The occurrence and conservation status of Tasmanian Pterostylis (Orchidaceae)

Orchids belong to one of the largest plant families present in Tasmania and yet they remain poorly researched. In Tasmania, Pterostylis R.Br. comprises about 37 terrestrial species, commonly called greenhoods. Little is understood about Tasmanian Pterostylis ecology and a recent assessment of species’ abundances and distributions have not been conducted. Over a two year period known Pterostylis locations within mainland Tasmania, King Island and Flinders Island were visited for the purpose of collecting detailed data for species abundance, distribution and flowering. Several species within the genus Pterostylis are facing significant threats, and recommendations to prevent the decline of these species are provided

QTL influencing growth and wood properties in Eucalyptus globulus

Regions of the genome affecting physical and chemical wood properties (QTL), as well as growth, were identified using a clonally replicated, outbred F2 family (112 genotypes, each with 2 ramets) of Eucalyptus globulus, planted in a field trial in north-west Tasmania. Traits studied were growth (assessed by stem diameter), wood density, cellulose content, pulp yield and lignin content. These traits are important in breeding for pulpwood, and will be important in breeding for carbon sequestration and biofuel production. Between one and four QTL were located for each trait, with each QTL explaining between 9% and 24% of the variation between genotype means. Several QTL for chemical wood properties were co-located, consistent with their high phenotypic correlations, and may reflect pleiotropic effects of the same genes. In contrast, QTL for density and lignin content with overlapping confidence intervals were considered to be due to independent genes, since the QTL effects were inherited from different parents. The inclusion of fully informative microsatellites on the linkage map allowed the determination of homology at the linkage group level between QTL and candidate genes in different pedigrees of E. globulus and different eucalypt species. None of the candidate genes mapped in comparable studies co-located with our major QTL for wood chemical properties, arguing that there are important candidate genes yet to be discovered

Genetic variation in the Epacris tasmanica complex (Epacridaceae).

RAPD (random amplified polymorphic DNA) markers were used to delimit species in the Epacris tasmanica complex (Epacridaceae) collected from various locations in Tasmania, Australia. The RAPD analysis placed morphologically similar taxa located closely geographically into discrete clusters. However, geographically distant populations of morphometrically similar taxa, such as the southern and northern Tasmanian populations of E. virgata and E. tasmanica, were less closely related to each other than those taxa classified as different species. The most geographically remote population (E. glabella [Serpentine Hill]) shared the least genetic similarities with the other taxa. The genetic information obtained from this study reinforces some previous morphometric data used to delimit species in the E. tasmanica complex. Furthermore, the strong geographical structure of the genetic variation is consistent with a model in which gene flow between populations is limited

Genetic parameters for lignin, extractives and decay in Eucalyptus globulus

Eucalyptus globulus is grown in temperate regions of the world for pulp production. The chemical composition of its wood including the proportion of cellulose, lignin and extractives, make it highly suited to this purpose. This study analysed genetic variation in these traits and decay, for nine localities of E. globulus. Heritability estimates were also obtained, and the relationships between these traits and the physical wood traits and growth were examined. Significant genetic variation was found between localities for lignin content (Klason lignin and acid-soluble lignin contents) and decay. The only trait for which significant variation between families within locality was detected was acid-soluble lignin content, which resulted in this trait also having the only significant narrow-sense heritability (0.51 0.26). Family means heritabilities were high for lignin content, extractives content and decay (0.42-0.64). The chemical wood traits were highly correlated with each other both phenotypically and genetically, with important correlations found with density and microfibril angle. Correlations suggested that during selection for the breeding objective traits, it is likely that favourable states in the chemical wood traits, decay resistance and fibre properties are concurrently being selected, whereas growth may be selected for independently. This initial study provides a stepping stone for future studies where particular localities of the breeding population may be characterised further