Patterns of Genetic Diversity and Nature of the Breeding System in Melaleuca alternifolia (Myrtaceae)

1992 ◽  
Vol 40 (3) ◽  
pp. 365 ◽  
Author(s):  
PA Butcher ◽  
JC Bell ◽  
GF Moran
Keyword(s):  
Genetic Diversity ◽  
Genetic Variation ◽  
Distance Measures ◽  
Melaleuca Alternifolia ◽  
Isolated Populations ◽  
Tea Tree ◽  
South Wales ◽  
Baseline Information ◽  
Geographic Separation ◽  
Natural Stands

Melaleuca alternifolia (Maiden & Betche) Cheel is harvested from natural stands and plantations for production of Australian tea-tree oil. Genetic variation was examined and outcrossing rates estimated to provide baseline information for breeding and selection programs. The overall genetic diversity (HT = 0.186) is comparable to other regionally distributed Australian tree species. There was a general trend for more isolated populations to have less genetic variation than populations from the centre of the species distribution. The level of differentiation among populations was low (12%), associated with a high outcrossing rate (93%) and high levels of gene flow. Geographic separation of Queensland and New South Wales populations corresponds with genetic distance measures.

Genetic and Ecological Variation in Atherosperma moschatum and the Implications for Conservation of Its Biodiversity

1994 ◽  
Vol 42 (6) ◽  
pp. 663 ◽  
Author(s):  
A Shapcott
Keyword(s):  
Genetic Diversity ◽  
Genetic Variation ◽  
New South ◽  
Genetic Distances ◽  
Isolated Populations ◽  
Canopy Tree ◽  
South Wales ◽  
Genetic Substructure ◽  
Temperate Rainforests ◽  
Vegetative Spread

Population genetics and ecology of Atherosperma moschatum Labill. (sassafras), a major canopy tree of Australian temperate rainforests, were examined and used to identify priorities and strategies for conservation of its genetic diversity. The genetic diversity among populations was fairly low, but higher than average for long-lived late successional or wind dispersed species (Hamrick and Godt 1989). Genetic distances between populations were correlated with geographic distances and climatic differences. The major genetic differentiation was between the mainland populations and those in Tasmania, with the New South Wales populations being quite genetically distinct. Most genetic variation was found within populations, however, most populations were inbred. This is likely to be due to selfing and spatial genetic substructure resulting from vegetative spread and local dispersal. There was evidence of regeneration in all populations, however no consistent regeneration patterns emerged. Population density was inexplicably correlated with genetic distance. There was as much diversity in all variables (ecological and genetic) measured in small isolated populations as there was in stands within larger assemblages; therefore, population size does not appear to be a major factor affecting viability. Genetic variation was spread throughout the distribution of A. moschatum. Therefore, populations from throughout its range would need to be conserved to retain the genetic diversity within this species.

scholarly journals Description of an Australian endemic species of Trioza (Hemiptera: Triozidae) pest of the endemic tea tree, Melaleuca alternifolia (Myrtaceae)

PLoS ONE ◽  
2021 ◽  
Vol 16 (9) ◽  
pp. e0257031
Author(s):  
Francesco Martoni ◽  
Mark J. Blacket
Keyword(s):  
Haplotype Network ◽  
Melaleuca Alternifolia ◽  
Indigenous Australian ◽  
Tea Tree ◽  
Plant Associations ◽  
South Wales ◽  
Exotic Pests ◽  
Close Relationship ◽  
Species Specific ◽  
First Time

Psyllids, also known as jumping plant lice, are phloem feeding Hemiptera that often show a strict species-specific relationship with their host plants. When psyllid-plant associations involve economically important crops, this may lead to the recognition of a psyllid species as an agricultural or horticultural pest. The Australian endemic tea tree, Melaleuca alternifolia (Maiden & Betche) Cheel., has been used for more than a century to extract essential oils and, long before that, as a traditional medicine by Indigenous Australian people. Recently, a triozid species has been found to damage the new growth of tea trees both in Queensland and New South Wales, raising interest around this previously undocumented pest. Furthermore, adults of the same species were also collected from Citrus plantations, leading to potential false-positive records of the exotic pest Trioza erytreae (Del Guercio 1918), the African Citrus psyllid. Here we describe for the first time Trioza melaleucae Martoni sp. nov. providing information on its distribution, host plant associations and phylogenetic relationships to other Trioza species. This work enables both morphological and molecular identification of this new species, allowing it to be recognized and distinguished for the first time from exotic pests as well as other Australian native psyllids. Furthermore, the haplotype network analysis presented here suggests a close relationship between Trioza melaleucae and the other Myrtaceae-feeding Trioza spp. from Australia, New Zealand, and Taiwan.

Effects of plant spacing and season on growth of Melaleuca alternifolia and yield of tea tree oil

1981 ◽  
Vol 21 (111) ◽  
pp. 439 ◽  
Author(s):  
BEJ Small
Keyword(s):  
Growth Rate ◽  
New South ◽  
Oil Yield ◽  
Production Plant ◽  
Plant Spacing ◽  
Average Increase ◽  
Tea Tree Oil ◽  
Melaleuca Alternifolia ◽  
Tea Tree ◽  
South Wales

A plant spacing experiment with the tea tree oil species, Melaleuca alternifolia was carried out at Castle Hill, New South Wales, from 1970 to 1979. The study compared the response to three within-row spacings and measured the effects of seasons over seven harvests. The planting patterns tested were 1.22 x 1.22, 0.61 and 0.305 m. For all years there was an average increase in leaf and oil yield of 93% (2.9 l/ha and 46 l/ha, respectively) in the highest population (26 908 trees/ha) compared with the lowest (6727 trees/ha). Large differences in growth rate and oil yield occurred between years. I conclude that M. alternifolia is amenable to cultivation for tea tree oil production, plant spacing is an important factor in its management and optimum population exceeds 27 000 trees/ha.

Diversity and genetic structure of cassava landraces and their wild relatives (Manihot spp.) in Colombia revealed by simple sequence repeats

2015 ◽  
Vol 14 (3) ◽  
pp. 200-210 ◽  
Author(s):  
E. Tovar ◽  
J. L. Bocanegra ◽  
C. Villafañe ◽  
L. Fory ◽  
A. Velásquez ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Genetic Variation ◽  
Gene Flow ◽  
Genetic Resources ◽  
Wild Relatives ◽  
Targeted Interventions ◽  
Genetic Diversity And Structure ◽  
Baseline Information ◽  
Cultivated Species ◽  
Simple Sequence

Understanding the genetic composition and population structure of plant species at a molecular level is essential for the development of adequate strategies aimed at enhancing the conservation and use of their genetic resources. In addition, such knowledge can help to plan ahead for a scenario under which wild and cultivated species come into contact with their genetically modified (GM) counterpart(s). Using ten simple sequence repeat markers, we genotyped 409 samples pertaining to the species in the Manihot genus known to occur in Colombia, i.e. cassava (Manihot esculenta) and its wild relatives Manihot brachyloba, Manihot carthaginensis and Manihot tristis. High genetic variation was observed in all the species (HE= 0.212–0.603), with cassava showing highest diversity. Most of the genetic variation was found within species populations. Our results suggest that outcrossing events among populations occur much more frequently in M. tristis and M. esculenta, and particularly so in the latter, where the exchange of varieties among local farmers plays a key role in maintaining and introducing new genetic diversity. The occurrence of gene flow within and among populations of Manihot species in Colombia becomes relevant in a biosafety context, where gene flow from GM cassava, if introduced to the country, might have detrimental effects on the structure and dynamics of populations of wild species. The baseline information on the genetic diversity and structure of the four Colombian species that we have presented here provides a first and indispensable step towards the development of targeted interventions necessary to preserve their genetic resources.

Population genetics of Melaleuca irbyana (Myrtaceae) the ‘swamp tea tree’ and implications for its conservation and restoration

2018 ◽  
Vol 66 (1) ◽  
pp. 13 ◽  
Author(s):  
Reuben Burrough ◽  
Gabriel Conroy ◽  
Robert W. Lamont ◽  
Yoko Shimizu-Kimura ◽  
Alison Shapcott
Keyword(s):  
Genetic Diversity ◽  
Land Use ◽  
Population Genetics ◽  
Genetic Information ◽  
Patch Size ◽  
Isolated Populations ◽  
Tea Tree ◽  
Human Land Use ◽  
Disjunct Populations ◽  
Geographic Regions

Habitat fragmentation is affecting greater numbers of species as human land use requirements increase. Melaleuca irbyana R.T.Baker (Myrtaceae) is an endangered tea tree which dominates critically endangered, south-east Queensland swamp tea tree forest. It is restricted to isolated populations in south-east Queensland. New disjunct populations have recently been found adjacent to gas pipeline developments in the Brigalow Belt in central Queensland. A population genetics study was undertaken on the species to investigate its diversity to advise conservation and restoration. Primers for microsatellite markers were developed and used to provide the genetic information for the study. M. irbyana was found to possess moderate levels of genetic diversity within populations but this was not correlated with patch size or isolation. However, inbreeding levels were moderately high in all populations, suggesting individuals may be self-fertilised as there was no evidence of clonality detected in this species despite evidence of resprouting. The disjunct populations in central Queensland were genetically distinct, which highlights their importance for conservation of the species. The northern NSW populations are potentially at risk as they are depauperate and genetically distinct. There is differentiation among populations between the geographic regions so care should be taken to consider local provenance in restoration plantings.

scholarly journals Minimal loss of genetic diversity and no inbreeding depression in blueflag iris (Iris versicolor) on islands in the Bay of Fundy

Botany ◽  
2016 ◽  
Vol 94 (7) ◽  
pp. 543-554 ◽  
Author(s):  
Nathaniel T. Wheelwright ◽  
Elise Begin ◽  
Claire Ellwanger ◽  
Samuel H. Taylor ◽  
Judy L. Stone
Keyword(s):  
Genetic Diversity ◽  
Genetic Variation ◽  
Inbreeding Depression ◽  
Leaf Tissue ◽  
Population Level ◽  
Bay Of Fundy ◽  
Isolated Populations ◽  
Tissue Samples ◽  
Island Populations ◽  
Hand Pollination

Isolated island plant populations founded by few individuals are often characterized by decreased genetic variation and increased inbreeding. Our aim was to measure population genetic diversity and inbreeding depression in blueflag iris (Iris versicolor L., Iridaceae), a native allotetraploid, on islands in the Bay of Fundy, Canada. Hand-pollination experiments (inbreeding, within-site outbreeding, between-island outbreeding) on Kent Island, New Brunswick, revealed no evidence for inbreeding depression across a broad array of morphological, physiological, and life-history traits. Leaf tissue samples collected from three mainland sites and 10 islands in the Bay of Fundy and genotyped using three microsatellite primer pairs showed that island populations were less genetically diverse than mainland populations. Island populations were genetically distinct from each other, indicating a bottleneck effect associated with colonization and continued isolation. Nonetheless, substantial genetic variation was maintained at the population level. Polyploidy and a history of self-fertilization may allow Iris versicolor to avoid inbreeding depression in isolated populations. Our study supports Anderson’s (1936) original hypothesis that substantial genetic diversity can be preserved within polyploid species, even with extensive inbreeding.

Microsatellite and cpDNA variation in island and mainland populations of a regionally rare eucalypt, Eucalyptus perriniana (Myrtaceae)

2007 ◽  
Vol 55 (5) ◽  
pp. 513 ◽  
Author(s):  
Damien A. Rathbone ◽  
Gay E. McKinnon ◽  
Brad M. Potts ◽  
Dorothy A. Steane ◽  
René E. Vaillancourt
Keyword(s):  
Genetic Diversity ◽  
Chloroplast Dna ◽  
Dna Marker ◽  
Isolated Populations ◽  
South Eastern ◽  
Eucalypt Species ◽  
Eastern Australia ◽  
Population Sizes ◽  
Nuclear Microsatellite ◽  
Geographic Separation

Eucalyptus perriniana F.Muell. ex Rodway is distributed over a wide geographic range in south-eastern Australia as a series of small and isolated populations. In Tasmania, there are only three known populations that are separated by 511 km from the closest population on mainland Australia, which is one of the largest disjunctions observed for any eucalypt species. This project utilised eight nuclear microsatellites and one chloroplast DNA marker to study the genetic diversity in E. perriniana and determine the affinities between the populations. In all, 302 individuals in nine populations across the whole range of the species were sampled. The overall nuclear microsatellite diversity in E. perriniana (Ht = 0.85), as well as the diversity in each population (He = 0.73), was comparable to that found in widespread eucalypt species that have much larger population sizes. The microsatellites revealed that the isolated Tasmanian populations were significantly differentiated from mainland populations (FST between regions = 0.08), although the mainland Baw Baw population was the most differentiated. Most populations harboured different chloroplast DNA haplotypes, but in general, there were more mutational differences among haplotypes found in Tasmania than between Tasmanian and mainland populations. The Tasmanian populations often shared chloroplast DNA haplotypes with other eucalypts from south-eastern Tasmania. In conclusion, the populations of E. perriniana are genetically variable and significantly differentiated, with geographic separation being a poor predictor of the amount of genetic divergence. The most divergent populations are those in Tasmania and on Mt Baw Baw and their conservation is important to capture the genetic diversity in the species.

Allozyme Variation and Population Substructuring in the Caucasian Ground Lizards Lacerta derjugini and Lacerta praticola

2011 ◽  
Vol 4 (2) ◽  
pp. 115-119 ◽  
Author(s):  
Ross D. MacCulloch ◽  
Ilya S. Darevsky ◽  
Robert W. Murphy ◽  
Jinzhong Fu
Keyword(s):  
Genetic Diversity ◽  
Allozyme Variation ◽  
Close Proximity ◽  
Geographic Separation ◽  
Population Substructuring ◽  
Allozyme Loci ◽  
Two Populations

Genetic diversity at 35 allozyme loci was surveyed in Lacerta derjugini (3 populations) and L. praticola (2 populations). Indices of variability were consistent with those found in other Caucasian Lacerta. There was little genetic substructuring between two populations of L. praticola despite considerable geographic separation. Conversely, populations of L. derjugini in close proximity to one another exhibited considerable substructuring.

Genetic Analysis of Chinese Cucumber Collections in the U.S. National Germplasm Collection

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 534e-534 ◽  
Author(s):  
J. Staub ◽  
Felix Sequen ◽  
Tom Horejsi ◽  
Jin Feng Chen
Keyword(s):  
Genetic Diversity ◽  
Principal Component Analysis ◽  
Genetic Variation ◽  
Genetic Analysis ◽  
Allelic Variation ◽  
Germplasm Collection ◽  
Principal Component ◽  
Isozyme Loci ◽  
National Plant Germplasm System ◽  
The U.S

Genetic variation in cucumber accessions from China was assessed by examining variation at 21 polymorphic isozyme loci. Principal component analysis of allelic variation allowed for the depiction of two distinct groupings of Chinese accessions collected in 1994 and 1996 (67 accessions). Six isozyme loci (Gpi, Gr, Mdh-2, Mpi-2, Pep-gl, and Pep-la) were important in elucidating these major groups. These groupings were different from a single grouping of Chinese 146 accessions acquired before 1994. Allelic variation in Chinese accessions allowed for comparisons with other accessions in the U.S. National Plant Germplasm System (U.S. NPGS) collection grouped by continent and sub-continent. When Chinese accessions taken collectively were compared with an array of 853 C. sativus U.S. NPGS accessions examined previously, relationships differed between accessions grouped by country or subcontinent. Data indicate that acquisition of additional Chinese and Indian cucumber accessions would be strategically important for increasing genetic diversity in the U.S. NPGS cucumber collection.

Sign in / Sign up

Export Citation Format

Share Document