Dissertations / Theses on the topic 'Disease and pest resistance'
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Melander, Margareta. "Transgenic resistance to pathogens and pests /." Alnarp : Dept. of Crop Science, Swedish Univ. of Agricultural Sciences, 2004. http://epsilon.slu.se/a496.pdf.
Full textKawchuk, Lawrence Michael. "Molecular characterization of potato leafroll luteovirus and development of genetically engineered resistance." Thesis, University of British Columbia, 1990. http://hdl.handle.net/2429/30684.
Full textLand and Food Systems, Faculty of
Graduate
Wilkes, Meredith Ann. "The Role Of Hydroxamic Acids In Take-all Resistance." Thesis, The University of Sydney, 1997. https://hdl.handle.net/2123/27618.
Full textMarino, Dante. "Screening of Germplasm Accessions from the Brassica Species for Resistance against PG3 and PG4 Isolates of Blackleg." Thesis, North Dakota State University, 2011. https://hdl.handle.net/10365/29053.
Full textNorth Dakota State University. Department of Plant Pathology
USDA North Central Canola Research Program
Northern Canola Growers Association
Gutschow, Minique. "Resistance to Botrytis cinerea in parts of leaves and bunches of grapevine." Thesis, Stellenbosch : Stellenbosch University, 2001. http://hdl.handle.net/10019.1/52435.
Full textENGLISH ABSTRACT: Knowledge of the presence of Botrytis cinerea in morphological parts of bunches and leaves of grapevine would help to find a reliable, sensitive, and specific assay to verify the actual occurrence of latent infection, and to plan strategies for the effective control of B. cinerea bunch rot. The aim of this study was (i) to determine natural B. cinerea infection at specific sites in leaves and bunches of grapevine at different phenological stages, and (ii) to determine resistance in the morphological parts to disease expression. Bunches and leaves of the wine grape cultivar Merlot and the table grape cultivar Dauphine, were collected at pea size, bunch closure and harvest from five vineyards in the Stellenbosch and De Dooms regions respectively. The material was divided into two groups and sealed in polythene bags. The bags were lined with wet paper towels to establish high relative humidity. Leaves and bunches incubated in one group of bags were first treated with paraquat in order to terminate active host responses. These treatments provided conditions that facilitated disease expression under two host resistance levels by different inocula during the period of moist incubation. Disease expression was positively identified by lesion development, and the formation of sporulating colonies of B. cinerea at a potential infection site. Sites in leaves were the blades and petioles. Sites in bunch parts were rachises, laterals and pedicels, and on berries sites were the pedicel-end, cheek and style-end. In Dauphine, the various sites were at all stages classified as resistant to moderately resistant. However, at pea size and bunch closure, in spite of their resistance, nearly all the sites carried high to very high inoculum levels. The only exception was the berry cheek, which carried intermediate inoculum levels at pea size, and low inoculum levels at bunch closure. In nearly all sites, inoculum levels were lower at harvest. The decrease was the most prominent in petioles, rachises, laterals, pedicels and the pedicel-end of the berry. All these sites carried intermediate to low inoculum levels at harvest. In Merlot, sites constantly exibited a resistant reaction, except for the pedicel and pedicel-end of the berry, which changed from resistant at the early developmental stages to susceptible at harvest. Inoculum levels decreased during the season in the rachises and laterals, but were constantly high during the season in the pedicel and pedicel-end of the berry. According to this pattern of natural occurrence, B. cinerea fruit rot in these vineyards was not caused by colonisation of the pistil, and subsequent latency in the style end of grape berries. However, fruit rot was primarily caused by colonisation of the pedicel, and subsequent latency in the pedicel or pedicel-end of the berry. These findings furthermore support the hypothesis of increased host resistance during development, but also indicate that in the Western Cape province, inoculum in vineyards is abundant during the early part of the season, and less abundant later in the season. More information is therefore needed on the behaviour of the different types of B. cinerea inocula on the different morphological parts of grapevine to validate the pathway described for natural B. cinerea infection in vineyards. The penetration and disease expression at the different morphological parts of bunches of two grape cultivars (Dauphine and Merlot) under conditions simulating natural infection by airborne conidia was therefore investigated. The two cultivars did not differ in resistance of the berry cheek, which was at all stages classified as resistant. However, in Dauphine, latent inoculum levels in berry cheeks declined from intermediate at pea size to low at the following stages, whereas in Merlot, levels were intermediate during pea size and at harvest. Some differences between cultivars were found in the resistance of the structural bunch parts, and of their latent inoculum levels. In Dauphine, the rachis reacted susceptible at pea size, and was classified moderately resistant later in the season. Laterals and pedicels were moderate resistant at pea size, and resistant at later stages. Inoculum levels in rachises, laterals and pedicels were high at pea size, but intermediate at bunch closure and at harvest. The finding that B. cinerea infected and naturally occurred more commonly in the tissues of immature than mature bunches, that the structural parts of the bunch carried more B. cinerea than the berry cheek, and that these infections may be more important in B. cinerea bunch rot than infection of the cheek or the style end, suggest that emphasis should be placed on the disease reaction of the pedicel and related parts of immature bunches rather than on the berry. The resistanc-e reaction of leaf blades, petioles, internodes and inflorescences on cuttings, compared to those on older shoots from the vineyard were therefore investigated. In the case of vinelets, leaf blades, petioles, internodes and inflorescences were all classified susceptible to highly susceptible. The different parts furthermore all carried very high latent inoculum levels. In vineyard shoots the petioles and inflorescences showed resistance, and carried intermediate to latent inoculum levels. This finding suggests that leaf blades are not appropriate parts for studying the behaviour of inoculum of B. cinerea and host responses in grape bunches. In stead, petioles and inflorescences of vineyard shoots should be used for this purpose.
AFRIKAANSE OPSOMMING: WEERSTAND TEEN BOTRYTIS CINEREA IN MORFOLOGIESE DELE VAN BLARE EN TROSSE VAN WINGERD Kennis oor die teenwoordigheid van Botrytis cinerea in morfologiese dele van wingerd word benodig vir die ontwerp van 'n betroubare, sensitiewe en spesifieke toets vir die bevestiging van latente infeksies, en vir die implementering van strategieë vir die effektiewe beheer van B. cinerea-vrot. Die doel van hierdie studie was om (i) natuurlike B. cinerea infeksie by spesifieke areas in blare en trosse van wingerd te bepaal, en (ii) om weerstand teen siekte-uitdrukking in hierdie morfologiese dele vas te stel. Trosse en blare van die wyndruif kultivar Merlot en die tafeldruif kultivar Dauphine, is by ertjiekorrel, tros-toemaak en oes in vyf wingerde in die Stellenbosch- en De Doomsomgewing, onderskeidelik, versamel. Die materiaal is in twee groepe verdeel en in polietileen sakkies verseël. Die sakkies is met klam papierdoekies uitgevoer om sodoende hoë relatiewe humiditeit te verseker. Blare en trosse wat in die een groep geïnkubeer is, is eers met paraquat behandel om aktiewe gasheerreaksies te beëindig. Hierdie behandelings het toestande geskep wat gedurende die periode van vogtige inkubasie gunstig was vir siekteontwikkeling deur verskillende inokula by twee gasheer-weerstandsvlakke. Siekteuitdrukking is positief geïdentifiseer deur letsel-ontwikkeling en die vorming van sporuierende kolonies van B. cinerea by 'n potensiële infeksie-area. Dele waarop in die blare gekonsentreer is, was die blaarskyf en -steel. In die trosse was die dele die rachis, lateraal en korrelsteel, en op korrels was dit die korrelsteel-end, wang en styl-end. In Dauphine is die verskillende dele tydens al die fenologiese stadia as weerstandbiedend tot matig weerstandbiedend geklassifiseer. Die verskillende dele her egter, ten spyte van hul weerstandbiedendheid, hoë tot baie hoë inokulumvlakke by ertjiekorrel- en tros-toemaakstadium gedra. Die enigste uitsondering was die korrelwang, wat 'n middelmatige inokulumvlak by ertjiekorrel, en 'n lae inokulumvlak by tros-toemaak, gedra het. Die inokulumvlakke was in byna al die dele laer by oes. Die afname in inokulumvlakke was die prominentste in die blaarstele, rachi, laterale, korreisteie en die korrelsteel-end van die korrel. Al hierdie dele het 'n middelmatige tot lae inokulumvlak by oes gehad. In Merlot was die dele konstant weerstandbiedend, behalwe vir die korrelsteel en die korrelsteel-end van die korrel, wat gewissel het van weerstandbiedend by die vroeë ontwikkelingstadia, tot vatbaar by oes. lnokulumvlakke in die rachis en lateraal het gedurende die seisoen afgeneem; maar was deur die seisoen konstant hoog in die korrelsteel en korrelsteel-end van die korrel. Volgens die patroon van natuurlike voorkoms, word B. cinerea-vrot in hierdie wingerde nie deur kolonisasie van die stamper, en die daaropvolgende latensie in die styl-end van die korrels, veroorsaak nie. Vrot word egter primêr deur kolonisasie van die korrelsteel, en die daaropvolgende latensie in die korrelsteel of korrelsteel-end van die korrel, veroorsaak. Hierdie bevindinge ondersteun die hipotese van toenemende gasheerweerstand gedurende ontwikkeling, en dui ook daarop dat inokulumvlakke in wingerde in die Wes-Kaap provinsie volop is gedurende die eerste deel van die seisoen, en minder volop is later in die seisoen. Meer inligting word dus benodig aangaande die gedrag van die verskillende inokulum tipes van B. cinerea op die verskillende morfologiese dele van wingerd, ten einde die infeksieweg vir natuurlike B. cinerea infeksie in wingerde te bevestig. Die vestiging van latente infeksies in die verskillende morfologiese dele van trosse van twee kultivars (Dauphine en Merlot), onder toestande wat natuurlike infeksie deur luggedraagde konidia simuleer, is dus ondersoek. Die twee kultivars se weerstand in die korrelwang het nie verskil nie en is by alle fenologiese stadia as weerstandbiedend geklassifiseer. Die latente inokulumvlakke in die korrelwang van Dauphine het egter van middelmatig by ertjiekorrel, tot laag in die daaropvolgende stadia afgeneem, terwyl die vlakke in Merlot middelmatig by ertjiekorrel en oes was. Verskille tussen die twee kultivars is gevind ten opsigte van die weerstand in die trosdele, asook hulle latente inokulumvlakke. Die rachis van Dauphine was by ertjiekorrel vatbaar, en matig weerstandbiedend later in die seisoen. Die lateraal en korrelsteel was matig weerstandbiedend by ertjiekorrel en weerstandbiedend by latere stadia. lnokulumvlakke in rachi, laterale en korreisteie was hoog by ertjiekorrel, maar middelmatig by tros-toemaak en oes. Die bevindinge dat B. cinerea natuurlik meer algemeen in die weefsel van onvolwasse trosse voorgekom en laasgenoemde meer algemeen geïnfekteer het, dat B. cinerea se voorkoms hoër was in die morfologiese dele van die tros as in die korrelwang, en dat hierdie infeksies van groter belang in B. cinerea-vrot mag wees as infeksie van die wang of styl-end, dui daarop dat klem gelê moet word op die siektereaksie van die strukturele dele van onvolwasse trosse, eerder as van die korrel. Die weerstand van blaarskywe, blaarstele, internodes en blomtrossies van steggies, in vergelyking met die op ouer lote in wingerde, is dus ondersoek. Blaarskywe, blaarstele, internodes en blomtrossies van steggies is almal as vatbaar tot hoogs vatbaar geklassifiseer. Die verskillende dele het verder ook almal baie hoë latente inokulumvlakke gedra. By die ouer lote van wingerde het die blaarstele en blomtrossies weerstandbiedend vertoon, en middelmatige latente inokulumvlakke gedra. Hierdie bevindinge dui daarop dat blaarskywe nie die ideale morfologiese deel is vir gedragstudies van B. cinerea in druiwetrosse nie. Blaarstele en blomtrossies van ouer lote moet eerder vir die doel gebruik word.
Singh, Rampal. "Characterization of virus disease resistance in Lactuca sativa." Thesis, McGill University, 1994. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=55529.
Full textGeddes, Jennifer M. H., and University of Lethbridge Faculty of Arts and Science. "Fusarium head blight of barley : resistance evaluation and identification of resistance mechanisms." Thesis, Lethbridge, Alta. : University of Lethbridge, Faculty of Arts and Science, 2006, 2006. http://hdl.handle.net/10133/399.
Full textxvii, 196 leaves : ill. ; 29 cm.
MacDonald, Gerald. "The long term effects of apple replant disease treatments on growth and yield of apple trees and an examination of Pratylenchus and Pythium as causal agents /." Thesis, McGill University, 1988. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=61700.
Full textZondo, Patience Thembelihle. "Assessment of inoculation techniques to evalute apple resistance to Phytophthora cactorum." Thesis, Stellenbosch : Stellenbosch University, 2001. http://hdl.handle.net/10019.1/52141.
Full textENGLISH ABSTRACT: Phytophthora cactorum (Lebert & Cohn) Schrot. is the primary cause of crown, collar and root rot diseases of apple (Malus domestica Borkh.) trees worldwide. This pathogen is most destructive in commercial apple orchards under waterlogged soil conditions and has recently been identified as causing serious disease in some South African apple orchards. Crown, collar and root diseases are difficult to control because of their unpredictability and catastrophic nature. The use of resistant cultivars and rootstocks is economical and environmentally considerate. Therefore the need to develop screening techniques that will enable the selection of desirable disease resistant traits as part of an apple-breeding program in South Africa was identified. The work undertaken in this study was aimed at optimizing different techniques to test resistance. Using two direct inoculation techniques (excised stem and intact stem) the aggressiveness of lO isolates of P. cactorum on apple rootstocks was determined. The susceptibilities of five apple rootstocks were also compared. Results have shown isolate by rootstock interaction which means isolate aggressiveness was influenced by rootstocks tested. The selectivity of isolates suggests that there may be several strains of the pathogen. Population studies of the pathogen might contribute valuable information that could lead to better interpretation of results. Rootstock susceptibility was monitored in vitro throughout the season by inoculating at monthly intervals for 26-months. It was observed that during winter, rootstock susceptibility was low compared to high susceptibility during summer. These results have revealed new information regarding changes in the relative resistance of the different rootstocks over the growing season, e.g. the susceptibility pattern of rootstock MMl06 occurred 1 to -2 months later than that of other rootstocks. This finding has important implications on the way in which resistance test results are interpreted, and emphasizes the importance of not relying on point sampling. Furthermore, useful information has been acquired regarding the epidemiology of the disease with regard to "windows of susceptibility". The phenomenon of a phase shift in susceptibility of different rootstocks needs to be tested on a broader scale to assess whether it has any practical application on resistance testing. Although different inoculation techniques are applied in breeding programs, up to now there is no consensus on which technique works best for seedling selections. Since large numbers of individuals must be tested to improve the chances of detecting resistant genotypes, mass inoculations of young seedlings is a rapid way of identifying resistant individuals. Two different screening methods were tested during this study. Using the sand-bran technique, seedlings were transplanted onto inoculated soil and the root mass was used as a measure of resistance. In a second method zoospore inoculum was applied to seedlings growing in a sand:bark mixture at different concentrations and the seedlings were subjected either to water drenching or not. In both trials the aggressiveness of isolates differed significantly from each other and only higher inoculum concentrations were effective in causing disease. The age of seedlings used in tests emerged as an important factor. Seedlings under five-months-old should not be used. Drenching inoculated seedlings enhanced disease development but the production of sufficiently high numbers of zoospores was a laborious task. Thus, it is recommended that the sand-bran inoculum technique be tested with the drenching treatment for mass selection. In conclusion this study confirms the importance of both choice of isolate and choice of inoculation intervals in determining susceptibility of rootstocks to infection. In spite of the fact that stem inoculation bioassays have limited resemblance to natural disease situations, these bioassays are useful for obtaining an indication as to whether genotypes have a degree of resistance and merit further testing. For this reason refinement of the stem inoculation bioassay is worthwhile pursuing. With regard to seedling trials, both the sand-bran and the zoospore technique appear promising but refinement of these techniques is necessary in order to present a more practical way of testing large volumes of seedlings.
AFRIKAANSE OPSOMMING: Evaluering van inokulasietegnieke om weerstand teen Phytophthora cactorum in appels te evalueer: Phytophthora cactorum (Lebert & Cohn) Schrot. is die primêre oorsaak van kroon-, kraag en wortelvrot van appelbome (Malus domestica Borkh.). Dit is die mees verwoestende patogeen in kommersiële appelboorde waar daar versuipte toestande grond voorkom. P. cactorum is onlangs identifiseer as die patogeen wat ernstige kroon- en kraag-verotting in Suid Afrikaanse appelboorde veroorsaak. Kroon-, kraag- en wortelvrot is moeilik om te beheer as gevolg van die onvoorspelbaarheid en rampspoedige aard van die siekte. Die gebruik van kultivars en onderstamme wat weerstandbiedend is teen siektes en plae is omgewingsvriendelik en is ekonomies van belang, dus het die behoefte ontstaan om inokulasietegnieke te ontwikkelom weerstandige saailinge te identifiseer en te selekteer as deel van 'n appelteelprogram in Suid Afrika. Die doelwit van hierdie studie is om verskillende inokulasietegnieke te toets en te verfyn om weerstand in appelsaailinge te identifiseer. Deur gebruik te maak van twee inokulasietegnieke (die afgesnyde loot- en intakte loot tegniek), is die relatiewe aggressiwiteit van 10 isolate van P. cactorum en die vatbaarheid van vyf appelonderstamme ondersoek. Resultate het aangetoon dat die aggressiwiteit van die isolate gevarieer het na aanleiding van die onderstam wat getoets is. Die selektiwiteit van die isolate is 'n aanduiding dat daar moontlik verskeie rasse van die patogeen voorkom. Toekomstige studies op die populasiestruktuur van P. cactorum sal 'n belangrike bydrae maak tot die interpretasie van resultate oor weerstand en weerstandsteling. Die vatbaarheid van onderstamme was ook in in vitro proewe ondersoek deur maandelikse inokulasies toe te pas oor 'n tydperk van 26 maande. Dit is opgemerk dat die onderstamvatbaarheid gedurende die winter laag was in vergelyking met die somer. Nie al die onderstamme het dieselfe gereageer gedurende verskillende toetstye nie. Hierdie resultate toon aan dat die relatiewe weerstand van verskillende onderstamme oor die groeiseisoen verskil, byvoorbeeld die vatbare reaksie van die onderstam 'l\.1MI06' het een tot twee maande later voorgekom in vergelyking met ander onderstamme wat getoets is. Hierdie bevinding het belangrike implikasies op die interpretasie van weerstandstoetsing en beklemtoon die moontlike tekortkominge in enkelproefwaarnemings. Bruikbare inligting ten opsigte van die epidemiologie van die siekte is versamel wat beskryf kan word in terme van vensters van vatbaarheid wat verskil van onderstam tot onderstam. Verdere ondersoeke in die verband word aanbeveel. Hoewel verskeie inokulasietegnieke bestaan om jong saailinge vir weerstand te toets, is daar tot op hierdie stadium nog nie ooreenstemming oor die beste tegniek wat toegepas moet word om saailingseleksie te doen nie. Omdat groot getalle saailinge getoets moet tydens die seleksieproses sal massa-inokulasie van saailinge die aangewese metode wees. Twee verskillende inokulasie tegnieke is getoets in die studie. Deur gebruik te maak van die sandsemel tegniek, is saailinge geplant in geinfesteerde plantmedium, waartydens die wortelmassa van saailinge gebruik is om die reaksie op infeksie te kwantifiseer. Die soëspoor inokulasietegniek was toegepas op saailinge wat in 'n sand en basmengsel geplant is teen verskillende inokulurnkonsentrasies. 'n Waterverdrenkingsbehandeling is ook getoets. In albei hierdie proewe het die aggressiwiteit van die isolate van mekaar verskil. Slegs die hoër inokulumkonsentrasies was effektief in die ontwikkeling van die siekte. Die ouderdom van saailinge is ook uitgewys as 'n belangrike faktor wat 'n rol speel in weerstandstoetsing. Saailinge jonger as 5 maande word nie aanbeveel vir hierdie toetse nie. Verdrenking van saailinge het die voorkoms van die siekte verhoog, maar die produksie van groot getalle soëspore was 'n beperkende faktor in die uitvoering van die proef Dit word aanbeveel dat die sand-semel inokulasietegniek verder evalueer moet word onder verskeie toestande, onder andere deur dit met verdrenkinghte kombineer. Die belang van die keuse van isolaat en inokulasiedatum in bepaling van relatiewe weerstand van onderstamme teen P. cactorum is tydens die studie bevestig. Afgesien van die beperking van die staminokulasietegnieke in soverre dit verwyderd is van natuurlike infeksie, word die tegnieke aanbeveel om 'n indikasie te kry van die relatiewe weerstand van onderstamme. Beide die sand-semel en soëspoor tegnieke kan gebruik word om weerstandige saailinge te identifiseer, maar tegniese verfyning van hierdie tegnieke is nodig om saailinge in massa te evalueer.
Golegaonkar, Prashant G. "Genetic and molecular analysis of resistance to rust diseases in barley." Thesis, The University of Sydney, 2007. http://hdl.handle.net/2123/3549.
Full textGolegaonkar, Prashant G. "Genetic and molecular analysis of resistance to rust diseases in barley." University of Sydney, 2007. http://hdl.handle.net/2123/3549.
Full textThe responses of 92 barley genotypes to selected P. hordei pathotypes was assessed in greenhouse tests at seedling growth stages and in the field at adult plant growth stages to determine known or unknown resistances. On the basis of multipathotype tests, 35 genotypes were postulated to carry Rph2, Rph4, Rph5, Rph12, RphCantala alone or combinations of Rph2 + Rph4 and Rph1 + Rph2, whereas 52 genotypes lacked detectable seedling resistance to P. hordei. Five genotypes carried seedling resistance that was effective to all pathotypes tested, of which four were believed to carry uncharacterised resistance based on pedigree information. Field tests at adult plant growth stages indicated that while 28 genotypes were susceptible, 57 carried uncharacterised APR to P. hordei. Pedigree analysis indicated that APR in the test genotypes could have been derived from three different sources. The resistant responses of seven cultivars at adult plant growth stages were believed to be due to the presence of seedling resistance effective against the field pathotypes. Genetic studies conducted on 10 barley genotypes suggested that ‘Vada’, ‘Nagrad’, ‘Gilbert’, ‘Ulandra (NT)’ and ‘WI3407’ each carry one gene providing adult plant resistance to P. hordei. Genotypes ‘Patty’, ‘Pompadour’ ‘Athos’, ‘Dash’ and ‘RAH1995’ showed digenic inheritance of APR at one field site and monogenic inheritance at a second. One of the genes identified in each of these cultivars provided high levels of APR and was effective at both field sites. The second APR gene was effective only at one field site, and it conferred low levels of APR. Tests of allelism between resistant genotypes confirmed a common APR gene in all genotypes with the exception of ‘WI3407’, which based on pedigree information was genetically distinct from the gene common in ‘Vada’, ‘Nagrad’, ‘Patty’, ‘RAH1995’ and ‘Pompadour’. An incompletely dominant gene, Rph14, identified previously in an accession of Hordeum vulgare confers resistance to all known pathotypes of P. hordei in Australia. The inheritance of Rph14 was confirmed using 146 and 106 F3 lines derived from the crosses ‘Baudin’/ ‘PI 584760’ (Rph14) and ‘Ricardo’/‘PI 584760’ (Rph14), respectively. Bulk segregant analysis on DNA from the parental genotypes and resistant and susceptible DNA bulks from F3 lines using diversity array technology (DArT) markers located Rph14 to the short arm of chromosome 2H. Polymerase chain reaction (PCR) based marker analysis identified a single simple sequence repeat (SSR) marker, Bmag692, linked closely to Rph14 at a map distance of 2.1 and 3.8 cM in the populations ‘Baudin’/ ‘PI 584760’and ‘Ricardo’/‘PI 584760’, respectively. Seedlings of 62 Australian and two exotic barley cultivars were assessed for resistance to a variant of Puccinia striiformis, referred to as BGYR, which causes stripe rust on several wild Hordeum species and some genotypes of cultivated barley. With the exception of six Australian barley cultivars and an exotic cultivar, all displayed resistance to the pathogen. Genetic analyses of six Australian barley cultivars and the Algerian barley ‘Sahara 3771’, suggested that they carried either one or two major seedling resistance genes to the pathogen. A single recessive seedling resistance gene, Bgyr1, identified in ‘Sahara 3771’ was located on the long arm of chromosome 7H and flanked by restriction fragment length polymorphism (RFLP) markers wg420 and cdo347 at genetic distances of 12.8 and 21.9 cM, respectively. Mapping resistance to BGYR at adult plant growth stages using a doubled haploid population derived from the cross ‘Clipper’/‘Sahara 3771’ identified two major QTLs on the long arms of chromosomes 3H and 7H that explained 26 and 18% of total phenotypic variation, respectively. The QTL located on chromosome 7HL corresponded to the seedling resistance gene Bgyr1. The second QTL was concluded to correspond to a single adult plant resistance gene designated Bgyr2, originating from cultivar ‘Clipper’.
Marchione, Wesley A. "Pathogen resistance genes and proteins in orchids." Virtual Press, 2003. http://liblink.bsu.edu/uhtbin/catkey/1260625.
Full textDepartment of Biology
Ubalijoro, Eliane. "Characterization of resistance to lettuce mosaic virus in Lactuca sativa." Thesis, McGill University, 1994. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=22821.
Full textGalagedara, Nelomie Nayanathara. "Identification of Quantitative Trait Loci for Resistance to Tan Spot in Durum Wheat." Thesis, North Dakota State University, 2018. https://hdl.handle.net/10365/28765.
Full textArcelin, Rachel. "A survey of carrot diseases on muck soils in the Montreal area and evaluation of partial resistance to Cercospora blight in carrot cultivars /." Thesis, McGill University, 1991. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=60521.
Full textGreenhouse and field studies were carried out to evaluate partial resistance to Cercospora blight in 111 carrot cultivars based on the mean incubation period (MIP), the proportion of leaf area diseased (PLAD), and the sporulation / mm$ sp2$ lesion area (SPO). Significant differences among varieties were observed for all the parameters studied under greenhouse conditions and a significant negative correlation was found between PLAD and MIP (r = $-$0.29). Resistance equivalents were calculated for the PLAD, as proportions of the cultivar Dagger, so that they could be incorporated in a fundamental forecast model.
Wellings, Colin Ross. "Host: pathogen studies of wheat stripe rust in Australia." Thesis, Department of Agricultural Genetics and Biometry, 1986. http://hdl.handle.net/2123/14544.
Full textByrne, Katharine. "Gene flow and insecticide resistance in the mosquito Culex pipiens." Thesis, Queen Mary, University of London, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.244074.
Full textReid, Lana M. (Lana Marie). "Resistance of maize silk to Fusarium graminearum." Thesis, McGill University, 1991. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=70316.
Full textMathieu, Danielle. "Effects of temperature and duration of leaf wetness on infection of celery by Septoria apiicola, and cultivar screening for partial resistance." Thesis, McGill University, 1991. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=61198.
Full textWang, Hongxia. "Identification of Molecular Markers Linked to X-Disease Resistance in Chokecherry." Diss., North Dakota State University, 2012. https://hdl.handle.net/10365/26565.
Full textFreeborough, Michael-John 1971. "A pathogen-derived resistance strategy for the broad-spectrum control of grapevine leafroll-associated virus infection." Thesis, Stellenbosch : Stellenbosch University, 2003. http://hdl.handle.net/10019.1/53285.
Full textENGLISH ABSTRACT: Grapevine leafroll-associated virus-3 is one of ten members of the C/osteroviridae that are known to infect grapevine. Nine of these viruses are associated with grapevine leafroll disease, of which GLRaV-1 and GLRaV-3 are the most important and widespread. Members of the C/osteroviridae are unique amongst the viruses, as it is the only known family whose members encode a heat shock protein 70 kOa homolog (Hsp70h). The Hsp70h is a movement protein (MP) that is required for the active translocation of the virion structure through the plasmodesmata into adjacent cells. Broad-spectrum resistance to unrelated viruses can be obtained by a pathogen-derived resistance (POR) strategy that is based on the expression of a dysfunctional MP in plants. The Hsp70h has two distinct domains. The N-terminal two thirds of the protein is an ATPase domain and shares high homology with the ATPase domains of all Hsp70h proteins from the C/osteroviridae and Hsp70 proteins from the prokaryote and eukaryote kingdoms. Conserved amino acids are found in the ATPase domain and are required for the positioning of the ATP at the catalytic site for ATP hydrolysis. The C-terminal domain is variable and the function of this domain in the Closteroviridae is not known. In prokaryote and eukaryote Hsp70 proteins, the C-terminal domain is required for protein-protein interactions. The American NY-1 isolate of GLRaV-3 has been sequenced and POR strategies have been attempted with the coat protein, divergent coat protein and replicase genes, but not with a dysfunctional form of the hsp70h gene. In this study, double-stranded RNA was isolated from a commercial vineyard with unknown virus status, but with distinct grapevine leafroll symptoms, and from two grapevine sources of known virus status, one with mild and one with severe symptoms. The GLRaV-3 hsp70h gene was amplified by RT-PCR from the dsRNA and the gene sequence was analysed. The hsp70h gene from the three virus sources contained more than 94% nucleotide sequence homology to the NY-1 isolate and the conserved amino acids required for ATPase activity were present. The hsp70h gene isolated from GLRaV-3 from a commercial Stellenbosch vineyard showing clear leafroll symptoms was selected for further work and was subjected to site-directed mutagenesis to engineer four point mutations in the gene. These four mutations resulted in the substitution of Asn for Asp", Gly for Thr1O, Lys for Glu 174 and Asn for Asp 197. The wild type (WT) and mutated (Mut) forms of the hsp 70h genes were cloned into a bacterial expression vector. Expression of both the WT- and Mut-Hsp proteins was achieved, and the protein was expressed in the insoluble inclusion bodies. All attempts to refold and isolate active proteins from the inclusion bodies were unsuccessful. Attempts to increase the concentration of soluble protein within the expressing bacteria were unsuccessful. Due to the lack of active protein, biochemical tests on the ATPase activity of the WT- and Mut-Hsp proteins could not be conducted. The wt- and mut-hsp genes were cloned into a plant expression vector for transformation into tobacco plants. These transformations were successful and gave rise to 22 Km' and 18 Km' plants from the WT- and Mut-Hsp constructs respectively. Two plant lines, M5 and M10, transformed with the mut-hsp transgene construct, appeared to have a high level of resistance to the challenging potato X potexvirus, whereas all the other tested plants were susceptible to the challenging virus. It was thus shown that a dysfunctional form of the GLRaV-3 Hsp70h could provide resistance to an unrelated virus in tobacco.
AFRIKAANSE OPSOMMING: Wingerdrolblaar-geassosieerde virus 3 (GLRaV-3) is een van 10 lede van die Closteroviridae wat wingerd kan infekteer. Nege van die virusse is met wingerdrolblaar geassosieer. Die GLRaV-1 en GLRaV-3 is die belangrikste en mees wyd verspreide lede van die rolblaar-geassosieerde Closteroviridae. Lede van die Closteroviridae is uniek in die opsig dat die virusse vir 'n 70 kDa-homoloë hitteresponsproteïen (Hsp70h) kodeer. Die Hsp70 is 'n bewegingsproteïen (MP) wat belangrik is vir die translokasie van die virus deur die plasmodesmata na die naasliggende sel. Breë-spektrum weerstand teen onverwante virusse kan behaal word deur 'n patogeen-afgeleide weerstandstrategie (POR), wat op die uitdrukking van 'n disfunksionele MP wat in plante uitgedruk word, gebaseer is. Die Hsp70hproteïen het twee gebiede. Die N-terminale gebied is In ATPase-gebied en toon hoë homologie met ander ATPase-gebiede van Hsp70h-proteïene van die Closteroviridae, asook die prokariotiese en eukariotiese koninkryke. Gekonserveerde aminosure wat belangrik is vir die posisionering van ATP in die katalitiese domein vir ATP-hidrolise is in die ATPase-gebied gevind. Die C-terminale gebied is variërend en die funksie van die gebied in die Closteroviridae is onbekend. In prokariotiese en eukariotiese Hsp70h-proteïene is die C-terminale gebied belangrik vir proteïenproteïen interaksies. Die nukleotiedvolgorde van die Amerikaanse NY-1-isolaat van GLRaV-3 is al bepaal en POR-strategieë is ook op die kapsiedproteïen, uiteenlopende kapsiedproteïen en die replikasie-proteïen uitgevoer, maar nog nie op 'n disfunksionele vorm van die Hsp70h-geen nie. In hierdie studie is dubbelstring-RNA (dsRNA) van 'n kommersiële wingerd met onbekende virusstatus wat rolblaarsimptome toon, geïsoleer, asook van twee wingerde met 'n bekende virusstatus, een met ligte en een met strawwe simptome. Die GLRaV-3 hsp70h-geen is met hulp van die polimerasekettingreaksie-metode (PKR) vanaf die dsRNA geamplifiseer en die geen se nukleotiedvolgorde is bepaal. Die hsp 70-gene van drie verskillende wingerde het meer as 94% homologie met die NY-1-isolaat getoon. Die gekonserveerde aminosure wat vir ATPase-aktiwiteit belangrik is, was teenwoordig. Die hsp70h-geen van GLRaV-3, wat uit 'n kommersiële wingerd met duidelike rolblaarsimptome in die Stellenbosch-gebied geïsoleer is, is vir verdere navorsing gekies en dit is aan setel-gerigte mutagenese blootgestelom vier mutasies van die geen te bewerkstellig. Die gevolg van hierdie vier mutasies was die verandering van Asn na Asp", Gly na Thr1o, Lys na Glu174 en Asn na Asp197. Die wilde (WT) en veranderde (Mut) vorms van die hsp-gene is in 'n bakteriese uitdrukkingsvektor gekloneer. Uitdrukking van beide die WT- en die Mut-Hspproteïene is behaal, maar die proteïene was in die onoplosbare fraksie geleë. Pogings om die onoplosbare proteïene te isoleer en in 'n aktiewe oplosbare vorm te verkry, was onsuksesvol. Verdere pogings om die proteïene in die oplosbare fraksie van die bakteriese ekspressiesisteem uit te druk, was ook onsuksesvol. As gevolg van die gebrek aan aktiewe proteïen kon biochemiese toetse nie op die ATPaseaktiwiteit van die WT- en Mut-Hsp proteïne gedoen word nie. Die wt- en mut-hsp-gene is ook in In plantekspressievektor gekloneer vir transformasie in tabakplante. Hierdie transformasies was suksesvol en het aanleiding gegee tot 22 kanamisienbestande (Km') en 18 Km' plante vanaf die WT- en Mut-Hspkonstrukte onderskeidelik. Twee plantlyne, M5 en M10, wat met die mut-hsptransgene getransformeer is, het 'n hoë vlak van weerstand teen die infekterende aartappelvirus X getoon in vergelyking met ander plante wat met die virus geïnfekteer is. Daar is dus bewys gelewer dat 'n disfunksionele vorm van die GLRaV-3 Hsp70h weerstand kan bied teen 'n onverwante virus in tabak.
au, lars kamphuis@csiro, and Lars Gian Kamphuis. "Genetic dissection of disease resistance to Phoma medicaginis in Medicago truncatula." Murdoch University, 2007. http://wwwlib.murdoch.edu.au/adt/browse/view/adt-MU20090424.121918.
Full textMazaheri, Lucy. "Development of a Molecular Marker to Track APA G40199 Introgression in Common Bean for Bruchid Resistance." Thesis, North Dakota State University, 2018. https://hdl.handle.net/10365/29300.
Full textUnited States. Agency for International Development
United States. Global Hunger and Food Security Initiative (Cooperative Agreement No. EDH-A-00-07-00005-00)
Ye, Xiang Sheng. "Mechanisms of resistance to bean rust, Uromyces appendiculatus, in bean, Phaseolus vulgaris." Thesis, The University of Sydney, 1987. https://hdl.handle.net/2123/26186.
Full textDufresne, Philippe J. "Development and validation of molecular markers for the detection of disease resistance alleles in Lactuca sativa." Thesis, McGill University, 2002. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=78352.
Full textBierman, Anandi. "Mapping and survey sequencing of Dn resistance genes in Triticum aestivum L." Thesis, Stellenbosch : Stellenbosch University, 2015. http://hdl.handle.net/10019.1/96912.
Full textENGLISH ABSTRACT : Diuraphis noxia Kurdjumov (Russian Wheat Aphid; RWA) is a pest of wheat and barley that has spread from its home range in the fertile crescent to most wheat producing countries except Australia. Since its first introduction to South Africa and the USA in the late 20th century, breeding programs for wheat phenotypes resistant to the aphid were put in place. Conventional breeding practices rely on phenotypic screening to verify traits carried by offspring and genetic tools such as marker assisted selection (MAS) have greatly aided this process in speed and accuracy. The size and complexity of the wheat genome, its allopolyploid nature and repetitive elements have, however, posed a challenge to studies on the genetics of this cereal crop. Many studies have focused on chromosome 3B which is the largest of the wheat chromosomes and easily separated from the redundant genomic background by techniques such as flow cytometry. The similarity in size of the remaining chromosomes however, limits the application of flow cytometry to their isolation. Databases such as Grain-Genes (http://wheat.pw.usda.gov/GG2/index.shtml) house marker data from various mapping studies for all wheat chromosomes and in 2014 the International Wheat Genome Sequencing Consortium (IWGSC) completed the draft genome sequence of wheat categorized by chromosome. Sources of resistance (Dn resistance genes) against RWA are located on chromosome 7D. but despite the marker and sequence data available currently, mapping studies specific for the Dn resistance genes are few. Additionally, sequence data available is derived from cultivars susceptible to RWA and is not comprehensively annotated and assembled in many cases. In this study, we demonstrate a novel, combined approach to isolate and characterize the Dn resistance genes through the use of a genetic map constructed from Amplified Fragment Length Polymorphism (AFLP), Expressed Sequence Tag (EST) and microsatellite markers and a physical map constructed from Next Generation Sequencing (NGS) data of ditelosomic chromosomes (7DS and 7DL) isolated by microdissection on the PALM microbeam system. A 122.8 cM genetic map was produced from 38 polymorphic AFLP markers and two ESTs with the microsatellite Xgwm111 as anchor to related genetic maps. Through comparison to maps available on GrainGenes the location of the Dn1 resistance gene was narrowed down to a deletion bin (7DS5-0.36-0.62) on the short arm of chromosome 7D with an AFLP marker (E-ACT/M-CTG_0270.84) mapping closely at 3.5 cM and two ESTs mapping at 15.3 cM and 15.9 cM from Dn1. Isolation of individual chromosome arms 7DS and 7DL using the PALM Microbeam system allowed sequencing of the chromosome without the redundancy of the remainder of the hexaploid genome. Through isolating the chromosome arms in this way, a >80-fold reduction in genome size was achieved as well as a major reduction in repetitive elements. Analysis of the sequencing data confirmed that 7DL is the physically shorter arm of the chromosome though it contains the majority of protein coding sequences.
AFRIKAANSE OPSOMMING : Diuraphis noxia Kurdjumov (Russiese koring-luis; RWA) is « pes wat op koring en gars voorkom. Die pes het vanaf sy tuiste in die midde Ooste na meeste koringproduserende lande behalwe Australië versprei. Sedert die eerste bekendstelling van RWA in Suid Afrika en die VSA in die vroeë 20ste eeu is teelprogramme ten gunste van koring lyne met weerstand teen RWA begin. Tradisionele teelprogramme maak op fisieise observasie van die fenotipe staat om te verifieer of plante in die nageslag die gewenste eienskap dra. Genetiese metodes soos merkerondersteunde seleksie (MAS) versnel hierdie selekteringsproses grootliks. Die grootte en kompleksiteit van die koring genoom asook die polyploïde en herhalende natuur daarvan is « groot hindernis vir genetiese studies van hierdie graangewas. Baie studies het op chromosoom 3B gefokus wat die grootste van die koring chromosome is en dus maklik vanaf die res van die oorbodige genomiese agtergond deur tegnieke soos vloeisitometrie geskei word. Die ooreenkoms in grootte tussen die res van die chromosome bemoeilik die toepassing van vloeisitometrie om hulle te isoleer. Databasisse soos GrainGenes (http://wheat.pw.usda.gov/GG2/index.shtml) bevat merker data vanaf verskeie karterings-studies vir al die chromosome en in 2014 het die "International Wheat Genome Sequencing Consortium"(IWGSC) die voorlopige basispaarvolgorde van die koring genoom bekendgestel, gekategoriseer volgens chromosoom. Weerstandsbronne (Dn weerstandsgene) teen RWA kom meestal op chromosoom 7D voor. Ten spyte van merker en basispaarvolgorde data tans beskikbaar is karterings-studies spesifiek tot die Dn gene skaars en basispaarvolgorde data is vanaf kultivars afkomstig wat nie weerstandbiedend teen RWA is nie en waarvan die annotasie en samestelling baie keer nie goed is nie. In hierdie studie demonstreer ons « nuwe, gekombineerde aanslag om die Dn weerstandsgene te isoleer en karakteriseer deur van « genetiese kaart opgestel met "Amplified Fragment Length Polymorphism"(AFLP), "Expressed Sequence Tag"(EST) en mikrosatelliet merkers asook « fisiese kaart saamgestel deur die volgende-generasiebasispaarvolgordebepaling van ditelosomiese chromosome (7DS en 7DL) geïsoleer deur mikrodisseksie met die "PALM Microbeam"sisteem gebruik te maak. « Genetiese kaart van 122.8 cM was met 38 polimorfiese AFLP merkers en twee EST merkers geskep. Die mikrosatelliet, Xgwm111, is ook ingesluit en het as anker vir verwante genetiese-kaarte gedien. Deur vergelyking met genetiese-kaarte op GrainGenes is die posisie van die Dn1 weerstandsgeen vernou na « delesie bin (7DS5-0.36-0.62) op die kort arm van chromosoom 7D met « AFLP merker (EACT/ M-CTG_0270.84) wat ongeveer 3.5 cM vanaf die geen karteer. Die twee EST merkers is 15.3 cM en 15.9 cM vanaf die geen gekarteer. Isolering van die individuele chromosoom arms, 7DS en 7DL, deur van die "PALM Microbeam"sisteem gebruik te maak het basispaarvolgordebepaling van die chromosoom toegelaat sonder die oortolligheid van die res van die hexaploïde genoom. Deur die chromosoom so te isoleer is « >80-maal verkleining in genoom grootte bereik insluitend « groot reduksie in herhalende elemente. Analise van die data vanaf basispaarvolgordebepaling het bevestig dat chromosoom 7D die fisiese kleiner chromosoom is maar dat dit die meerderheid van proteïn koderende basispaarvolgordes bevat.
Kusmiyati, Florentina. "Pubescence in red clover : its inheritance and its relationship to potato leafhopper resistance." Thesis, McGill University, 1995. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=22750.
Full textDeng, Yinghai 1966. "Development and disease resistance of leafy reduced stature maize (Zea mays L.)." Thesis, McGill University, 2001. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=38177.
Full textUsing a wide range of the most recently developed LRS hybrids and some conventional hybrids, a two-year field experiment was conducted to examine the HI and disease resistance of LRS maize. HI, yield, and yield components were compared between the two genotype groups (LRS and conventional) under different population densities. The resistance to the natural incidence of common smut and artificially inoculated Gibberella ear rot was also tested. Morphology and fractal dimension analyses of roots at an early development stage were conducted in indoor experiments. These analyses were performed with WinRHIZO (version 3.9), an interactive scanner-based image analysis system.
This work showed that: (1) There was no relationship between the HI and maturity; higher HIs can also exist among the medium and late maturity LRS hybrids. (2) While LRS maize hybrids have the potential for high yield this was not realized in the LRS hybrids used in this work. Further breeding and development of optimum management practices are needed to fully exploit this potential. (3) During early development LRS hybrids generally had more branching and more complex root systems than conventional hybrids. (4) Fractal dimension, as a comprehensive estimation of root complexity, was highly related to major root morphological variables, such as root total length, surface area, branching frequency and dry mass. (5) Of the hybrids tested the greatest resistance to both common smut and Gibberella ear rot, two major ear diseases, occurred in some of the LRS types.
Hossain, Mohammad Abul. "Powdery mildew on barley : pathogen variability in South Australia : resistance genes in cv. Galleon /." Title page, contents and abstract only, 1986. http://web4.library.adelaide.edu.au/theses/09PH/09phh8287.pdf.
Full textVan, Straten Celene Debra. "The construction of plant expression vectors for the introduction of leafroll disease resistance in grapevine." Thesis, Stellenbosch : Stellenbosch University, 2000. http://hdl.handle.net/10019.1/51950.
Full textENGLISH ABSTRACT: Grapevine leafroll is one of the most damaging viral diseases that affect many viticultural regions of the world. Numerous reports over the last few years have associated closterovirus-like particles with leafroll disease. To date, eight serologically distinct closteroviruses have been isolated from leafroll infected vines, of which grapevine leafroll associated closterovirus-3 (GLRaV-3) is the best characterized. Virus resistance in transgenic plants based on the expression of a virusderived gene is known as pathogen-derived resistance. The viral coat protein (CP) gene, which expresses a structural protein responsible for coating the virus particles, was used in the first demonstration of virus-derived resistance. Coat protein-mediated resistance is currently the most feasible and most widely used method to obtain virus resistance in crop plants. The CP gene of a South African isolate of GLRaV-3 infected grapevine was isolated, cloned and sequenced. Double stranded RNA (dsRNA) was extracted from GLRaV-3 infected material and a high molecular weight band, of -18 kb was identified from infected vines. The dsRNA was used as a template in a reverse transcription PCR together with GLRaV-3 CP gene specific primers for the amplification of the GLRaV-3 CP gene (975 bp). The GLRaV-3 CP gene was cloned into the pGem®-T Easy vector. Clones hosting the CP gene in the sense (pLR3CP+) and antisense (pLR3CP-) orientations respectively were obtained. The sequence obtained from these two clones showed 99.26 % similarity to the only other GLRaV-3 CP nucleotide sequence available. The GLRaV-3 CP gene was excised from pLR3CP+ and pLR3CP- and subcloned into a plant expression vector, pCAMBIA 3301 in the sense (pCamBLR3CP+) and antisense (pCamBLR3CP-) orientations respectively, therefore enabling sense and antisense gene expression in transgenic plants. The GLRaV-3 CP gene was also subcloned from pCamBLR3CP+ into another plant expression vector, pCAMBIA 2301 in the sense orientation and designated as pCVSLR3CP+. These three constructs were given to Dr. M. Vivier (Institute for Wine Biotechnology, Stellenbosch) for grapevine transformation experiments. Two of these constructs, pCamBLR3CP+ and pCamBLR3CP- as well as pCAMBIA 3301 were used to transform Nicotiana tabacum by Agrobacterium tumefaciens-mediated transformation. Plants were selected for their ability to withstand the herbicide, Basta. This resistance is due to the presence of a plant selectable marker gene on each of these constructs, known as the bar gene. PCR with GLRaV-3 CP gene specific primers showed no amplification of the GLRaV-3 CP gene in the plants transformed with pCamBLR3CP+ and pCamBLR3CP-. Southern blot analysis with the GLRaV-3 CP gene as hybridization probe showed no signal for these plants, thus confirming the PCR results. PCR with bar gene specific primers showed no amplification of the bar gene in the plants infected with pCAMBIA 3301. The plants transformed with pCamBLR3CP+ and pCamBLR3CP- were also screened for the presence of the bar gene. Three of the eight plants tested showed amplification of the -560 bp bar gene. This result suggests that these plants were transformed with pCAMBIA 3301 (vector without the ligated GLRaV-3 CP gene) and not pCamBLR3CP+ or pCamBLR3CP- as had been expected. This project provides preliminary work for the subsequent transformation of grapevine with the GLRaV-3 CP gene, in an attempt to impart virus resistance.
AFRIKAANSE OPSOMMING: Wingerd rolblaar is een van die mees beskadigende virale siektes wat baie wingerd areas in die wêreld aantas. In Aantal verslae oor die afgelope jare het closterovirus partikels met wingerd rolblaar geassosieer. Tot hede, is agt serologiese onderskeibare closterovirusse geïsoleer vanuit geaffekteerde wingerde, waarvan wingerd rolblaar geassosieerde closterovirus-3 (GLRaV-3) die beste gekarakteriseerd is. Virus bestandheid in transgeniese plante gebaseer op die uitdrukking van gene afkomstig vanaf virusse, staan bekend as patogeen-afgeleide weerstand. Die virale kapsule protein (CP) geen vervaardig In strukturele protein wat verantwoordelik is vir die bedekking van die virus partikel. Dié geen was gebruik in die eerste demonstrasie van patogeen-afgeleide weerstand. Kapsuul protein-bemiddelde weerstand is tans die mees praktiese en algemene gebruikte metode om virus weerstand in plant gewasse te verkry. Die CP geen van In Suid Afrikaanse isolaat van GLRaV-3 geïnfekteerde wingerde is geïsoleer, gekloneer en die volgorde is bepaal. Dubbelstring RNA (dsRNA) was uit GLRaV-3 geïnfekteerde materiaal geëkstraheer en In hoë molekulêre gewig band van -18 kb is geïdentifiseer. Die dsRNA is gebruik as In templaat vir In omgekeerde transkripsie PKR saam met GLRaV-3 CP geen spesifieke inleiers vir die amplifikasie van die GLRaV-3 CP geen (975 bp). Die GLRaV-3 CP geen is gekloneer in die pGem®-T Easy vektor. Klone met die CP geen in die sin (pLR3CP+) en teensin (pLR3CP-) oriëntasies respektiewelik is verkry. Die volgorde wat verkry is vanuit hierdie twee klone dui op In 99.26 % ooreenstemming met die enigste ander GLRaV-3 CP geen volgorde wat beskikbaar is. Die GLRaV-3 CP geen is uit pLR3CP+ en pLR3CP- gesny en is gesubkloneer in In plant ekspressie vektor, pCAMBIA 3301 in die sin (pCamBLR3CP+) en teensin (pCamBLR3CP-) oriëntasies respektiewelik, wat die sin en teensin geen ekspressie in transgeniese plante in staat stel. Die GLRaV-3 CP geen was ook gesubkloneer vanaf pCamBLR3CP+ in In ander plant ekspressie vektor, pCAMBIA 2301 in die sin orientasie en is as pCVSLR3CP+ benoem. Hierdie drie konstruksies is aan Dr. M. Vivier (Instituut vir Wyn Biotegnologie, Stellenbosch) gegee vir wingerd transformasie eksperimente. Twee van hierdie konstruksies, pCamBLR3CP+ en pCamBLR3CP- asook pCAMBIA 3301 is gebruik om Nicotiana tabacum deur middel van Agrobacterium tumefaciens-bemiddelde transformasie te transformeer. Plante is geselekteer vir hul vermoë om die onkruiddoder, Basta, te weerstaan. Die teenwoordigheid van die plant selekteerbare merker geen, bar, op elke konstruksie lui tot dié weerstand. Die plante wat getransformeer is met pCamBLR3CP+ en pCamBLR3CP- is deur PKR saam met die GLRaV-3 CP geen spesifieke inleiers getoets, en geen amplifikasie van die GLRaV-3 CP geen is getoon nie. Southern blot analise met die GLRaV-3 CP geen as hibridisasie peiler het geen sein gewys vir hierdie plante nie, wat die PKR resultate bevestig. Die plante wat getransformeer is met pCAMBIA 3301 is deur PKR saam met die bar geen spesifieke inleiers getoets, en geen amplifikasie van die bar geen is getoon nie. Die plante wat getransformeer is met pCamBLR3CP+ en pCamBLR3CP- is ook getoets vir die teenwoordigheid vir die bar geen. Drie van die agt plante wat getoets is, het amplifikasie van die -560 bp bar geen getoon. Hierdie onverwagte resultate stel voor dat dié plante met pCAMBIA 3301 (vektor sonder die geligeerde GLRaV-3 CP geen) en nie met pCamBLR3CP+ en pCamBLR3CPgetransformeer is nie. Hierdie projek verskaf voorlopige werk vir die daaropvolgende transformasie van wingerd met die GLRaV-3 CP geen in 'n poging om virus bestandheid te verskaf.
Ramburan, Viresh Premraj. "Genetic mapping of adult plant stripe rust resistance in the wheat cultivar Kariega." Thesis, Stellenbosch : Stellenbosch University, 2003. http://hdl.handle.net/10019.1/53438.
Full textENGLISH ABSTRACT: Stripe (yellow) rust of wheat, caused by Puccinia striiformis f.sp. tritici, was first detected as a single introduction into South Africa in 1996. Two additional pathotypes have since been identified. Control of the disease may be achieved by use of genetic adult plant resistance (APR) as is present in the local cultivar 'Kariega'. The aim of this project was to understand the genetic basis of the APR in 'Kariega' to facilitate breeding of new varieties with genetic resistance to stripe rust. A partial linkage map of a 'Kariega X Avocet S' doubled haploid population covering all 21 wheat chromosomes was generated using 208 DNA markers, viz, 62 SSR, 133 AFLP, 3 RGA and 10 SRAP markers, and 4 alternative loci. The different marker techniques detected varying polymorphism, viz, overall SSR: 46%, AFLP: 7%, SRAP: 6% and RGA: 9%, and the markers produced low levels of missing data (4%) and segregation distortion (5%). A significant feature of the linkage map was the low polymorphism found in the D genome, viz, 19% of all mapped DNA markers, 11% of all AFLP markers and 30% of the total genome map distance. A region exhibiting significant segregation distortion was mapped to chromosome 4A and a seedling resistance gene for stem rust (Puccinia graminis f.sp . tritici), Sr26, mapped to chromosome 6A close to three SSR markers. The leaf tip necrosis gene, Ltn, which was also segregating in the population, mapped to chromosome 7D. Protocols for SRAP and RGA were optimised, and SRAP marker use in wheat genetic linkage studies is reported for the first time. The linkage map was used together with growth chamber and replicated field disease scores for QTL mapping. Chromosomes showing statistically significant QTL effects were then targeted with supplementary SSR markers for higher resolution mapping. The quality of disease resistance phenotypic data was confirmed by correlation analysis between the different scorers for reaction type (0.799±0.023) and for transformed percentage leaf area infected (0.942±0.007). Major QTL were consistently identified on chromosome 7D (explaining some 25-48% of the variation) and on chromosome 2B (21-46%) using transformed percentage leaf area infected and transformed reaction type scores (early and final) with interval mapping and modified interval mapping techniques. Both chromosomal regions have previously been identified in other studies and the 7D QTL is thought likely to be the previously mapped APR gene Yr 18. Minor QTL were identified on chromosomes lA and 4A with the QTL on 4A being more prominent at the early field scoring for both score types. A QTL evidently originating from 'Avocet S' was detected under growth chamber conditions but was not detected in the field, suggesting genotype-environment interaction and highlighting the need for modifications of growth chamber conditions to better simulate conditions in the field. The genetic basis of the APR to stripe rust exhibited by 'Kariega' was established by mapping of QTL controlling this trait. The linkage map constructed will be a valuable resource for future genetic studies and provides a facility for mapping other polymorphic traits in the parents of this population with a considerable saving in costs.
AFRIKAANSE OPSOMMING: Streep of geelroes van koring word veroorsaak deur Puccinia striiformis f. sp tritici, en is die eerste keer in 1996 in Suid-Afrika na introduksie van 'n enkele patotipe waargeneem. Twee verdere patotipes is sedertdien in Suid-Afrika gei"dentifiseer. Beheer van die siekte word veral moontlik gemaak deur die gebruik van genetiese volwasseplantweerstand soos gei"dentifiseer in die plaaslike kultivar 'Kariega'. Die doel van hierdie studie was om die genetiese grondslag van die streeproesweerstand te ontrafel ten einde die teling van nuwe bestande kultivars moontlik te maak. 'n Verdubbelde haplo1ede populasie uit die kruising 'Kariega X Avocet S' is aangewend om 'n gedeeltelike koppelingskaart vir die volle stel van 21 koring chromosome saam te stel. Die kaart het uit 208 DNA merkers, nl., 62 SSR, 133 AFLP, 3 RGA, 10 SRAP merkers en 4 ander lokusse bestaan. Totale polimorfisme wat deur die verskillende merkersisteme opgespoor is, was as volg: SSR: 46%, RGA: 9%, AFLP: 7% en SRAP: 6%. Die mate van ontbrekende data was gering (4%) asook die mate van segregasie distorsie (5%) van 'n enkele geval wat op chromosoom 4A gekarteer is. 'n Prominente kenmerk van die koppelingskaart is die relatiewe gebrek aan polimorfiese merkers op die D-genoom, nl., slegs 19% van alle DNA merkers en 11% van alle AFLP merkers wat slegs 30% van die totale genoom kaartafstand bestaan het. Die stamroes (Puccinia graminis f. sp. tritici) saailingweerstandsgeen, Sr26, karteer op chromosoom 6A naby drie SSR merkers. Die geen vir blaartipnekrose, Ltn, karteer op chromosoom 7D. Protokolle vir SRAP en RGA merkers is ge-optimiseer en gebruik van SRAP merkers in koppelings-analise word vir die eerste keer in koring gerapporteer. Die koppelingskaart is in kombinasie met groeikamerdata en gerepliseerde veldproefdata gebruik om die gene (QTL) vir volwasseplant streeproesweerstand te karteer. Chromosome met statisties betekenisvolle QTL is met aanvullende SSR merkers geteiken om die resolusie van kartering verder te verhoog. Die kwaliteit van fenotipiese data, soos in die proewe aangeteken, is bevestig deur korrelasies te bereken tussen lesings geneem deur onafhanklike plantpataloe (0.799 ± 0.023 vir reaksietipe en 0.942 ± 0.007 vir getransformeerde persentasie blaaroppervlakte besmet). Hoofeffek QTL vir die twee maatstawwe van weerstand is deur middel van die metodes van interval QTL kartering en gemodifiseerde interval QTL kartering konsekwent op chromosome 7D (25-48% van variasie verklaar) en 2B (21-46% van variasie verklaar) ge"identifiseer. In vorige studies is aangetoon dat beide chromosome 7D en 2B QTL vir volwasseplant streeproesweerstand dra. Die 7D QTL is waarskynlik die weerstandsgeen, Yr 18. QTL met klein effekte op weerstand is op chromosome lA en 4A ge"identifiseer. Die effek van laasgenoemde geen was meer prominent in die velddata in die vroee datum van weerstandsbeoordeling. Een QTL, afkomstig van 'Avocet S', is slegs onder groeikamertoestande identifiseerbaar. Dit dui op moontlike genotipe-omgewing wisselwerking en beklemtoon die noodsaaklikheid om aanpassings te maak in groeikamertoestande vir beter simulasie van veldproeftoestande. Die genetiese grondslag van volwasseplantweerstand teen streeproes in die kultivar 'Kariega' is deur QTL kartering bepaal. Die 'Kariega X Avocet S' koppelingskaart kan as 'n waardevolle basis dien vir toekomstige genetiese ontledings van ander polimorfiese kenmerke in die populasie.
Collins, Nicholas C. "The genetics of barley yellow dwarf virus resistance in barley and rice." Title page, table of contents and summary only, 1996. http://hdl.handle.net/2440/46063.
Full textThesis (Ph.D.) -- University of Adelaide, Dept. of Plant Science, 1996
Maios, Claudia. "Expression of defence-related genes in sugar beet plants infected with Rhizoctonia solani and treated with benzo-(1,2,3)-thiadiazole-7-carbothioic acid S-methyl ester (BTH)." Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=99349.
Full textBrière, Stéphan C. "Selection of partial resistance for crown rust (Puccinia ćoronata Cda.) race 264 in oat." Thesis, McGill University, 1992. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=60678.
Full textAbu-Nada, Yousef. "Metabolic profiling of potato cultivars varying in horizontal resistance to late blight, Phytophthora infestans." Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=102947.
Full textNjom, Henry Akum. "Mechanism and synchronicity of wheat (Triticum aestivum) resistance to leaf rust (Puccinia triticina) and Russian wheat aphid (Duiraphis noxia) SA1." Thesis, University of Fort Hare, 2016. http://hdl.handle.net/10353/2700.
Full textBarnett, Stephen J. "Directed evolution of disease suppressive bacteria : the role of root lesions on take - all diseased wheat." Title page, contents and abstract only, 1998. http://hdl.handle.net/2440/37768.
Full textThesis (Ph.D.)--Department of Crop Protection, 1998.
Horn, Marizanne. "Transfer of genetic resistance to the Russian wheat aphid from rye to wheat." Thesis, Stellenbosch : Stellenbosch University, 1997. http://hdl.handle.net/10019.1/55770.
Full textENGLISH ABSTRACT: An octoploid triticale was derived from the F1 of a Russian wheat aphid resistant rye, 'Turkey 77', and 'Chinese Spring' wheat. The alloploid was crossed (a) to common wheat, and (b) to the 'Imperial' rye to 'Chinese Spring' disomic addition lines. F2 progeny from these crosses were tested for Russian wheat aphid resistance and C-banded. Resistance was found to be associated with chromosome arm 1RS of the 'Turkey 77' rye genome. This initial work was done by MARAIS (1991) who made a RWA resistant, monotelosomic 1RS ('Turkey 77') addition plant available for the study. The F3 progeny of this monotelosomic addition plant was used to confirm the RWA resistance on chromosome 1RS. The monotelosomic addition plant was then crossed with the wheat cultivar 'Gamtoos', which has the 1BL.1 RS 'Veery' translocation. Unlike the 1RS segment in 'Gamtoos', the 'Turkey 77'- derived 1RS telosome did not express the rust resistance genes 5r31 and Lr26 which could then be used as markers. From the F1 a monotelosomic 1RS addition plant that was also heterozygous for the 1BL.1 RS translocation, was selected and testcrossed with an aphid susceptible common wheat, 'Inia 66'. Meiotic pairing between the .rye arms resulted in the recovery of five euploid, Russian wheat aphid resistant plants out of a progeny of 99 euploids. One recombinant also retained 5r31 and Lr26 and was allowed to self pollinate. With the aid of SOS-PAGE profiles, Russian wheat aphid resistant 1BL.1 RS translocation homozygotes were identified and it was possible to confirm that the Russian wheat aphid resistance gene was in fact transferred to the 1BL.1RS ('Veery') translocation. Two attempts were made to map the Russiar, wheat aphid locus or loci. (1) Telosomic mapping was attempted. For this purpose a plant with 2n = 40 + 1BL.1 RS + 1RS was obtained, and testcrossed with a Russian wheat aphid susceptible wheat. (2) A disomic, recombined 1BL.1 RS translocation line with Russian wheat aphid resistance but lacking the Lr26 and Sr31 alleles was crossed with 'Gamtoos' and the F1 testcrossed. The testcross in both strategies were done with 'Chinese Spring'. In the first experiment the Sr31 locus was located 10.42 map units from the Lr26 locus. The rust resistance data implied that the genetic distance estimates may be unreliable and therefore the laborious Russian wheat aphid resistance tests were not done. In the second experiment a Russian wheat aphid resistance gene was located 14.5 map units from the Lr26 locus. In the latter cross nonmendel ian segregation of the Russian wheat aphid resistance evidently occurred which implied that the estimated map distance may be inaccurate. It was also not possible to determine the number of genes involved from the data.
Digitized at 300 dpi Colour & b/W PDF format (OCR), using ,KODAK i 1220 PLUS scanner. Digitised, Ricardo Davids on request from ILL 25 April 2013
AFRIKAANSE OPSOMMING: 'n Oktaplo"lede triticale is gemaak vanaf die F1 van 'n kruising tussen 'n Russiese koringluis-weerstandbiedende rog, 'Turkey 77', en die koringkultivar 'Chinese Spring'. Die alloplo"led is gekruis met gewone broodkoring en met 'Imperial' rog/'Chinese Spring' disomiese addissielyne. Die F2 nageslag vanaf hierdie kruisings is getoets vir Russiese koringluisweerstandbiedendheid en C-bande is ook gedoen. Weerstand is gevind wat geassosieer is met die 1RS chromosoomarm van 'Turkey 77'. Hierdie oorspronklike werk is deur MARAIS (1991) gedoen en uit sy materiaal is 'n monotelosomiese 1RS ('Turkey 77') addissieplant beskikbaar gestel vir die huidige studie. Die F3 nageslag van hierdie monotelosomiese addissieplant is gebruik om die weerstand teen die Russiese koringluis op chromosoom 1RS te bevestig. Die monotelosomiese addissieplant is ook gekruis met die koringkultivar 'Gamtoos' wat die 1BL.1 RS-translokasie dra. Hoewel die 1RS segment van 'Gamtoos' die roesweerstandsgene, Sr31 en Lr26 uitdruk, is dit nie die geval met die 'Turkey 77' 1RS telosoom nie. Hierdie gene kon dus as merkergene gebruik word. Vanuit die F1 is 'n monotelosomiese 1RS addissieplant geselekteer wat ook heterosigoties was vir die 1BL.1 RStranslokasie. Hierdie plant is getoetskruis met 'n luisvatbare gewone broodkoring, 'Inia 66'. Meiotiese paring tussen die rogarms het daartoe gelei dat vyf euplo"lede Russiese koringluis-weerstandbiedende nageslag uit 99 euplo"lede nageslag geselekteer kon word. Een rekombinant het ook Sr31 en Lr26 behou en is toegelaat om self te bestuif. Met behulp van SDSPAGE profiele is Russiese koringluis-weerstandbiedende 1BL.1 RStranslokasie homosigote ge"ldentifiseer en kon bevestig word dat die weerstandsgeen vir die Russiese koringluis oorgedra is na die 1BL.1 RS ('Veery') -translokasie. Twee strategies is gevolg om die Russiese koringluislokus of -loci te karteer: (1) 'n Telosomiese analise is gedoen. 'n Plant met 2n = 40 + 1BL.1 RS + 1RS is verkry en met 'n luisvatbare koring bestuif. (2) 'n Gerekombineerde, disomiese plant met Russiese koringluis-weerstandbiedendheid maar sonder die Lr26 en Sr31 allele is gekruis met 'Gamtoos' en die F1 getoetskruis. Die toetskruisouer in beide die strategiee was 'Chinese Spring'. In die eerste eksperiment is die Sr31-lokus 10.42 kaarteenhede vanaf die Lr26-lokus gelokaliseer. Die raesdata het ge"impliseer dat onbetraubare genetiese kaarteenhede geskat sou word en daarom is die omslagtige Russiese koringluis weerstandsbepalings nie gedoen nie. In die tweede eksperiment is die Russiese koringluis-weerstandsgeen op 14.5 kaarteenhede vanaf die Lr26-lokus gelokaliseer. Nie-Mendeliese segregasie van die Russiese koringluis-weerstand in hierdie karteringseksperiment het ge'impliseer dat die berekende kaartafstand onakkuraat mag wees. Dit was ook nie moontlik om op grand van die data die aantal gene betrakke af te lei nie.
Krsikapa, Nenad. "Variation for resistance to Fusarium graminearum ear rot in selfed families from the corn population Zapalote Chico." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape16/PQDD_0021/MQ37137.pdf.
Full textPooranampillai, Christina D. "Evaluation of resistance to Sclerotinia crown and stem rot caused by Sclerotinia trifoliorum in selected alfalfa cultivars." Thesis, Virginia Tech, 1988. http://hdl.handle.net/10919/43273.
Full textMaster of Science
Suidgeest, Faira. "Evaluation of two pathogen-derived resistance strategies for Grapevine leafroll-associated virus 3." Thesis, Stellenbosch : Stellenbosch University, 2015. http://hdl.handle.net/10019.1/96776.
Full textENGLISH ABSTRACT: Grapevine leafroll disease (GLD), caused by the members of the family Closteroviridae, is one of the most economic important viral diseases affecting grapevine. Grapevine leafroll associated virus 3 (GLRaV-3), of the genus Ampelovirus, is the most widespread member of the leafroll associated virus family. To prevent the spread of GLD, management strategies such as rogueing and insect vector control are required to limit crop losses. Alternative control strategies based on genetic modification of the grapevine genome, such as pathogen-derived resistance (PDR), is proven to be effective in conferring resistance to several viruses. Therefore, the focus of this study was to evaluate pathogen-derived resistance strategies for GLRaV-3 using the following two approaches; 1) evaluation of transgenic plants expressing a dysfunctional GLRaV-3 heat shock protein 70 homolog (HSP70h) in order to confer resistance against GLRaV-3, and 2) the construction of artificial microRNAs (amiRNAs) to use as a tool for silencing specific sequences of GLRaV-3 in the grapevine host and the development of an amiRNA-mediated silencing validation system. In the first part of this study, six transgenic plant lines (plant lines #1, #3, #9, #14, #15 and #17) as well as a non-modified plant line, were inoculated with GLRaV-3 by grafting buds of each onto GLRaV-3 infected plant material. After approximately five months, GLRaV-3 virus titres of all grafted plants were quantified relative to two reference genes using RT-qPCR. Results were evaluated by comparing the relative virus titre of each transgenic plant line to that of the non-modified control plant line. Results showed that resistance levels of plant line #3 was significantly enhanced (>99%) and remarkably, plant line #14, showed to be more susceptible to the virus. The second part of the study was the construction and validation of amiRNAs targeting GLRaV-3 sequences. Two 21 nt regions of GLRaV-3 were successfully incorporated into miRNA backbone vvi167b of grapevine. Moreover, target constructs were developed by incorporating corresponding GLRaV-3 target sequences into the 3’ UTR of a green fluorescence protein (GFP) gene. Subsequently, the target constructs were co-infiltrated with the constructed amiRNA in Nicotiana benthamiana and GFP expression levels were quantified to determine the silencing efficiency of the amiRNAs. Results showed that the amiRNAs were successful in silencing the GFP target construct, however, they were not specific in silencing exclusively their corresponding target. These amiRNA constructs are ideal for further viral studies to determine the efficiency of silencing GLRaV-3 in GLD infected grapevines.
AFRIKAANSE OPSOMMING: Wingerd rolblaar siekte (GLD), wat veroorsaak word deur die lede van die familie Closteroviridae, is een van die ekonomies mees belangrike virus siektes van wingerd. Grapevine leafroll-associated virus 3 (GLRaV-3), van die genus Ampelovirus, is die mees wydverspreide lid van die rolblaar geassosieerde virus familie. Om die verspreiding van GLD te voorkom, is bestuur strategieë, soos die verwydering van geïnfekteerde plante en insekvektor beheer, ’n vereiste om oes verliese te beperk. Alternatiewe beheer strategieë gebaseer op genetiese modifikasie van die wingerdgenoom, soos patogeen-afgeleide weerstand (PDR), is bewys om effektief te wees in die verlening van weerstand teen verskeie virusse. Daarom was die fokus van hierdie studie om patogeen-afgeleide weerstand strategieë vir GLRaV-3 te evalueer met behulp van die volgende twee benaderings; 1) die evaluering van transgeniese plante wat 'n disfunksionele GLRaV-3 hitte-skok proteïen 70 homoloog (HSP70h) uitdruk, ten einde weerstand te verleen teen GLRaV-3, en 2) die konstruksie van kunsmatige mikroRNAs (amiRNAs) om te gebruik as 'n instrument vir die ondrukking van spesifieke genoomvolgordes van GLRaV-3 in die wingerd gasheer en die ontwikkeling van ’n stelsel om amiRNA-bemiddelde onderdrukking te bevestig. In die eerste deel van hierdie studie, is ses transgeniese plant lyne (plant lyne # 1, # 3, # 9, # 14, # 15 en # 17) sowel as 'n nie-gemodifiseerde gesonde plant lyn, geïnokuleer met GLRaV- 3 deur enting van ogies van elk op GLRaV-3 besmette plantmateriaal. Na ongeveer vyf maande, is GLRaV-3 virus konsentrasies van alle ingeënte plante gekwantifiseer relatief tot twee verwysing gene deur gebruik te maak van tru-transkripsie kwantitatiewe PCR (RTqPCR). Resultate is geëvalueer deur die relatiewe virus konsentrasie van elke transgeniese plant lyn te vergelyk met dié van die nie-gemodifiseerde kontrole lyn. Resultate het getoon dat weerstand vlakke van plant lyn # 3 beduidend verbeter is (> 99%) en merkwaardig is plant lyn # 14 bewys om meer vatbaar vir die virus te wees. Die tweede deel van die studie was die konstruksie en bevestiging van kunsmatige mikroRNAs (amiRNAs) wat GLRaV-3 genoomvolgordes teiken. Twee 21 nt streke van GLRaV-3 is suksesvol geïnkorporeer in die ruggraat van wingerd mikroRNA vvi167b. Verder is teiken konstrukte ontwikkel deur die inkorporering van ooreenstemmende GLRaV-3 teiken genoomvolgordes in die 3'UTR (3’ ongetransleerde area) van 'n groen fluoressensie proteïen (GFP) geen. Daarna is die teiken konstrukte gesamentlik geïnfiltreer met die gekonstrueerde amiRNA in Nicotiana benthamiana en GFP uitdrukkingsvlakke is gekwantifiseer deur die onderdrukkingsdoeltreffendheid van die amiRNAs te bepaal. Resultate het getoon dat die amiRNAs suksesvol was in die onderdrukking van die GFP teiken konstruk, maar hulle was egter nie-spesifiek in die eksklusiewe onderdrukking van die ooreenstemmende teiken. Hierdie amiRNA konstrukte is ideaal vir verdere virus studies om die doeltreffendheid van GLRaV-3 onderdrukking in GLD besmette wingerdstokke te bepaal.
Tashtemirov, Behzod. "Inheritance of Partial Resistance to White Mold in Field Pea (Pisum sativum L.)." Thesis, North Dakota State University, 2012. https://hdl.handle.net/10365/26387.
Full textSyme, Jennifer. "Characterization of Arabidopsis thaliana (Columbia) infected with turnip mosaic virus (TuMV)." Thesis, McGill University, 1996. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=24043.
Full textDias, Katia. "Evaluation of resistance to tomato curly stunt virus in tomato." Thesis, 2013. http://hdl.handle.net/10539/12342.
Full textCowger, Christina. "Cephalosporium stripe of wheat : seedling-based resistance screening and pathogenic variability." Thesis, 1997. http://hdl.handle.net/1957/33687.
Full textGraduation date: 1998
Mienie, Charlotte Maria Susanna. "Towards marker assisted selection for nematode resistance in soybean." Thesis, 2000. http://hdl.handle.net/10413/10262.
Full textThesis (Ph.D.)-University of Natal, Pietermaritzburg, 2000.
Kempster, Valerie Noel. "Soil microbes as potential control agents for plant-parasitic nematodes in pasture / by Valerie N. Kempster." Thesis, 2000. http://hdl.handle.net/2440/14767.
Full textviii, 152 leaves : ill. ; 30 cm.
This study investigates the induction of resistance to the clover cyst nematode, Heterodera trifolii Goffart, an economic pest in white clover pastures that are a key to high milk yields in dairy cattle...it explores the potential of soil and rhizosphere bacteria to induce systemic resistance in white clover, Trifolium repens L. (summary)
Thesis (Ph.D.)--University of Adelaide, Dept. of Applied and Molecular Ecology, 2000
Kempster, Valerie Noel. "Soil microbes as potential control agents for plant-parasitic nematodes in pasture / by Valerie N. Kempster." 2000. http://hdl.handle.net/2440/14767.
Full textviii, 152 leaves : ill. ; 30 cm.
Title page, contents and abstract only. The complete thesis in print form is available from the University Library.
This study investigates the induction of resistance to the clover cyst nematode, Heterodera trifolii Goffart, an economic pest in white clover pastures that are a key to high milk yields in dairy cattle...it explores the potential of soil and rhizosphere bacteria to induce systemic resistance in white clover, Trifolium repens L. (summary)
Thesis (Ph.D.)--University of Adelaide, Dept. of Applied and Molecular Ecology, 2000
Oelofse, Dean. "Molecular strategies towards anthracnose resistance in lupin." Thesis, 2008. http://hdl.handle.net/10210/809.
Full textProf. Ian Dubery
Abbott, David Colin. "Pyramiding scald resistance genes in barley." Phd thesis, 1997. http://hdl.handle.net/1885/145297.
Full text