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1
Uddin, Md Nizam. "Heterosis in wheat (Triticum aestivum L.)." Thesis, The University of Sydney, 1991. https://hdl.handle.net/2123/26310.
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Three field experiments were established to provide information upon which strategic decisions could be made on the advisability of breeding hybrid wheat versus pure lines for Australian wheat growing conditions. These experiments would determine the level and stability of heterosis for grain yield, provide data on how hybrids obtained their yield, indicate the accuracy of different planting arrangements for measuring heterosis and compare the performance of pure lines derived from heterotic hybrids with the F1 hybrids.
Six hand-made, two produced using a chemical gametocide and two commercial hybrids were tested along with their parents (except for the commercial hybrids for which the parents were unavailable) in replicated hill plots in three environments (sowing date s) for two seasons, 1987 and 1988. The hybrids produced significantly more grain yield in all six environments and were marginally more stable than their parents. The best hybrid outyielded the commercial cultivar by 18.2 %. Mea n protein content of the hybrids was marginally lower r than that for the parents, i. e., 14.4 % compared with 14.8 %. Howe ver, the three high est yielding hybrids, despite their 14.5 —18. 3% yield advantage over the best yielding check cultivar were high er in protein than it by as much as 1.2% protein.
Kernel weight appeared to contribute most consistently to yield heterosis. All hybrids were taller than the mid-parent value and half of them were taller than the high-parent. However, the increased height did not affect their harvest indices adversely. With only one exception the hybrids had significantly higher harvest indices compared with the mid-parent value.
Eight of the hybrids from the above experiment were tested in hill plots, space-planted plots and in multiple row plots (large plots) planted at a seeding density comparable with commercial practice Genotype means from the three plot types for grain yield. Its components, plant height and harvest index were positively and significantly correlated. The three plot types determined genotypic differences with similar precision. Similar levels of heterosis were observed in hill plots and space-planted plots. 22.1 and 22.9%, respectively, whereas a relatively lower level was observed in large plots (11.7%). This reduction was mainly due to reduced heterosis for tiller number.
The potential to develop pure lines with similar yield to the heterotic F1 hybrids was investigated using four hand-made hybrids and the commercial hybrid, Comet. Seventy five single seed descent derived F- (F6 in the case of Comet) lines were compared with their parents (except for Comet) and the F1 hybrid in replicated hill plots. Significant high-parent heterosis up to 15.1% for grain yield was observed for the hand-made hybrids. Estimation of heterosis for Comet was not possible because of the unavailability of its parents.
All crosses produced pure lines which yielded similarly to their Fi hybrid indicating that pure lines of equivalent yield to the heterotic Fi could be developed by conventional breeding. There was no consistent pattern amongst the pure lines as to how they achieved their yield via their components. Optimal plant height was in the range of 70-90 cm, i.e., semidwarf types, for all crosses.
The results of the experiments conducted indicate that although considerable and stable levels of heterosis were observed, pure lines of comparable yield to the hybrids could be produced. The decision to breed hybrids as opposed to breeding pure lines would appear therefore to depend on commercial rather than scientific considerations.
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Collin, François. "The tolerance of wheat (Triticum aestivum L.) to Septori tritici blotch." Thesis, University of Nottingham, 2018. http://eprints.nottingham.ac.uk/49156/.
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The Septoria tritici blotch disease (STB, pathogen Zymoseptoria tritici) is the most damaging foliar infection of wheat crops in Europe. Disease management strategies include cultivar resistance, disease escape strategy and fungicides. However, these strategies have failed to provide a complete protection of wheat crops. The STB tolerance is a complementary approach which aims to maintain yield in the presence of the symptoms. The tolerance of STB relies on plant physiology and source/sink balance: the sink demand (the grain growth) must be satisfied in spite of reduced source availability (photosynthetic capacity as affected by the STB symptoms on the leaves). The green canopy area, the senescence timing and the grain yield components are interesting potential sources of tolerance that were studied in this project. A data-mining study, one glasshouse experiment and two field experiments were carried out providing complementary insights on STB tolerance mechanisms. The genotype/environment interaction effects on tolerance traits were investigated for two seasons five locations/nine cultivars datasets. The nitrogen nutrition and metabolism of four doubled-haploid (DH) lines contrasting for STB tolerance were examined in a controlled glasshouse experiment at UMR ECOSYS (INRA,AgroParisTech) Grignon, France. The source/sink balance of six DH lines contrasting for STB tolerance was also examined according to their responses to a spikelet removal treatment, applied in a field experiment in Hereford, UK. Finally, a field experiment with two fungicide regimes (full disease control and non-target (STB) disease control) probed the STB tolerance of six modern UK winter wheat cultivars in Leicestershire, UK. The main objective was to verify identified potential STB tolerance traits in commercial cultivars. Putative STB tolerance traits have been identified such as the early heading date, the low degree of grain-source availability of healthy crops during the grain filling phase, the vertical canopy distribution favouring a relatively larger flag-leaf. Results showed these traits might be selectable in wheat breeding without a trade-off with the potential yield. Finally, the project also discussed the need for alternative STB tolerance quantification methods, as well as the importance of environmental variations which have to be taken into account to study genetic variation in tolerance, but which could also be used to discriminate tolerant environment.
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Zainuddin. "Genetic transformation of wheat (Triticum aestivum L.)." Title page, Contents and Abstract only, 2000. http://web4.library.adelaide.edu.au/theses/09APSP/09apspz21.pdf.
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Bibliography: leaves 127-151. The successful application of genetic engineering in wheat is dependent on the availability of suitable tissue culture and transformation methods. The primary object of this project was the development of these technologies using elite Australian wheat varieties.
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Lewis, Rebecca Sian. "Charcterising mismatch repair in wheat (triticum aestivum)." Thesis, University of Bristol, 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.681489.
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To meet the nutritional requirements of a growing population, world agricultural output must increase by 70-100% by 2050. However, worldwide wheat yields are close to reaching a 'glass ceiling'. In order to meet the challenges of a rapidly growing population, scarcity of resources and a trend toward high-protein diets, traditional agriculture has looked towards molecular biology for insight and innovation for the future. Studying the mechanisms underlying DNA damage and repair is crucially important to facilitating generation of novel variation and developing breeding techniques. The Mismatch Repair (MMR) system is a highly-conserved series of pathways responsible for maintaining genomic integrity in prokaryotes and eukaryotes. The constituent proteins repair DNA mismatches and prevent meiotic recombination between homoeologous sequences. Work in Arabidopsis, tobacco and tomato has shown that plants with an impaired MMR system accumulate point mutations and undergo increased homoeologous recombination, which may be useful in breeding programs. Two key MMR genes are explored: MutS Homologue 2 (MSH2) acts as a heterodimer with MSH3, MSH6 or MSH7 to detect point mutations, insertions and deletions. Post Meiotic Segregation increased 2 (PMS2) is a homologue of the MutL gene, which co-ordinates repair of mismatches. The two genes were cloned and sequenced from elite cultivar Cadenza, and the sequences subsequently compared to next generation sequencing data from Chinese Spring. Three homoeologous copies of each gene were identified in the genome of wheat, and two of these were sequenced from the transcriptome. The expression of MSH2 was studied using qPCR in the transcriptome of Cadenza and four gamma-irradiated deletion lines, generated in a Paragon background. The four deletion lines showed varying responses: from down-regulation of MSH2 expression by 57% to upregulation by 82%. The expression of the individual homoeologues of MSH2 were also explored using a qPCR based method and by examining RNAseq data, but this was inconclusive.
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McNulty, Melissa S. "Preliminary characterization of wheat, Triticum aestivum , embryo globulins." Thesis, University of Ottawa (Canada), 2006. http://hdl.handle.net/10393/27392.
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The 7S globulins are a subclass of seed storage proteins characterized by their solubility in saline solution. These proteins are major legume storage reserves, and have been studied extensively; in the cereals, they represent a minor seed protein fraction and have been characterized to a lesser extent. Recently, a study associating a wheat 7S globulin, WP5212, with the development of type 1 diabetes in diabetes-prone rats, has renewed interest in this protein class. The present study aimed to better characterize the 7S globulins of wheat. The majority of the wheat embryo globulins were detected by anti-WP5212 polyclonal serum. These proteins varied significantly in their molecular masses and isoelectric points. Six major polypeptides were identified by mass spectrometry and/or N-terminal sequencing as belonging to the globulin 1 family. These results combined with prior studies have allowed the construction of a hypothetical model of the post-translational events contributing to the wheat 7S globulin profile in mature kernels.
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Jerkovic, Ante. "Proteomics of wheat bran (Triticum aestivum var. Babbler)." Australia : Macquarie University, 2006. http://hdl.handle.net/1959.14/43954.
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Thesis (MSc (Hons))--Macquarie University, Division of Environmental & Life Sciences, Dept. of Chemistry & Biomolecular Sciences, 2006.Bibliography: leaves 153-158.
Wheat is a major crop in Australia with around 25 million tonnes of grain harvested in an average year. Improved wheat grain cultivars and wheat grain milling can result in higher biological yields and flour quality. The introduction covers the general aspects of the wheat grain from bran development and structure through to millings and the importance of flour quality in flour-based products. It also highlights the problem with bran contamination in flour during milling and other factors that may have an effect on flour quality. Proteomics was used to identify proteins in three separate bran tissue fractions: the inner fraction (aleurone), intermediate fraction (nucellar tissue, testa, tube cells and cross cells) and the outer faction (hypodermis and epidermis). The aim of the project was to identify proteins in bran tissue fractions which may potentially be useful in improvements in wheat quality for farmers and consumers and flour yield for millers. The results show that more than 80% of the identified proteins in the outer and intermediate tissue factions are defence-and stress-related proteins (chitinase, xylanase, thaumatin-like protein, wheatwin 1, lipid-transfer protein, oxalatae oxidase (OXO), polyphenol oxidase (PPO), peroxidase (POX)). Almost 60% of the proteins identified in the inner tissue fraction are 7S Globulin storage proteins and around 15% are protein synthesis-and energy-related. Water-soluble proteins were also identified and it was found that endochitinase, OXO, PPO and POX all leach out from the grain durings imbibition. This study has added to the knowledge of bran tissue-specific proteins and has broad implications for improving crop yield and flour quality.
Mode of access: World Wide Web.
xiii, 158 leaves ill
7
Liu, Chunji. "Biochemical marker genes in hexaploid wheat, Triticum aestivum." Thesis, University of Cambridge, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.386183.
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Barbieri, Marciele. "Histopatologia da interação Triticum aestivum x Magnaporthe oryzae." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2016. http://hdl.handle.net/10183/184754.
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O trigo é o segundo cereal mais produzido no mundo, com significativo peso na economia agrícola global. No Brasil, o trigo é cultivado nas regiões Sul, Sudeste e Centro-Oeste. A brusone, conhecida pelos danos causados à cultura do arroz, também denominada de branqueamento das espigas, consiste em uma das principais doenças fúngicas presentes em trigo no Brasil. A partir dessa problemática na cultura do trigo buscou-se investigar a interação entre Triticum aestivum e o patógeno Magnaporthe oryzae utilizando como principal ferramenta de estudo a histopatologia. Foram investigadas as quatro cultivares de trigo Anahuac, BR18, BRS229 e Ônix. As plantas de trigo foram inoculadas na sexta (6ª) folha com o isolado de M. oryzae Py 145, oriundo do arroz, ajustada a concentração de esporos para 1 x 105 esporos por Ml. Após esse período, as plantas foram acondicionadas em uma câmara úmida, no escuro, por 24 horas. Amostras de segmentos de folhas de 2,5 cm cada foram imediatamente submetidas às reações de fixação e preparo para exame de microscopia de luz e fluorescência Os parâmetros avaliados foram germinação de esporos, formação de apressórios, penetração, formação de colônias, morte celular e formação de papilas nos tempos de coleta 6, 12, 18, 24, 36, 48 e 72 horas após a inoculação (hai). A análise estatística foi feita pelo Teste Exato de Fisher, com correções de Bonferroni. A germinação de esporos nas cultivares manteve-se constante a partir de 12 hai. Quanto à formação de apressórios, todas as cultivares produziram apressórios melanizados. A partir de 36 hai obteve-se uma elevação na infecção das células. Em 48 hai observou-se uma maior invasão das hifas infectivas sobre diversas células do hospedeiro, destacando-se um percentual elevado de formação de colônias na cultivar suscetível Anahuac, com 71%. A cultivar BR18 apresentou morte celular crescente para todos os horários, diferindo em 48 hai das demais cultivares para esse parâmetro. A cultivar Ônix foi a única a desenvolver papilas como estruturas de resistência em 72 hai. Os resultados deste trabalho sugerem a existência de resistência em trigo ao brusone, possivelmente com distintos mecanismos.Wheat is the second most produced cereal in the world, with significant importance in the global agricultural economy. In Brazil, wheat is grown in the South, Southeast and Midwest. The production receives systematic strengthening of government agencies, since weather conditions are unfavorable to the crop. Blast, known for damage to rice crops, also called bleaching of ears, consists of a major fungal disease found in wheat in Brazil. The objective of this work is to investigate the interaction between Triticum aestivum and the pathogen Magnaporthe oryzae at histopathological level. The four wheat cultivars Anahuac, BR18, BRS229 and Ônix were investigated. Wheat plants were inoculated on their sixth leaves with the isolate Py 145, from rice, with a spore concentration adjusted to 1 x 105 spores per ml. After inoculation the plants were placed in a wet, dark chamber for 24 hours. Samples of leaf segments of 2.5 cm each were cut and fixed and prepared for light and fluorescence microscopy examination. The parameters evaluated were germination of spores, appressoria formation, penetration, colony formation, cell death and papillae formation. Statistical analysis used Fisher's exact test with Bonferroni corrections. The germination of spores in cultivars remained constant from 12 hai. All cultivars produced melanized appressoria. 48 hai there was a greater invasion of infective hyphae of different host cells, especially a high percentage of colonies formation in the susceptible cultivar Anahuac, with 71%. BR18 showed increased cell death in all times measured. Ônix was the only variety to develop papillae as resistance structures at 72 hai. The results of this work suggest the existence of resistance amongst wheat varieties and that their mechanisms are different from each other.
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Ihorai, Tania. "Etude de gènes codant des protéines du sustème thiorédoxine NADP-dépendant chez le blé." Montpellier 2, 1998. http://www.theses.fr/1998MON20120.
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Un gene tatrxh2 codant une thioredoxine $$ du ble tendre a ete isole par criblage de banque d'adn genomique et par acp. Sa structure est proche de celle des genes de thioredoxines $$ vegetales connues. La regulation spatio-temporelle de l'expression du gene tatrxh2 a ete etudiee par expression stable dans le riz et le gene gus codant la -glucuronidase a ete utilise comme gene rapporteur. Les tests fluorimetriques et histochimiques ont montre qu'au cours de la maturation, le promoteur a une activite faible exclusivement localisee dans le grain de riz au niveau de l'albumen amylace. Des deletions ont permis de delimiter des regions du promoteur impliquees dans l'expression tissulaire et temporelle du gene tatrxh2. Les sequences cis regulant l'expression dans le grain sont comprises dans les 288 pb en amont de l'atg et d'autres, permettant l'expression transitoire dans l'epithelium du scutellum sont presentes entre 1111 pb et 451 pb. Des sequences cis regulant l'expression temporelle du gene sont comprises dans les 451 pb en amont de l'atg. Cette etude suggere qu'au cours de la maturation du grain de ble, la thioredoxine $$ correspondante est accumulee dans l'albumen amylace en meme temps que les proteines de reserve dont elle pourrait assurer la reduction.
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Le, Guerroue Jean-Louis. "Caractérisation de farines de blé tendre turboséparées : Comparaison du comportement de leurs protéines dans la pâte, à celui des protéines du gluten et de farines de force." Nantes, 1991. http://www.theses.fr/1991NANT2028.
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L'enrichissement en proteines d'une farine par voie seche (turboseparation) s'accompagne de diverses modifications de celle-ci: granulometrie, teneur en lipides en amidon endommage. L'amelioration de la force boulangere d'une farine par incorporation de fraction surproteinee (mesuree par le w de l'alveographe) est relativement similaire a celle obtenue par addition soit de gluten, soit de farine de force. Il apparait cependant des differences d'extensibilite et de tenacite de la pate provenant de la nature meme de la fraction ameliorante. L'etude de l'extractibilite des proteines dans la pate en presence de divers composes actifs, montre que selon la farine amelioree consideree, il existe certaines differences d'extractibilite liees essentiellement a la nature des interactions s'etablissant entre les proteines. Nous ne pouvons cependant pas preciser qu'elle est l'influence des proteines des fractions ameliorantes par rapport aux proteines endogenes de la farine de base, dans l'etablissement de ces interactions. L'enrichissement en proteines d'une farine par turboseparation, confere a cette fraction surproteinee, de reelles capacites ameliorantes. Cependant, ce caractere ameliorant reste tout a fait dependant de l'origine genetique de la farine turboseparee
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Feiz, Leila. "Functional analysis of puroindoline genes in wheat (Triticum aestivum)." Thesis, Montana State University, 2008. http://etd.lib.montana.edu/etd/2008/feiz/FeizL1208.pdf.
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Grain hardness variation has large effects upon many different end-use properties of wheat (Triticum aestivum). The Hardness (Ha) locus consisting of the Puroindoline a and b genes (Pina and Pinb) controls the majority of grain hardness variation. Starch production is a growing end-use of wheat. The first objective of this study was to estimate the differences in starch yield due to natural and transgenically conditioned grain hardness differences. To accomplish this goal, a small scale wet milling protocol was used to characterize the wet milling properties of two independent groups of isogenic materials varying in grain hardness and in Pin expression level. The results of the first study demonstrate that the Ha locus and puroindoline expression are both linked to wet-milling starch yield and that selection for increased Ha function increases starch yield via enhanced separation of starch granules and the protein matrix during wet milling. The lack of Pin allelic diversity is a major factor limiting Ha functional analyses and wheat quality improvement. So the second objective of this study was to create new Ha alleles in the soft white spring cultivar Alpowa using ethylmethane sulfonate (EMS) mutagenesis. The M 2 population was screened to identify new alleles of Pina and Pinb. One hundred and forty eight new Pin alleles, including 68 missense alleles, were identified. F 2 populations for 49 of the new Pin alleles including 43 unique missense ones were developed after crossing each back to non-mutant Alpowa. Grain hardness was then measured on F 2:3 seeds and the impact of each allele on grain hardness was quantified. The tested mutations comprised a range of functionality from neutral to function abolishing mutations. Seed weight and vigor of all mutation lines was restored among all of the F 2 populations. The new alleles have the potential to improve end use properties of soft and hard wheats.
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Thomas, Stephen W. "Molecular studies of homologous chromosome pairing in Triticum aestivum /." Title page, table of contents and abstract only, 1997. http://web4.library.adelaide.edu.au/theses/09PH/09pht462.pdf.
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Craufurd, P. Q. "Plant development and yield in wheat (Triticum aestivum L.)." Thesis, University of Reading, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.352335.
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Jenkinson, Peter. "Epidemiology of Fusarium in winter wheat (Triticum aestivum L.)." Thesis, Open University, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.386201.
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Hall, Sharon Anita. "Defence related lignin deposition in wheat (Triticum aestivum L.)." Thesis, University of Southampton, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.284581.
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Heyns, I. C. "Mapping of chromosome arm 7DL of Triticum aestivum L." Thesis, Stellenbosch : University of Stellenbosch, 2005. http://hdl.handle.net/10019.1/1584.
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Thesis (MSc (Genetics))--University of Stellenbosch, 2005.The Russian wheat aphid, Diuraphis noxia (Mordvilko), is a serious insect pest of wheat and barley. It affects the quality and yield of grain by sucking plant sap from the newest growth whilst toxic substances are injected that destroy plant tissue. The Russian wheat aphid also acts as a vector of plant viruses. The cultivation of aphid resistant cultivars is the preferred control strategy and nine resistance genes, designated Dn1 to Dn9, have been identified. Another undesignated gene, Dnx, was found in the wheat accession PI220127. Mapping of the resistance genes relative to known markers will improve their use in breeding programs. The dominant RWA resistance gene, Dn5, was identified in the accession PI294994 and mapped to chromosome arm 7DL. However, recent reports have placed Dn5 on ...
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Jelena, Tomić. "Karakterizacija albumina i biohemijski aspekti kvaliteta pšenice (Triticum aestivum)." Phd thesis, Univerzitet u Novom Sadu, Tehnološki fakultet Novi Sad, 2016. http://www.cris.uns.ac.rs/record.jsf?recordId=97038&source=NDLTD&language=en.
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U okviru disertacije ispitivan je uticaj sorte i mikroklimatskih uslova tokom dve proizvodne godine pšenice na sadržaj i strukturu albumina; izvršena je karakterizacija albumina pomoću Lab–on– a–Chip elektroforeze; određena je aktivnost proteolitičkih i amilolitičkih enzima, sadržaj slobodnih sulfhidrilnih i slobodnih amino grupa; ispitana su reološka svojstva testa primenom uobičajenih metoda za procenu tehnološkog kvaliteta brašna i izvedena je karakterizacija gotovog proizvoda-hleba. Jedan deo istraživanja se odnosio na period posležetvenog dozrevanja pšenice i stabilizacije brašna.Obe ispitivane godine odlikovao je toplotni stres s tim što su u 2012. godini maksimalnetemperature prelazile 35 °C i broj tropskih dana je bio izrazito veći u odnosu na 2011., što je uslovilo promene u sastavu i kvalitetu proteina i skroba u zrnu pšenice. Sadržaj ukupnih albumina uzoraka pšeničnog brašna iz 2012. bio je značajno manji u odnosu na 2011. proizvodnu godinu. Rezultati određivanja proteolitičke i amilolitičke aktivnosti uzoraka pšeničnog brašna iz dve proizvodne godine su pokazali da su za 2012. proizvodnu godinu karakteristične znatno niže vrednosti ovih pokazatelja u odnosu na 2011. proizvodnu godinu i da je enzimska aktivnost pre svega sortna karakteristika.Sadržaj slobodnih sulfhidrilnih grupa uzoraka pšeničnog brašna iz 2012. proizvodne godine bio je značajno veći dok je sadržaj disulfidnih veza bio manji u odnosu na 2011. Sadržaj slobodnih amino grupa se razlikovao između uzoraka iz dve proizvodne godine, kako između različitih sorti, tako i u pogledu sva tri primenjena tretmana inkubacije glutena. Značajne razlike između vrednosti slobodnih amino grupa izmerenih nakon inkubacije gluten na 37 °C, ukazuju na različitu proteolitičku aktivnost ispitivanih uzoraka pšeničnih sorti. U poređenju sa uzorcima iz 2011. proizvodne godine, uzorci iz 2012. su imali znatno niže vrednosti specifične zapremine hleba.Dodatkom dvostruke količine sopstvenih albumina odabranom setu uzoraka dobijenisu rezultati, koji ukazuju da su uzorci brašna iz 2011. imali manjak amilolitičkih enzima, a uzorci iz 2012. manjak proteolitičkih enzima za postizanje optimalnog tehnološkog kvaliteta.In this dissertation, the influence of variety and microclimatic conditions that prevailed during the two production years on the content and structure of wheat albumins were investigated; characterization of albumins was performed by Lab-on-a-Chip capillary electrophoresis; the proteolytic and α- amylolytic activity, as well as the content of free sulfhydryl and free amino groups were also determined; the rheological properties of dough were estimated using conventional methods for the assessment of flour technological quality and characterization of the final product- bread was performed. One part of the research covered the period of postharvest wheat and flour maturation. Heat stress was characteristic of both production years; however, in 2012, maximum temperatures exceeded 35 °C and the number of days with maximum temperatures above 30 °C was markedly higher than in the 2011 production year. These conditions have caused the changes in the composition and quality of protein and starch in wheat kernels. The albumin content of wheat flour samples from 2012 was significantly lower compared to 2011 production year. Results of proteolytic and amilolytic activities of wheat flour samples from two production years, showed that the values of these indicators were significantly lower for 2012 in relation to the 2011 production year, and that the enzyme activity is primarily varietal characteristic. The content of free sulfhydryl groups of wheat flour samples from the 2012 production year was significantly higher while the content of disulfide bonds was lower than in 2011. The content of free amino groups differed between samples from two production years. Differences in the amount of free amino content were evident between the varieties and between different treatments of gluten incubation. Significant differences between the values of the free amino groups measured after gluten incubation at 37 °C, indicate a different proteolytic activity of tested wheat flour samples. In comparison with the samples from the 2011 production year, samples from 2012 had significantly lower values of specific bread volume. The addition of double amount of its own albumins to the selected samples indicated that the flour samples from 2011 had a deficit of amylolytic enzymes and samples from 2012 had a deficit of proteolytic enzymes for achieving optimal technological quality.
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Shenouda, Samar. "β-amylase genes in common/bread wheat (Triticum aestivum)." Thesis, University of Sydney, 2020. https://hdl.handle.net/2123/23713.
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β-amylase is an exoenzyme that releases successive maltose units from the non-reducing end of a polysaccharide chain. This thesis examined the complement of β-amylases in wheat, placing focus on the endosperm-specific (BAM1) and tissue-ubiquitous (BAM2) β-amylases. Ten forms of β-amylase genes were identified in bread wheat. Nine of these had homologues in other cereals, but only BAM1 forms had homologues in Triticeae species. The BAM1 gene sequences showed that there were three types of Gly-rich repeat sequences containing putative N-myristoylation sites: a five-repeat form and two forms with three repeats. There were three main forms of BAM1 genes in wheat cultivar Chinese Spring (CS) of 525, 526 and 550 amino acids in length, respectively. Each form was found to be unique to one chromosome per genome. Each form had within-form variation, and only one copy of each form was found to be an active gene. PCR performed on CS nullisomic-tetrasomic lines showed that there were at least five, three and four copies of BAM1 gene on chromosomes 4B, 4D and 5A, respectively. Exons II, V and VI of BAM1 genes were the most variable regions, enriched with numerous putative single-nucleotide-polymorphic sites. PCR showed that the most variable regions were introns II and III, which were variable both between copies of the same cultivar and between cultivars. This research established that BAM1 genes had undergone limited variation, especially along the coding sequence, during evolution, as well as after polyploidisation. This was supported by genomic and EST sequences of BAM1 that are 99-100% identical in diploid, tetraploid and hexaploid wheat and similar electrophoretogram patterns of PCR amplicons. In conclusion, wheat β-amylases are a complex group of genes found on 28 loci in the hexaploid wheat genome. Further research is needed to understand their functions and their potential utilisation in breeding and industry.
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Elangovan, M. "Molecular dissection of breadmaking quality in wheat (triticum aestivum)." Thesis(Ph.D.), CSIR-National Chemical Laboratory, Pune, 2007. http://dspace.ncl.res.in:8080/xmlui/handle/20.500.12252/2606.
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Capron, Delphine. "Analyse transcriptomique du développement du grain de blé (Triticum aestivum) : implication des E3 ligases et des gènes relatifs aux hormones." Thesis, Clermont-Ferrand 2, 2011. http://www.theses.fr/2011CLF22199.
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Le blé tendre, Triticum aestivum, représente une grande ressource dans l’alimentation humaine mais également dans l’industrie. En conséquence, la taille finale du grain de blé constitue une cible privilégiée des programmes de sélections variétales. Pour ces raisons, comprendre les mécanismes moléculaires qui contrôlent le développement du grain, en particulier lors des phases précoces de la mise en place des structures cellulaires et leur remplissage par des réserves, constitue un enjeu majeur. Le développement du grain de blé est un processus complexe qui nécessite l’intervention séquentielle ou combinée d’un très grand nombre de gènes et de voies métaboliques. Parmi ces voies, le métabolisme carboné (en particulier celui du saccharose), les voies de signalisation par les hormones et la voie Ubiquitine / Protéasome 26S (UPS) semblent jouer un rôle déterminant dans la taille finale et donc le rendement en grain chez les céréales. Pour étudier le développement du grain de blé tendre, des plantes de la variété Récital ont été cultivées en serre dans des conditions optimales sans contraintes. Les grains ont été récoltés à onze stades de développement après floraison, allant de 40°CJ (soit deux jours après floraison) à 500°CJ (soit 25 jours après floraison). Les ARN totaux ont été extraits à partir de ces grains et utilisés pour analyser l’expression des gènes par une approche transcriptomique, soit en utilisant une lame « dédiée », soit en utilisant une lame Nimblegen comprenant 39 179 gènes. Une analyse différentielle utilisant le test LIMMA a permis d’identifier 9284 gènes différentiellement exprimés. L’analyse globale de ces gènes a montré que des modifications transcriptionnelles majeures ont lieu entre les stades 80 et 120 °CJ ainsi qu’entre 220 et 240°CJ. La répartition de ces 9284 en 10 clusters, en fonction de leurs profils d’expression, permet d’identifier les gènes activés en début de la phase de division cellulaire chez le grain, ceux activés pendant la phase de remplissage et ceux présentant un profil dit en « cloche ». Parmi les gènes différentiellement exprimés, nous nous sommes intéressés à ceux qui codent pour des E3 ligases impliquées dans la voie UPS et aux gènes relatifs à 7 hormones végétales (auxine, acide abscissique, acide jasmonique, brassinostéroïdes, cytokinines, gibbérellines et éthylène). Nous avons alors identifié 173 gènes codant pour des E3 ligases (dont certaines sont également des récepteurs hormonaux) et 126 gènes impliqués dans les voies hormonales. Un modèle global décrivant la chronologie d’intervention de ces gènes a été proposé. La majorité des gènes E3 de type SCF (SKP1-Cullin-Fbox), APC/C, Cul3-BTB et Ubox interviendrait dans les phases précoces du développement du grain de blé. Parallèlement, la majorité des gènes relatifs à l’auxine, à l’acide jasmonique et aux brassinostéroïdes interviendrait lors des phases de divisions cellulaires alors que les gènes relatifs à l’éthylène et à l’acide abscissique interviendraient dans les phases de remplissage. Par ailleurs, une méta-analyse a été réalisée et a permis d’identifier 26 gènes candidats codants pour des E3 ligases ainsi que de 12 gènes candidats impliqués dans les voies hormonales qui seraient préférentiellement exprimés dans l’albumen, un tissu du grain à haute valeur agro-économique. Le modèle proposé et l’identification de ces gènes candidats établissent un cadre pour de futures études visant à comprendre les mécanismes moléculaires contrôlant le développement du grain de bléWheat grain is an important source of food, feed, and industrial raw materials, but current production levels cannot meet world needs. Elucidation of the molecular mechanisms underlying wheat grain development will contribute valuable information to improving wheat cultivation. One of the most important mechanisms implicated in plant developmental processes is the Ubiquitin-Proteasome System (UPS). Among several implications of the UPS, it has become clear that it plays an essential role in hormone signaling. In particular E3 ubiquitin ligases, from the UPS, have been demonstrated to play critical roles in hormone perception and signal transduction. During these work, wheat cv. Recital were grown in optimum growth conditions. By comparing eleven consecutive time-points from 40°CJ (2 days after anthesis) to 500°CJ (around 25 days after anthesis), 9284 differentially expressed genes were identified during this study. A comparison of these genes in terms of time revealed dynamic transcript accumulation profiles with major re-programming events that occurred during the time intervals of 80-120°Cdays and 220-240°Cdays. The gene expression comparison allows observing genes potentially involved in cell division or grain filling stage. An emphasis was made on the E3 ligases and hormone-related genes (Abscisic acid, Auxin, Brassinosteroid, Cytokinine, Gibberellic acid, Ethylene and Jasmonic acid). 173 E3 ligase coding genes and 126 hormone–related genes were found to be differentially expressed during the cell division and grain filling stages, with a different expression profile for each family. A model describing the timing of the involvement of these genes is proposed to provide a framework for the design of future experiments and for the identification of genes and pathways for further characterization. A majority of the E3 SCF (SKP1-Cullin-F-box), APC/C, Cul3-BTB and Ubox are found expressed in early wheat developmental stages (cell division stage). A majority of auxin, jasmonic acid and brassinostéroïde related genes were found to be up-regulated in early wheat developmental stages while ethylene and abscisic acid related genes were found to be activated during grain filling stage. The differential expression of genes involved in E3 ligase pathways and plant hormone signalling suggested that phytohormones and UPS crosstalk might play a critical role in the wheat grain developmental process. A meta-analysis of these genes led to the identification of 26 E3 ligase candidate genes and 12 hormones-related candidate genes that are preferentially expressed in the endosperm. The functional model that we proposed and the identification of candidate genes should help to better understand wheat grain development
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Michard, Robin. "Identification des facteurs déterminant le ciblage de la recombinaison méiotique chez le blé tendre (Triticum aestivum L.)." Thesis, Université Clermont Auvergne (2017-2020), 2019. http://www.theses.fr/2019CLFAC023/document.
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La compréhension des mécanismes régissant la recombinaison méiotique chez le blé tendre (Triticum aestivum L.) devient essentielle puisqu’elle est le levier principal utilisé par les sélectionneurs pour le brassage génétique et obtenir de nouvelles variétés élites comportant des introgressions de régions d’intérêt provenant de ressources génétiques exotiques. A cette fin, l’utilisation chez le blé tendre d’une nouvelle biotechnologie de ciblage de la recombinaison méiotique développée chez la levure par la société Meiogenix semble être prometteuse. Cette biotechnologie, nommée SpiX, fait intervenir un domaine protéique de liaison à l’ADN couplé à la protéine SPO11 responsable des cassures double-brins de l’ADN, initiatrices de la recombinaison méiotique ou crossovers (CO). Le développement d’une nouvelle technique de conservation des embryons immatures a permis d’améliorer les conditions de transformation par biolistique du blé tendre pour l’application de la technologie SpiX. L’exploitation de la séquence du génome du blé a permis d’isoler les gènes codant pour les protéines SPO11 du blé tendre. La complémentation hétérologue inédite de mutants pour les protéines SPO11 d’Arabidopsis thaliana avec les orthologues ainsi découverts chez le blé tendre montre leur grande conservation de séquence et de fonction au sein des plantes et leur potentielle fonctionnalité pour la biotechnologie SpiX. Enfin le test de différents domaines de liaison à l’ADN et de différentes cibles le long du chromosome 3B de blé tendre montre que la biotechnologie SpiX requiert des ajustements en fonction de l’espèce chez laquelle celle-ci doit fonctionner. Ces résultats sont ainsi l’opportunité de lever un premier voile sur le ciblage de la recombinaison méiotique chez une espèce de grande culture et de mieux comprendre les mécanismes de détermination des sites de cassures double-brins initiatrices de la recombinaison méiotique chez le blé tendreUnderstanding the mechanisms governing meiotic recombination in bread wheat (Triticum aestivum L.) is essential since it is the main tool used by breeders for genetic admixing and obtaining new elite varieties with introgression of regions of interest from exotic genetic resources. To this end, the use in bread wheat of a new biotechnology targeting meiotic recombination developed in yeast by Meiogenix seems to be promising. This biotechnology, named SpiX, involves a DNA-binding domain fused to the SPO11 protein responsible for DNA double-strand breaks, initiating meiotic recombination or crossovers (CO). The development of a new conservation protocol for wheat immature embryos has improved the conditions for bread wheat transformation through biolistic, and thus for the application of SpiX technology. The exploitation of the wheat genome sequence made it possible to isolate the bread wheat genes for SPO11 proteins. A novel heterologous complementation of Arabidopsis thaliana mutants for SPO11s with the bread wheat orthologous freshly discovered shows their great conservation of sequence and function within plants and their potential functionality for SpiX biotechnology. Finally, the testing of different DNA-binding domains and different targets along bread wheat 3B chromosome shows that SpiX biotechnology requires adjustments depending on the species in which it has to function. These results are the opportunity to uncover the targeting of meiotic recombination in a widely cultivated crop species and to understand the mechanisms determining sites for double-strand breaks prior to meiotic recombination in wheat
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Debiton, Clément. "Identification des critères du grain de blé (Triticum aestivum L.) favorables à la production de bioéthanol par l'étude d'un ensemble de cultivars et par l'analyse protéomique de lignées isogéniques waxy." Phd thesis, Université Blaise Pascal - Clermont-Ferrand II, 2010. http://tel.archives-ouvertes.fr/tel-00625530.
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Dans le but d'identifier des critères de sélection du blé (T. aestivum L.) destiné à la production de bioéthanol, les objectifs de cette thèse étaient (1) de mettre en évidence les caractéristiques physico-chimiques du grain associées aux rendements en glucose et éthanol, et (2), d'étudier par approche protéomique l'effet de variants génétiques affectant la quantité d'amylose sur le métabolisme des sucres et de l'amidon. L'analyse de trente variétés implantées dans un essai multilocal pluriannuel a mis en évidence l'importance du taux de protéines, de la dureté et de la distribution des granules d'amidon sur les rendements en glucose et éthanol. Dans une moindre mesure, la composition allélique des protéines de réserves et la viscosité des arabinoxylanes ont également un effet lors de l'étape de transformation de l'amidon en sucres fermentescibles. Huit lignées isogéniques waxy de trois variétés françaises ont été implantées dans un essai multilocal. Les lignées dépourvues d'amylose ont produit moins de glucose et d'éthanol que les variétés normales. Les analyses protéomiques des protéines de l'albumen (albumines, globulines et amphiphiles) ainsi que des protéines associées aux granules d'amidon des grains matures des lignées isogéniques de la variété Trémie ont mis en évidence : (1) une relation entre le volume spécifique des GBSS et la quantité d'amylose et (2) une modification de l'expression d'enzymes impliquées dans le métabolisme des sucres et de l'amidon (Susy, AGPase, fructose biphosphate aldolase) mais aussi de protéines de stress et de défense (serpines et HSP). Ces observations suggèrent un développement du grain incomplet pour la lignée dépourvue d'amylose.
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Salgado, Adliz Ayram de Bastos Budziak. "Efeito residual da aplicação de gesso na eficiência da adubação fosfatada para a sucessão trigo-soja em sistema plantio direto." Universidade Estadual de Ponta Grossa, 2017. http://tede2.uepg.br/jspui/handle/prefix/2562.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
O P é o nutriente que mais limita a produtividade agrícola no Brasil, devido ao material de origem dos solos brasileiros, pela forte interação do P com o solo e pela sua precipitação com compostos de Fe, Al e Ca, por esse motivo os adubos fosfatados tem sido utilizado em maiores quantidades comprometendo as reservas mundiais que vem diminuindo. Com isso, há necessidade de se aprimorar a eficiência do uso de P na agricultura e o uso de gesso pode ser uma alternativa, devido à presença em sua composição de P e ao favorecimento do crescimento radicular. Sendo assim o objetivo deste trabalho foi avaliar o efeito residual da aplicação de gesso na eficiência da adubação fosfatada para a sucessão trigo-soja em sistema plantio direto. O experimento foi instalado em outubro de 2013, no município de Ponta Grossa, em um Latossolo Vermelho distrófico típico, textura argilosa. O delineamento experimental empregado foi o de blocos ao acaso, em parcelas subdivididas, com três repetições. Nas parcelas (180 m2) foram aplicadas, no sulco de semeadura, nas safras de inverno e verão, quatro doses de P (0, 30, 60 e 90 kg P2O5 ha-1) na forma de superfosfato triplo (SFT) e, nas subparcelas (45 m2) foram empregadas quatro doses de gesso agrícola (0, 2, 4, 6 t ha-1), em outubro de 2013. A sucessão de culturas do experimento foi: trigo (2015) e soja (2015/2016), sendo avaliado o efeito residual de gesso agrícola após 33 meses de sua aplicação (outubro de 2013) e os efeitos das doses de P. As avaliações realizadas foram os atributos químicos do solo (pH, Al3+, Ca2+, Mg2+, K+, S-SO42- e P) nas camadas (0-10, 10-20, 20-40 e 40-60 cm de profundidade), e nas culturas do trigo (2015) e soja (2015/2016) foram avaliados: (diagnose foliar, extração, rendimento de grãos e o fator parcial de produtividade). O efeito residual de gesso agrícola na superfície e a adubação fosfatada no sulco de semeadura ocasionaram melhoria nos atributos químicos do solo, sendo que o incremento das doses de P ocasionaram aumento de P (0-20 cm), SO42- (20-40 cm), Ca2+ e K+ (40-60 cm) e diminuição de P (20-40 cm), SO42- (0-10 cm) e Mg2+ (40-60 cm). O efeito residual do gesso agrícola ocasionou aumento de Ca2+ (0-60 cm), P (0-20 cm), SO42- (10-60 cm) e K+ (40-60 cm), e diminuição de Al3+ (10-20 cm). Na cultura do trigo, o incremento das doses de P aumentaram o teor foliar de P, Ca e S e diminuiu a extração de Fe, já com o incremento de gesso ocorreu aumento do teor foliar de Ca e S e diminuição do teor de Mg, e aumento da extração de P, S e Cu. Na cultura da soja o incremento das doses de P e de gesso não ocasionaram diferenças estatísticas na diagnose da cultura, já para a extração da planta, houve aumento da extração de K, Fe, Mn e Zn com o incremento das doses de P, e aumento na extração de P, Ca, S e Fe com o incremento das doses de gesso. Para o rendimento de grãos o aumento das doses de P não foram eficientes para aumentar a produtividade das culturas de trigo e soja, já o incremento das doses de gesso foi eficiente somente para a cultura do trigo aumentando em 21,8% o rendimento de grãos. O incremento nas doses de P aplicadas aumentou o fator parcial de produtividade de P (FPPP) nas culturas de trigo e soja, quando a menor dose de P (30 kg ha-1) foi aplicada. O efeito residual do gesso no aumento da produtividade de trigo não foi ocasionado por melhoria na eficiência de utilização de P pelas plantas.
P is the nutrient, which most limits agricultural productivity in Brazil, due to the material from Brazilian soils, because of the strong interaction of P with soil, and its precipitation with compounds Fe, Al and Ca, for this reason, phosphate fertilization has been utilized in larger quantities, compromising world supplies, which have been diminishing. Therefore, it is necessary to improve the efficiency of the utilization of P in agriculture, and the utilization of gypsum may be an alternative, due to the presence of P in its composition and the favoring of root growth. Thus, this paper is aimed at evaluating residual effect of gypsum application in the efficiency of phosphate fertilization for the succession wheat-soybean in no tillage system. The experiment was installed in October 2013, in the municipality of Ponta Grossa, in a typical dystrophic Red Latosol, clay texture. The experimental delineation applied was the blocks by chance, in subdivided parcels, with three repetitions. In the (180 m2) parcels, four doses of P (0, 30, 60 and 90 kg P2O5 ha-1) were applied, in-furrow, for winter and summer harvests, in the form of Triple SuperPhosphate (TSP) and, in the (45 m2) subparcels, four doses of agricultural gypsum were applied (0, 2, 4, 6 t ha-1), in October of 2013. The succession of crops for the experiment was: wheat (2015) and soybean (2015/2016), residual effect of agricultural gypsum was evaluated 33 months after its application (October of 2013), along with the effects of P doses. The evaluations performed were about the chemical attributes of the soil (pH, Al3+, Ca2+, Mg2+, K+, S-SO42- and P) in layers (0-10, 10-20, 20-40 and 40-60 cm deep) in wheat crops (2015), and in soybean crops (2015/2016); foliar diagnosis, extraction, grain yield, and the partial factor productivity were evaluated. The residual effect of agricultural gypsum in the surface and phosphate fertilization in-furrow caused improvements to the chemical attributes of the soil, where the addition of P doses caused an increase of P (0-20 cm), SO42- (20-40 cm), Ca2+ and K+ (40-60 cm) and a decrease of P (20-40 cm), SO42- (0-10 cm) and Mg2+ (40-60 cm). The residual effect of agricultural gypsum caused an increase of Ca2+ (0-60 cm), P (0-20 cm), SO42- (10-60 cm) and K+ (40-60 cm), and a decrease of Al3+ (10-20 cm). In wheat crops, the addition of P doses increased the foliar content of P, Ca and S, and decreased the extraction of Fe, on the other hand with the addition of gypsum an increase of Ca and S foliar content occurred and a decrease of Mg content, and an increase of P, S and Cu extraction. In soybean crops, the addition of P doses and gypsum caused statistical differences in the crop diagnosis, and then again, for the extraction of the plant, there was an increase of K, Fe, Mn and Zn extraction with the addition of P doses, and an increase of P, Ca, S and Fe extraction with the addition of gypsum doses. For grain yield, the increase of P doses were not efficient to boost productivity in wheat and soybean crops, as for the addition of gypsum doses, it was only efficient for wheat crops with a 21,8% increase of grain yield. The addition in applied P doses increased the partial factor productivity (PFP) of P in wheat and soybean crops, when the lowest dose of P (30 kg ha-1) was applied. The residual effect of gypsum in the increase of wheat productivity did not happen because of improvements in the efficiency of P usage by plants.
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Rodrigues, Mario Sergio. "Composted societal organic wastes for sustainable wheat (Triticum aestivum) production." Thesis, Imperial College London, 1996. http://hdl.handle.net/10044/1/7884.
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Taylor, Victoria Louise. "The activities of herbicide safeners in wheat (Triticum aestivum L.)." Thesis, Durham University, 2012. http://etheses.dur.ac.uk/3926/.
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Commercialised herbicide safeners (also known as protectants or antidotes) are synthetic chemicals used to enhance herbicide tolerance in cereal crops. They do this by causing an up-regulation in xenobiotic detoxifying enzymes such as glutathione transferases (GSTs). Seedlings of wheat (Triticum aestivum cv ‘Einstein’) were sprayed with the safeners cloquintocet mexyl, fenchlorazole ethyl and mefenpyr diethyl. All three compounds caused an identical up regulation of GSTs from the phi, tau and lambda classes, despite their differences in chemistry. Using cloquintocet mexyl as a classic wheat safener treatment, it was found that GST induction was both dose and time dependent. Safening was found to be associated with the rapid hydrolysis of the parent ester to cloquintocet acid. When the free acid was tested, the GST-induction response obtained was identical to that determined with the parent ester, suggesting that cloquintocet itself is the active safener. GST induction was found to be tissue specific within the wheat shoots, with the lambda GSTs being preferentially expressed in the meristematic tissue. Proteomic 2 D gel analysis revealed that the tau TaGSTU3 was a major up-regulated GST. In addition, six GSTs that were previously shown in literature to be up-regulated by herbicide safeners in wheat were cloned, expressed and characterized as the respective recombinant enzymes and renamed to bring them in line with existing nomenclature. The GSTs cloned included TaGSTU3, TaGSTU6, TaGSTF4, TaGSTF10 and TaGSTL1. Metabolism studies showed that following the hydrolysis of cloquintocet mexyl, no further down- stream metabolites could be identified and none of the up-regulated GSTs showed any activity toward the safener. However TaGSTU3 was found to bind and be inhibited by cloquintocet free acid as determined by isothermal titration calorimetry. Safener treatment also led to a transient inhibition of GST activity in crude wheat extracts after spraying the seedlings. In addition to the induction of GSTs, safener treatments also resulted in an enhanced growth of wheat seedlings. The work presented in this thesis confirms that very different compounds can induce apparently identical downstream events at the level of GST enhancement and that these induction events underpin wider changes in plant physiology.
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Kosma, Dylan K. "Interaction of cyanide with nitrogen metabolism in wheat (Triticum aestivum) /." Available to subscribers only, 2005. http://proquest.umi.com/pqdweb?did=1075707051&sid=17&Fmt=2&clientId=1509&RQT=309&VName=PQD.
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Bernard, SteÌphanie M. "Manipulating the expression of glutamine synthetase in wheat (Triticum aestivum)." Thesis, Lancaster University, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.436734.
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McCallum, John Allan. "Biochemistry of phenolic compounds in wheat grain (Triticum aestivum L.)." Thesis, University of Canterbury. Botany, 1989. http://hdl.handle.net/10092/5723.
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Phenolic content, o-diphenol oxidase activity, flour colour and bread crumb colour have been examined for flour streams from a commercial flour mill and in flours and wholemeals of a number of New Zealand wheat cultivars. Phenolic content and o-diphenol oxidase activity varied significantly both between milling flour streams and between cultivars. Flour and bread crumb colour correlated significantly with phenolic content and o-diphenol oxidase activity in the milling flour streams. A similar relationship was also observed between o-diphenol oxidase activity and the colour of flour and bread prepared from several different cultivars. These observations are consistent with an involvement of o-diphenol oxidase and phenolics in the pigmentation of both wheat flour and bread.
Commercial wheat bran has been found to contain low levels (<50 µg.g-1) of (+)catechin and soluble proanthocyanidins soluble in aqueous acetone. Detection of these compounds in crude extracts by conventional methods was complicated by the presence of methoxyhydroquinone glycosides and other interfering substances. Chromatographic studies indicated that, in addition to several dimeric proanthocyanidins, bran contains trimeric and/or other oligomeric proanthocyanidins. The oligomeric proanthocyanidins contained mostly prodelphinidin and some procyanidin units, whilst the dimeric proanthocyanidins may also contain some propelargonidin units. Two dimeric proanthocyanidins were isolated and tentatively characterized as catechin-(4α→)-catechin (procyanidin B3) and gallocatechin (4α→8)-catechin (prodelphinidin B3). These observations suggest that the flavanol content of wheat grain may be qualitatively similar to that of barley, although quantitatively much smaller. The identification of these compounds in mature wheat grain confirmed earlier reports of their presence in immature grain and supports the hypothesis that they contribute to seedcoat pigmentation.
Changes in soluble phenolics and hydroxycinnamic acids and the activities of L-phenylalanine ammonia-lyase (PAL, EC No. 4.3.1.5) and chalcone-flavanone isomerase (CHI E.C. 5.5.1.6) were examined during the development and maturation of several spring bread wheat cultivars.
Activities of both PAL and CHI were high in the early milk stage of grain development and this activity was located principally in the testa and pericarp tissues. Comparison of enzyme activities at this stage indicated significant differences between red- and white-grained cultivars. These different patterns of activity also correlated with significant differences in germinability at maturity. It is suggested that the
common association between red seedcoat pigmentation and dormancy may be related to differences in the regulation of phenolic biosynthesis in the immature seedcoat. Studies of the tissue distribution of enzyme activities suggested that phenolic biosynthetic activities were higher in the embryo during the dough stage of grain development.
Chromatographic studies suggested that there were significant qualitative and quantitative changes in phenolic content during grain development and maturation. Changes in ferulic and other hydroxycinnamic acids indicated that these were subject to considerable turnover and metabolism during grain development.
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Rees, R. T. "Metabolic activity of isolated Glycine max and Triticum aestivum cells." Thesis, Nottingham Trent University, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.370504.
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Triggs, Heidi M. "Haploid production and genetic transformation of wheat (Triticum aestivum L.)." Thesis, University of Nottingham, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.243689.
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Mohammady-D, Shahram. "Inheritance of tolerance to water-stress in wheat (Triticum aestivum)." Thesis, University of Newcastle Upon Tyne, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.250130.
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Vaux, P. "Ribonucleotide content of wheat embryos (Triticum aestivum L.) during imbibition." Thesis, University of Manchester, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.378808.
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Verma, Vinesh. "Genetic analysis of agronomic traits in wheat (Triticum aestivum L.)." Thesis, University of Reading, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.270848.
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Noori, Seyed Ahmad Sadat. "Salinity tolerance in wheat (Triticum aestivum L.) and its relatives." Thesis, University of Liverpool, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.367305.
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Mohamed, Abulgasem Besheir. "Genetic basis of salt tolerance in wheat triticum aestivum (L)." Thesis, University of Liverpool, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.337214.
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Deswarte, Fabien. "Extraction of high-value chemicals from wheat straw (Triticum aestivum)." Thesis, University of York, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.437630.
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Steinmeyer, Frederick Thomas. "Spike temperature depression of wheat (Triticum aestivum L.) at anthesis." Thesis, University of Reading, 2016. http://centaur.reading.ac.uk/68662/.
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Global climate change has been forecast to result in significant alterations to current temperature and precipitation patterns in cereal growing regions worldwide. The increased occurrence of elevated temperature stress at anthesis is likely to result in significant yield losses in wheat (Triticum aestivum L.). The ability of plant tissue to depress its temperature has been reported in relation to the canopy but recent work has demonstrated that spike temperature depression (STD) can be assessed in controlled environments (CE). The findings from two consecutive years of potbased CE experiments, a field-based experiment under polytunnel cover and a rhizobox-based experiment, in which the thermal dynamics of the spike and flag leaf under contrasting conditions of elevated temperature and water-deficit stress at anthesis, are reported. Flag leaf temperature depression (FLTD) was significantly greater than STD at anthesis. The data do not demonstrate an increased cooling capacity of the spike in the early stages of anthesis but rather in the latter stages, a phenomenon hypothesized to be primarily associated with the onset of senescence in the canopy. The inconsistent relationship observed between FLTD/STD at anthesis and grain yield (GY) does not currently elucidate whether a failure to depress tissue temperature at anthesis is associated with a yield penalty. The effect of experimental design on the physiological response to abiotic stress at anthesis was explored. The plant-wide distribution of photoassimilates at mid-anthesis was examined. Starch and water-soluble carbohydrate content in the flag leaf, peduncle and glumes was not found to correlate to GY. Further examination of the effects that abiotic stress at anthesis have on the photoassimilate distribution and GY need to take place in field-grown wheat.
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Goodwin, Hazel Emma. "The evolution and spread of Triticum aestivum L. in Europe." Thesis, University of Manchester, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.702440.
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Cartelat, Aurélie. "Etude de l'autofluorescence des feuilles de blé (triticum aestivum L. )." Paris 6, 2004. http://www.theses.fr/2004PA066444.
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Livesey, Nancy L. "Towards the haploid production of transgenic wheat (Triticum aestivum L.)." Thesis, University of Nottingham, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.395623.
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Collin, François. "La tolérance du blé (Triticum aestivum L.) à la Septoriose." Thesis, Paris, Institut agronomique, vétérinaire et forestier de France, 2017. http://www.theses.fr/2017IAVF0028/document.
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La septoriose (pathogène Zymoseptoria tritici) est la plus importante maladie foliaire des cultures de blé en Europe. Les méthodes de lutte comprennent la résistance variétale, les stratégies d’évitement de la maladie et le recours aux fongicides. Cependant, ces stratégies n’assurent pas une protection complète des cultures de blé. La tolérance à la septoriose est une approche complémentaire qui vise justement à maintenir le rendement en présence de symptômes. La tolérance à la septoriose dépend de traits physiologiques de la plante et d’équilibres source/puits : la demande des puits (croissance des grains) doit être satisfaite malgré une disponibilité réduite des sources (capacité photosynthétique réduite par les symptômes foliaires). La surface verte du couvert, la sénescence et les composantes du rendement sont des traits potentiels de tolérance intéressants qui ont été étudiés lors de ce projet. Une étude de datamining, une expérience en serre et deux expériences au champ ont été menées pour fournir des informations complémentaires sur les mécanismes de tolérance à la septoriose. Les effets des interactions génotype × environnement sur les traits de tolérance ont été étudiés pour deux saisons × cinq localisations × neuf cultivars. La nutrition azotée et le métabolisme de quatre lignées double-haploïdes (DH, contrastées du point de vue de leur tolérance à la septoriose) ont été examinés dans une expérience en conditions contrôlées à l'UMR ECOSYS (INRA, AgroParisTech Grignon, France). Les bilans source/puits de six lignées DH contrastant pour la tolérance ont également été examinés en fonction de leurs réponses à un traitement d'égrainage, appliqué dans une expérience au champ à Hereford (Royaume-Uni). Enfin, une expérience au champ avec deux stratégies fongicides (contrôle total des maladies / lutte contre les maladies non-ciblées) a permis d’étudier la tolérance à la septoriose de six cultivars modernes (Leicestershire, Royaume-Uni). L'objectif principal était de vérifier les traits potentiels de tolérance à la septoriose sur des cultivars actuellement commercialisés. Des traits potentiels de tolérance à la septoriose ont été identifiés tels que la date d’épiaison, le faible degré de limitation des puits par les sources lors de la phase de remplissage du grain des couverts sains, la distribution verticale des surfaces foliaires favorisant des feuilles supérieures relativement grandes. Les résultats ont montré que ces caractères pourraient être sélectionnables, sans compromis avec le rendement potentiel. Enfin, le projet a également discuté du besoin de méthodes alternatives de quantification de la tolérance du blé à la septoriose, ainsi que de l'importance des variations environnementales qui doivent être prises en compte pour étudier les variations génétiques de la tolérance, mais qui pourraient également être utilisées pour identifier des environnements tolérantsThe Septoria tritici blotch disease (STB, pathogen Zymoseptoria tritici) is the most damaging foliar infection of wheat crops in Europe. Disease management strategies include cultivar resistance, disease escape strategy and fungicides. However, these strategies have failed to provide a complete protection of wheat crops. The STB tolerance is a complementary approach which aims to maintain yield in the presence of the symptoms. The tolerance of STB relies on plant physiology and source/sink balance: the sink demand (the grain growth) must be satisfied in spite of reduced source availability (photosynthetic capacity as affected by the STB symptoms on the leaves). The green canopy area, the senescence timing and the grain yield components are interesting potential sources of tolerance that were studied in this project. A data-mining study, one glasshouse experiment and two field experiments were carried out providing complementary insights on STB tolerance mechanisms. The genotype × environment interaction effects on tolerance traits were investigated for two seasons × five locations × nine cultivars datasets. The nitrogen nutrition and metabolism of four doubled-haploid (DH) lines contrasting for STB tolerance were examined in a controlled-glasshouse experiment at UMR ECOSYS (INRA,AgroParisTech) Grignon, France. The source/sink balance of six DH lines contrasting for STB tolerance was also examined according to their responses to a spikelet removal treatment, applied in a field experiment in Hereford, UK. Finally, a field experiment with two fungicide regimes (full disease control and non-target (STB) disease control) probed the STB tolerance of six modern UK winter wheat cultivars in Leicestershire, UK. The main objective was to verify identified potential STB tolerance traits in commercial cultivars. Putative STB tolerance traits have been identified such as the early heading date, the low degree of grain-source limitation of healthy crops during the grain filling phase, the vertical canopy distribution favouring a relatively larger flag-leaf. Results showed these traits might be selectable in wheat breeding without a trade-off with the potential yield. Finally, the project also discussed the need for alternative STB tolerance quantification methods, as well as the importance of environmental variations which have to be taken into account to study genetic variation in tolerance, but which could also be used to discriminate tolerant environment
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Dimmock, Jeremy. "Effects of modern fungicides on the quality of winter wheat." Thesis, University of Reading, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.367746.
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Talouizte, Ahmed. "Absorption et assimilation des nitrates en relation avec l'utilisation des photosynthétats chez le blé Triticum Aestivum L. : influence de la nutrition nitrique et de l'alimentation en eau." Paris 11, 1987. http://www.theses.fr/1987PA112185.
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L’étude est conduite avec de jeunes plantes de Blé de trois semaines. Elles représentent un système simple constitué des trois organes qui permettent les relations fondamentales d’échanges métaboliques entre les feuilles assimilatrices du carbone et les racines par lesquelles l’absorption des nitrates est contrôlée. Il s’agit d’une feuille adulte donneuse de phytosynthetats, et de deux receveurs qui sont en compétition pour les assimilats, racines et jeune feuille en croissance. L’outil utilisé pour modifier la distribution et le métabolisme au 14c fixe, en relation avec l’absorption et l’assimilation des nitrates est la privation azotée pendant quelques jours et sa variante, la réalimentation des plantes privées, ce qui permet de créer des plantes pauvres et des plantes riches en nitrate. Le déficit hydrique est induit par l’addition de polyéthylène glycol dans le milieu de culture pendant des temps de 7 à 36 h. Dans les plantes toujours riches en nitrate, la distribution des photoassimilats est en faveur des receveurs aériens. Dans les plantes pauvres, elle est en faveur des racines. Celles-ci s’enrichissent alors en glucides et croissent activement en mobilisant les réserves d’azote pré-existantes à la privation. Les racines contribuent pour environ 50 % à la réduction des nitrates dans la jeune plante de blé. Le double marquage 14C/15N a permis de déterminer que lors de la levée de privation par apport de nitrate dans le milieu, une active synthèse protéique prend place dans les racines, utilisant les chaines carbonées et probablement l’énergie des glucides. Lors de la réalimentation en nitrate des plantes privées, les vitesses d’absorption et d’assimilation sont étroitement liées à la teneur en glucides des tissus racinaires. Les glucides racinaires est de stimuler l’absorption. La réduction de cet anion dépend davantage du flux de nitrate que de l’état glucidique des tissus. Le déficit hydrique diminue la fixation de carbone, mais la translocation des photoassimilats se poursuit à court terme. L’action du déficit hydrique sur l’absorption et l’assimilation du nitrate dépend de la nutrition azotée reçue antérieurement par les plantes. Alors que l’influx apparait insensible. L’efflux de nitrate est inhibé par le déficit hydrique.
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Juery, Caroline. "Expression et régulation épigénétique des gènes homéologues chez le blé tendre." Thesis, Université Clermont Auvergne (2017-2020), 2020. http://www.theses.fr/2020CLFAC037.
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De nombreuses espèces de plantes sont polyploïdes, c’est-à-dire qu’elles possèdent plusieurs sous-génomes au sein du noyau de leurs cellules. La polyploïdie s’accompagne d’une redondance génétique qui offre un potentiel d’innovations évolutives important par un relâchement de la pression de sélection autorisant sous-fonctionnalisation, néo-fonctionnalisation, perte de gènes. Le blé tendre est une espèce polyploïde récente, apparue suite à deux hybridations interspécifiques (800 000 et 10 000 ans). Il possède un génome hexaploïde composé de trois sous-génomes : AABBDD et théoriquement, il possède trois copies homéologues de chaque gène (1A:1B:1D). Cependant, les analyses génomiques ont révélées que la moitié des séquences codantes présentaient un nombre de copie de type NA:NB:ND. Comment évolue cette redondance génétique après la polyploïdisation chez le blé tendre? Peut-on observer des différences d’expression des copies de gènes témoignant d’une évolution fonctionnelle pour cette espèce formée très récemment? Quels sont les mécanismes sous-jacents ? L’objectif de cette thèse a été d’analyser les expressions relatives des copies de gènes homéologues pour des groupes présentant trois (1 :1 :1, triades), deux (0:1:1, 1:0:1 ou 1:1:0, dyades) ou quatre copies (2:1:1, 1:2:1 ou 1:1:2, tétrades). Nous avons également relié les résultats aux caractéristiques structurales (position génomique), évolutives (présence ou absence des copies chez les espèces ancêtres) et épigénétiques (marques histones) des gènes pour répondre aux questions de recherche. Nous avons utilisé les données de RNA-seq et de ChIP-seq mises à disposition lors de la publication dela séquence génomique de référence du blé tendre (IWGSC 2018). Nous avons mis en évidence que les 51,1% de gènes en triades présentent en majorité (81%) une expression équilibrée sur l’ensemble des tissus et au cours du développement (expression élevée et constitutive). Ces gènes sont majoritairement associés la marque épigénétique d’activation de l’expression : H3K9ac. A contrario, les gènes en dyades (11,7% des gènes) et en tétrades (2,8% des gènes) présentent plus fréquemment des biais d’expression (36% et 75,4% respectivement). Ces gènes sont plus associés à la marque épigénétique liée à la répression ciblée et transitoire des séquences (H3K27me3). En revanche, aucune dominance d’expression n’a été décelée à l’échelle du génome entier. Ceci met en évidence de potentielles sous-fonctionnalisations des gènes, plus fréquentes pour des gènes différents des triades, présents dans les régions distales des chromosomes. Même si les biais d’expression correspondent à des différences déjà existantes chez les espèces ancêtres, nous avons cependant distingué des traits d’expression correspondant aux différentes étapes de l’histoire évolutive du blé : les copies du sous-génome D sont moins réprimées et moins associées à la marque H3K27me3 ; les biais d’expression entre les copies AABB sont plus prononcés. Ainsi, la coévolution des deux sous-génomes AABB pendant 800 000 ans est décelable alors que le sous-génome D semble encore s’exprimer de façon autonome. Ces résultats suggèrent que ce génome comprend des gènes très contraints évolutivement qui constitueraient le « core » génome de l’espèce avec des fonctions de bases conservées (gènes en triades) et des gènes présentant des variations du nombre de copies, des régulations différentielles et des fonctions spécifiques témoignant de possibles innovations évolutives, appartenant probablement au génome dit « dispensable » (dyades et tétrades)Within the plant kingdom, a lot of species are polyploids, meaning that they present two or more sub-genomes in the nucleus of their cells. Polyploidy confers genetic redundancy that offers a high potential of innovations and adaptations by relaxing natural selection on genic sequences. This allows faster sub and neo-functionalization of genes but also a loss of sequences that might be stochastic or not between the sub-genomes. Bread wheat is a recent polyploidy species that derived from two interspecific hybridizations that occurred 800 000 and 10 000 years ago. The genome of this species contains three sub-genomes: AABBDD and in theory three copies of each gene (1A:1B:1D). However, genomic analysis of the genome sequences reveals that half of the genes present copy number variations (NA:NB:ND). Within this scientific context, we wanted to answer questions such as: How this genetic redundancy evaluates after the polyploïdisation process? Is-it possible to observe differences in terms of gene expression that could correspond to functional evolution for this recently formed species? Which mechanisms could explain those processes? The objective of this PhD was to analyses relative expressions of homoeologous genes of bread wheat for groups presenting one copy on each sub-genomes (1 :1 :1, triades) and groups presenting a copy number variation with a loss (0:1:1, 1:0:1 ou 1:1:0), dyads or a duplication (2:1:1, 1:2:1 ou 1:1:2, tetrads) of sequences. We linked this analysis to genomic characteristics such as chromosome structure (genomic position of genes for exemple), evolution (presence or absence of lost and duplicated copies within diploid genomes of the progenitor species) and epigenetics (histone modifications). We used RNA-seq and ChIP-seq data released at the same time as the publication of the genomic reference sequence of bread wheat (IWGSC 2018). We highlight that the 51,1% of triads genes present mostly (81%) a balanced expression across the 15 tissues and developmental stages analyzed (high and constitutive expression) Those genes are mainly associated with the H3K9ac histone mark that is linked to an active transcription of genes. At the opposite, dyad genes (11,7% of High Confidence wheat genes) and tetrad genes (2,8%) present more frequently unbalanced expression patterns (36% and 74,5% respectively). Those genes are more associated with the histone mark H3K27me3 defining facultative heterochromatin and that target genes with transient expression. No dominance of one sub-genome on the others was discovered at the whole genome scale but rather stochastic suppression of genes copies. These results reveals potential sub-functionalization of genes, more frequent for copies present I the distal regions of chromosomes and associated with the epigenetic mark H3K27me3. Even if the homoeolog expression bias mostly corresponds to already existing divergence between diploid progenitor species, we nevertheless observe expression bias corresponding to the different step of bread wheat evolutive history: copies from sub-genome D are less repressed than the A or B copies; expression bias between AABB copies are more pronounced. In that respect the co-evolution of the two sub-genomes AABB during 800 000 years are traceable while D sub-genome seems to still present a nearly autonomous expression Combined together, these results suggest that wheat genome contains genes evolutionary constraints that correspond to a “core” genome of the species with basic conserved function (triad genes) and genes that present variation of the number of gene copies with differential regulations and specific functions that correspond to “dispensable” genes (dyads and tetrads)
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Potter, Tara. "AFLP markers linked to Fusarium head blight resistance in Triticum aestivum." Thesis, University of Ottawa (Canada), 2002. http://hdl.handle.net/10393/6321.
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In this study, AFLP technology was used to find markers linked to genes controlling Fusarium head blight (FHB) resistance in Triticum aestivum L. FHB is a disease of cereal crops that results in reduced wheat yields, discoloured, shrivelled kernels, mycotoxin accumulation, and reduced seed and grain quality. Since resistance mechanisms in wheat are complex, often being confounded by environmental effects, and there is high genotypic variance for resistance, molecular markers closely linked to FHB resistance would help in the screening of resistant germplasm. Candidate markers for resistance that were found among three varieties of wheat, two being susceptible to FHB ('Karena' and 'AC Cartier') and one being resistant to FHB (FHB 148), were followed into double haploid (DH) F2 from crosses between each of the susceptible varieties and the resistant variety. These DH lines were evaluated for resistance after inoculation with F. graminearum and MAXR linear regression was done to determine whether any of the candidate markers could explain the variation in phenotype. In the 'Karena'/FHB 148 DH lines, 67% of the polymorphisms segregated in a 1:1 Mendelian fashion (p ≥ 0.05), while 50% segregated 1:1 in the 'AC Cartier'/FHB 148 DH lines (p ≥ 0.05). In the 'Karena'/FHB 148 population, 35% of the variation in the FHB resistance phenotype was explained by two markers (p ≤ 0.05), while in the 'AC Cartier'/FHB 148 population, two markers explained 29% of the variation in phenotype (p ≤ 0.05). Cloning and sequencing of these markers would be useful in the development of cultivars resistant to FHB by marker assisted selection.
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Canova, Eduardo. "TECNOLOGIA DE APLICAÇÃO DE FUNGICIDAS NO PATOSSISTEMA Triticum aestivum - Puccinia triticina." Universidade Federal de Santa Maria, 2015. http://repositorio.ufsm.br/handle/1/7608.
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Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorThe wheat cultivation is subject to a certain number of limiting factors, such as climate adversities and diseases. Besides contributing to the incidence of infections that arise from diseases such as leaf rust (Puccinia triticina), climatic factors affect the applications behavior of foliar fungicide. This work aimed to evaluate the applications of fungicide carried out at different times using different rates and spectra of drops in wheat plants. A field experiment was then conducted in Itaara/RS. The experiment was arranged in random blocks with sub-split parcels in factorial arrangement of 5x3x2, with four replications. The first factor was composed by the time of application (05:00, 09:00, 13:00, 17:00, 21:00). The second factor consisted of the application rates (70, 100, 140 L/ha), and lastly, two drops spectra (fine and medium) composed the third factor. The fungicide used was composed by Trifloxystrobin + Prothioconazole (70.0 + 60.0 g active ingredient/ha) with addition of Aureo® at 0.375 L commercial product/ha. The parameters evaluated were: median volume diameter (MVD), covered area (%), drop density (cm2), area under the disease-progress curve (AUDPC), productivity (kg/ha), thousand seed weight, hectoliter weight and the Normalized Difference Vegetation Index (NDVI). The obtained results indicate that the penetration and the area covered by the fungicide volume are higher when high application rates are used alongside fine droplet spectrum. It was found that the fungicide application with fine droplet spectrum and higher spray volumes provides an increase on the control of wheat rust. The fungicide application held at 09:00 presented the best rust control.
O cultivo do trigo está sujeito a certo número de limitação, tais como adversidades do clima e doenças. Os fatores climáticos além de contribuírem para a ocorrência de infecções advindas de doenças como a ferrugem da folha, afetam o comportamento de aplicações de fungicidas foliares na cultura. O presente trabalho objetivou avaliar o comportamento de aplicações de fungicida realizadas em distintos horários utilizando diferentes taxas e espectros de gotas em plantas de trigo. Para isso foi conduzido um experimento à campo no município de Itaara RS. Foi utilizado o delineamento experimental blocos ao acaso com parcelas sub-subdivididas. O experimento constituiu-se com quatro repetições, em arranjo fatorial 5x3x2. O primeiro fator foi composto pelos horários de aplicação (05:00, 09:00, 13:00, 17:00, 21:00 horas). O segundo fator foi composto pelas taxas de aplicação (70, 100, 140 L/ha) e o por fim, o terceiro fator, foi composto por dois espectros de gotas (Fino e Médio). Foi utilizado o fungicida composto pelos ingredientes ativos Trifloxistrobina + Protioconazol (70,0 + 60,0 g i.a/ha) com adição de Aureo® na dose de 0,375 L p.c/ha. Os parâmetros avaliados foram o diâmetro mediano volumétrico (DMV), a área coberta (%), a densidade de gotas (cm2), área abaixo da curva de progresso da doença (AACPD), produtividade (kg/ha), peso de mil sementes (PMS), peso hectolitro (PH) e índice de vegetação por diferença normalizada (NDVI). Os resultados obtidos indicaram que a penetração e a área coberta pela calda de fungicida é elevada quando utilizou-se taxas de aplicação maiores conciliada a espectro de gotas fino. Verificou-se que a aplicação de fungicida com espectro de gota fina e volumes de calda maior proporcionam um aumento no controle da ferrugem do trigo. A aplicação de fungicida realizada às 09:00 horas apresentou o melhor controle da ferrugem.
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Malik, Iram. "The effects of ozone and salinity on wheat (Triticum aestivum L.)." Thesis, Imperial College London, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.343901.
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Bhutto, Liaquat Ali. "Understanding the mechanisms of drought tolerance in wheat (Triticum aestivum L.)." Thesis, University of Sheffield, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.522505.
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Howladar, Saad Mohammed. "Effects of salicylic acid on salinity tolerance of wheat (Triticum aestivum)." Thesis, University of Reading, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.553172.
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Four glasshouse experiments examined salinity stress and tolerance in wheat. The first experiment examined the responses of three wheat cultivars from Saudi Arabia (Local wheat, West bread and Yecora Rojo) and two UK wheat cultivars (Paragon and Belvoir) to different levels of salinity (Tap water, 25, 50, 100, 150 and 200 mM NaCI). In the second experiment, Yecora Rojo and Paragon were selected to test whether improved wheat tolerance to salinity could be obtained by applying exogenous Salicylic acid (0, 0.5, 1 and 2 mM SA) via priming seeds for 6 hours. The third experiment further tested the effect of SA on tolerance to salinity with SA applied through seed soaking for 6h and 24h. Two salinity tolerant cultivars (S24 and Sakha 93) were included for comparison. The fourth experiment compared the effect of SA applied by seed soaking (6h) or by foliar spray. In all experiments, saline conditions gave significant declines in wheat growth parameters, gas exchange, yield and yield components with increases in salinity concentration, whereas protein and chlorophyll content increased. Cultivar Paragon grew significantly better than cultivar Yecora Rojo in non-saline conditions but not under salinity stress. Treating wheat with SA produced only a minor improvement in growth parameters, yield and yield components under salinity stress. Compared to salt tolerant cultivars, Paragon showed significant response to SA in most variables. The influence of SA depended on genotype, plant stage and SA concentration more than soaking time and application method with 0.5 and 1 mM SA concentrations being the most effective. SA mitigates but does not prevent salinity impacts and has a dual function which can give positive or negative effects under salinity stress.
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Semikhodskii, Andrei G. "Mapping quantitative traits for salinity responses in wheat (Triticum aestivum L.)." Thesis, University of East Anglia, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.302054.
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