An evaluation of the genetic structure of seed sources and the maintenance of genetic diversity during establishment of two yellow box (Eucalyptus melliodora) seed-production areas

2015 ◽  
Vol 63 (5) ◽  
pp. 455 ◽  
Author(s):  
Linda M. Broadhurst ◽  
Graham Fifield ◽  
Bindi Vanzella ◽  
Melinda Pickup
Keyword(s):  
Genetic Diversity ◽  
Genetic Structure ◽  
Seed Production ◽  
Significant Loss ◽  
Evolutionary Potential ◽  
Seed Collection ◽  
Seed Sources ◽  
Significant Difference ◽  
Genetic Bottlenecks ◽  
Production Areas

Vegetation clearing and land-use change have depleted many natural plant communities to the point where restoration is required. A major impediment to the success of rebuilding complex vegetation communities is having regular access to sufficient quantities of high-quality seed. Seed-production areas (SPAs) can help generate this seed, but these must be underpinned by a broad genetic base to maximise the evolutionary potential of restored populations. However, genetic bottlenecks can occur at the collection, establishment and production stages in SPAs, requiring genetic evaluation. This is especially relevant for species that may take many years before a return on SPA investment is realised. Two recently established yellow box (Eucalyptus melliodora A.Cunn. ex Schauer, Myrtaceae) SPAs were evaluated to determine whether genetic bottlenecks had occurred between seed collection and SPA establishment. No evidence was found to suggest that a significant loss of genetic diversity had occurred at this stage, although there was a significant difference in diversity between the two SPAs. Complex population genetic structure was also observed in the seed used to source the SPAs, with up to eight groups identified. Plant survival in the SPAs was influenced by seed collection location but not by SPA location and was not associated with genetic diversity. There were also no associations between genetic diversity and plant growth. These data highlighted the importance of chance events when establishing SPAs and indicated that the two yellow box SPAs are likely to provide genetically diverse seed sources for future restoration projects, especially by pooling seed from both SPAs.

scholarly journals Managing Genetic Diversity and Representation in Banksia marginata (Proteaceae) Seed Production Areas Used for Conservation and Restoration

Diversity ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 39
Author(s):  
Linda Broadhurst ◽  
David Bush ◽  
Jim Begley
Keyword(s):  
Genetic Diversity ◽  
Genetic Structure ◽  
Seed Production ◽  
Population Genetic Structure ◽  
Population Genetic ◽  
Wild Populations ◽  
Landscape Degradation ◽  
Native Seed ◽  
Seed Crops ◽  
Production Areas

Landscape degradation is a major threat to global biodiversity that is being further exacerbated by climate change. Halting or reversing biodiversity decline using seed-based restoration requires tons of seed, most of which is sourced from wild populations. However, in regions where restoration is most urgent, wild seed sources are often fragmented, declining and producing seed with low genetic diversity. Seed production areas (SPAs) can help to reduce the burden of collecting native seed from remnant vegetation, improve genetic diversity in managed seed crops and contribute to species conservation. Banksia marginata (Proteaceae) is a key restoration species in south-eastern Australia but is highly fragmented and declining across much of its range. We evaluated genetic diversity, population genetic structure and relatedness in two B. marginata SPAs and the wild populations from which the SPA germplasm was sourced. We found high levels of relatedness within most remnants and that the population genetic structure was best described by three groups of trees. We suggest that SPAs are likely to be important to meet future native seed demand but that best practice protocols are required to assist land managers design and manage these resources including genetic analyses to guide the selection of germplasm.

Intact genetic structure and high levels of genetic diversity in bottlenecked sockeye salmon (Oncorhynchus nerka) populations of the Fraser River, British Columbia, Canada

2000 ◽  
Vol 57 (10) ◽  
pp. 1985-1998 ◽  
Author(s):  
Ruth E Withler ◽  
Khai D Le ◽  
R John Nelson ◽  
Kristina M Miller ◽  
Terry D Beacham
Keyword(s):  
Genetic Diversity ◽  
Gene Flow ◽  
Genetic Structure ◽  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
Allelic Diversity ◽  
Lower Proportion ◽  
Fraser River ◽  
Rare Alleles ◽  
Genetic Bottlenecks

Analysis of six microsatellite loci in 5800 sockeye salmon (Oncorhynchus nerka) from 29 Fraser River populations provided little evidence of genetic bottlenecks or mass straying in upper Fraser sockeye salmon resulting from reduced abundances following 1913-1914 rockslides in the Fraser canyon and successive decades of high exploitation. Upper Fraser populations were not characterized by a paucity of rare alleles, a sensitive indicator of populations in which effective size has been recently reduced. Heterozygosity and allelic diversity did not differ consistently between lower and upper Fraser populations. Throughout the watershed, early-migrating populations had lower allelic diversity and a lower proportion of rare alleles than did late-migrating ones. Genetic differentiation between upper and lower Fraser populations and heterogeneity among lower Fraser populations supported the suggestion that Fraser sockeye salmon are descendants of at least two postglacial "races." Variation among lakes within regions was the strongest component of genetic structure, accounting for five times the variation among populations within lakes and more than two times the variation among regions. Extensive historical transplants of eggs and juveniles apparently resulted in lit tle gene flow among regions, but three populations were reestablished or rebuilt as the result of more recent transplants.

Characterizing genetically diverse blue grama [Bouteloua gracilis (Willd. ex Kunth) Lag. ex Griffiths] seed sources

Botany ◽  
2020 ◽  
Vol 98 (11) ◽  
pp. 661-671
Author(s):  
G.M.A. Friesen ◽  
S.R. Smith ◽  
D.J. Cattani ◽  
A.T. Phan
Keyword(s):  
Genetic Diversity ◽  
Bouteloua Gracilis ◽  
Geographic Region ◽  
Morphological Data ◽  
Northern Great Plains ◽  
Plant Materials ◽  
Blue Grama ◽  
Seed Sources ◽  
Plant Nursery ◽  
Significant Difference

The need for regionally adapted native grass seed sources for the northern Great Plains has resulted in the commercial release of a range of plant materials, including ecovars™ 1 . Ecovars™ are multisite composite populations developed to combine broad genetic diversity from a geographic region. The objective of this study was to determine whether morphological data could be used to distinguish between genetically diverse blue grama [Bouteloua gracilis (Willd. ex Kunth) Lag. ex Griffiths] seed sources through classical statistical methods. Entries included a Manitoba (MB) ecovar™, a USDA–NRCS released cultivar ‘Bad River’, and ecotypes from Wyoming and Minnesota. Vegetative and reproductive measurements and ratings were taken from a spaced-plant nursery during 2000–2001 in Carman, Manitoba, Canada. The results were analyzed using statistical techniques including: ANOVA, least significant difference, canonical discriminant analysis (CDA), and coefficients of variation. These techniques distinguished four genetically diverse seed sources from each other through CDA. As hypothesized, there was greater within-population genetic diversity for the MB ecovar™ and Wyoming and Minnesota ecotypes, compared with ‘Bad River’. Our results indicate that genetically diverse blue grama seed sources can be distinguished, based on phenotypic measurements.

scholarly journals Demographic and genetic structure of a severely fragmented population of the endangered hog deer (Axis porcinus) in the Indo-Burma biodiversity hotspot

2019 ◽  
Author(s):  
Sangeeta Angom ◽  
Chongpi Tuboi ◽  
Mirza Ghazanfar Ullah ◽  
Syed Ainul Hussain
Keyword(s):  
Genetic Diversity ◽  
Genetic Structure ◽  
Polymorphic Information Content ◽  
Distance Sampling ◽  
Northeast India ◽  
Biodiversity Hotspot ◽  
Evolutionary Potential ◽  
Female Ratio ◽  
Management Regime ◽  
Rare Alleles

AbstractThe population of the globally endangered hog deer (Axis porcinus) has declined severely across its geographic range. Intensive monitoring of its demographic and genetic status is necessary. Northeast India is a stronghold of the species; however, in recent years the population has been getting fragmented, and it is vulnerable to extinction. We examined the demographic and genetic structure of a small hog deer population in the floating meadows of Keibul Lamjao National Park (KLNP), located on the western fringe of the Indo-Burma biodiversity hotspot for conservation planning. We used a double-observer distance sampling method to derive the hog deer abundance and population structure. We also derived the genetic diversity of the population through microsatellite screening and bottleneck detection. Our study revealed that the abundance of the deer in the park was 1.82–4.32 individuals/km2. The adult male to female ratio and fawn to doe ratio were 36.2 ± 1.9 males/100 females and 16.5 ± 0.4 fawns/100 females, respectively. The mean number of alleles at 23 loci was 2.70 ± 0.18, the observed heterozygosity (HO) ranged from 0.26 to 0.63 (mean 0.42 ± 0.02), the expected heterozygosity (HE) ranged from 0.23 to 0.73 (χ = 0.51 ± 0.03), and the polymorphic information content (PIC) ranged from 0.2 to 0.67 (χ = 0.43 ± 0.03). The observed allelic distribution reveals that the population has not encountered any genetic bottleneck in the recent past. Although the population is declining, it still retains some rare alleles, and the genetic diversity is 50%. This diversity will probably not affect the short-term population growth but may affect the evolutionary potential by limiting the selection flexibility. Conservation measures coupled with a scientifically sound management regime may help the persistence of the population in the region at a time when the population still retains rare alleles and maintains reproductive fitness.

scholarly journals Range-wide neutral and adaptive genetic structure of an endemic herb from Amazonian Savannas

AoB Plants ◽  
2020 ◽  
Vol 12 (1) ◽  
Author(s):  
Amanda R Silva ◽  
Luciana C Resende-Moreira ◽  
Carolina S Carvalho ◽  
Eder C M Lanes ◽  
Mabel P Ortiz-Vera ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Genetic Structure ◽  
Extinction Risk ◽  
Clustering Methods ◽  
Effective Population ◽  
Evolutionary Potential ◽  
Management Actions ◽  
Temperature And Precipitation ◽  
Population Sizes ◽  
Genetic Clustering

Abstract Conserving genetic diversity in rare and narrowly distributed endemic species is essential to maintain their evolutionary potential and minimize extinction risk under future environmental change. In this study we assess neutral and adaptive genetic structure and genetic diversity in Brasilianthus carajensis (Melastomataceae), an endemic herb from Amazonian Savannas. Using RAD sequencing we identified a total of 9365 SNPs in 150 individuals collected across the species’ entire distribution range. Relying on assumption-free genetic clustering methods and environmental association tests we then compared neutral with adaptive genetic structure. We found three neutral and six adaptive genetic clusters, which could be considered management units (MU) and adaptive units (AU), respectively. Pairwise genetic differentiation (FST) ranged between 0.024 and 0.048, and even though effective population sizes were below 100, no significant inbreeding was found in any inferred cluster. Nearly 10 % of all analysed sequences contained loci associated with temperature and precipitation, from which only 25 sequences contained annotated proteins, with some of them being very relevant for physiological processes in plants. Our findings provide a detailed insight into genetic diversity, neutral and adaptive genetic structure in a rare endemic herb, which can help guide conservation and management actions to avoid the loss of unique genetic variation.

scholarly journals High genetic diversity and strong genetic structure of Strongyllodes variegatus (Coleoptera: Nitidulidae) demonstrate the genetic mechanism of its distribution in oilseed rape production areas in China

2020 ◽  
Author(s):  
HaiXia Zhan ◽  
ZhongPing Hao ◽  
JingJiang Zhou ◽  
Rui Tang ◽  
LiNi Zhu ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Population Genetics ◽  
Gene Flow ◽  
Genetic Structure ◽  
Oilseed Rape ◽  
Population Genetic ◽  
Distribution Analysis ◽  
Geographical Regions ◽  
Genetic Diversity And Structure ◽  
Production Areas

Abstract Background : Strongyllodes variegatus (Fairmaire) is a major insect pest of oilseed rape in China. Despite its economic importance, the population genetics of this pest contributing to the development of suitable management and control strategies is poorly known. To understand the population genetics and assess the geographical patterns and genetic structure of S. variegates in China. Using mitochondrial DNA cytochrome c oxidase subunit I and cytochrome b region sequences as genetic markers, we analyzed population genetic diversity and structure from 437 individuals collected in 15 S. variegates populations located in different oilseed rape production areas in China. In addition, we estimated the demographic history using neutrality test and mismatch distribution analysis. Results : The high level of genetic diversity was detected among the mtDNA region sequences of S. variegates . The population structure analysis strongly suggested that three genetic and geographical regions occur with limited gene flow. The Mantel test showed that the genetic distance was greatly influenced by geographical distance. The demographic analyses showed that S. variegates experienced population fluctuation during the Pleistocene, which was likely to be related to the climatic changes. Conclusion : Overall, these results demonstrated that the strong population genetic structure of this beetle may attribute to the geographical barriers and subsequently adapt to the regional ecological conditions for the distribution of S. variegates in China. Keywords : Gene flow, Genetic differentiation, Haplotype, Oilseed rape, Population genetic pattern, Strongyllodes variegates

scholarly journals Diversity and spatial genetic structure of a natural population of Theobroma speciosum (Malvaceae) in the Brazilian Amazon

2016 ◽  
Vol 64 (3) ◽  
Author(s):  
Juliana De Freitas Encinas Dardengo ◽  
Ana Aparecida Bandini Rossi ◽  
Bruna Mezzalira da Silva ◽  
Ivone Vieira da Silva ◽  
Carolina Joana da Silva ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Genetic Structure ◽  
Natural Population ◽  
Short Distance ◽  
Ex Situ Conservation ◽  
Spatial Genetic Structure ◽  
Near Neighbor ◽  
Ex Situ ◽  
Conservation Areas ◽  
Seed Collection

The quantification of genetic diversity and intrapopulation spatial genetic structure (SGS) of tree species are important aspects for in and ex situ conservation practices. In this study we seek to understand the importance of conservation areas by quantifying the genetic diversity and the spatial genetic structure of a natural population of Theobroma speciosum. Within this population, 49 adults and 51 subadults were genotyped for five microsatellite loci. The results showed that adults and subadults have similar levels of genetic diversity and inbreeding (adults: A= 10.4, Ae = 10.3, F= 0.68, subadults: A= 10.6, Ae= 10.6, F= 0.57). Genetic diversity was spatially structured within the population, and the results suggest that near-neighbor trees up to a distance of 70 m are likely related. SGS is likely the result of short-distance seed dispersal, the short-distance range of pollinators, and infrequent breaches of the self-incompatible mating system. Considering the high demographic density of the species and size of the study area, as well as the high average number of alleles per locus and the presence of rare alleles, we believe that the study population is an excellent resource for in situ genetic conservation of T. speciosum. The study area is also a useful resource for collecting germplasm for ex situ conservation and seed collection, either for breeding programs used in the restoration of degraded areas or forest improvement. 

scholarly journals High genetic diversity and strong genetic structure of Strongyllodes variegatus populations in oilseed rape production areas of China

2020 ◽  
Author(s):  
HaiXia Zhan ◽  
ZhongPing Hao ◽  
Rui Tang ◽  
LiNi Zhu ◽  
JingJiang Zhou ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Genetic Structure ◽  
Oilseed Rape ◽  
Demographic History ◽  
Insect Pest ◽  
Distribution Analysis ◽  
Geographical Distance ◽  
Geographical Regions ◽  
Genetic Diversity And Structure ◽  
Production Areas

Abstract Background: Strongyllodes variegatus (Fairmaire) is a major insect pest of oilseed rape in China. Despite its economic importance, the contribution of its population genetics in the development of any suitable protection control strategy for the management of oilseed rape crops is poorly studied. It is a much urgent need to prevent its spread to the rest of the world. Results: Using the sequences of mitochondrial DNA cytochrome c oxidase subunit I (COI) and cytochrome b (Cytb) as genetic markers, we analyzed the population genetic diversity and structure of 437 individuals collected from 15 S. variegates populations located in different oilseed rape production areas in China. In addition, we estimated the demographic history using neutrality test and mismatch distribution analysis. The high level of genetic diversity was detected among the COI and Cytb sequences of S. variegates. The population structure analyses strongly suggested three distinct genetic and geographical regions in China with limited gene flow. The Mantel test showed that the genetic distance was greatly influenced by the geographical distance. The demographic analyses showed that S. variegates had experienced population fluctuation during the Pleistocene Epoch, which was likely to be related to the climatic changes.Conclusion: Overall, these results demonstrate that the strong genetic structure of S. variegates populations in China, which is attributed by the isolation through the geographical distance among populations, their weak flight capacity and subsequent adaptation to the regional ecological conditions.

High nuclear genetic differentiation, but low chloroplast diversity in a rare species, Aluta quadrata (Myrtaceae), with a disjunct distribution in the Pilbara, Western Australia

2016 ◽  
Vol 64 (8) ◽  
pp. 687 ◽  
Author(s):  
M. Byrne ◽  
D. J. Coates ◽  
B. M. Macdonald ◽  
M. Hankinson ◽  
S. M. McArthur ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Gene Flow ◽  
Genetic Structure ◽  
Genetic Differentiation ◽  
Microsatellite Loci ◽  
Disjunct Distribution ◽  
Chloroplast Gene ◽  
Seed Sources ◽  
Chloroplast Haplotype ◽  
Haplotype Variation

Geographically separated populations may show high levels of genetic differentiation, depending on the levels of current and historical isolation. In the ancient landscape of the Pilbara region, there are few plant species with restricted distributions, and one such species, Aluta quadrata Rye & Trudgen, is restricted to three separate locations on the southern edge of the Hamersley Range. We investigated genetic diversity and differentiation among geographically isolated locations of A. quadrata, using 10 microsatellite loci to assess contemporary genetic structure, and sequences of seven chloroplast gene regions to infer historical isolation. Nuclear genetic diversity was moderate, with moderate to high genetic differentiation among the three locations, and low differentiation among populations within locations. In contrast, there was no detected variation in the chloroplast genome. The high genetic differentiation is consistent with limited contemporary connectivity among the geographically separated locations, although lack of chloroplast haplotype variation indicates that limited connectivity has occurred more recently and is not due to historical isolation. The level of differentiation suggests use of local seed sources for augmentation or establishment of populations within gene flow distance of existing populations, whereas an experimental translocation established on more distant sites could use mixed seed sources to maximise genetic diversity.

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