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Stangoulis, James Constantine Roy. "Genotypic variation in oilseed rape to low boron nutrition and the mechanism of boron efficiency". Title page, contents and summary only, 1998. http://web4.library.adelaide.edu.au/theses/09PH/09phs7856.pdf.
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Bibliography: leaves 132-159. Boron efficiency in oilseed rape (Brassica napua L. and B. juncea L.) was investigated in a wide range of genotypes. Using a solution culture screening of 10 day old seedlings, root length best described shoot growth response, and was used to characterise a total of 65 genotypes. Varieties and breeders lines tolerant of B-deficient growing conditions were identified, and the screening process validated through field trials. B responses in plants sampled at the 'green bud' stage indicated that vegetative growth is important in B efficiency. Studies were conducted to investigate the mechanism of B efficiency in oilseed rape. Results suggest no association between B efficiency and the capacity to acidify the root rhizosphere, or an increased translocation of B from root to shoot. Boron retranslocation was also studied as a mechanism of B efficiency.
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Pollock, Stephanie. "A study of genetic diversity and genome organization of Brassica napus using EST (expressed sequence tags) of Arabidopsis and SSR (simple sequence repeat) markers of B. napus /". Thesis, McGill University, 2001. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=33023.
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Arabidopsis expressed sequence tags (ESTs) and microsatellites of Brassica napus have been developed and used as PCR-based markers for both mapping and genetic diversity studies in B. napus . Out of 300 random Arabidopsis ESTs screened, 43 markers were mapped onto a genetic map of B. napus and then used in a diversity study involving 48 B. napus cultivars. A second set of EST markers were developed from chromosome 1 of Arabidopsis and used in genetic mapping studies of B. napus. From 192 primer pairs developed, 50 markers were added onto the B. napus reference map. Microsatellite markers were developed using a "GA" enriched genomic library from B. napus. From 152 designed primer pairs, 23 markers were added onto the B. napus reference map. Microsatellite markers were also used in genetic diversity studies of B. napus, where, from the 152 primer pairs, 40 revealed polymorphism between the 48 B. napus cultivars.
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Schelfhout, Christopher James. "DNA marker assisted breeding in interspecific crosses to improve canola (Brassica napus L.)". University of Western Australia. School of Plant Biology, 2008. http://theses.library.uwa.edu.au/adt-WU2008.0167.
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[Truncated abstract] In order to expand the gene pool of canola-quality rapeseed (Brassica napus) reciprocal interspecific crosses were made between B. napus cv. Mystic and near canola-quality B. juncea breeding line JN29. F1 progeny from these crosses were used to make backcrosses to both parents in all possible combinations and directions, and were selfed to form F2-derived lines. The highest frequencies of viable F2 and BC1 progeny were obtained when B. napus was the maternal parent of the interspecific hybrid. BC1 and F2 progeny (and subsequent generations) were grown under field conditions to identify agronomic improvements over the parents. Transgressive segregation was observed in F2 and BC1 and in subsequent generations for agronomic traits (seed yield under high or low rainfall conditions, plant biomass, harvest index, height, branching and days to anthesis) and seed quality traits (oil, protein, glucosinolates, oleic acid). The majority of progeny conformed to B. napus morphology, and a minority segregated to B. juncea morphology in subsequent generations. Some of the B. juncea morphotypes had lower glucosinolates and higher oleic acid than the parent JN29, with no detectable erucic acid, and thereby conformed to canola quality. Methods were developed for tracing B-genome in interspecific progeny. A repetitive DNA sequence pBNBH35 from B. nigra (genome BB, 2n = 16) was used to identify B-genome chromosomes and introgressions in interspecific progeny. Specific primers were designed for pBNBH35 in order to amplify the repetitive sequence by PCR. A cloned sub-fragment of 329 bp was confirmed by sequencing as part of pBNBH35. PCR and hybridisation techniques were used on an array of Brassica species to confirm that the pBNBH35 subfragment was Brassica B-genome specific. Fluorescence in situ hybridisation (FISH) in B nigra, B. juncea (AABB, 2n=36) and B. napus (AACC, 2n=38) showed that the pBNBH35 sub-fragment was present on all eight Brassica Bgenome chromosomes and absent from A- and C-genome chromosomes. The pBNBH35 repeat was localised to the centromeric region of each B-genome chromosome. FISH clearly distinguished the B-genome chromosomes from the A-genome chromosomes in the amphidiploid species B. juncea. This is the first known report of a B-genome repetitive marker that is present on all Brassica Bgenome chromosomes. ... The results suggest that novel B. napus genotypes have been generated containing introgressions of B-genome chromatin from B. juncea chromosomes. B. juncea morphology occurred in interspecific progeny with a chromosome complement similar to B. napus (2n = 38) and without the entire Bgenome present. It also is highly likely that recombination has occurred between the A-genome of the two Brassica species. This research has demonstrated that the secondary gene pool of B. napus may be accessed by selfing interspecific hybrids, and without sacrificing canola quality, if the B. juncea parent is near canola-quality. Interspecific progeny may be screened to enhance the proportion with B-genome positive signals. Some progeny with B. junceatype morphology had improved seed quality over the JN29 parent.
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Geddy, Rachel Gwyneth. "Location and expression of genes related to the cytoplasmic male sterility system of Brassica napus". Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=100608.
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Cytoplasrnic male sterility (CMS) is a maternally inherited defect in the production of pollen, the male gamete of the flower. This sterility can be suppressed by nuclear Restorer of Fertility (Rf) genes that normally downregulate the expression of the CMS-associated novel mitochondrial gene. In Brassica napus, nap CMS and pol CMS are associated with related chimeric mitochondrial genes orf222 and orf224, respectively. CMS in both nap and pol is associated with a polar loss of locule development, loss of synchronous locule development and clumping of sporogenous tissue away from the tapetal cell layer, as well as secondary effects on petal and bud formation. In nap CMS, early accumulation of orf222 transcripts in the locule regions of developing anthers is associated with sterility, while the absence of orf222 transcripts from the locules is associated with fertility restoration. Accumulation of novel antisense transcripts of atp6 in a cell specific manner which matches that of sense transcripts of orf222 and atp6 in nap CMS anthers may be indicative of a post-transcriptional regulatory mechanism associated with CMS in flower buds.Restoration of fertility in Brassica napus nap and pol CMS is associated with nuclearly encoded genes Rfn and Rfp, respectively. These restorers are very closely linked to one another, and may be allelic. Further efforts to isolate Rfp have narrowed the genomic region to approximately 105 kb of a syntenic region in Arabidopsis thaliana. Cosmid clones isolated from a library of Brassica rapa genomic DNA introgressed with Rfp have been successfully sorted into contigs through the application of the amplified fragment length polymorphism technique. The region to which Rfp is mapped is syntenic to a region of Arabidopsis DNA that is a duplication of a second location at the 23 megabase region of chromosome 1 of that genome. This region contains pentatricopeptide (PPR) motif-encoding genes that are highly related to other restorers of fertility of other species. By inference, Rfp from Brassica napus may encode PPR motifs. The PPR genes related to these previously characterized restorers of fertility are often found alongside the restorer genes existing as mini-clusters of several PPR-encoding genes. This is likely caused by selective pressure acting on PPR-encoding genes that resulted in diversification and multiplication of these genes. In addition, the PPR genes of this duplicated region are not syntenically located, whereas the non-PPR-encoding genes maintain their syntenic locations. The same is true for orthologous comparisons between Arabidopsis and other plant species. PPR genes are therefore malleable and capable of alteration in response to changing environmental pressures, such as the evolution of sterility inducing genes.
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Fiebelkorn, Wrucke Danielle. "Genetic Analysis of Frost Tolerance in Rapeseed/Canola (Brassica Napus L.)". Diss., North Dakota State University, 2017. https://hdl.handle.net/10365/28362.
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Frost can be detrimental to canola (Brassica napus L.) production. Depending on the severity, the entire field can be killed. Having frost tolerance in canola would benefit growers by allowing them to plant early, utilize early season moisture, and avoid high heat during flowering. However, frost tolerance in canola has not been well studied. A protocol was developed that determined 14 day old seedlings should be acclimated at 4?C for 7 days before being exposed to overnight frost (-4?C) in a small freezing chamber. However, when a larger chamber was used for freezing, the protocol was optimized to -8?C instead. A greenhouse study was conducted on a diverse collection of 231 genotypes and genome-wide association scan (GWAS) was conducted to identify potential genes that were related to frost tolerance or abiotic stress tolerance. Thirty-eight significant single nucleotide polymorphism (SNP) markers were selected based on 10,000 bootstraps and 0.1 percent tail of the empirical distribution. The markers were located on chromosomes A01, A02, A03, A04, A07, A08, A09, A10, C03, C05, C06, C07, and C09. Stepwise regression highlighted a QTL located on chromosomes A02. Another GWAS was done on 147 canola germplasm lines phenotyped under natural conditions. Thirty-eight significant SNPs identified from this study were located on chromosomes A05, A07, A09, C01, C02, C03, C04, C05, C06, C07, and C09. Stepwise regression identified a QTL located on chromosome C04. A protocol was developed to measure the freezing induced electrolyte leakage from leaves of rapeseed/canola. A total of 157 germplasm lines were evaluated for freezing induced (-12?C for 2 h) electrolyte leakage. Thirty-six significant SNPs located on chromosomes A01, A02, A03, A04, A05, A06, A07, A08, A09, A10, C01, C02, C04, C05, C06, C07, and C09 were identified. Stepwise regression identified 10 QTL located on chromosomes A01, A02, A04, A06, A07, C02, C05, C07, C09, and one that could not be assigned. All GWAS studies identified potential genes of interest that were related to frost tolerance, abiotic stress, and transcription factors.Northern Canola Growers Association
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McCue, Kimberlie A. "The ecological genetics of rarity : a study of genetic structure, inbreeding and seed bank dynamics in a rare annual plant /". free to MU campus, to others for purchase, 1997. http://wwwlib.umi.com/cr/mo/fullcit?p9841324.
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McCracken, Carrie L. "Genetic Relationships Between Two Rare Plant Species, Aliciella caespitosa and A. tenuis, and Their Putative Progenitor, A. subnuda". DigitalCommons@USU, 2001. https://digitalcommons.usu.edu/etd/7333.
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Isolated populations have potential to become new species that should have less genetic variation than their ancestors. Small populations are more likely to lose genetic variation, which is, thus, expected to be greater in ancestors. Aliciella caespitosa and A. tenuis, two endemic species, may be derived from small populations of A. subnuda, a widespread species. Chloroplast DNA sequences were used to test this hypothesis. Allozyme data were used to compare genetic variation and numbers of alleles. Chloroplast data do not support the proposed relationships between A. subnuda and the other two species. Allozyme data were not more variable in A. subnuda. The data suggest that A. tenuis is derived from A. caespitosa, although the former did not show lower allozyme diversity. I detected fewer alleles in A. tenuis. These data suggest that the original population of A. tenuis was not small enough to lose genetic variation relative to its progenitor.
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Jean, Martine. "Genetic mapping of restorer genes for cytoplasmic male sterility in Brassica napus using DNA markers". Thesis, McGill University, 1995. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=40147.
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DNA markers tightly-linked to nuclear fertility restorer genes for cytoplasmic male sterility (CMS) are valuable tools for breeders and researchers working with these genes. Two different targeting approaches were used to identify markers linked to the Rfp1 restorer gene for the pol CMS of canola (Brassica napus L.): nearly isogenic line (NIL) comparison and bulked segregant analysis. These methods were equally efficient in identifying markers linked to Rfp1; combining them allowed a targeting efficiency of 100% to be achieved. The efficiency of bulked segregant analysis was found to be limited by the inadvertent occurrence of shared homozygosity at specific chromosomal regions in the bulks, in contrast with the efficiency of NIL comparison which was limited by the occurrence of residual DNA from the donor cultivar at scattered sites around the genome of the NILs. Eleven DNA markers linked to the Rfp1 gene were identified, one of which perfectly co-segregates with Rfp1. The linkage group on which Rfp1 is localized contains 17 DNA markers. Two restorer genes of the pol CMS, Rfp1 and Rfp2, and a Rfn restorer gene of the nap CMS were found to be at least tightly linked to one another and may all reside at the same locus. A fourth restorer gene, the Rfo restorer for the ogu CMS, was, however, found to be unlinked to the other restorer genes. Different restorer genes for the nap CMS were found in the lines 'Westar-Rf and 'Karat'. A linkage map of the B. napus genome containing 146 markers organized into 23 linkage groups covering a total length of 850.2 cM was constructed from a BC$ sb1$ population. This map contains 63 loci previously localized on the B. napus genome through analysis of an F$ sb2$ population. Comparative analysis indicates that the total length of the BC$ sb1$-derived map is smaller than that of the F$ sb2$-derived map, which suggests that a reduction in recombination frequency is occurring in male gametes. The preferential use of two or three probe-
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Babwah, Andy Videsh. "Development and application of biotechnological tools in the major crop plant, Brassica napus". Thesis, McGill University, 2001. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=37867.
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A two-component transposable element system consisting of a stabilized Activator (Acst) and a chimeric Dissociation (Ds) element has been introduced into the genome of Brassica napus. This Acst/ Ds system incorporates the use of several highly effective screenable and selectable markers. One of these markers is the maize Lc gene, a transcriptional regulator of flavonoid biosynthetic genes. This substrate-independent screenable marker was tested for the first time in B. napus and I show that when overexpressed, there is augmented trichome production and a light-dependent, enhanced accumulation of anthocyanins in B. napus plants. The phenotypes are expressed under a wide range of conditions, are visually distinct, and are observed throughout plant development. When used as a visual marker for the Acst element, Lc B. napus plants were rapidly identified among F2 segregating populations. As part of my goal to develop a very efficient Acst/Ds system for use in B. napus, a conditional negative selectable marker, the E. coli codA gene, was also tested for the first time in B. napus. This was done because use of a substrate-dependent negative selectable marker can facilitate the rapid and reliable identification of stable Ds transposition events when used as a marker for the Acst T-DNA. The enzyme cytosine deaminase, encoded by the codA gene, catalyzes the deamination of the non-toxic compound 5-fluorocytosine (5-FC) to the highly toxic compound 5-fluorouracil. In codA transformed B. napus seedlings, expression of cytosine deaminase results in a severe suppression of growth and this phenotype is dependent on the presence of the 5-FC substrate. Wild-type seedlings, however, lack endogenous cytosine deaminase activity and appear unaffected by the presence of 5-FC in the growth media. These results indicate that codA has the potential to be used effectively in B. napus as a substrate-dependent negative selectable marker for the Acst T-DNA. To determine if Ac transposase cou
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Hamel, Nancy. "Nuclear regulation of mitochondrial gene expression in Brassica napus". Thesis, McGill University, 1996. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=27331.
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Previous studies have shown that transcriptional differences in the orf224-atp6 mitochondrial gene region are correlated with fertility restoration of the pol CMS trait by the dominant nuclear Rfp gene in Brassica napus. Recently, the recessive rfp allele, or a tightly linked gene, was found to act as a dominant gene, designated Mmt, in controlling the production of additional, smaller transcripts of two other mitochondrial loci. The results presented in this thesis reveal that Mmt-specific transcripts lack sequences found at the $5 sp prime$ end of the full-length transcripts of these loci and contain a common sequence, UUGUGG, which maps immediately downstream of their $5 sp prime$ termini. A similar sequence, UUGUUG, is found within orf224 downstream of the major Rfp-specific $5 sp prime$ transcript terminus; these hexanucleotide sequences may serve as recognition motifs in the generation of Mmt- and Rfp-specific transcripts. These results suggest that Rfp/Mmt is a novel nuclear locus affecting the expression of multiple mitochondrial gene regions, with different alleles or haplotypes affecting different mitochondrial genes.
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Orvis, Julie Dawn. "An investigation into the specificity of race 3 of Pseudomonas syringae pathovar pisi". Thesis, University of the West of England, Bristol, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.315474.
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Clarke, Belinda. "The rate of starch synthesis as a determinant of starch composition". Thesis, University of East Anglia, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.267540.
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Llorens, Tanya M. "Conservation genetics and ecology of two rare grevillea species". Department of Biological Sciences - Faculty of Science, 2004. http://ro.uow.edu.au/theses/374.
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Small and isolated plant populations have a higher probability of extinction – they are more susceptible to a range of environmental, demographic and genetic processes that may reduce population viability. In recent times, the number of populations and species that are susceptible to these processes has increased as a result of world-wide, human-induced habitat fragmentation. Habitat fragmentation typically reduces the formerly more continuous natural distribution of a species to a series of smaller and more isolated populations that occur in smaller and more isolated habitat patches. Such populations are often exposed to a range of additional processes that may threaten their viability, such as changes to disturbance regimes, environmental conditions and interactions with other species. However, our current understanding of the complex effects and interactions of these processes is poor. Species responses vary widely, studies are biased towards trees, herbs and self-incompatible species, and most studies investigate only one or two processes that may affect viability. Consequently, we are unable to make accurate predictions about the likely impacts of habitat fragmentation on population and species viability. I tested several hypotheses about the impact of habitat fragmentation, small population size, and population isolation on populations of two Grevillea species (Proteaceae) that occur in the Sydney region of New South Wales, Australia. These species provided an opportunity to investigate some of the ecological and genetic consequences of small population size and isolation, and to contrast them between a species for which the small size and isolation of its populations is the natural state (G. longifolia) and one for which it arose recently due to severe habitat fragmentation (G. caleyi). This comparative approach is important in identifying the processes involved in reducing population and species viability. The species share many aspects of their biology and ecology. Both are large, perennial shrubs that are self-compatible and naturally bird-pollinated. They are fire-sensitive and regenerate post-fire by mass germination from a long-lived, soil-stored seed bank. Both species consist of populations that vary dramatically in size and degree of isolation. I used microsatellite and AFLP markers to investigate aspects of the population genetics and mating system of these species, with the primary focus on G. caleyi. Both species showed a surprisingly large amount of genetic structuring among populations, although G. caleyi populations showed more structuring (FST = 0.46) than those of G. longifolia (FST = 0.33), despite being distributed over a much smaller area. In addition, for G. caleyi, most (63%) of the structuring was due to differences among recently-fragmented populations. By examining fine scale genetic structure within existing large populations, I determined that this was probably due to historic genetic structuring within formerly larger, more continuous populations. This has probably arisen due to both a lack of gene flow (no seed dispersal and limited pollen dispersal) and a large amount of inbreeding. Indeed, adult fixation indices were very high in G. caleyi (average f = 0.40, f > 0 in 16/18 populations). For both species, genetic diversity was not strongly correlated with population size. Genetic diversity was significantly lower in more isolated populations of G. caleyi, but this was probably due to a historic lack of gene flow to the more isolated parts of the species’ natural range, rather than to recent fragmentation. Levels of inbreeding (fixation indices) among adult plants did not vary with population size or isolation for either species. However, by genotyping fresh seeds from a range of small and large G. caleyi populations, I revealed that current outcrossing rates were much lower in small populations (t = 0.18 cf. 0.37). Observations of pollinator foraging indicated that this might be due to a very low visitation rate by birds and by a less diverse suite of species, resulting in a higher proportion of self-fertilisation. In contrast, even very small G. longifolia populations received many bird visits. In addition, G. caleyi plants in small populations were much smaller, had higher mortality, and produced fewer inflorescences and fruits, while this pattern was not apparent among G. longifolia populations. The contrast among the species in pollinator visits, plant vigour and reproduction may have been due to edge effects combined with the habitat degradation that was apparent at sites containing small G. caleyi populations. Small populations were typically found within very small and disturbed bush remnants, while small G. longifolia populations all occurred in relatively pristine habitat. Therefore, habitat quality rather than population size per se may be the most important factor that determines the mating system, plant vigour and fecundity in G. caleyi. The lack of obvious impacts of habitat fragmentation on the genetic haracteristics of adult G. caleyi plants may have been due to the soil-stored seed bank, which can contain seeds produced by at least two adult generations. Various authors have hypothesised that a persistent seed bank has the potential to reduce the rate of genetic change in a population. The seed banks of both G. caleyi and G. longifolia do appear to have this ability. I found that the seed bank of each species maintains the genetic characteristics of populations and stores genetic diversity and alleles that were not expressed in the extant adult plants. Nevertheless, the seed bank also showed greater spatial structuring than adults, which indicates that genetic changes may be occurring within these small populations despite the buffering power of the seed bank. Finally, I investigated some aspects of the ecology of G. caleyi and G. longifolia seed banks, with the aim of increasing our understanding of this important conservation resource. Soil sieving revealed that the seeds of both pecies occur at very low densities beneath adult plants (1 – 6 m-2), were vastly outnumbered by seed fragments, and were not found away from adult canopies. This supports previous evidence that indicated a lack of seed dispersal and very high rates of post-dispersal seed predation, which will restrict population size and extent. To some degree, the seed bank may buffer demographic changes that affected the previous adult generation – monitoring of post-fire seedling emergence revealed that population size typically increased, often dramatically, after a fire. Germination experiments showed that smoke elicited the greatest germination response from intact seeds of both species, and that dormancy polymorphism in the seed bank may allow both species to survive two fires in rapid succession and long inter-fire intervals. However, germination was low in field fire experiments, which may have been due to low fire intensity, and hence smoke production, resulting from a winter prescription burn. For both species, herefore, population viability may be compromised if the imposed fire regime includes fires that are too cool or too frequent. This study has demonstrated, for these species, that small populations that exist in recently fragmented habitat patches are far more likely to experience adverse ecological and genetic effects than those in continuous, relatively undisturbed, bushland. The process of demographic and genetic decline in small G. caleyi populations is likely to continue with the ongoing pressures of edge effects, habitat degradation and pollinator declines, and the increased isolation of some populations. The seed bank may buffer these declines to some extent, but this ability is limited by a lack of habitat for population expansion, which means that effective population sizes will remain very small or decrease further. The various differences detected between small and large G. caleyi populations emphasises the importance of large populations, and the ecological processes occurring within larger habitat patches, for the long-term conservation of the species.
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Rohrer, Wendy L. "A biosystematic study of the rare plant Paronychia virginica Sprengel (Caryophyllaceae) employing morphometric and allozyme analyses". Thesis, Virginia Tech, 1997. http://hdl.handle.net/10919/46520.
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Paronychia virginica Spreng. (Caryophyllaceae) is a perennial evergreen herb of exposed, relatively xeric habitats. Approximately 10 mid-Appalachian populations remain in Virginia, West Virginia, and Maryland and are disjunct from populations located primarily in Texas, Oklahoma, and Arkansas. A study was conducted to test the hypothesis that eastern and western populations differ significantly and, therefore, represent at least two distinct taxa. Statistical analyses of 8 qualitative and 24 quantitative morphological characters indicated very highly significant (P < 0.001) variation between eastern and western populations of P. virginica. Characters differing most significantly included sepal pubescence, awn length, awn pubescence, awn curvature, length-width ratio of leaves, and shape of leaf apices. Starch gel electrophoresis was performed and six enzyme systems/nine loci (EST-2, EST-3, LAP, MDH-1, MDH-2, PGI, PGM-1, PGM-2, and SKDH) were identified as being consistently scorable and informative. Although gene flow between populations of P. virginica was shown to be restricted (mean FST = 0.353), populations are maintaining relatively high levels of genetic diversity. Genetic variability was quantified for each population and mean values for number of alleles per locus (A), percent loci polymorphic (P), and expected heterozygosity (HEXP) were found to be 1.95, 47.22%, and 0.204, respectively, exceeding those values reported for seed plants, widespread species, and endemic species. Hierarchical F statistics suggest higher levels of genetic variability within individual populations than among populations, regardless of geographic location. All statistically significant (P < 0.05) deviations from Hardy-Weinberg equilibrium indicated a deficiency in heterozygotes at the respective loci. Considering results from both the morphometric and allozyme analyses, the current author suggests recognizing two distinct subspecies, P. virginica subsp. virginica in the eastern U.S. and P. virginica subsp. scoparia in the south-central U.S. Conservation efforts should be focused on the maintenance of existing populations in both eastern and western regions of the U.S. in order to preserve the genetic and evolutionary potential of these taxa.Master of Science
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Newbert, Max John. "The genetic diversity of Turnip yellows virus in oilseed rape (Brassica napus) in Europe : pathogenic determinants, new sources of resistance and host range". Thesis, University of Warwick, 2016. http://wrap.warwick.ac.uk/79104/.
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The aphid transmitted Polerovirus Turnip yellows virus (TuYV) was found to be widespread with high incidences in oilseed rape (OSR) across Europe. UK, France, Germany and Poland all having >90% TuYV incidence in some OSR crops. From the 179 whole TuYV genomes sequenced in this study the phylogenetic analyses indicated three distinct genetic groups in the UK, two of which were also detected in Europe. These three genotypes were also distinct from the original sequenced TuYV-FL. These groups are proposed to be distinct species due to their genetic distance based on the most variable gene ORF5 and phylogenetic analyses of ORF1, ORF3, ORF4 and ORF5. Mixed TuYV infection was uncommon and only two plant samples had genetically distinct isolates. Whole genome analysis also provided valuable information on two recombination hotspots located within TuYV genes ORF3 and ORF5. Investigation into the epidemiology of TuYV revealed many weed and crop species as hosts, including sugar beet, which it was previously thought not to infect. TuYV isolates detected infecting weed plants in the UK were successfully transmitted to OSR. Previously undescribed hosts, verbascum, geranium, teasel, spear thistle, dock and previously described hosts in the Brassicaceae, Compositae and Lepidium families were found in the UK. A full-length infectious clone of a UK isolate of TuYV has been produced, this will allow further assessment of TuYV in the future. The infectious clone was able to cause systemic infection of TuYV and was aphid transmissible. The Arabidopsis thaliana gene knock-out study did not reveal a single eIF gene or gene linked to virus movement or silencing that could provide extreme broad-spectrum resistance. The gene eIF(iso)4G.1 was able to give a broad-spectrum quantitative resistance, and the potential of eIF3D.2 as well as sucrose symporters SUC1 and SUC2 as candidates for extreme TuYV resistance were discovered. This understanding of the epidemiology and diversity of TuYV is being used to develop strategies for control.
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Horrill, James Christopher. "Demographic genetics of the polymorphism for capitulum type and associated outcrossing rate in Senecio vulgaris L". Thesis, University of St Andrews, 1989. http://hdl.handle.net/10023/14403.
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The primary aim of this project was to examine factors which are likely to provide a mechanism by which the polymorphism for capitulum type and associated outcrossing rate in Senecio vulgaris may be maintained. The majority of studies conducted examined the demographic genetics (i.e. the changes in the number of individuals of the two morphs at different life history stages) in field experiments initiated either in Spring or Autumn, The first series examined the demography of each morph raised from seedlings to senescence in pure stand and mixture. The second series examined the demography of each morph from seed to senescence and thereby investigated the effect on fitness of any difference between morphs in germination behaviour. The importance of inbreeding depression on the maintenance of the polymorphism was examined by comparing the relative fitness of self and open pollinated offspring of each morph under glasshouse conditions. Germination behaviour of seeds of each morph was also investigated in a series of field trials conducted over an extended period. These field studies were complemented by a series of synchronous laboratory studies to examine the effect of temperature on morph germination behaviour. It was found that inbreeding depression is not an important factor in the maintenance of the polymorphism. No short term advantage of the radiate over the non-radiate morph was evident in the first series of demography experiments. The germination studies showed that differences between morphs in germination behaviour may occur frequently in autumn sown seed. The second series of demography experiments showed that under certain conditions this difference in germination can lead to the radiate morph attaining a greater relative fitness than the non-radiate morph. Temperature was found to be a major factor controlling the initial dormancy of seeds after sowing. It is concluded that the difference between morphs in germination behaviour is the most likely factor that could maintain the polymorphism for capitulum type in Edinburgh populations of 8. vulgaris.
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Parsons, Matthew C. "Ecotypic Variation in Elymus Elymoides Subspecies Brevifolius Race C in the Northern Intermountain West". DigitalCommons@USU, 2008. https://digitalcommons.usu.edu/etd/183.
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Little information is available on the extent of local adaptation for many native grass species. This is the case for squirreltail (Elymus section Sitanion), despite this group's prevalence and importance in rangeland restoration efforts. I evaluated 32 populations of E. elymoides ssp. brevifolius race C, a phylogenetic subdivision of bottlebrush squirreltail (E. elymoides) centered in the northern Intermountain West, for phenotypic variables and neutral genetic markers to measure their association with geographical origin. Phenotypic traits were measured in common field and greenhouse environments, and genetic diversity was assessed using Amplified Fragment Length Polymorphism. Three factors were extracted from the phenotypic data set using common factor analysis. Factor 1 explained 37.7% of the variation among all of the variables; it had positive factor loadings for phenology (late maturity), biomass, and leaf area index, negative loadings for leaf area and root length, and was negatively correlated with elevation (r = -0.71). Factor 2 explained 14.5% of the variation among all of the variables; it had positive factor loadings for plant height and leaf number per tiller, negative loadings for seed yield and tiller number, and was positively correlated with longitude (r = 0.54) and average annual minimum temperature (r = 0.39). Factor 3 explained 12.8% of the variation among all of the variables; it had highly positive factor loadings for specific root length and specific leaf area, negative loadings for canopy height and mass per tiller. Correlations among phenotypic, environmental, genotypic, and geographic-origin distances were positive (r = 0.723-0.900), which suggests that ecotypic variation is an important feature of this group. This information, in conjunction with previously established Level III ecoregions, was used to delineate four adaptive zones for race C.
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Gilbert, Cynthia. "Aspects of community ecology, population growth and genetic structure applied to the conservation of Polemonium pectinatum (Polemoniaceae), a rare and threatened shrub-steppe perennial /". Thesis, Connect to this title online; UW restricted, 1998. http://hdl.handle.net/1773/5535.
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Micha, Caterina. "Establishment of phylogenetic relationships within the genus Phragmipedium using RAPD-PCR fingerprinting". Virtual Press, 1995. http://liblink.bsu.edu/uhtbin/catkey/958787.
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DNA fingerprinting was applied for the molecular elucidation of taxonomic relationships within a genus of orchids which have previously been based on morphological characteristics. Phragmipediwn consists of 15-20 species native to Central and South America. This research project included two studies. In the first study DNA was isolated from 11 samples (including two unidentified ones). These individuals, which were mostly hybrids, were found in the Wheeler Orchid Collection and Species Bank at Ball State University. In order to position Phragmipediwn within the orchid family fingerprinting was also performed on individuals in the sister taxa, Cypripedium and Paphiopedium, which are members of the same subfamily, and on a member of the outgroup taxon Vanda. The polymerase chain reaction (PCR) was employed to yield fingerprints resulting from the use of random primers. Fifty nine random amplified polymorphic DNA (RAPD) bands were obtained using 5 different primers to yield 107 polymorphic bands. As many as 75% of genetic loci were found to be shared between hybrids that resulted from a cross of more than one individual in the same section. However the percentage dropped to 35-65 % when only one parent was shared in the cross. Furthermore, the sister group taxa Cypripedium and Paphilopedium shared from 12 % -35 % of their polymorphic loci with the members of the genus Phragmipedium. The outgroup taxon Vanda shared 17% of its polymorphic loci with the rest of the samples.In a second study DNA was isolated from one member of each of the five sections of the genus Phragmipedium, and RAPD-PCR fingerprinting was used to compare their genetic similarities to that of the two sister taxa and the outgroup taxon. It was found that individuals in different genera shared 25% or less of their polymorphic bands. Between sections of the same genus 20-50% of genetic loci were shared. Two sections, Platypetalwn and Phragmipedium showed the highest degree of genetic relatedness (41-53%). Again the outgoup taxon shared less than 20% Phragmipediwn samples on the phenograms produced but the percentage was again insignificant. However, genetic analyses of the members of the section Lorifolia gave conflicting results: 46% genetic identity was observed in the first trial and 20% in the second.In conclusion, RAPD-PCR fingerprinting results appeared to be effective in the positioning of sections within a genus indicating the degree of similarity of closely related taxa. Also RAPD-PCR was able to place an unknown individual within a specific section of the genus. However, it could not be employed to determine the identity of unknown species due to the high degree of genetic diversity observed between even closely related individuals.Department of Biology
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Brown, Susan Ann. "Genetic variation within and between some rare and common taxa of Cape Proteaceae and the implications for their conservation". Thesis, Rhodes University, 2000. http://hdl.handle.net/10962/d1003964.
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Barriball, Kelly. "Population structure and mating system of the invasive shrub Lonicera maackii in Ohio". Kent State University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=kent1342357868.
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Van, den Berg Noëlani. "Identification of genes associated with tolerance in the C Cavendish banana selection, GCTCV 218, against Fusarium oxysporum f.sp. cubense 'subtropical' race 4". Pretoria : [s.n.], 2006. http://upetd.up.ac.za/thesis/available/etd-11082006-171800.
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Snyder, Melissa. "Ecological and Genetic Variation Among Populations of Boechera caeruleamontana sp. nov. (Brassicaceae) from Blue Mountain and Dinosaur National Monumentin Eastern Utah and Western Colorado". BYU ScholarsArchive, 2017. https://scholarsarchive.byu.edu/etd/6344.
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Boechera is a large genus of flowering plants whose taxa are found primarily in North America. Boechera vivariensis (S.L. Welsh) W.A. Weber (the Park rockcress) is restricted to the Uintah Basin on Weber sandstone substrates in the vicinity of Dinosaur National Monument and Blue Mountain. The nomenclature of Park rockcress is significantly impacted by the discovery that the type collections of the taxon represent a rare, apomictic diploid resulting from the hybridization between B. thompsonii and an undescribed sexual diploid (to be called Boechera caeruleamontana sp. nov. Allphin and Windham). As a result, greater information is needed regarding how B. vivariensis and B. caeruleamontana. are distributed geographically in the region of Dinosaur National Monument and surrounding areas. Thus, we performed genetic analyses on leaf samples taken from over 50 individuals at known sites of B. vivariensis throughout its geographic range. Individuals from each site were also compared morphologically. We also compared associated plant communities at each site and characterized the soils. In our thorough sampling, we did not pick up B. vivariensis. All individuals sampled belonged to B. caeruleamontana, suggesting that most individuals previously assigned to B. vivariensis, are actually representative of B. caeruleamonanta. Populations of B. caeruleamontana were genetically diverse compared to other Boechera species, most likely indicative of its insect pollination strategy. However, all populations had lower heterozygosity than expected based upon Hardy-Weinberg expectations. Reproductive and genetic data indicated that populations are showing signs of inbreeding. The population at Jones Hole Fish Hatchery was most unique genetically, morphologically, and reproductively.
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Kolkailah, Naiyerah F. "Genes Encoding Flower- and Root-Specific Functions are More Resistant to Fractionation than Globally Expressed Genes in Brassica rapa". DigitalCommons@CalPoly, 2016. https://digitalcommons.calpoly.edu/theses/1586.
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Like many angiosperms, Brassica rapa underwent several rounds of whole genome duplication during its evolutionary history. Brassica rapa is particularly valuable for studying genome evolution because it also experienced whole genome triplication shortly after it diverged from the common ancestor it shares with Arabidopsis thaliana about 17-20 million years ago. While many B. rapa genes appear resistant to paralog retention, close to 50% of B. rapa genes have retained multiple, paralogous loci for millions of years and appear to be multi-copy tolerant. Based on previous studies, gene function may contribute to the selective pressure driving certain genes back to singleton status. It is suspected that other factors, such as gene expression patterns, also play a role in determining the fate of genes following whole genome triplication. Published RNA-seq data was used to determine if gene expression patterns influence the retention of extra gene copies. It is hypothesized that retention of genes in duplicate and triplicate is more likely if those genes are expressed in a tissue-specific manner, as opposed to being expressed globally across all tissues. This study shows that genes expressed specifically in flowers and roots in B. rapa are more resistant to fractionation than globally expressed genes following whole genome triplication. In particular, there appears to have been selection on genes expressed specifically in flower tissues to retain higher copy numbers and for all three copies to exhibit the same flower-specific expression pattern. Future research to determine if these observations in Brassica rapa are consistent with other angiosperms that have undergone recent whole genome duplication would confirm that retention of flower-specific-expressed genes is a general feature in plant genome evolution and not specific to B. rapa.
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Vazquez-Carrasquer, Victor. "Identification and genotypic variability of plant traits early determining nitrogen use efficiency (NUE) in winter oilseed rape under low-N inputs". Thesis, université Paris-Saclay, 2021. http://www.theses.fr/2021UPASB002.
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Améliorer le rendement du colza dans un contexte de bas intrants azotés (N) est un enjeu majeur de sélection. Ceci impose une connaissance approfondie de la variabilité génétique des processus sous-tendant l’efficacité d’utilisation de l’azote (NUE, rendement en graines par unité d’azote disponible). Cette thèse vise à mieux comprendre les processus écophysiologiques contribuant à la NUE et à ses composantes sous faible nutrition azotée, en identifiant et hiérarchisant les principaux traits sous-tendant leur variabilité génotypique. Six génotypes de colza d’hiver ont été étudiés en conditions semi-contrôlées sous des doses d’azote contrastées. Nous avons montré que la variable NUE_DM (biomasse totale produite par unité d’azote disponible) est un indicateur précoce de la NUE à la récolte valable dès la montaison, qui nous a permis de caractériser dynamiquement la NUE. L’efficience d'absorption d’azote (NUpE, N absorbé par unité d’azote disponible) s’est révélée être une composante majeure de la NUE sous contrainte azotée, expliquant 80 % des variations avant la floraison, et plus de 30 % après. De plus, sa variabilité génotypique dépend de la biomasse des racines fines et non de l’absorption spécifique d'azote. Grâce au développement d’un cadre conceptuel de modélisation du fonctionnement du colza décrivant les flux de carbone et d’azote dans la plante entière et valable jusqu’à floraison, nous avons fait ressortir l'assimilation spécifique de carbone, la part de carbone allouée aux tiges et la proportion de racines fines comme paramètres clés de la réponse génotypique à l’azote. Nos résultats suggèrent que la NUpE et la proportion de racines fines seraient des indicateurs de la NUE permettant de cribler précocement des variétés à haut débitImproving rapeseed yields in a low-Nitrogen (N) agricultural context is a major issue for breeding. It requires a thorough knowledge of the genotypic variation of the processes related to Nitrogen Use Efficiency (NUE, seed yield per unit of N available). This PhD aims at better understanding the ecophysiological processes determining the NUE and its components under low-N availability by identifying and hierarchizing the main traits supporting observed genotypic variation. Six winter oilseed rape genotypes were investigated throughout the crop cycle under semi-controlled conditions and contrasting N-conditions. We proposed NUE_DM (plant dry matter per unit of N available), as a new proxy of NUE at harvest, valid as early as the beginning of stem elongation. This proxy allowed us to dynamically characterize NUE, highlighting NUpE (plant N-amount per unit of N available) as a main contributor of NUE under low-N conditions, which explained up to 80% of the NUE_DM variations before flowering, and more than 30% after. Moreover, NUpE genotypic variability resulted from fine root growth rather than specific N-uptake differences. We developed a whole-plant conceptual modeling framework of carbon and nitrogen absorption and partitioning for winter oilseed rape. This framework, validated up to flowering, highlighted specific carbon assimilation, carbon partitioning between leaves and stems, and fine root ratio as critical traits explaining contrasting genotypic behavior to N-conditions. Our results suggest NUpE and fine root ratio as promising traits for screening larger sets of varieties for NUE breeding purposes
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Davis, Samantha Lynn. "Evaluating threats to the rare butterfly, Pieris virginiensis". Wright State University / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=wright1431882480.
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Jenkins, Toni E. "Introgression of genes from rape to wild turnip". Lincoln University, 2005. http://hdl.handle.net/10182/1844.
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Introgression of genes from crops into ruderal populations is a multi-step process requiring sympatry, synchronous flowering, chromosomal compatibility, successful pollination and development of the zygote, germination, establishment and reproduction of hybrid progeny. The goal of this thesis was to generate data on as many steps in this process as possible and integrate them into a predictive statistical model to estimate the likelihood of successful introgression under a range of scenarios. Rape (Brassica napus) and wild turnip (B. rapa var. oleifera) were used as a model system. A homozygous dominant mutation in the rape genome conferring herbicide resistance provided a convenient marker for the study of introgression. Potential differences between wild turnip populations from a wide range of geographic locations in New Zealand were examined. Hand pollination established the genetic compatibility of rape and wild turnip and a high potential for gene introgression from rape to wild turnip. Interspecific hybrids were easily generated using wild turnip as the maternal plant, with some minor differences between wild turnip populations. The frequency of successful hybridisation between the two species was higher on the lower raceme. However, the upper raceme produced more dormant interspecific hybrid seed. Field trials, designed to imitate rare rape crop escapes into the ruderal environment, examined the ability of rare rape plants to pollinate wild turnip plants over four summers. At a ratio of 1 rape plant for every 400 wild turnip plants, the incidence of interspecific hybridisation was consistently low (<0.1 to 2.1 % of total seed on wild turnip plants). There was a significant year effect with the first season producing significantly more seed and a greater frequency of interspecific hybrid progeny than the other years. The frequency of interspecific hybrid progeny increases when the ratio of rape: wild turnip plant numbers increases. The relative importance of anemophily and entomophily in the production of interspecific hybrids was examined. Wild turnip plants produced twice as many seeds with bee pollination relative to wind pollination. However, the frequency of interspecific hybrids under wind pollination was nearly twice that for bee pollination. Light reflectance patterns under UV light revealed a marked difference between wild turnip and rape flowers compared to near identical appearance under visible light. The data indicates that bees are able to distinguish between rape and wild turnip flowers and exhibit floral constancy when foraging among populations with these two species. Hybrid survival in the seed bank, germination and seedling establishment in the field are important components of fitness. Seed banks established in the soil after the field trials described above germinated in subsequent spring seasons. The predominantly brassica weed populations were screened for herbicide resistance and the numbers of interspecific hybrids germinating compared to the original frequency in the field trial results. Frequency of interspecific hybrids was reduced in the populations compared to the original seed deposit. Seed with a known frequency of interspecific hybrid seed was sown in a separate trial, and the frequency of interspecific hybrids compared at 0, 4, 6, and 8 weeks after sowing. Poor germination resulted limited competition between seedlings, however the frequency of interspecific hybrids declined over time indicating low plant fitness. There were no significant population effects on any parameters tested. Interspecific hybrids grown in a glasshouse were backcrossed to the parental species and selfed within the plant and within populations. Pollen from the interspecific hybrids was found to have markedly reduced fertility. Interspecific hybrid plants had low female fertility, with the majority (88%) of the pollinated flowers aborting the siliques. Of the remaining siliques, most (98%) had only one to three seeds per silique. Inheritance of the herbicide resistance gene was regular in backcrosses but highly skewed following self pollination with an excess of herbicide-sensitive progeny. Production of a stochastic predictive model integrated the information acquired over the practical work phase of this thesis and utilised the capabilities of @risk, a new application of a risk analysis tool. The three outputs examined were the number of flowering plants resulting from backcrosses to rape and wild turnip and self pollination of the interspecific hybrid progeny. Five scenarios were modelled and all demonstrated the high likelihood of introgression failure in this system. In all scenarios, >75% of simulations resulted in no interspecific hybrid progeny surviving to flowering in the third generation. In all scenarios, and for all three outputs, the seed set on the interspecific hybrids of the second generation was the major factor that limited the number interspecific hybrid progeny surviving to flowering in the third generation.
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Mesa, Laura A. "The influence of pollinator diversity and behaviour on pollen movement in Brassica rapa chinensis (Pak-Choi) crops, and its significance for gene escape". Thesis, University of Canterbury. School of Biological Sciences, 2008. http://hdl.handle.net/10092/2685.
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The overall aim of the study was to assess the risk of gene flow from Brassica crops by insectmediated pollen transport. I measured the viability of pollen in Brassica flowers throughout crop development and compared this with the viability of pollen transported by insects inside and outside one early- and one late-season crop. In order to evaluate the relative importance of different species in pollen transport, I measured abundance of flower visitors during crop development, and measured the foraging behaviour of five key pollinator species throughout the growing season, in relation to variation in microclimate, crop phenology and the relative abundance of other pollinator species competing for flower resources. Flower visiting insects of Brassica rapa crops were highly diverse, and their abundance and diversity changed with crop phenology. I found similar abundances at the family level for both crops studied, although capture rates were greater in the early- than in the late-season crop. Across flowering development, the greatest numbers of insects were captured at the peak of flowering for both crops. During the flowering period, Diptera was the most abundant order collected, followed by Hymenoptera. The most abundant family in Hymenoptera was Apidae which tracked crop development in both fields, with greater numbers of insects captured inside than outside the field. Standardized-count pollen loads were smaller in Diptera than in Hymenoptera. Of the five key pollinator species sampled, Lasioglossum sordidum (Hymenoptera: Halictidae), Apis mellifera (Hymenoptera: Apidae) and Bombus terrestris (Hymenoptera: Apidae) transported similar pollen loads, which were much greater than those carried by Eristalis tenax (Diptera: Syrphidae) and Melangyna novae-zealandiae (Diptera: Syrphidae). The numbers of insects captured outside of the crop were 10% and 33% of the totals captured inside for the early- and the late-season crop, respectively. The proportion of insects entering versus leaving the crop varied considerably across species, crops and trap location (i.e., whether traps were inside or 50 m outside the border of the crop). However, it is worth noting that not uncommonly more insects were attracted into the crop early in the season, staying there rather than leaving, and then when flowers started to disappear there was a massive escape of insects leaving. This research provides evidence for the influence of crop age on the foraging behaviour of key pollinators and for species-specific variation in the foraging behaviour of Brassica visitors with crop development. Temporal variation in the rate and variability of movement between flowers, and the duration and variability in time spent on each flower, throughout the growing season differed markedly between pollinator species. Flower density, plant density, and the abundance of other insects contributed to the observed variation in pollinator behavioural activity for A. mellifera, E. tenax, M. novae-zelandiae and L. sordidum. Bombus terrestris had the greatest rates and variability of movement, and the greatest rates of flower visitation among all key pollinators studied. Therefore B. terrestris might contribute to gene flow to a greater extent than other key pollinators. Additionally B. terrestris had the greatest variability in the rate of movement, increasing the risk of pollen movement over long distances. In summary, I found that (i) insect abundance and diversity changed with crop phenology and Diptera was the most abundant order collected, (ii) flower density, plant density, and the abundance of other insect pollinators were important factors explaining pollinator behaviour for all key pollinators, except B. terrestris, (iii) B. terrestris might contribute to gene flow to a greater extent than other key pollinators, because it has a greater rate of flower visitation and a greater flight distance between flowers than other pollinators, and (iv) pollen viability tended to decrease with crop development and declined sharply even just 50 m outside the edge of the crop.
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Antes, Vanessa Aparecida. "Parasitismo de Meloidogyne spp. em plantas nativas do oeste paranaense e variabilidade genética de populações de Meloidogyne incognita raça 3". Universidade Estadual do Oeste do Paraná, 2008. http://tede.unioeste.br:8080/tede/handle/tede/1356.
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The aim of this work was to study the parasitism of Meloidogyne incognita on native plants from Western Paraná, Brazil, as well as to assess the genetic variability among different populations belonging to the race 3 of this nematode by RAPD technique. Natural infection was studied in thirty six native plant species, which were identified on the basis of the perineal pattern from mature females and esterase phenotype. Native species that showed no infestation on the root system were inoculated with 1.000 eggs and/or J2 of M. incognita. After 60 days, the inoculated plants were evaluated regarding the number of galls and the number of eggs/or J2 per root. The genetic variability from different single female populations of M. incognita race 3 was studied by RAPD technique, having been tested 10 primers. The native plants that were susceptible to M. incognita parasitism were Rabo-de-Bugio (Lonchocarpus muehlbergianus Hassl.), Ipê Roxo (Tabebuia impetiginosa Mart. Ex DC. Standl), Sanga D água (Croton urucurana Boill), Ipê Amarelo (Tabebuia ahrysotricha Mart ex DC. Standl.), Genipapo (Genipa americana L.), Ariticum Comum (Rollinia mucosa (Jacq.) Baill.) and Aroeira Vermelha (Schinus terebinthifolius Raddi.). On the other hand, M. javanica was found parasiting Café de Bugre (Cordia ecalyculata Vell.), Guatambu Vermelho (Aspidosperma subincanun Mart.) and Tarumã Branco (Cytrarexllum myruanthum Cham.). The DNA polymorphism showed that there was genetic variability among populations from a same race (3) of M. incognita, allowing the separation of them into five genetic groups, through reactions with the primers (O)AK20, A10, AQ12, AS08 and (OP)F01
Objetivou-se com o presente trabalho estudar o parasitismo de Meloidogyne incognita em plantas nativas do oeste paranaense, bem como a variabilidade genética de populações de M. incognita raça 3 pela técnica RAPD. Trinta e seis espécies de plantas nativas foram analisadas com relação à infecção natural por Meloidogyne spp. A identificação de Meloidogyne foi feita com base na configuração perineal de fêmeas maduras e no fenótipo para a isoenzima esterase. Espécies nativas com ausência de galhas no sistema radicular foram inoculadas com 1.000 ovos e/ou J2 de uma população de campo de M. incognita. Após 60 dias da inoculação, as plantas foram avaliadas com relação ao número de galhas e número de ovos e/ou juvenis por raiz. A variabilidade genética de diferentes populações monoespecíficas de M. incognita raça 3 do noroeste paranaense foi estudada pela técnica RAPD com o teste de 10 primers. As plantas nativas hospedeiras de M. incognita foram Rabo-de-Bugio (Lonchocarpus muehlbergianus Hassl.), Ipê Roxo (Tabebuia impetiginosa Mart. Ex DC. Standl), Sanga D água (Croton urucurana Boill), Ipê Amarelo (Tabebuia ahrysotricha Mart ex DC. Standl.), Genipapo (Genipa americana L.), Ariticum Comum (Rollinia mucosa (Jacq.) Baill.) e Aroeira Vermelha (Schinus terebinthifolius Raddi.). Já M. javanica foi encontrado parasitando Café de Bugre (Cordia ecalyculata Vell.), Guatambu Vermelho (Aspidosperma subincanun Mart.) e Tarumã Branco (Cytrarexllum myruanthum Cham.). A análise do polimorfismo do DNA possibilitou a detecção de variabilidade genética para diferentes populações de uma mesma raça (3) de M. incognita, permitindo a separação das populações em 5 grupos genéticos, através de reações com os primers AK20, A10, AQ12, AS08 e F01
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Milton, Joseph J. "Phylogenetic analyses and taxonomic studies of Senecioninae : southern African Senecio section Senecio". Thesis, St Andrews, 2009. http://hdl.handle.net/10023/701.
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Asselin, Sean Robert. "Seed quality improvement in the ogu-INRA CMS system in Oilseed Rape (Brassica napus L.)". 2012. http://hdl.handle.net/1993/8363.
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The ogu-INRA cytoplasmic male sterility (CMS) system is the global leader for the development of high quality hybrid canola and high erucic acid rapeseed (HEAR) cultivars of oilseed rape (Brassica napus L.). The largest challenge for plant breeders using this system is the development of high quality restorer lines (R-lines) due to tight linkage of the radish (Raphanus sativus L.) derived restorer gene PPR-B and elevated seed glucosinolate concentration.
The purpose of this study was to identify improved quality restorer lines for hybrid cultivar development through both field studies and molecular marker development. In the first study 67 R-lines of different genetic backgrounds were screened over the course of two growing seasons and lines with significantly reduced glucosinolate concentration were identified. In the second study a new sequence characterized amplified region (SCAR) marker was successfully developed for the rapid screening of selections for the ogu-INRA CMS restorer gene PPR-B.
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Stangoulis, James Constantine Roy. "Genotypic variation in oilseed rape to low boron nutrition and the mechanism of boron efficiency / by James Constantine Roy Stangoulis". Thesis, 1998. http://hdl.handle.net/2440/19320.
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Bibliography: leaves 132-159.xv, 159 leaves : ill. (some col.) ; 30 cm.
Boron efficiency in oilseed rape (Brassica napua L. and B. juncea L.) was investigated in a wide range of genotypes. Using a solution culture screening of 10 day old seedlings, root length best described shoot growth response, and was used to characterise a total of 65 genotypes. Varieties and breeders lines tolerant of B-deficient growing conditions were identified, and the screening process validated through field trials. B responses in plants sampled at the 'green bud' stage indicated that vegetative growth is important in B efficiency. Studies were conducted to investigate the mechanism of B efficiency in oilseed rape. Results suggest no association between B efficiency and the capacity to acidify the root rhizosphere, or an increased translocation of B from root to shoot. Boron retranslocation was also studied as a mechanism of B efficiency.
Thesis (Ph.D.)--University of Adelaide, Dept. of Plant Science, 1999?
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Kelley, Kerry. "Genetic Variability in Hydrastis Canadensis L. Using Rapd Analysis". 2009. https://scholarworks.umass.edu/theses/253.
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ABSTRACT GENETIC VARIABILITY IN HYDRASTIS CANADENSIS L. USING RAPD ANALYSIS FEBRUARY 2009 KERRY J. KELLEY, B.A. MOUNT HOLYOKE COLLEGE M.A. UNIVERSITY OF MASSACHUSETTS AMHERST Directed by: Professor Lyle Craker Hydrastis canadensis L. (goldenseal) is an endangered perennial wildflower species native to eastern North America. In this study, several populations of goldenseal, (both cultivated and wild type) were analyzed for genetic variability. The samples were collected from plant populations in North Carolina, Ohio, Pennsylvania and West Virginia and preserved using silica gel during collection. Random amplified polymorphic DNA (RAPD) analysis technique was used to generate DNA profiles from individual plants and to estimate genetic variability between groups (cultivated and wild type), among populations within groups and within populations using analysis of molecular variance (AMOVA) and a UPGMA clustering phenogram. Our results demonstrate that the bulk of genetic diversity may be within and among populations, but not between groups. This indicates the need for preservation and conservation efforts at the population level. The next step would be to study goldenseal populations more in depth for underlying causes of the genetic variability observed in this study. Further study of genetic variability with different molecular markers may be needed to clarify the level of diversity for the species at the group level. Increased knowledge of genetic variability and the identification of accessions of goldenseal would prove useful for reintroduction and cultivation strategies.
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Azhagiri, Arun. "Rare paternal plastid inheritance in arabidopsis". 2007. http://hdl.rutgers.edu/1782.2/rucore10001600001.ETD.15779.
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"Metabolomic analysis of transgenic rice engineered for increasing photosynthetic rate and lysine content". 2013. http://library.cuhk.edu.hk/record=b5884448.
Pełny tekst źródłaStreszczenie:
Long, Xiaohang.Thesis (Ph.D.)--Chinese University of Hong Kong, 2013.
Includes bibliographical references (leaves 146-165).
Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web.
Abstract also in Chinese.
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Edwards, Nicola Rachel. "Optimisation of the randomly amplified polymorphic DNA (RAPD) technique for the characterisation of selected South African maize (Zea mays L.) breeding material". Thesis, 2000. http://hdl.handle.net/10413/9812.
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Maize (Zea mays L.) is an important agronomic crop with the maize industry forming an
important component of the South African economy. Considerable effort has been directed
towards the genetic improvement of maize through both conventional breeding and
biotechnology. Genotype identification by DNA fingerprinting is becoming an important activity
in plant breeding. A widely used molecular based and relatively inexpensive method for DNA
fingerprinting is the randomly amplified polymorphic DNA (RAPD) technique. The RAPD
technique was tested in this study for its potential use in maize breeding programmes. Initial
results using the technique showed a low degree of reproducibility, therefore both the DNA
isolation and RAPD protocols were extensively optimised. DNA quality and quantity, and choice
of Taq polymerase buffer were three of the variables found to be influential in ensuring
reproducibility. The ability of the RAPD technique to characterise seven maize genotypes was
evaluated. Sixty random oligonucleotide primers were screened. Forty two primers scored a
total of 233 fragments (an average of 5.5 per primer), but not all primers gave reproducible
profiles. Eighteen primers scored a total of 110 loci for the presence (1) and absence (0) of DNA
fragments. RAPD markers were able to distinguish between all seven genotypes with five primers
producing specific fragments for four genotypes. Genetic similarity matrices were calculated
using two software programmes i.e. Genstat 5™ release 4.1 (1993) and PAUP (Phylogenetic
Analysis Using Parsimony) 4.0 beta version (Swafford, 1998). Cluster analysis was used to
generate dendrograms to visualise the genetic relationships of the seven maize genotypes (only
minor differences were observed between the Genstat or PAUP method of analysis). Genetic
diversity ranged from 0.62 to 0.96. The estimation of genetic relationship was in accordance with
the presumed pedigree of the genotypes showing that the RAPD technique demonstrates potential
for genome analysis of maize. The applicability of the technique for marker assisted selection was
also evaluated. Near-isogenic lines (NILs) for leaf blight (Helminthosporium spp.) were screened
for polymorphisms using a total of 120 primers. Ten primers identified polymorphisms between
the NILs. Four primers produced five polymorphic fragments present in the resistant inbred
K0315Y and absent in the susceptible inbred D0940Y. A small F2 population of 14 individuals
was produced by selfing the F1 of a cross between K0315Y and D0940Y. To speed up the generation time, the F1 and F2 plants were cultured by embryo rescue from 18d old harvested
seed. One fragment of 627 base pairs produced by primer OPB-01 (5' GTTTCGCTCC 3')
showed a 3: 1 segregation in the small F2 population and was considered putatively linked to the
HtN gene for leaf blight resistance. This study shows that the RAPD technique does have
application in maize breeding programmes.Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 2000.
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Kishore, Venkata Krishna. "Mapping quantitative trait loci underlying genome-wide recombination rate and mating system differences in meadowfoam". Thesis, 2002. http://hdl.handle.net/1957/32553.
Pełny tekst źródłaStreszczenie:
Meadowfoam (Limnanthes alba Bentham; Order: Brassicales; Family:
Limnanthaceae) is a self-compatible, predominantly allogamous, insect pollinated
species. Meadowfoam oil is a source of novel unsaturated very-long-chain (VLC) seed
oils (C������ and C������) with low concentrations of saturated fatty acids (typically less than
2%) and outstanding oxidative stability. Here we report the development of 389 SSR
markers for meadowfoam. All the 389 SSRs were screened on 14 meadowfoam
germplasm accessions to assess their utility and efficiency. Ninety-six percent of the
SSR markers (373 out of 389) were polymorphic among the 14-germplasm accessions
(from nine taxa) with a mean heterozygosity of 0.63.
We also report that the physical size of the meadowfoam genome was
estimated to be 5.52 pg using flow cytometry; thus, the meadowfoam genome is ca. 16
times larger than the Arabidopsis genome. Karyotype analyses revealed that the
meadowfoam genome is made up of two metacentric and three submetacentric
chromosomes. Meadowfoam has two pairs of chromosomes with subterminal
nucleolar organizing regions (NOR's). A genetic map comprised of 84 SSR loci
dispersed among five linkage groups with 11 to 22 SSR loci per linkage (6 SSR loci
segregated independently) was constructed. The map was 988.7 cM long with a mean
density of 11.8 cM and minimal clustering of loci.
A total of 20 quantitative trait loci (QTL) were identified for five mating
system characters in meadowfoam, using the SSR linkage map of meadowfoam.
Individual QTL for mating system traits peta1 area (pa), seeds per plant (spp) and
seeds per flower (spf)I account for up to 20% of the backcross phenotypic variance,
with most traits showing QTL effects of 5-15%. The QTL for protandry and chiasma
frequency were adjacent to the QTL for spp and spf. This study has provided evidence
that the correlation between the chiasma frequency and the type of mating system is
not a direct developmental relationship between these factors, but is due to a selective
advantage of the combination of the characters found. The speculation that the genetic
factors underlying chiasma frequency and autonomous seed set have co-evolved
during evolution negates the self-fertilization as an "evolutionary dead end".Graduation date: 2002
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Naguran, Riann. "Fingerprinting of full and half-sib black wattle (Acacia mearnsii) progenies using Random Amplified Polymorphic DNA (RAPD)". Thesis, 2005. http://hdl.handle.net/10413/4745.
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Black wattle (Acacia mearnsii), which belongs to the genus Acacia, is one of the many species of trees or hardwoods grown commercially in South Africa. Black wattle is a species indigenous to Australia and was introduced into South Africa by the van der Plank brothers in 1864. These trees are grown in South Africa because of its tannin-rich bark, the extract of which is used by the leather tanning industry. Black wattle is also grown for its timber, timber products and pulp. The introduction and cultivation history of
black wattle suggests that the South African plantations contain limited genetic variation with relatedness amongst groups estimated to be high, thus implying a narrow genetic base in the South African black wattle population. In this investigation, Random Amplified Polymorphic DNA (RAPD) was used to estimate the genetic variation between seven different black wattle groups. A total number of 34 individuals obtained from different areas in South Africa were examined; Piet Retief (group 47 and 50: half-sibs), Kumbula (group 85: unrelated individuals), Howick (group 400: unrelated individuals) and an unknown area (groups 88, 89, 91: full-sibs). As this investigation was the first of its kind, a DNA isolation method as well as a PCR-RAPD protocol had to be modified. Total genomic DNA was successfully extracted using the CTAB DNA extraction method. This method removed large amounts of tannin present in the cells of the black wattle
leaves and extracted high quality DNA to conduct between 50-100 RAPD reactions. The DNA purities ranged from 0.1 to 1.8, with an average of 1.46. A total of fourteen 10-mer RAPD primer sequences were randomly selected from the Operon Technologies primer list A, and tested in this investigation. Of the 14 primers used, only nine primers produced clear, single and repeatable bands. Therefore nine primers were selected for
subsequent analyses. Ninety one loci that generated bands ranging from 300-3050 base pairs were produced. Seven to 13 loci per primer were generated. A total of 95.6 % of the loci were polymorphic. The overall expected mean heterozygosity (H = 0.3) obtained in this study was high in comparison to other studies conducted on acacias. The high levels of genetic variation were attributed to mating systems, dissortative mating and geographic distribution. The statistical packages POPGENE and ARLEQUIN were used to analyse the RAPD fingerprints. The genetic measures, Nei's diversity and Shannon's Information Index, showed that there was greater diversity exhibited (Nei's gene diversity = 32.09 % and Shannon's = 48.31 %), in the whole population than in each of the groups (with average of Nei's gene diversity = 20.33 % and Shannon's = 34.64 %).
With regards to individual group analyses, low levels of genetic variation was obtained in group 400 (unrelated), from the Howick region, and group 85 (unrelated), from the Kumbula region, (mean 0.14 and 0.17 respectively). The low genetic values were attributed to limited gene exchange occurring in these two areas, bottlenecks and selection pressures. Groups 88, 89 and 91, from the unknown region (full-sib groups), were the most variable in comparison to the other groups, with means of (0.27,0.24 and 0.18 respectively). These high genetic variation values could be due to the fact that gene migration could have occurred between these groups and others in the area. It is thought that most acacias are insect-pollinated and this could have lead to gene migration between groups or populations, thereby explaining the high mean values. The gene flow obtained for the seven groups (FST = 0.174) indicated that great genetic differentiation existed in this population of black wattle studied. This value is higher in comparison to other woody species; however it is similar to other acacia species. UPGMA cluster analysis using Nei's unbiased genetic distance, revealed four distinct clusters of groups corresponding to the distribution areas represented in this study. The
Howick (group 400: unrelated) and Kumbula (group 85: unrelated) were more closely related to each other than to the other groups, since both these groups are from Natal. The Piet Retief groups (groups 47 and 50: half-sibs), branched-off together, indicating that they are distinct from the other groups. The pairwise analysis of identity showed that
the relationship between the group from Howick (group 400: unrelated) and all the other groups from the other regions was the lowest, ranging from 64 % to 79 %. The relationship between all the groups beside the group from Howick (group 400: unrelated) was reasonably high, ranging from 78 % to 90 %. This distance displayed by group 400 (unrelated) from Howick in relation to the groups, is attributed to the fact that it is frost
resistant and the other groups not. Genetic variation was also detected and partitioned, between and within groups, by Analysis of Molecular Variance (AMQVA). Majority of the variation existed within groups (82.65 %) but significant differentiation was recorded between groups (17.44 %). This high level of within group differentiation may be explained by many aspects, such as the species breeding system, genetic drift or genetic isolation of groups or populations. The application of RAPD fingerprinting in
black wattle has provided a more in depth understanding of the genetic variation residing in the South African population. The results achieved implementing this technique has shown that significant genetic variation exists within the black wattle population in South Africa. The results obtained in this study are also important since it is contrary to the expectation that the black wattle population in South Africa has low
genetic variation. This knowledge is of great value to genetically discriminate between individuals or groups, to improve the selection of superior genotypes and allowing improved quality control in breeding programmes and seed orchard management.Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2005.
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Winder, Charles Thomas. "Levels and patterns of genetic diversity in the rare and endangered Cumberland Stitchwort, Minuartia cumberlandensis (Caryophyllaceae)". 2004. http://etd.utk.edu/2004/WinderCharles.pdf.
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Thesis (M.S.)--University of Tennessee, Knoxville, 2004.Title from title page screen (viewed Feb. 2, 2005). Thesis advisor: Randall L. Small. Document formatted into pages (viii, 73 p. : ill. (some col.), maps). Vita. Includes bibliographical references (p. 39-44).
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Sewpersad, Yaksha. "Estimation of genetic variation and marker identification in black wattle (Acacia mearnsii De Wild) with RAPD fingerprinting". Thesis, 2004. http://hdl.handle.net/10413/10016.
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Hadziabdic, Denita. "Evaluation of genetic diversity of flowering dogwood (Cornus florida L.) in the eastern United States using microsatellites". 2010. http://trace.tennessee.edu/utk_graddiss/694.
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Feller, Danielle Sky. "A study of the distribution, ecology, and genetic diversity of Pseudognaphalium saxicola (Fassett) comb. nov. (Asteraceae), a rare annual plant endemic to Wisconsin". 2000. http://catalog.hathitrust.org/api/volumes/oclc/45549422.html.
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Kongjaroon, Chutima. "Investigation into the use of molecular methods to distinguish between species of Caladenia subgenus Calonema". Thesis, 2012. https://vuir.vu.edu.au/21337/.
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The phylogeny of typical spider orchid (Caladenia subgenus Calonema) is investigated for the first time. The analyses were performed using 17 RAPD and 10 ISSR primers on 30 taxa representing the three spider orchid groups (the dilatata, patersonii and reticulata groups) yielding 135 RAPD and 63 ISSR polymorphic markers. The average number of polymorphic markers produced from 17 RAPD and 10 ISSR primers were 5.12 and 4.48, respectively. 76 RAPD markers and 38 ISSR markers were polymorphic within spider orchid species. The highest number of amplified DNA fragments were produced from OPE15 (8.77 fragments) and UBC 842 (6.71 fragments) while OPF04 (2.93 fragments) and UBC 825 (3.02 fragments) gave the smallest number of amplification products. The average Dice genetic similarity of pairs of individuals within a species ranged from 0.772 to 0.939 based on RAPD and from 0.770 to 0.976 for ISSR data.
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Eckstein, Lutz [Verfasser]. "Population biology of rare plants : the effects of ecological and genetic processes for the growth and viability of populations of three endangered floodplain violets = Populationsbiologie seltener Pflanzenarten / von Lutz Eckstein". 2008. http://d-nb.info/991665791/34.
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