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1
Marchant, Robert. "Biotechnological approaches to rose breeding." Thesis, University of Nottingham, 1994. http://eprints.nottingham.ac.uk/13901/.
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The production of new rose cultivars by sexual crossing is problematic and time consuming due to sexual incompatibility. the failure of seeds to genninate. and to a limited gene pool. Biotechnology provides an obvious alternative for the creation of genetic novelty in rose. This thesis focuses on the development of novel approaches, based on embryo rescue, pollen cryopreservation, protoplast and transformation technologies. A reproducible embryo rescue technique was developed in which embryos were excised and genninated on agar solidified medium containing a basic salt mixture and carbohydrate. The choice of carbohydrate and the growth conditions employed were demonstrated to markedly affect the percentage germination and subsequent plantlet development. This technique was used to greatly increase the production of F, hybrid progeny when compared to conventional germination methods. The failure of sexual crosses between several English rose cultivars was shown to be due to a combination of low pollen viability and to the operation of a pollen-style incompatibility mechanism (probably of the gametophytic self-incompatibility type). Degree of flower opening and method of pollen dehiscence were shown to significantly affect pollen viability. A technique was developed for the effective cryopreservation of English rose pollen. Using this technique it was possible to store pollen at ultra-low temperatures without any significant loss in viability. Such a technique compared favourably with conventional techniques (refrigeration and freezing) in which a loss in viability over time was demonstrated to occur. In vitro shoot cultures of English rose were established on MS-based media containing BAP. GA3 and NAA following the treatment of explants with an antioxidant solution to negate the effects of phenolic oxidation. The production of callus was shown to be genotype dependant and lacked regeneration potential. Rhizogenic responses were observed in leaf discs of two cultivars however shoot regeneration was not observed. Using a variety of enzyme mixtures it was possible to isolate protoplasts from both In vitro leaf material and from cell suspensions. Both mesophyll and cell suspension derived protoplasts were cultured to a microcallus stage. Plating density, growth regulator concentration and the use of antioxidants were all demonstrated to have a significant effect on the protoplast plating efficiency. Rhizogenesis was achieved from mesophyll protoplast-derived calli. Protoplasts, sometimes labelled with a fluorescent marker, were subjected to both chemical and electrofusion. Using micromanipulation, heterokaryons, formed during electrofusion, were recovered. Such heterokaryons, when cultured. underwent division and formed microcalli which subsequently developed into calli. The hybrid nature of such calli were conftrmed by isozyme analysis, determination of ploidy level and RAPD analysis. The introduction of a plasmid containing a gus marker gene into zygotic embryos of English rose was shown to be possible. This was achieved by microprojectile-mediated DNA delivery using a laboratory built electrical discharge device. The efficiency of this technique was influenced by the concentration of microprojectiles and DNA used. And by firing distance and choice of DNA construct. The relevance of this study and its applications, in the context of rose breeding are discussed.
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Butler-Stoney, Thomas Richard. "Breeding for rust-resistance in antirrhinum." Thesis, Royal Holloway, University of London, 1988. http://repository.royalholloway.ac.uk/items/7e32381b-2f35-4bc4-b93a-b24c63dbde25/1/.
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Recent trials of Antirrhinum majus cultivars have revealed a wide range of susceptibility to rust (Puccinia antirrhini). The best plants were used as parents in a breeding programme to produce a useful level of durable field resistance. The F1 generation was self-pollinated but the F2 to F4 were selectively cross-pollinated within lines. The segregating generations were grown outdoors at two sites in Surrey, where they were subject to natural rust epidemics encouraged by the use of spreader rows. Individual plants were selected for rust-resistance and horticultural quality. By the F4 generation, lines showed greater resistance to rust than existing varieties and were becoming uniform in flower colour, growth habit and horticultural quality. Many floral abnormalities arose, especially in the F3. Their expression was usually highly variable and was enhanced by environmental stress. Tests of rust isolates against individual antirrhinum plants showed that there is considerable genetic variation within the rust population. Some monitoring of resistant varieties is desirable to identify future changes in the rust population. The spread of spores between widely spaced patches of susceptible host was simulated using a computer, which indicated that small, isolated patches may escape infection. The effect of rate-reducing resistance is increased when plants are widely separated. This is in agreement with practical experience. The urediniospores of Puccinia antirrhini cannot survive the winter in Britain and, though teliospores are regularly produced, no alternate host is known. However, overwintered antirrhinum plants produce viable urediniospores which start epidemics in early summer: there is no need to postulate an alternate host in the British Isles. Treating antirrhinum as a summer annual might be an important hygienic measure, reducing the local build up of inoculum early in the season. Acceptable control of rust should be possible, provided only the more resistant varieties are grown.
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Daniels, Stephen J. "Studies in the production of microspore-derived haploids in lupin." Thesis, University of Reading, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.266148.
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Lennefors, Britt-Louise. "Molecular breeding for resistance to rhizomania in sugar beets /." Uppsala : Department of Plant Biology and Forest Genetics, Swedish University of Agricultural Sciences, 2006. http://epsilon.slu.se/2006106.pdf.
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Montes, Juan Manuel. "Application of near-infrared spectroscopy in plant breeding programs." [S.l. : s.n.], 2006. http://nbn-resolving.de/urn:nbn:de:bsz:100-opus-1735.
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Gustavsson, Björn A. "Plant breeding and domestication of lingonberry (Vaccinium vitis-idaea L.) /." Alnarp : Swedish Univ. of Agricultural Sciences (Sveriges lantbruksuniv.), 1999. http://epsilon.slu.se/avh/1999/91-576-5707-6.pdf.
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Zhong, Shengqiang. "Integrating QTL analysis into plant breeding practice using Bayesian statistics." [Ames, Iowa : Iowa State University], 2008.
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8
Iori, Luca <1983>. "Agricultural Genetics and Plant Breeding in Early Twentieth-Century Italy." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2013. http://amsdottorato.unibo.it/5680/1/iori_luca_tesi.pdf.
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This thesis is about plant breeding in Early 20th-Century Italy. The stories of the two most prominent Italian plant-breeders of the time, Nazareno Strampelli and Francesco Todaro, are used to explore a fragment of the often-neglected history of Italian agricultural research. While Italy was not at the forefront of agricultural innovation, research programs aimed at varietal innovation did emerge in the country, along with an early diffusion of Mendelism. Using philosophical as well as historical analysis, plant breeding is analysed throughout this thesis as a process: a sequence of steps that lays on practical skills and theoretical assumptions, acting on various elements of production. Systematic plant-breeding programs in Italy started from small individual efforts, attracting more and more resources until they became a crucial part of the fascist regime's infamous agricultural policy. Hybrid varieties developed in the early 20th century survived World War II and are now ancestors of the varieties that are still cultivated today. Despite this relevance, the history of Italian wheat hybrids is today largely forgotten: this thesis is an effort to re-evaluate a part of it. The research did allow previously unknown or neglected facts to emerge, giving a new perspective on the infamous alliance between plant-breeding programs and the fascist regime. This thesis undertakes an analysis of Italian plant-breeding programs as processes. Those processes had a practical as well as a theoretical side, and involved various elements of production. Although a complete history of Italian plant breeding still remains to be written, the Italian case can now be considered along with the other case-studies that other scholars have developed in the history of plant breeding. The hope is that this historical and philosophical analysis will contribute to the on-going effort to understand the history of plants.
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Iori, Luca <1983>. "Agricultural Genetics and Plant Breeding in Early Twentieth-Century Italy." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2013. http://amsdottorato.unibo.it/5680/.
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This thesis is about plant breeding in Early 20th-Century Italy. The stories of the two most prominent Italian plant-breeders of the time, Nazareno Strampelli and Francesco Todaro, are used to explore a fragment of the often-neglected history of Italian agricultural research. While Italy was not at the forefront of agricultural innovation, research programs aimed at varietal innovation did emerge in the country, along with an early diffusion of Mendelism. Using philosophical as well as historical analysis, plant breeding is analysed throughout this thesis as a process: a sequence of steps that lays on practical skills and theoretical assumptions, acting on various elements of production. Systematic plant-breeding programs in Italy started from small individual efforts, attracting more and more resources until they became a crucial part of the fascist regime's infamous agricultural policy. Hybrid varieties developed in the early 20th century survived World War II and are now ancestors of the varieties that are still cultivated today. Despite this relevance, the history of Italian wheat hybrids is today largely forgotten: this thesis is an effort to re-evaluate a part of it. The research did allow previously unknown or neglected facts to emerge, giving a new perspective on the infamous alliance between plant-breeding programs and the fascist regime. This thesis undertakes an analysis of Italian plant-breeding programs as processes. Those processes had a practical as well as a theoretical side, and involved various elements of production. Although a complete history of Italian plant breeding still remains to be written, the Italian case can now be considered along with the other case-studies that other scholars have developed in the history of plant breeding. The hope is that this historical and philosophical analysis will contribute to the on-going effort to understand the history of plants.
10
Palumbo, Fabio. "Exploiting genomics and molecular markers for plant genetics and breeding." Doctoral thesis, Università degli studi di Padova, 2018. http://hdl.handle.net/11577/3422297.
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Co-dominant molecular markers, such as Microsatellites (or Simple Sequence Repeats, SSRs), are powerful tools for basic and applied research programs in crop plant species. Among the possible applications, they are frequently adopted for genetic traceability of food products, for assessing the genetic diversity of local varieties as well as the genetic identity of modern varieties, and also for marker-assisted breeding purposes. In fact, SSR markers are known to be highly polymorphic and discriminant, well distributed throughout the genome, not affected by environmental factors, more efficient and robust than phenotype-based field trials to detect and predict large numbers of distinct differences/traits among genotypes. However, a review of 90 original articles concerning the varietal characterization of some economically relevant crops in Italy, pointed out a lack of wider consensus among the authors regarding the strategy to design and to adopt for genotyping plant varieties with SSR markers. This study emphasized the urgent need to establish a common procedure concerning: i) the criteria adopted for selecting the marker loci and ii) the genetic parameters to be employed for varietal genotyping.
In order to demonstrate the potentials of these molecular markers, two case studies are presented. A study performed in Agordino, a very old local Venetian landrace of barley (Hordeum vulgare L.), stressed the concrete possibility to use SSR markers for genetic traceability of local varieties and, in particular, of their food derivatives. The genetic characterization of four main corn (Zea mays L.) landraces grown in Veneto (Italy), namely Sponcio, Marano, Biancoperla and Rosso Piave, by means of SSR markers, has shown great utility for monitoring and preventing further genetic erosion, thus preserving their gene pools, phenotypic identities and qualitative traits.
Despite the economic relevance of some crop species, it is common for researchers to deal with the complete lack of SSR data and, more in general, of genomic information. Fennel (Foeniculum vulgare Mill., 2n=2x=22) represents a brilliant example. To overcome this shortage, an Illumina HiSeq 2500 sequencing was carried out in this species, enabling the assembly of the first genome draft in 300,408 scaffolds. The subsequent annotation, permitted to detect and to characterize 103,306 SSR regions. Of these 40 were randomly chosen to design specific primer pairs, preliminary tested and 14 were successfully validated using a core collection of 118 fennel individuals potentially useful for F1 hybrid development. Moreover, the first fennel leaf transcriptome was produced overlapping two transcriptomes, one assembled de novo, the other with an in silico genome-guided approach. A total of 47,775 out of the 79,263 assembled transcripts were annotated and, among them, 11,853 loci contained a putative full-length CDS. Detailed analysis revealed 1,011 transcripts encoding for transcription factors (TFs), 6,411 EST-SSRs, 43,237 SNPs and 3,955 In/Dels. Assembled transcripts were also used to conduct the identification of loci related to the t-anethole biosynthesis, the major component of the fennel essential oils, well-known for its capability in reducing mild spasmodic gastro-intestinal pains as well as for its antithrombotic and hypotensive activity. Finally, detailed analysis revealed 1,011 transcripts encoding for transcription factors (TFs), 6,411 EST-SSRs, 3,955 In/Dels and 43,237 SNPs.
Single nucleotide polymorphisms (SNPs) represent another class of co-dominant markers heavily exploited for the discovery of Mendelian inheritance genes and for the analysis of polygenes or QTLs (quantitative trait loci). Adopting a Genotyping By Sequencing (GBS) approach, the first SNP-based genetic linkage map of leaf chicory (Cichorium intybus L. subsp. intybus var. foliosum, 2n=2x=18) was built using a BC1 population segregating 1:1 for the male sterility (ms) trait. This study enabled the genetic localization of the nuclear ms gene, termed Cims1, within linkage group 9 and the identification of four SNPs that proved to fully co-segregate with the target gene. Considering that this form of male-sterility, controlled by a single recessive nuclear gene, is one of the most effective methods to develop F1 hybrids, our data will be exploitable for marker-assisted selection purposes.I marcatori co-dominanti, tra cui i Microsatelliti (o SSR), sono strumenti molecolari ampiamente utilizzati nell’ambito della ricerca di base e applicata in specie di interesse alimentare. Tra le possibili applicazioni ricordiamo il loro impiego per studi di tracciabilità genetica di prodotti alimentari, per analisi di diversità genetica di varietà locali e identità genetica di varietà moderne e per il miglioramento genetico. Infatti gli SSR sono noti per essere altamente polimorfici e discriminanti, ben distribuiti all’interno del genoma, non influenzati da fattori ambientali, più efficienti e robusti dei marcatori fenotipici nelle analisi di diversità tra genotipi. Tuttavia, un’indagine condotta su 90 articoli scientifici basati sull’identificazione varietale delle specie economicamente più rilevanti in Italia, ha messo in luce la mancanza di un approccio comune tra gli autori in relazione alle strategie da utilizzare per questo tipo di studi. Inoltre lo studio ha evidenziato il bisogno improrogabile di stabilire procedure comuni riguardanti: i) i criteri da adottare per la scelta dei marcatori SSR ii) i parametri genetici più utili a questo scopo. Per dimostrare il potenziale di questa classe di marcatori, vengono presentati due casi studio. Il primo, che ha come oggetto Agordino, un’antica varietà locale veneta di orzo (Hordeum vulgare L.), ha permesso di enfatizzare la possibilità concreta di utilizzare i microsatelliti per la tracciabilità genetica di varietà locali ed, in particolare, di prodotti alimentari derivati. La caratterizzazione delle quattro principali varietà di mais (Zea mays L.) in Veneto -Sponcio, Marano, Biancoperla e Rosso Piave- attraverso marcatori SSR si è dimostrata invece estremamente utile per monitorare e prevenire fenomeni di erosione genetica, consentendo così di preservare la ricchezza genetica che le caratterizza, la loro identità fenotipica e i tratti qualitativi. Nonostante l’interesse economico di alcune specie, non è così raro per i ricercatori doversi interfacciare con la totale mancanza di dati SSR e, più in generale, di informazioni genomiche. Finocchio (Foeniculum vulgare Mill., 2n=2x=22), a tal proposito, rappresenta un esempio calzante. Per sopperire a questa carenza di dati, è stato condotto un sequenziamento su piattaforma Illumina Hiseq 2500, permettendo così l’assemblaggio del prima bozza del genoma di finocchio in 300408 sequenze. La successiva annotazione ha consentito quindi di individuare e caratterizzare 103306 regioni altamente ripetute. Di queste, 40 scelte in modo casuale per il disegno di primer specifici, sono state testate e 14 sono state validate su una popolazione commerciale di 118 individui potenzialmente fruibili per lo sviluppo di ibridi F1. Inoltre, il primo trascrittoma di foglia di finocchio è stato prodotto sovrapponendo due trascrittomi uno assemblato de novo e l’altro in silico, tramite allineamento sul genoma. 47775 dei 79263 trascritti totali sono stati annotati e 11853 risultano contenere una sequenza codificante completa. L’assemblaggio ha quindi consentito l’identificazione di loci coinvolti nella via biosintetica dei trans-anetolo, componente preponderante degli oli essenziali di finocchio e noto per le sue abilità nel ridurre dolori gastro-intestinali nonché per la sua attività antitrombotica e ipotensiva. Analisi dettagliate hanno infine messo in luce 1011 trascritti codificanti per fattori di trascrizione (FT), 6411 microsatelliti (EST-SSR), 3955 inserzioni/delezioni e 43237 polimorfismi a singolo nucleotide (SNP). I marcatori di tipo SNP costituiscono un’altra classe di marcatori codominanti largamente sfruttati per la caratterizzazione di geni ad eredità Mendeliana e per l’analisi di poligeni o loci codificanti tratti quantitativi (QTL). Attraverso un approccio di genotipizzazione tramite sequenziamento (GBS) è stata costruita la prima mappa genetica in radicchio (Cichorium intybus L. subsp. intybus var. foliosum, 2n=2x=18) utilizzando una popolazione BC1 (ottenuta tramite tecniche di reincrocio) segregante 1:1 per il tratto “maschio sterilità”. Questo studio ha permesso di localizzare finemente il gene nucleare della maschio sterilità Cims1 all’interno del gruppo di associazione 9 e ha consentito l’identificazione di 4 SNP co-segreganti a 0 cM con il suddetto gene. Considerato che questa forma di maschio-sterilità, controllata da un singolo allele recessivo nucleare, è uno dei metodi più efficaci per produrre ibridi F1, questi risultati saranno di estrema utilità per studi di miglioramento genetico.
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Small, Ian. "Resistance in maize to Fusarium verticillioides and fumonisin." Thesis, Stellenbosch : University of Stellenbosch, 2010. http://hdl.handle.net/10019.1/4803.
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Thesis (MScAgric (Plant Pathology))--University of Stellenbosch, 2010.ENGLISH ABSTRACT: Maize is the most important cereal crop produced in southern Africa. Maize producers, processors, and consumers in the region, however, are affected by Fusarium ear rot, a disease caused primarily by the fungal pathogen Fusarium verticillioides that reduces grain quality and potentially contaminates the grain with mycotoxins (fumonisin). Due to the threat of fumonisin to human and animal health, and the economic losses associated with reductions in grain quality, strategies aimed at the prevention of Fusarium ear rot and fumonisin contamination are required. These preventative strategies should be focused on protecting the crop prior to harvest, as damage is known to occur in the field before storage. Chapter 1 provides the reader with a broad overview of maize production in southern Africa, the disease Fusarium ear rot caused by F. verticillioides, and the contamination of grain with fumonisins. Potential disease management practices are summarised, and the role of host resistance and its underlying mechanisms emphasised. Finally, the use of plant breeding and resistance elicitors as methods to enhance host resistance in maize towards Fusarium ear rot and fumonisin contamination are discussed in detail. The planting of maize genotypes with enhanced host resistance potentially offers the most efficient method to reduce Fusarium ear rot and mycotoxin contamination. If plant breeding is to be used to enhance resistance, sources of genetic resistance are required. These sources would ideally be in the form of locally adapted maize genotypes, such as inbred lines. In Chapter 2, maize inbred lines used in local breeding programmes, which are adapted to the production conditions in southern Africa, were evaluated as potential sources of resistance to Fusarium ear rot and fumonisin contamination. If inbred lines with good genetic resistance were to be identified they could be used by breeding programmes to develop commercial maize cultivars with resistance to Fusarium ear rot and fumonisin. Activation of resistance responses in normally susceptible maize genotypes using resistance elicitors could provide a novel management strategy for Fusarium ear rot control, as no commercial cultivars with complete resistance to this disease have been identified in southern Africa. Elicitors have previously been found to induce resistance to plant pathogens, mostly in dicotyledonous crops, but the ability of a range of elicitors to reduce Fusarium ear rot and fumonisin contamination in maize has not been investigated. In Chapter 3, a variety of chemical elicitors that induced resistance in other plant-pathogen systems were selected based on the different defence pathways that they stimulate, and evaluated in field and greenhouse trials. Three commercial maize hybrids were included in the trial, conducted at two different field sites, and the elicitors were tested for their ability to reduce Fusarium ear rot and fumonisin contamination of grain, as well as for their effect on yield. These elicitors could be applied in the field as part of an integrated disease management programme, are environmentally friendly, and would be affordable to commercial producers that produce the majority of maize in South Africa.
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Hunter, Clifford Paul. "Plant regeneration from microspores of barley Hordeum vulgare L." Thesis, Imperial College London, 1988. http://hdl.handle.net/10044/1/7765.
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Pannell, J. R. "Models of androdioecy and studies on Mercurialis annua L." Thesis, University of Oxford, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.308744.
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Lopez-Montes, Antonio JoseÌ. "Integrating farmers' knowledge and decision-making in the planning of participatory research of cassava/maize intercropping." Thesis, Bangor University, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.248899.
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Chen, Dong Fang. "Genetic transformation in the Gramineae." Thesis, Open University, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.293321.
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Wilson, F. D., and H. M. Flint. "Host Plant Resistance." College of Agriculture, University of Arizona (Tucson, AZ), 1986. http://hdl.handle.net/10150/219754.
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The 1985 and 1986 Cotton Reports have the same publication and P-Series numbers.Cotton breeding stocks were evaluated for resistance to pink bollworm. Resistance is being transferred into improved agronomic stocks.
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Arendse, Brittany. "Variation in breeding systems and consequences for reproductive traits in Erica." Master's thesis, University of Cape Town, 2015. http://hdl.handle.net/11427/15494.
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Includes bibliographical referencesErica makes up 7% of all species in the Cape flora. It is the most species-rich genus in the Cape Floristic Region (CFR), which has an area 0f 90 000km². Erica species have great inter- and intra-specific variation in floral form as well as in post-fire regeneration strategies. Previous studies of other plant groups (Barrett et al. 1996; Button et al. 2012) have illustrated changes in floral traits with a shift from outcrossing to selfing. The aim of this thesis was to determine whether similar changes occur in Erica. I thus analysed breeding systems in Erica in relation to floral traits, pollinators, and fire survivals strategies. Seed and fruit set data obtained from hand-pollination treatments suggested that self- fertilization occurs rarely. Autonomous selfing did not generally yield significant seed set. When comparing changes in floral traits with increased selfing ability and pollination syndromes weak relationships were observed. Average plant height showed a positive relationship with selfing ability but this correlation was not significant. Comparing traits within small and large flowered species separately yielded significant relationships between corolla size and selfing ability of small-flowered species.. Furthermore, general trends indicate that small-flowered species have increased ability to self-fertilise when corolla sizes are larger, corolla apertures larger and herkogamy reduced. Large-flowered species employ the same strategy but average corolla aperture is reduced. A trade-off between the size and the number of flowers was seen within the Erica genus. Small-flowered species had significantly more flowers compared to larger- flowered species that had markedly fewer flowers per unit height. This finding has implications for the selfing potential of small-flowered species as increased self- incompatibility may have evolved in order to reduce the effects of increased geitonogamy due to increased floral number. The prediction that self-fertilisation would be increased in seeders compared to resprouters, on the basis that seeders are more reliant on seeds for persistence than resprouters, was not realised when comparing the selfing ability of different fire- survival strategies. Erica mammosa, a species with morphs possessing both fire-survival strategies, shows no significant differences in selfing ability, this includes differences in pollen-ovule (P/O) ratios. However, indices suggest the resprouting form of E. mammosa to have an increased ability to self-fertilize while the seeder form has an increased ability for autonomous selfing. The 29 species analysed were divided into outcrossers and facultative outcrossers based on selfing indices but these did not fit neatly within Cruden’s proposed P/O ranges (facultative autogamy: P/Os= 32-397; facultative outcrossers: P/Os= 160.7 - 2258.6; outcrossers: P/Os= 1062 - 19525). This may be due to his classification of species into breeding systems being based on relatively few distantly related species per category with extremely variable P/O ratios per category. For example, outcrossers ranged an order of magnitude (from 1000+ to 20 000). It is also true that this ratio can be influenced by a variety of different factors, these include: habitat, evolutionary history and pollination syndrome. Consequently, P/O ratios in Erica do not seem to reflect pollination syndromes very well. Presumably, sex allocation theory may explain the relationship of breeding system with P/O ratios better. Histological studies of pollen tube growth for self- and cross-pollinated flowers of eight species suggested that Erica has late acting self-incompatibility (LSI). LSI is a barrier to selfing that occurs in the ovary. However, I could not determine if the rejection process occurs pre- or post-fertilization. Although, a large amount of knowledge is still lacking, this preliminary study provided insight into the reproductive biology of Erica.
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Stewart, Alan V. "Plant breeding aspects of ryegrasses (Lolium sp.) infected with endophytic fungi." Phd thesis, University of Canterbury. Lincoln College, 1987. http://theses.lincoln.ac.nz/public/adt-NZLIU20071005.172250/.
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Some aspects of the presence of systemic endophytic fungi in agriculturally important New Zealand grasses were studied in relation to plant breeding. Seedling resistance to adult Argentine stem weevil feeding in perennial ryegrass, Italian ryegrass and tall fescue was found to be related to the presence of their respective Acremonium endophytes in the seed rather than to plant genetic resistance. In addition a study of perennial ryegrass revealed that this resistance was independent of endophyte viability. The seedling resistance conferred by the endophyte of Italian ryegrass was found to be beneficial for field establishment. This endophyte differs from that in perennial ryegrass and tall fescue in that it does not confer resistance to Argentine stem weevil on mature plants, but only on seedlings. The extent of plant genetic seedling tolerance to adult Argentine stem weevil feeding was limited to broad inter-specific differences, with tall fescue more tolerant than perennial ryegrass and both of these more tolerant than Italian ryegrass. This ranking corresponds with previous observations on feeding preference on mature plants. A study of factors affecting the concentration of endophyte mycelia in infected seed of perennial ryegrass revealed that plant genetic factors had little effect. The major factors studied were: 1) the endophyte concentration in the maternal parent plant directly influenced the endophyte concentration in the seed. 2) nitrogen fertilizer applications to a seed crop reduced the concentration of mycelia in the seed, with earlier applications having a greater effect. 3) application of the fungicide propiconazole (Tilt) to a seed crop reduced the endophyte concentration in the seed. 4) the endophyte concentration in the seed was found to directly influence the endophyte concentration in seedlings, six month old plants and that of seed harvested from a first year seed crop. As there have been no previous reports of tetraploid perennial ryegrass cultivars with endophyte an experiment was conducted to determine if these could be developed by the standard procedure of colchicine treatment. The results revealed that endophyte was retained following colchicine treatment.
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Paris, Maxime. "Development of high-throughput genotyping methods for market-assisted plant breeding." Thesis, Paris, Maxime (2002) Development of high-throughput genotyping methods for market-assisted plant breeding. PhD thesis, Murdoch University, 2002. https://researchrepository.murdoch.edu.au/id/eprint/52422/.
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Cultivated plant varieties are constantly being improved by selecting progeny for quality and disease resistance traits. Based on the knowledge that DNA sequence variations can cause phenotypic differences, technologies amenable to automation and multiplexing were developed to identify and select progeny carrying superior alleles of economically important genes.
A cost-effective DNA extraction method was developed to facilitate the implementation of molecular markers. The method enabled extraction of DNA suitable for PCR from 96 samples simultaneously and was used for routine selection of plant progeny carrying specific traits of interest, including barley yellow dwarf virus resistance (Yd2) and p-amylase activity in barley and stem rust resistance in wheat. PCR assays were multiplexed and robotic equipment was used to increase throughput further.
Single Nucleotide Polymorphisms (SNPs) are the most frequent mutations encountered in most genomes. To demonstrate the suitability of SNPs as molecular markers for plant breeding, a high-throughput method was developed to enable their validation and routine implementation. Single and multi-nucleotide primer extension assays enabling co-dominant SNP genotyping from small quantities of plant tissue were developed. In the Single Nucleotide Primer Extension (SNuPE) assay, a genotyping primer with its 3’ end directly flanking a SNP was annealed to target sequence and extended by a single dideoxynucleotide triphosphate (ddNTP) complementary to the polymorphic base. In the multi-nucleotide primer extension assay, designed to facilitate genotyping of heterozygous progeny, the genotyping primer with its 3’ end flanking the SNP was extended by either one or two nucleotides, depending on the allele encountered. Extension products were analysed using Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (MALDI-ToF MS) and, making use of the molecular weight difference between DNA bases, the incorporated nucleotides were identified by the increase in mass of the extended primers.
In barley, mutation-induced recessive alleles (mlo) of the Mlo locus provide broadspectrum resistance to an important fungal pathogen, powdery mildew. The Mlo gene of susceptible and resistant varieties were sequenced and aligned to identify mutations linked to the resistance. A SNP identified and confirmed from a resistant variety, Alexis (mlo-9), was used to develop single and multiple primer extension assays. Two DH populations were characterised for their response to powdery mildew and used for validation of the molecular marker. The assay enabled accurate co-dominant selection of plants carrying the mlo-9 allele providing ra/o-mediated powdery mildew resistance.
MALDI-ToF MS is a platform amenable to multiplexing and automation. An investigation of its use for the analysis of microsatellites, another common form of mutation, resulted in the development of a novel genotyping technique. Following amplification of the target sequence, a primer with its 3’ end directly flanking the microsatellite was extended for its length by the deoxynucleotide triphosphates (dNTPs) complementary to the repeat motif. The extension was interrupted by a single ddNTP complementary to the nucleotide following the repeated region. Extension products were analysed using MALDI-ToF MS and differences in the molecular weights of the products enabled identification of the microsatellite alleles. The technique enabled identification of heterozygous progeny in which alleles differed by a single tri-nucleotide repeat. The method is illustrated by genotyping a polymorphic microsatellite identified in an intron of the barley Mlo gene.
A novel strategy was designed to develop a perfectly linked marker. In the malting process, P-amylase is a key enzyme involved in the degradation of starch. Four allelic forms of the enzyme are found in barley and each exhibits a different rate of thermal inactivation, or thermostability. The level of thermostability influences starch degradation, which determines the yield of fermentable sugars for alcohol production during brewing. Alignment of the cDNA sequences encoding the four enzyme forms revealed six SNPs (cSNPs). The four alleles could be unambiguously identified by co-dominantly genotyping two of the cSNPs using a duplex SNuPE assay. A Cleaved Amplified Polymorphic Sequence (CAPS) assay enabling broader classification of the alleles was also developed to facilitate the transfer of this marker to other laboratories. These markers were used to select plants carrying alternative P-amylase alleles for barley breeding.
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Basu, Saikat Kumar, and University of Lethbridge Faculty of Arts and Science. "Seed production technology for fenugreek (Trigonella foenum-graecum L.) in the Canadian prairies." Thesis, Lethbridge, Alta. : University of Lethbridge, Faculty of Arts and Science, 2006, 2006. http://hdl.handle.net/10133/242.
Full textAbstract:
Fenugreek (Trigonella foenum-graecum L.) is an annual legume mainly used as a spice crop in many parts of the world. "Tristar" is a new forage cultivar that requires - 120 days to produce mature seed in western Canada where only - 100 frost-free days are available. The goal for this study was to reduce maturity duration for the crop through a series of studies on the genetics and agronomic aspects of fenugreek. This two year study suggests that: 1)mutation breeding using Tristar seed as a base population could be successfull; 2)multi-location trials using world accessions exhibited genotype X environment interaction; 3)swathing of plants before freezing temperatures set in; 4)application of phosphate fertilizer increased seed yield and; 5)foliar sprays of chemicals can be used for production of high quality seed. In this study some short duration, high yielding and determine lines of fenugreek were produced improving the potential for use of fenugreek and the economics of beef production in western Canada.xix, 184 leaves : ill. (some col.) ; 29 cm.
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Wilson, F. D., and H. M. Flint. "Host Plant Resistance." College of Agriculture, University of Arizona (Tucson, AZ), 1985. http://hdl.handle.net/10150/203923.
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Kuhlman, Leslie Charles. "Sorghum introgression breeding utilizing S. macrospermum." [College Station, Tex. : Texas A&M University, 2007. http://hdl.handle.net/1969.1/ETD-TAMU-1598.
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Jensen, Nicole Michelle. "Investigating quantitative genetic issues for a pedigree plant breeding program using computer simulation /." [St. Lucia, Qld.], 2004. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe18058.pdf.
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Tinker, Nicholas Andrew. "Studies on the analysis of genetic markers and quantitative trait loci in plant breeding populations." Thesis, McGill University, 1994. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=41774.
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Laboratory experiments, genetic simulation, and theoretical analyses were performed to address several objectives related to the use of genetic markers in plant breeding programs. Two software packages were developed: GREGOR provides flexible and efficient computer algorithms for performing genetic simulation experiments, and KIN provides improved methods for estimating coancestry from known pedigrees. Random amplified polymorphic DNA (RAPD) markers were investigated in elite barley lines, and estimates of genetic distance based on RAPD markers were compared to estimates based on coancestry. Both types of estimate can provide information that is useful to breeders and geneticists. Genetic simulation was used to investigate the power, accuracy and precision of several methods that are available for analyzing quantitative trait loci (QTL). In most cases, simplified methods of QTL analysis based on linear regression were similar or superior to more complex methods based on mixture models. Methods for genetic analysis using selective genotyping and pooled DNA were also investigated. These methods may allow precise estimates of the positions of markers and QTL to be made.
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Dohle, Sarah. "Development of Resources for Lima Bean (Phaseolus lunatus ) Breeding and Genetics Research." Thesis, University of California, Davis, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10607596.
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Lima bean (Phaseolus lunatus) is a semi-perennial, leguminous species characterized by large flat, crescent-moon-shaped pods and trifoliate leaves with generally vigorous growth habit. Lima bean is naturally distributed from the southern United States to northern Argentina, from sea level to over 2,700m and has been grown commercially in California since the late 1800’s. The objective of the University of California Davis Lima bean breeding program is to develop improved large and baby, bush- and vine-type dry bean varieties with lygus (L. hesperus) and nematode (M. incognita ) resistance and to develop breeding tools such as genetic maps and molecular markers linked to important traits to facilitate future breeding efforts. To broaden the genetic base of the California Lima bean breeding program and add novel sources of stress resistance, 313 exotic accessions of Lima beans were field-tested at UC Davis (38.54N, -121.79W). Only nine percent of accessions produced seed and were evaluated for a second season for yield and lygus tolerance relative to ‘UC Haskell’, a leading baby-vine cultivar. Ten accessions outperformed the check for either yield or insect damage and may be good candidates to incorporate into California breeding. To facilitate breeding and research at a genetic level, several tools were developed for this semi-orphan crop, including the first large Recombinant Inbred (RI) population (n ∼300) derived from California cultivars originating from the conspecific Mesoamerican and Andean gene pools which show transgressive segregation for most agronomic traits. Traits including flowering time, inflorescent position, plant height, pod position and pod density showed correlation with yield that varied with and without lygus pressure, indicating potential tolerance mechanisms, which should be studied in more depth. This population was used to create a genetic linkage map containing 515 SNPs spanning 1622 cM across 13 linkage groups with synteny to common bean. This genetic map in combination with two seasons of field phenotypic data were used for composite interval mapping of 27 QTLs for germination rate, plant height, seed weight, yield, flowering time, inflorescence position, growth habit, and hydrogen cyanide potential in Lima bean. Seven of the new Lima bean QTLs for flowering time, plant height and seed weight are in similar locations to common bean QTLs. This research has increased our scientific and agronomic knowledge of Lima bean, a semi-orphan crop that has potential for increased utilization in California and globally.
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Miller, Erin Suzanne. "Increasing Expression of Hepatitis B Surface Antigen in Maize through Breeding." DigitalCommons@CalPoly, 2015. https://digitalcommons.calpoly.edu/theses/1359.
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The hepatitis B virus (HBV) is a common virus, with two billion people infected worldwide. It causes approximately 600,000 deaths each year, despite the availability of an effective vaccine since 1982. Maize as a platform for oral vaccination can supply a heat stable vaccine, which does not require syringes or trained personnel to administer. The Hepatitis B Surface antigen was transformed into maize and this seed was used to evaluate expression levels through the breeding process. The transgene was transferred into two elite maize inbreds by backcrossing. Highest expressing ears were selected each generation until approximately 99% commercial parent was obtained with a single gene coding for the vaccine present. Selected individuals were crossed to create hybrid plants. This work was done to create high expressing high yielding lines that could be used as a plant-based oral vaccine for Hepatitis B.
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Andersson, Erik W. "Gain and diversity in multi-generation breeding programs /." Umeå : Swedish Univ. of Agricultural Sciences (Sveriges lantbruksuniv.), 1999. http://epsilon.slu.se/avh/1999/91-576-5629-0.pdf.
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Merlin, Catherine M. "Artificial hybridization in the genus Impatiens." Thesis, McGill University, 1985. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=63252.
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Khalid, Norzulaani. "Somaclonal variation through tissue culture studies in Chrysanthemum morifolium." Thesis, University of Nottingham, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.329847.
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Burridge, C. Y. "Latent variable models for genotype-environment interaction." Thesis, University of Reading, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.383469.
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Ellis, Marc Harvey. "The inheritance of transgene by DNA methylation in Nicotiana tabacum." Thesis, University of Cambridge, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.240918.
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Schmidt, Paul [Verfasser], and Hans-Peter [Akademischer Betreuer] Piepho. "Estimating heritability in plant breeding programs / Paul Schmidt ; Betreuer: Hans-Peter Piepho." Hohenheim : Kommunikations-, Informations- und Medienzentrum der Universität Hohenheim, 2020. http://d-nb.info/1209196328/34.
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Perryman, A. Linda M. "Irradiated gametes as a means of limited gene transfer in plant breeding." Thesis, University of St Andrews, 1991. http://hdl.handle.net/10023/14362.
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Following reports that limited gene transfer may be facilitated by making crosses with irradiated pollen, a debate has arisen as to the cause of the observed results. If maternal trends that occurred in the second generation (the M2) were largely due to the persistence of radiation induced damage, then pollen irradiation would be of little value to plant breeders. But if much of the paternal genome had been eliminated, the method could offer breeders a cheap and simple means of transferring just a few characters from one plant genome to another. By carrying out reciprocal irradiated and control crosses, it was shown in this study with barley that mutational damage is not widespread in the M2. However, consistent trends away from the F2 towards the maternal expression were not observed either. When instead the female gamete was irradiated, moderate shifts to the paternal expression did occur. As trends were for increased vigour, mutational damage is unlikely to have been the cause of these observations. By contrast, when irradiated pollen crosses were made between three varieties of potato, the M1 and M2 were consistently lower scoring than the controls. It is suggested that the results may have been different in the two species because polyploids such as the potato may be better able to tolerate radiation damage than diploids such as barley. Gamete irradiation may, therefore, be of little value in polyploid crops. It is recommended that, at least in diploid species, ovule irradiation should be further investigated because not only may it be more effective than its male equivalent, but it may also be easier to perform. Both techniques may be useful in breaking down linkages resistant to conventional crossing.
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Stevens, J. P. "The meiotic and breeding systems of Allium schoenoprasum L. in natural populations." Thesis, University of York, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.356844.
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Essomba, Nehru Bengono. "The inheritance of four morphological traits in peanut (Arachis hypogaea L.)." Thesis, Virginia Polytechnic Institute and State University, 1987. http://hdl.handle.net/10919/90969.
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Studies of the inheritance of morphological traits contribute to the understanding of peanut genetics. Investigations of the fertility and cytogenetics of interspecific progenies between Arachis hypogaea and wild Arachis species have provided invaluable information on the phylogenetic relationships within the genus Arachis and on the amphidiploid nature of peanut. However, the inheritance of morphological traits using interspecific progenies has not been elucidated to date. The objective of this study was to identify and to analyze genetic factors controlling growth habit, stem color, root nodulation, and leaflet size in peanut. F1 and F2 progenies were obtained from diallel crosses between A. hypogaea cvs. Argentine and T2442, and A. monticola. Fz progenies and parents were grown at the Tidewater Agricultural Experiment Station in 1985. F1 plants were grown in the greenhouse in 1986. Five, six, and seven phenotypic classes, respectively, were assigned to characterize growth habit, stem color, and leaflet size. Root nodulation was indirectly determined through leaf color. Chi-squares were computed to test homogeneity of reciprocal crosses and genetic ratios for growth habit, stem color, and root nodulation. Leaflet size distributions were analyzed graphically and independence of inheritance was tested among all traits studied. Analysis of results indicates that: 1) growth habit may be determined by four genes having two types of isoalleles, 2) the relationship between and within these four genes may be essentially additive, 3) all loci may not contribute with the same weight to growth habit phenotype, 4) purple and green pigmentations may be determined by two distinctive sets of epistatic genes, 5) the two genes responsible for green pigmentation may be duplicate, 6) more than two types of alleles may have been involved for one or more loci responsible for stem color, 7) root nodulation may be determined by three independent non-duplicate genes, 8) leaflet size may be quasi-quantitatively determined in peanut, 9) extranuclear factors may interact additively and/or epistaticly with nuclear factors determining growth habit, stem color, and leaflet size, 10) the relatively high number of segregating loci observed for all the traits studied may have resulted from the use of A. monticola as one of the parents, and 11) extranuclear factors may induce or modify relationships between traits when they interfere with nuclear genes determining these traits.M.S.
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Ahmadi, Firouzabad Abdolhadi. "Introgression of resistance to powdery mildew (Erysiphe graminis f.sp. tritici) from alien species into bread wheat (Triticum aestivum)." Thesis, University of Newcastle Upon Tyne, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.340688.
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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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Davidson, Jacob B. "Natural History and Breeding System of Maguire Primrose." DigitalCommons@USU, 2010. https://digitalcommons.usu.edu/etd/696.
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The goal of this thesis was to examine the breeding system and natural history of the Maguire primrose (Primula cusickiana var. maguirei). Maguire primrose is an endemic, threatened subspecies found only along a narrow corridor within Logan Canyon in northern Utah, USA. This plant displays distinct flower distyly, with clear distinction of pin and thrum morphologies (morphs). The timing of Maguire primrose flower blooms was disparate between upper and lower canyon populations, and the flowers experienced cool temperatures occasionally. I captured eight different species of flying insects visiting Maguire primrose flowers, and made 67 observations of insect visitation. Inter-morph outcrossing hand pollinations were the most successful hand pollinations performed, but were usually not as successful as those that were naturally pollinated. Selfing rates were quite low compared to outcrossing reproductive scenarios. Morph-specific fecundity differences were detected in my hand pollinations, but not in the naturally pollinated maternal plants. I did not observe clear fecundity differences based on the canyon location of Maguire primrose.
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Capelin, Marcio Andrei. "Heterose e capacidade de combinação em trigo envolvendo fontes de genes de nanismo." Universidade Tecnológica Federal do Paraná, 2014. http://repositorio.utfpr.edu.br/jspui/handle/1/857.
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A introdução de genes Rht, oriundos principalmente de programas de melhoramento
da Ásia, Europa, Estados Unidos e México permitiu o avanço da cultura do trigo
(Triticum aestivum L.) para áreas consideradas marginais. Nesse contexto, este
trabalho se propõe avaliar a capacidade de combinação, heterose e heterobeltiose
em um dialelo 8x8 afim de verificar o efeito pleiotrópico (único gene controla diversas
características do fenótipo), ou seja, além da estatura, quais os componentes de
rendimento que estão sendo alterados quando cultivares de maior estatura são
cruzados com as linhas anãs CD 0827, CD 0985 e UTF 0605 disponibilizadas por programas de melhoramento genético nacionais de trigo. O experimento foi conduzido em Pato Branco – PR, na safra agrícola de 2012, em delineamento experimental de blocos casualizados com três repetições. As hibridações foram realizadas com oito genitores, sendo três anões (CD 0827, CD 0985 e UTF 0605) e BRS Pardela, Safira, BRS Tangará, CD 111 e CD 108, escolhidos por apresentarem estatura de planta média à elevada, potencial produtivo e demais caracteres agronômicos de interesse. Os valores dos quadrados médios da capacidade geral de combinação (CGC) foram superiores à capacidade específica de combinação
(CEC) para todos os caracteres estudados, demonstrando maior contribuição dos
efeitos gênicos aditivos. A capacidade geral de combinação das linhagens anãs (CD
0827, CD 0985 e UTF 0605) indicou as maiores contribuições para a redução da estatura de planta, em ambas as gerações avaliadas, com destaque para a linhagem UTF 0605. A CGC também indica que os genitores UTF 0605, Safira e BRS Tangará maximizam o número de afilhos férteis por planta (AFPL) e CD 0985 e CD 111 se mostraram efetivos em aumentar o número de grãos por planta (NGE). Os genitores Safira, BRS Tangará, CD 108 e entre as anãs CD 0827 se destacaram com os mais elevados valores quanto a CGC para rendimento de grãos por planta (RGP). Os
genitores anãos UTF 0605, CD 0985 e CD 0827 são fontes promissoras de genes aditivos para o desenvolvimento de progênies de menor estatura de planta e maior número de afilhos férteis por planta, grãos por espiga e massa de mil grãos. Os cruzamentos CD 0827 x Safira, UTF 0605 x Safira, CD 0985 x CD 111, CD 0985 x CD 108, UTF 0605 x CD 111, UTF 0605 x BRS Tangará destacaram-se com maiores
valores de capacidade específica de combinação para rendimento de grãos, e os
dois primeiros foram superiores quando se considera os valores de heterose e
heterobeltiose e depressão endogâmica. Os resultados deste estudo demonstram a
viabilidade de utilização de linhagens anãs em programas de melhoramento genético.The introduction of Rht genes, mainly from breeding programs in Asia, Europe, United States and Mexico has allowed the advancement of wheat (Triticum aestivum L.) to marginal areas considered. In this context, this study aims to evaluate the combining ability, heterosis and heterosis in a 8x8 diallel order to verify the pleiotropic effect (single gene controls several features of the phenotype), in other words, beyond the stature which components of income that are being changed when taller cultivars are crossed with dwarf lines CD 0827, CD 0985 and UTF 0605 provided by national wheat breeding programs. The experiment was conducted in Pato Branco - PR in the 2012 harvest, in a randomized block design with three replications. Hybridizations were performed with eight parents, three of them dwarfs (CD 0827 , CD 0985 and UTF 0605), BRS Pardela, Safira , BRS Tangara, CD 111 and CD 108. The values of the mean squares for GCA were higher than SCA for all traits indicating higher contribution of additive genetic effects. The general combining ability of the dwarf lines (CD 0827 , CD 0985 and UTF 0605) indicated the greatest contributions to the reduction of plant height in both generations evaluated, highlighting the UTF 0605 lineage. The CGC also indicates that UTF 0605, Safira and BRS Tangará parents maximize the number of fertile tillers per plant (NFPP) and CD 0985 , CD 111 were effective in increasing the number of grains per spike (NGS). The Safira, BRS Tangará, CD 108 and CD 0827 between dwarf parents stood out with the highest values for GCA for grain yield per plant (GYP) . The dwarf parents UTF 0605, CD 0985 and CD 0827 are promising sources of additive genes for the development of progenies of lower plant height and increased number of fertile tillers per plant, grains per spike and thousand grain weight. The CD 0827 x Safira, UTF 0605 x Safira, CD 0985 x CD 111, CD 0985 x CD 108, UTF 0605 x CD 111, UTF 0605 x BRS Tangará stood out with higher values of specific combining ability for grain yield, and the first two were higher when considering the values of heterosis and heterosis and inbreeding depression. The results of this study demonstrate the feasibility of using plant population used in breeding programs.
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Campbell, Lesley Geills. "Rapid evolution in a crop-weed complex (Raphanus spp.)." Columbus, Ohio : Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1166549627.
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Hofheinz, Nina [Verfasser]. "Implementation of genome-wide prediction methods in applied plant breeding programs / Nina Hofheinz." Gießen : Universitätsbibliothek, 2014. http://d-nb.info/106882509X/34.
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Vekemans, Xavier. "Evolution of plant breeding systems: armeria maritima Mill.(Willd.) as a study case." Doctoral thesis, Universite Libre de Bruxelles, 1992. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/212934.
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Mahmoud, Sayed Hassan. "Biochemical marker genes for molecular genetics and plant breeding in Pisum sativum L." Thesis, Durham University, 1985. http://etheses.dur.ac.uk/7853/.
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Three isoenzyme systems (amylase, esterase and glutamate oxalo acetate transaminase) were examined in seeds of pea ( Pisum sativum L.) and showed clear variations in their band patterns on gel electro phoresis between different lines. The inheritance of these isoenzyme systems, and the location of their structural genes on the pea genome were investigated. Reciprocal crosses were made between lines, F2 seeds were analysed for segregation in the band patterns of the isoenzymes, and F2 plants were investigated to find linkage between the genes for these isoenzymes and genes for selected morphological markers. The results obtained showed that each of the investigated isoenzyme systems is genetically controlled by co-dominant alleles at a single locus. The gene for amylase ( Amy ) was found to be on chromosome 2, linked to the loci k and wb ( wb.. .9-k. . .25.. .Amy ). The gene for esterase ( Est ) was found to be linked to the gene Br (chromosome 4) but the exact location is uncertain because of a lack of morphological markers. The gene for glutamate oxaloacetate transaminase ( Got ) was found to be on chromosome 1 linked to the loci a and d ( a...24...Got...41.. d). Gel electrophoresis techniques have also been used to investigate genetically controlled variation in the major subunits (50,000 Mr) of vicilin, a storage protein of Pisum sativum L. The Fl protein band patterns were shown to be additive with respect to those of the parental lines and to be identical in reciprocal crosses. Genetic analysis of the F2 plants indicated that the 50,000 Mr vicilin subunits band pattern is controlled by a pair of co-dominant genes at a single locus. The F2 data were used to locate this major vicilin gene locus ( Vc-1 ) to chromoscane 7, closely linked to the r locus (for round and wrinkled seed surface). A third member of pea legumin gene family, denoted legB, has been sequenced using the "dideoxy chain termination" method with the M1 3 sequencing system. The complete nucleotide sequence showed that this gene has a general form typical of an eukaryotic gene. The homolgies between this gene and the previously published gene "legA" 'were estimated and showed strong homology between the two genes with eight amino acid substitutions and deletion of 14 bp in the third intron (IVS-3).The inheritance of ribosomal RNA (rRNA) genes in ( Pisum sativum L.) was investigated in a cross between two different lines, where length variation in rDNA fragments of Eco RI digests was observed. The results obtained showed that the rRNA genes are controlled by simple Mendelian system with "co-dominance" between alleles. In order to locate the rRNA gene sites to positions on the chromosomes, the segregation of ECO. RI restriction fragments of rDNA from F2 plants with respect to genes for selected morphological markers on chromosomes 4 and 7 (the chromosomes known to have nucleolus organizer regions) were tested. The F2 data showed no linkages between the selected markers and rRNA genes, therefore, in situ hybridization using rDNA radioactive probe ((^3)H- labelled rDNA clone, pHAI) and physical mapping procedures were used. The results obtained have located the rRNA gene sites to nucleolus organizer regions (satellite constrictions) at 138 and 60 map units from the centromeres of chromosomes 4 and 7, respectively.
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Modrzejewski, Dominik [Verfasser]. "Evidence synthesis on the impact of genome editing on plant breeding / Dominik Modrzejewski." Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2020. http://d-nb.info/1222738201/34.
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Rife, Trevor W. "Utilizing a historical wheat collection to develop new tools for modern plant breeding." Diss., Kansas State University, 2016. http://hdl.handle.net/2097/34503.
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Doctor of PhilosophyGenetics Interdepartmental Program
Jesse Poland
The Green Revolution is credited with saving billions of lives by effectively harnessing new genetic resources and breeding strategies to create high-yielding varieties for countries lacking adequate food security. To keep the next billion people in a state of food security, plant breeders will need to rapidly incorporate novel approaches and technologies into their breeding programs. The work presented here describes new genomic and phenomic strategies and tools aimed at accelerating genetic gain in plant breeding. Plant breeders have long relied on regional testing networks to evaluate new breeding lines across many locations. These are an attractive resource for both retrospective and contemporary analysis due to the vast amount of data available. To characterize genetic progress of plant breeding programs in the Central Plains, entries from the Southern Regional Performance Nursery dating back to 1992 were evaluated in field trials. The trend for annual improvement was 1.1% yr⁻¹, matching similar reports for genetic gain. During the same time period, growth of on-farm yields stagnated. Genomic selection, a promising method to increase genetic gain, was tested using historical data from the SRPN. A temporal-based model showed that, on average, yield predictions outperformed a year-to-year phenotypic correlation. A program-based model found that the predictability of a breeding program was similar when using either data from a single program or from the entire regional collection. Modern DNA marker platforms either characterize a small number of loci or profile an entire genome. Spiked genotyping-by-sequencing (sGBS) was developed to address the need in breeding programs for both targeted loci and whole-genome selection. sGBS uses a low-cost, integrated approach that combines targeted amplicons with reduced representation genotyping-by-sequencing. This approach was validated using converted and newly-designed markers targeting known polymorphisms in the leaf rust resistance gene Lr34. Plant breeding programs generate vast quantities of data during evaluation and selection of superior genotypes. Many programs still rely on manual, error-prone methods to collect data. To make this process more robust, we have developed several open-source phenotyping apps with simple, intuitive interfaces. A contemporary Green Revolution will rely on integrating many of these innovative technologies into modern breeding programs.
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Dighe, Nilesh Deoram. "Introgression of reniform nematode resistance and other germplasm from G. longicalyx and G. armourianum into G. hirsutum." [College Station, Tex. : Texas A&M University, 2007. http://hdl.handle.net/1969.1/ETD-TAMU-2579.
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Brown, Jack. "The efficiency of selection in the early generations of a potato breeding programme." Thesis, University of St Andrews, 1988. http://hdl.handle.net/10023/7107.
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The efficiency of selection in the early generations of a potato breeding programme is examined. A number of unselected potato (Solanum tuberosum L) clones were grown in a glasshouse, from true botanical seed, and thereafter in the field at two locations (a seed site and a ware site) for three consecutive years. At each stage, a number of tuber characteristics were visually assessed and yield plus the yield components were recorded. Four potato breeders visually assessed the produce from each clone after harvesting each years trials and were in good agreement as to which clones would be selected in each environment. Selection for visually assessed characters in both the glasshouse and first clonal year produced a desirable response. However, such selection carried a high cost in terms of losing clones with commercial potential. Selecting clones for yield in the seedling and first clonal year was only marginally more effective than a random reduction in number of genotypes, while selection in the second clonal year appeared to be somewhat more effective as judged by performance in later generations. Comparison of a random sample of clones with ones from the same crosses which had been selected at the seedling and first clonal year stage was at best random, with some suggestion, however, of a negative effect. The causes behind the inefficiency of selection were found to be complex. The inefficiency was ascribed, at least in part, to (i) the inaccuracy of assessment on single plant plots; (ii) the "carry-over" effect of the mother tubers and (iii) selection under a short growing season. Although there was a formally significant interaction between progenies and environments, the rank of the mean of a cross remained relatively consistent over different growing conditions. It was found that the mean and square root of the variance obtained from breeders' preference in any of the environments provided a good basis for prediction of the number of clones in each cross which would exceed (or equal) a given target value. The square root of the variance added increasingly to the accuracy of the prediction as the target value increased but was never a major component in such predictions. When the predictions were used to provide ranking of the crosses, the rank correlations showed good agreement between the different environments and between observed and expected ranks. There was no evidence to suggest that univariate cross prediction for any of the other characters under study would not be effective. A new cultivar is unlikely to be successful simply because of high expression for a single character, but will rather be an all round improvement over cultivars already available. Three methods of multivariate cross prediction were therefore examined namely multivariate probabilities, sum of ranks and the frequency of genotypes in a sample that transgress set target values. The characters total tuber weigh t, mean tuber weight, number of tubers and regularity of tuber shape were examined. It was found that a sample as small as 25 clones provided good predictions (as judged by the observed frequencies in a larger progeny sample examined in various environments). The best estimates were obtained using multivariate probabilities based on the means, within progeny variances,. and the phenotypic correlations between variates. The ranking of crosses according to these multivariate probabilities provided good indications of the number of clones which survived selection in an actual breeding scheme. Thus it is suggested that an empirical examination of a sub-sample of the progeny from a cross could be used to determine the crosses which would have the highest probability of producing improved, potato cultivars. Selection of crosses rather than individual clones has several advantages which would favour such techniques being used in the early generations of a potato breeding programme. Cross prediction based on parental performance also provided an indication of the crosses, .and parents, .which would give the highest frequency of desirable recombinants. These predictions were not as accurate as those derived from examination of a sub-sample of progeny from each cross. But they would allow an earlier, and hence powerful, method of prediction.
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Milbern, Lana Cecile. "Habitat usage of breeding songbirds in urban Columbus, Ohio." The Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu1587476090513815.
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Mayfield, Kerry L. "Preharvest aflatoxin in maize genotypes under inoculation with Aspergillus flavus." [College Station, Tex. : Texas A&M University, 2006. http://hdl.handle.net/1969.1/ETD-TAMU-1184.
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Mani, Dhananjay. "Characterization and genetic analysis of a very high tillering and dwarf rice (Oryza sativa L.) mutant." [College Station, Tex. : Texas A&M University, 2008. http://hdl.handle.net/1969.1/ETD-TAMU-3042.
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