Ref ID: 10923
Ref Type: Journal
Authors: Jones, R. C., McKinnon, G. E., Potts, B. M., and Vaillancourt, R. E.
Pub Date: 2005
Journal Name: Australian Journal of Botany
Volume: 53
Issue: 4
Start Page: 367
End Page: 377
ISBN/ISSN:
Keywords: agriculture/allele/chloroplast/collection/combination/conservation/conservation genetics/decline/diversity/endangered/eucalypt/Eucalyptus/Eucalyptus morrisbyi/genetic/genetic diversity/genotype/health/high/hypervariable/inbreeding/island/ITS/lignotuber/marker/mating/mating system/mechanism/microsatellite/microsatellites/nuclear/outcrossing/outcrossing rate/outcrossing rates/planting/population/rate/regeneration/seed/seedling/self incompatibility/species/system/Tasmania/tree/trees
Abstract: Eucalyptus morrisbyi is an endangered eucalypt, restricted to four populations on the island of Tasmania. The two main populations are separated by 20 km, occurring in the Risdon Hills and on Calvert Hill, and differ markedly in size and health. While they are both in reserves, the small population at Risdon Hills has experienced a marked decline in the last two decades. The other two populations (Lumeah Point and Honeywood Drive) are very small, and under threat due to urbanisation. They are close to the large Calverts Hill population and may be remnants of a once larger population in this area prior to clearing for agriculture in the 19th century. A hypervariable chloroplast marker and six nuclear microsatellites used to quantify genetic diversity between and within populations, indicate marked genetic differences between the two main populations (Risdon and Calverts Hills), with virtually no sharing of chloroplast haplotypes, and little sharing of microsatellite alleles among populations. Both the main populations are clearly required to adequately conserve the genetic diversity in this species, whereas the Lumeah Point and Honeywood Drive populations are similar to the proximal Calverts Hill population. The two main populations showed equally high levels of genetic diversity (average HE = 0.69) in the adult trees, using microsatellites, and little difference in inbreeding levels despite the large difference in population size. Analyses of 366 offspring from 9-11 trees from each main population revealed high outcrossing rates, little bi-parental inbreeding, and high genetic diversity (average HE = 0.65) in both seedling populations. This indicates that open-pollinated seed collections from these populations capture sufficient genetic diversity for ex situ conservation plantings. It is argued that the high genetic diversity maintained in the small Risdon Hills population is due to a combination of the longevity of its genotypes (up to 1155-1523 years), through a well developed mechanism of vegetative regeneration from lignotubers, coupled with high outcrossing rates maintained by a strong self-incompatibility mechanism
Notes: Entered by Rene Vaillancourt (10/06/2004)
Reprint: Not in File
Program: SPF Genetic Improvement
Project: A4
Deliverable:
Confidentiality: Confidential to All Partners until Published
Availability: Authors
Report: Annual Report 2004/5
Type: Article
Address: Rebecca.Jones@utas.edu.au