Implementing a breeding or hybridisation program should be a priority for the industry.
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Claims 6
Claim · model-written summary
Commercial clones are highly susceptible to myrtle rust, with production losses up to 70%.
- Taxon
- Lemon myrtlet0
- Material
- main commercial clonese0
- Interactor
- Austropuccinia psidii
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Austropuccinia psidiit0pathogen - Outcome
- production lossese0
- Value
- up to 70%e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
.jpg?width=500)
Verbatim
e0“The main commercial clones are highly susceptible to infection, with plantations experiencing up to 70% production losses.”
t0“lemon myrtle (Backhousia citriodora) to myrtle rust (Austropuccinia psidii)”
Claim · model-written summary
Infection symptoms ranged from restricted sori on few leaves to infection of all leaves with distorted shoots and severe stem dieback.
- Taxon
- lemon myrtlet0
- Interactor
- Austropuccinia psidiiAustropuccinia psidiit0pathogen
- Outcome
- symptoms ranging from small, restricted sori on a low percentage of leaves, to infection on up to 100% of leaves, with distorted shoots and severe dieback on infected stemse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“lemon myrtle (Backhousia citriodora) to myrtle rust (Austropuccinia psidii)”
e0“Infection caused symptoms ranging from small, restricted sori on a low percentage of leaves, to infection on up to 100% of leaves, with distorted shoots and severe dieback on infected stems.”
Claim · model-written summary
No fully resistant germplasm was found, but disease severity differed significantly among germplasm.
- Taxon
- Lemon myrtlet0
- Interactor
- Austropuccinia psidiiAustropuccinia psidiit0pathogen
- Outcome
- No fully resistant germplasm was identifiede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“No fully resistant germplasm was identified, but significant differences in observed disease offer opportunities to select more resistant clones than those currently relied on by the industry.”
t0“lemon myrtle (Backhousia citriodora) to myrtle rust (Austropuccinia psidii)”
Claim · model-written summary
Eumundi, Noosa, Woondum and Silver Valley germplasm showed superior resistance across assessments and sites.
- Taxon
- Lemon myrtlet0
- Interactor
- A. psidiiAustropuccinia psidiie0pathogen
- Outcome
- superior resistance to A. psidiie0
- Direction
- superiore0
- Setting
- southern Queenslande0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Germplasm from Eumundi, Noosa and Woondum (southern Queensland), and Silver Valley (northern Queensland), showed superior resistance to A. psidii across assessments and trial sites.”
t0“lemon myrtle (Backhousia citriodora) to myrtle rust (Austropuccinia psidii)”
Claim · model-written summary
Commercially relevant canopy structure and foliage density varied substantially among provenances, families and clones.
Verbatim
e0“Substantial variation in plant growth traits of importance to commercial production (e.g. canopy structure and foliage density) was observed among the provenances, families, and clones evaluated across the trials”
t0“lemon myrtle (Backhousia citriodora) to myrtle rust (Austropuccinia psidii)”
Claim · model-written summary
The authors recommend prioritizing a breeding or hybridisation program.
Verbatim
t0“lemon myrtle”
e0“Implementing a breeding or hybridisation program should be a priority for the industry.”