Conecte-se

Bibliografias temáticas / Wheat / Teses / dissertações

Siga este link para ver outros tipos de publicações sobre o tema: Wheat.

Teses / dissertações sobre o tema "Wheat"

Autor: Grafiati

Publicado: 4 de junho de 2021

Última modificação: 1 de agosto de 2024

Crie uma referência precisa em APA, MLA, Chicago, Harvard, e outros estilos

Selecione um tipo de fonte:

Veja os 50 melhores trabalhos (teses / dissertações) para estudos sobre o assunto "Wheat".

Ao lado de cada fonte na lista de referências, há um botão "Adicionar à bibliografia". Clique e geraremos automaticamente a citação bibliográfica do trabalho escolhido no estilo de citação de que você precisa: APA, MLA, Harvard, Chicago, Vancouver, etc.

Você também pode baixar o texto completo da publicação científica em formato .pdf e ler o resumo do trabalho online se estiver presente nos metadados.

Veja as teses / dissertações das mais diversas áreas científicas e compile uma bibliografia correta.

1

Biddulph, Thomas Benjamin. "Mechanisms of dormancy, preharvest sprouting tolerance and how they are influenced by the environment during grain filling and maturation in wheat (Triticum aestivum L.) /". Connect to this title, 2006. http://theses.library.uwa.edu.au/adt-WU2007.0168.

Texto completo da fonte

Estilos ABNT, Harvard, Vancouver, APA, etc.

2

Zahedi, Morteza. "Physiological aspects of the responses of grain filling to high temperature in wheat". Title page, abstract and contents only, 2001. http://web4.library.adelaide.edu.au/theses/09PH/09phz19.pdf.

Texto completo da fonte

Resumo:

"June 2001." Includes bibliographical references (leaves 217-248). The effects of a sustained period of moderately high temperature on physiological and biochemical aspects of grain development were investigated in wheat cultivars grown under controlled environment conditions. The effect of variation in plant nutrition on the responses of cultivars to high temperature was also studied.

Estilos ABNT, Harvard, Vancouver, APA, etc.

3

Kim, Renee Boyoung. "Quality preferences for wheat and wheat flour, noodle wheat markets in Japan and South Korea". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape3/PQDD_0010/NQ60313.pdf.

Texto completo da fonte

Estilos ABNT, Harvard, Vancouver, APA, etc.

4

Moussavi-Nik, Mohsen. "Seed quality and crop establishment in wheat". Title page, contents and abstract only, 1997. http://web4.library.adelaide.edu.au/theses/09PH/09phm933.pdf.

Texto completo da fonte

Resumo:

Bibliography: leaves 247-268. A series of laboratory, greenhouse and field experiments were conducted to investigate aspects of seed quality in a range of bread wheat genotypes important in South Australia as well as a durum cultivar, Yallaroi. It was concluded that sound healthy seed does vary in quality and this affects seedling vigour, crop establishment and grain yield. Seed source can affect genotype performance in evaluation trials. There is genetic variability for embryo size, coleoptile length, nutrient efficiency and nutrient loading in to the seed which can be exploited by breeders. Agronomically, seed quality can be improved by managing seed crops to aid accumulation of mineral nutrients in the seed and then selecting, by grading, only large seed for sowing.

Estilos ABNT, Harvard, Vancouver, APA, etc.

5

Dick, G., J. Harper, L. Moore e M. Ottman. "Effect of Russian Wheat Aphid on Durum Wheat Yield". College of Agriculture, University of Arizona (Tucson, AZ), 1988. http://hdl.handle.net/10150/200817.

Texto completo da fonte

Estilos ABNT, Harvard, Vancouver, APA, etc.

6

Harrison, Leigh Ann. "Epidemiology of the resistance to Wheat streak mosaic virus in perennial wheat". Online access for everyone, 2006. http://www.dissertations.wsu.edu/Thesis/Fall2006/l_harrison_121806.pdf.

Texto completo da fonte

Estilos ABNT, Harvard, Vancouver, APA, etc.

7

Tolmay, John Peter Cleggenett. "Morphological and physiological responses of spring wheat (Triticum aevstivum L.) to spatial arrangements /". Link to the online version, 2008. http://hdl.handle.net/10019.1/1358.

Texto completo da fonte

Estilos ABNT, Harvard, Vancouver, APA, etc.

8

Cooke, Julie A. "Nutritional requirement of wheat in relation to tolerance to Rhizoctonia solani Kühn /". Title page, contents and abstract only, 2000. http://web4.library.adelaide.edu.au/theses/09APSP/09apspc772.pdf.

Texto completo da fonte

Estilos ABNT, Harvard, Vancouver, APA, etc.

9

Sandhu, Devinder. "Molecular characterization of a major gene-rich region in wheat (Triticum aestivum L.)". [Lincoln, Neb. : University of Nebraska-Lincoln], 2000. http://international.unl.edu/Private/2000/sandhuab.pdf.

Texto completo da fonte

Resumo:

Thesis (Ph. D.)--University of Nebraska--Lincoln, 2000.
PDF text: [6] leaves table of contents and acknowledgments, [2] leaves abstract, 236 leaves dissertation : ill. Includes bibliographical references (leaves 97-105 of dissertation).

Estilos ABNT, Harvard, Vancouver, APA, etc.

10

Carter, Arron Hyrum. "Identification of quantitative trait loci and molecular markers for disease, insent and agronomic traits in spring wheat (Triticum aestivum L.)". Pullman, Wash. : Washington State University, 2009. http://www.dissertations.wsu.edu/Dissertations/Spring2009/A_Carter_041509.pdf.

Texto completo da fonte

Estilos ABNT, Harvard, Vancouver, APA, etc.

11

Ahmed, Anikka Susan. "Investigation into interactions between emulsifiers and wheat starch/wheat flour". Thesis, Kansas State University, 2011. http://hdl.handle.net/2097/13249.

Texto completo da fonte

Resumo:

Master of Science
Department of Grain Science and Industry
Yong-Cheng Shi
Jon M. Faubion
One long-term goal of cereal science research is to increase the shelf life of baked products and one approach to that goal has been the use of emulsifiers. Emulsifiers are surface-active agents, some of which improve specific properties of baked products. Two emulsifiers, sodium stearoyl lactylate (SSL) and oleyl lactylic acid (OLA) are similar in structure, the difference being the acid moiety: stearic versus oleic acid. Widely researched, SSL has found many uses in baked products. However, how OLA interacts with starch/flour in baked products or how that interaction affects product quality is not well understood. The objective of this study was to understand the interactions between normal wheat starch and these emulsifiers, as well as the differences between SSL and OLA in those regards. The effects of the two emulsifiers on the pasting properties of wheat starch and wheat flour were determined using a MicroViscoAmylograph. Heating at 6oC/min with increased emulsifier concentration (0-2%) resulted in increased hot paste viscosity and apparent interaction of both emulsifiers with wheat starch. Solid content affected both maximum hot and final viscosity. OLA produced increased maximum hot and final viscosities with increased starch concentration and emulsifier concentrations. For wheat flour, higher concentrations of SSL reduced both maximum hot paste and final viscosities. OLA behaves differently with wheat flour. At lower flour concentrations, higher concentrations of OLA reduced maximum hot viscosity. The effects of SSL on starch were affected by an increased heating and cooling rate (10oC/min). Heating stage microscopic analysis revealed that the presence of emulsifiers inhibited granular swelling beyond the normal gelatinization temperature (65oC) in both starch and flour systems. OLA’s effect in this respect was greater than that of SSL. Complex formation between emulsifiers and wheat starch and wheat flour was determined using differential scanning calorimetry (DSC) and X-ray diffraction (XRD). For isolated wheat starch and hard wheat flour, DSC and XRD indicated that OLA complexes to a greater extent than does SSL. For flour, XRD indicated no difference exhibited in the interaction of the emulsifiers with the flours. KEYWORDS: Emulsifiers, Starch, Wheat flour

Estilos ABNT, Harvard, Vancouver, APA, etc.

12

Bahrami, Niloufar. "Impact of wheat lipids on the functionality of wheat flour". Thesis, University of Nottingham, 2016. http://eprints.nottingham.ac.uk/33526/.

Texto completo da fonte

Resumo:

Lipids are minor constituents of wheat flour, but are functional in bread making. As a result they have been extensively studied, but the published results are conflicting. It was therefore the objective of this study to understand better the impact of wheat lipids on wheat flour functionality and to propose approaches for positive modification of the flours. Initial work established quantitative and qualitative assessment methods for the non-starch lipids occurring in starch based systems. Seven solvent systems were compared for their ability to extract the non- starch lipids at ambient temperature. The choice of solvent system greatly influenced the total extractable amounts of lipid and there were differences in the relative composition. Bligh and Dyer methodology showed good extraction ability based on the total amount of non-starch lipids and there was good representation of the different lipid classes (neutral lipids, glycolipids, phospholipids). As this method was reasonable fast, with high extraction ability and showed low coefficient of variation (typically 16%) it was used in subsequent studies including the assessment of lipids in wheats of different variety and the levels and class of lipids segregating in the different mill fractions. As part of a larger study the impact of agriculture based variation in wheat flour chemistry and quality parameters was tested on high quality wheat varieties. Wheat variety was found as the major factor determining wheat flour properties, but environmental effects and post- harvest processing i.e. milling also had an impact. Correlations were made for the composition, flour quality parameters and the bread quality and results showed that whilst proteins are a major determinant for bread texture, lipids significantly influenced bread volume with non-polar lipids significantly and positively associated with bread volume, while the phospholipids reduced dough resistance and therefore may be associated with a decrease in loaf volume. Despite the acknowledged limitation of the data sets in some aspects, the wheats were tested for their “stability” within and over the growing sites. From these data, suggested wheat varieties worthy of further examination have been made. To see if positive modifications could be induced into wheat flours the technique of cold plasma (0.2-0.4 Wcm-2) was applied. It was shown that measureable free fatty acids and phospholipids significantly reduced after treatment and that there was a shift towards higher molecular weight proteins. Markers of oxidation increased and there was a significant increase in hydrogen peroxide and the formation of secondary oxidation products (n-hexanal). All the changes that occurred in the wheat flour during cold plasma treatment ultimately resulted in stronger dough. This suggests that cold plasma is an effective treatment for modifying functionality and enhancing the oxidative state of wheat flour.

Estilos ABNT, Harvard, Vancouver, APA, etc.

13

Fenton, Haelee Kim. "Defining the wheat quality requirements for Indian whole wheat chapatti". Thesis, Curtin University, 2012. http://hdl.handle.net/20.500.11937/68405.

Texto completo da fonte

Resumo:

The ability of Australian wheat varieties, which had varying wheat qualities, to make the Indian unleavened flat bread chapatti was investigated. Flour and chapatti quality of the Australian wheat varieties was characterised and benchmarked against Indian wheat varieties. The research provided insight into the important flour quality, chapatti quality and chapatti making methodology needed for future selection of Australian wheat for the Indian market.

Estilos ABNT, Harvard, Vancouver, APA, etc.

14

De, Fazio Luigia <1986&gt. "Wheat proteins evolution and environmental triggers of Wheat-related diseases". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2020. http://amsdottorato.unibo.it/9199/1/De%20Fazio_Luigia_tesi.pdf.

Texto completo da fonte

Resumo:

Cereals, and in particular wheat, have always been recognized as a fundamental food worldwide. In particular, the success of wheat is linked with unique properties of the gluten protein fraction used in bread making process to obtain products that are widely used in traditional and modern diets. The rapid increase in the world population let to a parallel increases in food production, particularly of wheat. Increasing yield potential and selection of cultivars much more resistant to plant disease and to environmental factors could have negatively affected the quality of the grain. Moreover, the “green revolution” was characterized by a widespread use of agricultural chemicals and by industrialization of food production that led to a huge rise in the consumption of refined products. Modern baking practices have shortened bread leavening, increased the use of chemical/yeast leavening agents and there is well-documented scientific evidence of the negative effects of ultra-processed food in human healthy. All this changes profoundly modified the human diet and, as a result, may have affected Gluten-related disease (GRDs) that has arisen in the whole word populations. Gluten-related diseases (GRDs) are multifactorial pathologies in which environmental factors and genetic background contribute to a low-grade chronic inflammation of the gastrointestinal tract. Here, I investigated the potential pro-inﬂammatory effect of different wheat varieties and whether bread making processing are involved in the onset or worsening of gut inflammation. In vitro, ex vivo and in vivo studies conducted throughout my Phd period have shown a pro-inflammatory effect of wheat especially marked in modern varieties and a higher inflammatory response linked to the use of common raising agent as Saccharomyces Cerevisiae and to the addiction of chemical bakery improver substances.

Estilos ABNT, Harvard, Vancouver, APA, etc.

15

Gaongalelwe, Motlhasedi Olebile. "Effect of delayed sowing and increased crop density on weed emergence and competition with wheat". Title page, table of contents and abstract only, 2002. http://web4.library.adelaide.edu.au/theses/09AFM/09afmg2118.pdf.

Texto completo da fonte

Estilos ABNT, Harvard, Vancouver, APA, etc.

16

Brooks, Brenton James. "Breeding durum wheat for South Australia /". Title page, table of contents and abstract only, 2004. http://web4.library.adelaide.edu.au/theses/09PH/09phb8731.pdf.

Texto completo da fonte

Estilos ABNT, Harvard, Vancouver, APA, etc.

17

Tickes, Barry. "Wheat Variety Demonstrations". College of Agriculture, University of Arizona (Tucson, AZ), 1985. http://hdl.handle.net/10150/200502.

Texto completo da fonte

Estilos ABNT, Harvard, Vancouver, APA, etc.

18

Reddy, Latha J. "Investigations in wheat (Triticum aestivum L. em Thell) using molecular and conventional breeding techniques for abiotic and biotic stress". Online access for everyone, 2006. http://www.dissertations.wsu.edu/Dissertations/Spring2006/l%5Freddy%5F042106.pdf.

Texto completo da fonte

Estilos ABNT, Harvard, Vancouver, APA, etc.

19

Mantovani, Eder Eduardo. "Wheat Traits Variations, Associations, and Potential Improvement from Crosses of Elite X Non-Adapted Germplasm". Thesis, North Dakota State University, 2011. https://hdl.handle.net/10365/29911.

Texto completo da fonte

Resumo:

Wheat improvement most often has been accompanied by a narrowing germplasm base, as newer cultivars have been derived from intercrosses between elite germplasm. However, there is a concern that narrow germplasm may restrict breeding improvement for important traits such as resistances to new biotic and abiotic stresses. In addition to germplasm base, the wheat kernel is a major component of wheat grain yield and an important factor for milling characteristics. Focusing on wheat kernel characteristics might be a key element to improve wheat genotypes for agronomic and quality traits. With the intention to broaden the wheat germplasm, and to explore the associations between kernel traits and agronomic as well as quality traits, a two-year study was initiated in 2009 to examine the influence of the kernel traits on the agronomic and quality attributes of a 160 Recombinant Inbred Lines (RIL) population developed from an adapted (ND 705) and a non-adapted genotype (PI 414566). The experiment was conducted at Prosper and Carrington, North Dakota, during 2009 and 2010. The RIL population had a better performance at Carrington than Prosper due to favorable climatic conditions at this location, in 2009 and 2010. The results in this study showed that kernel traits had a high correlation among them and they exhibited continuous variations suggesting a polygenic inheritance. Grain yield, kernel volume weight (KVW), and flour extraction were highly correlated with kernel width, length/width ratio, weight, and area. Eight RIL yielded better than the adapted parent ND 705 and two of the RIL along with three checks were significantly superior for gram yield compared with the other genotypes across all environments. Although the non-adapted parent has a facultative grown habit, several RIL required fewer days to flower compared to the adapted parent. Two RIL had better flour extraction compared to the other genotypes included in this study. These results indicated that kernel traits can play a significant role in improving agronomic and quality traits. Higher values for grain yield, KVW, and flour extraction were significantly associated with spheroid or round shape (short and plump), large, and heavy kernels. The high agronomic and quality attributes showed by some RIL demonstrated that the use of a non-adapted parent can broaden the genetic variability while increasing the genetic gain for certain traits. Also, breeders should pay attention to kernel size and shape during the parental selection for the development of populations with improved agronomic and quality traits.

Estilos ABNT, Harvard, Vancouver, APA, etc.

20

Harwood, Eric D. "Improving the yields of late-planted winter wheat with seeding rate and phosphorus fertility". Pullman, Wash. : Washington State University, 2009. http://www.dissertations.wsu.edu/Thesis/Fall2009/e_harwood_120309.pdf.

Texto completo da fonte

Resumo:

Thesis (M.S. in soil sciences)--Washington State University, December 2009.
Title from PDF title page (viewed on Jan. 25, 2010). "Department of Crop and Soil Sciences." Includes bibliographical references.

Estilos ABNT, Harvard, Vancouver, APA, etc.

21

Turnbull, Kym-Marie. "Genomic and developmental analyses of grain hardness in wheat / Kym-Marie Turnbull". Thesis, The University of Sydney, 2001. https://hdl.handle.net/2123/27751.

Texto completo da fonte

Estilos ABNT, Harvard, Vancouver, APA, etc.

22

Wynter, Hugh. "Price risk management strategies for South Australian wheat growers /". Title page, table of contents and abstract only, 2004. http://web4.library.adelaide.edu.au/theses/09AS/09asw991.pdf.

Texto completo da fonte

Estilos ABNT, Harvard, Vancouver, APA, etc.

23

Singh, Narinder. "Genetic diversity of wheat wild relative, Aegilops tauschii, for wheat improvement". Diss., Kansas State University, 2017. http://hdl.handle.net/2097/38259.

Texto completo da fonte

Resumo:

Doctor of Philosophy
Genetics Interdepartmental Program
Jesse A. Poland
Wheat is perhaps the most important component in human diet introduced since the conception of modern agriculture, which provides about 20% of the daily protein and calorie intake to billions of people. Adaptable to wide range of climates, wheat is grown worldwide, lending it the potential to mitigate the imminent risk of food security for future population of 9.5 billion people. For developing improved crop varieties in the future, genetic diversity is a key factor in plant breeding. Constraints in wheat evolution and artificial selection practices have resulted in erosion of this ingredient in elite germplasm. However, wheat wild relatives, such as Ae. tauschii, D-genome donor of wheat, are a storehouse for unexploited genetic diversity that can be used for improving wheat for disease and insect resistance, yield, quality, and tolerance to abiotic stresses. More than 1700 genebanks around the world hold over 7 million accessions of these wild relatives. These genebanks are expensive to maintain, therefore, efficient curation is necessary. We developed and implemented a protocol to identify duplicate accessions using genomic tools. Implementing this approach with three genebanks, we identified over 50% duplicated accessions across genebanks. There are over a million Triticeae accessions held collectively, and it is likely as more number of genebanks are tested, there will be decreasing number of unique accessions. Selecting and utilizing the wild genetic diversity is no easy task. Historically, breeders and geneticists have chosen the accessions primarily based on associated phenotypic data. Unless focusing on a targeted trait, this practice is imperfect in capturing the genetic diversity with some other limitations, such as confounding phenotypic data with the testing environment. Utilizing next-generation sequencing methods, we selected a MiniCore consisting of only 40 accessions out of 574 capturing more than 95% of the allelic diversity. This MiniCore will facilitate the use of genetic diversity present in Ae. tauschii for wheat improvement including resistance to leaf rust, stem rust, Hessian fly, and tolerance to abiotic stresses. Hessian fly is an important insect pest of wheat worldwide. Out of 34 known resistance genes, only six have been mapped on the D sub-genome. With swift HF evolution, we need to rapidly map and deploy the resistance genes. Some of the undefeated HF resistance genes, such as H26 and H32, were introgressed from Ae. tauschii. In this study, we mapped three previously known genes, and a new gene from Ae. tauschii accession KU2147. Genes were mapped on chromosomes 6B, 3D, and 6D. Further, identification and cloning of resistance genes will enhance our understanding about its function and mode of action. In conclusion, wild wheat relatives are genetically diverse species, and utilizing the novel genetic diversity in Ae. tauschii will be fruitful for wheat improvement in the wake of climate change to ensure future food security to expected 2 billion newcomers by 2050.

Estilos ABNT, Harvard, Vancouver, APA, etc.

24

Sharma, Sapna. "Genetics of Wheat Domestication and Septoria Nodorum Blotch Susceptibility in Wheat". Thesis, North Dakota State University, 2019. https://hdl.handle.net/10365/29767.

Texto completo da fonte

Resumo:

T. aestivum ssp. spelta Iranian type has long been thought to potentially be the direct non-free threshing hexaploid progenitor. I evaluated a RIL population derived from a cross between CS and Iranian spelta accession P503 to identify loci suppressing free-threshabilty in P503. Identification of QTL associated with threshability in region known to harbor the Tg2A gene, and an inactive tg2D allele supported the hypothesis of Iranian spelta being derived from a more recent hybridization between free-threshing hexaploid and emmer wheat. Parastagonospora nodorum is an important fungal pathogen and secretes necrotrophic effectors that evoke cell death. In this research, a DH population segregating for Snn5 was used to saturate Snn5 region of chromosome 4B with molecular markers. The physical distance between Snn5 flanking markers was narrowed to 1.38 Mb with genetic distance of 2.8 cM. The markers developed in this study will provide a strong foundation for map-based cloning of Snn5.

Estilos ABNT, Harvard, Vancouver, APA, etc.

25

Khalid, Khairunizah. "Whole Wheat Milling and Baking Studies of Hard Red Spring Wheat". Diss., North Dakota State University, 2016. http://hdl.handle.net/10365/25570.

Texto completo da fonte

Resumo:

End product quality of whole wheat bread is affected by many complex parameters. The milling method and chemical composition of bran both affect whole wheat bread quality. When using a centrifugal mill, the combination of low tempering moisture level and high rotor speed produced whole-wheat flour with fine particle size, desirable whole-wheat flour quality, manageable dough, and high loaf volume. Fine bran powder was produced with the combination of low tempering moisture level, low feed rate, and high rotor speed. It was also determined that flour attached to bran affects the bran powder?s temperature, protein content, and starch content. Study of the impact of bran components on whole-wheat bread revealed that fiber (FB) highly impacted gluten quality, farinograph parameters, gassing power, oven spring, loaf volume, and bread crumb protein solubility. FB interacted with other bran components (oils, extractable and hydrolysable phenolics) to increase polymeric protein solubility in bread crumb. Hydrolysable phenolics (HP) improved the farinograph stability. However, the interaction of FB with other components decreased bread loaf volume, especially for the interaction of FB-HP. The baking method and the type of wheat used for whole-wheat bread are also important factors to evaluate whole-wheat bread quality. Sponge-and-dough (SpD), straight dough (StD), and no-time dough (NoD) methods were compared. StD had the highest variation in baking mix time, baked weight, crumb grain score, and symmetry score compared to other baking methods. The StD method was the most sensitive method to distinguish variation in whole-wheat flour samples. Location and cultivar effects were investigated for whole-wheat bread quality. Twenty-one hard red spring wheat cultivars grown at 6 locations across North Dakota were evaluated for whole-wheat bread quality. Location contributed 89% to the variability in whole-wheat baking absorption. Cultivar contributed 47% and 41% to the variability in whole-wheat loaf volume and loaf symmetry, respectively. Loaf volume and crumb color were largely under genetic control, and breeders can aim at high loaf volume in whole wheat bread made from hard spring wheat. Overall, whole-wheat flour and bread quality are greatly affected by: milling method, bran composition, baking method, as well as the environment and genotype.
North Dakota Wheat Commission

Estilos ABNT, Harvard, Vancouver, APA, etc.

26

Kopp, Daniela B. (Daniela Barbara) Carleton University Dissertation Geography. "Wheat imports and consumption changes in non-traditionally wheat producing countries". Ottawa, 1988.

Encontre o texto completo da fonte

Estilos ABNT, Harvard, Vancouver, APA, etc.

27

Ottman, Michael. "Predicting Wheat Growth Using the CSM-Cropsim-CERES - Wheat Crop Model". College of Agriculture, University of Arizona (Tucson, AZ), 2008. http://hdl.handle.net/10150/203650.

Texto completo da fonte

Resumo:

CSM-Cropsim-CERES -Wheat is a crop growth model that predicts crop development stages, among other things, using genetic coefficients for vernalization and photoperiod. We used this model to predict flowering date for 12 durum varieties seeded in trials at Maricopa and Yuma from 1998 to 2006. The difference between simulated and measured flowering date averaged 4 days without genetic coefficients and improved to 3.5 days if genetic coefficients for flowering and vernalization were included for each variety.

Estilos ABNT, Harvard, Vancouver, APA, etc.

28

Afshar-Sterle, Shoukat. "Cell, tissue culture and transformation of Triticum tauschii /". Title page, abstract and contents only, 2000. http://web4.library.adelaide.edu.au/theses/09APSP/09apspa258.pdf.

Texto completo da fonte

Estilos ABNT, Harvard, Vancouver, APA, etc.

29

Ryan, Karon Magadalene Leanne. "Variation of flour colour in Western Australia adapted wheat : comparative genomics, molecular markers and QTL analysis /". Access via Murdoch University Digital Theses Project, 2005. http://wwwlib.murdoch.edu.au/adt/browse/view/adt-MU20061019.130337.

Texto completo da fonte

Estilos ABNT, Harvard, Vancouver, APA, etc.

30

Zubaidi, Akhmad. "Growth and yield of durum and bread wheat". Title page, contents and summary only, 1996. http://web4.library.adelaide.edu.au/theses/09A/09az93.pdf.

Texto completo da fonte

Resumo:

Bibliography: leaves 148-160. A series of experiments was conducted to examine the growth and nutrient uptake of durum and bread wheat at a number of sites in South Australia. The experiments examined response to water stress, the pattern of root and shoot growth, soil water extraction and nutrient uptake among a range of adapted bread wheat and durum wheat cultivars.

Estilos ABNT, Harvard, Vancouver, APA, etc.

31

Liu, Chao-yin. "Variation and genetic control of prolamins in tetraploid wheats and their association with quality in durum wheat". Title page, contents and summary only, 1994. http://web4.library.adelaide.edu.au/theses/09PH/09phl783.pdf.

Texto completo da fonte

Estilos ABNT, Harvard, Vancouver, APA, etc.

32

Ormanbekova, Danara <1987&gt. "Durum wheat gene annotation and selection signature detection in the tetraploid wheat germplasm from wild emmer to modern durum wheat". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2019. http://amsdottorato.unibo.it/8908/1/Tesi_Dottorato_Ormanbekova_Danara.pdf.

Texto completo da fonte

Resumo:

The domestication of the wild emmer wheat nearly 10,000 years ago in the Fertile Crescent lead to the evolution of the free-threshing and easy to harvest tetraploid Triticum durum wheat. We annotated the gene models and assessed the gene expression pattern of a 10.45-gigabase assembly of durum wheat cultivar Svevo and predicted 66,559 high-confidence genes with 95.8% expression evidence. 75.0, 70.5 and 74.5% of high-confidence genes were expressed in grain, leaf and root tissues, respectively, of the 13 elite worldwide durum wheat varieties. Additionally, we annotated 1,487 loci associated with NBS-LRR genes that are prominently involved in signaling and plant disease resistance. Using the Global Tetraploid wheat Collection composed of 1,856 accessions representing the four principal germplasm groups involved in the tetraploid domestication and selection history, we detected the genetic diversity and selection signature regions associated with wild emmer domestication and durum wheat evolution on the pericentromeric regions of chromosome groups 2, 4, 6 and on chromosomes 1A, 7B. Several diversity reduction and selection signature peaks overlapped with loci associated with domestication, disease resistance, yellow pigment content and seed dormancy. Population structure of the tetraploid diversity panel assessed by ADMIXTURE subdivided wild emmer (WEW) in two main populations, domesticated emmer (DEW) and durum landraces (DWL) in six populations each, and durum cultivars (DWC) in five subpopulations. The modern durum wheat germplasm showed the highest relationship to the North African and Turkey to Transcaucasia DWL populations, while the Ethiopian and T. turanicum populations were the most differentiated with a minimal contribution to the modern durum germplasm. The selection signature detection provided an insight into the dynamics of tetraploid wheat domestication and selection. The reference assembly of durum wheat is a valuable resource directed to accelerate the progress and accuracy of genome-assisted advancement of modern wheat.

Estilos ABNT, Harvard, Vancouver, APA, etc.

33

Guan, Lan. "Wet-milling of waxy wheat flours and characteristics of waxy wheat starch". Thesis, Manhattan, Kan. : Kansas State University, 2008. http://hdl.handle.net/2097/955.

Texto completo da fonte

Estilos ABNT, Harvard, Vancouver, APA, etc.

34

Hussain, Syed Bilal. "Chromosomal location of wheat tolerance character in the D-genome of wheat". Thesis, Bangor University, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.321386.

Texto completo da fonte

Estilos ABNT, Harvard, Vancouver, APA, etc.

35

McCarthy, Patrick Kieran. "HPLC and immunochemical detection of gliadin impurities in wheat and wheat products". Thesis, Nottingham Trent University, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.253810.

Texto completo da fonte

Estilos ABNT, Harvard, Vancouver, APA, etc.

36

McGinley, Susan. "Irrigation Efficiency for Durum Wheat: Growing Pasta Wheat and Barley in Arizona". College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2003. http://hdl.handle.net/10150/622226.

Texto completo da fonte

Estilos ABNT, Harvard, Vancouver, APA, etc.

37

Curato, John. "Inheritance of resistance to wheat streak mosaic virus in wheat line KS06HW79". Thesis, Kansas State University, 2016. http://hdl.handle.net/2097/32918.

Texto completo da fonte

Resumo:

Master of Science
Department of Agronomy
Guorong Zhang
Guihua Bai
Wheat streak mosaic virus (WSMV) is a disease that causes significant yield losses in wheat (Triticum aestivum L.). Host resistance is the primary approach for control. KS06HW79 is a wheat line with WSMV resistance up to 21°C. To study the inheritance of resistance in KS06HW79, it was crossed with two WSMV-susceptible wheat genotypes, KS020638-M-5 and Brawl CL Plus. Parental lines, F₁, F₂, and check varieties were mechanically inoculated and evaluated for WSMV resistance at 21°C in growth chambers. The segregation pattern in two F₂ populations fit a one-recessive-gene model (1 resistant : 3 susceptible) and a dominant-suppression-epistasis model (3 resistant : 13 susceptible). To determine which model was a better fit, WSMV resistance was evaluated for F₂:₃ families generated from resistant F₂ plants in both crosses. Approximately two thirds of the F₂:₃ families in each cross showed segregation for WSMV resistance, suggesting that the dominant-suppression epistasis model better explained the WSMV resistance in KS06HW79. This model was also supported by two KS06HW79-derived doubled haploid populations, which had a segregation ratio of 1 resistant : 3 susceptible. Therefore, the WSMV resistance in KS06HW79 is likely controlled by two dominant genes, one of which is a suppressor.

Estilos ABNT, Harvard, Vancouver, APA, etc.

38

Ma'arup, Rohayu. "The use of genetic diversity from emmer wheat to improve bread wheat". Thesis, The University of Sydney, 2016. http://hdl.handle.net/2123/16634.

Texto completo da fonte

Resumo:

Drought can be defined by Cambridge Dictionary as long period with little or no rain. Australia is the seventh largest wheat producer in the world, but it is the driest inhabited continent from the viewpoint of continental rainfall and streamflow. So, genetic improvement through crossing high-yielding cultivars of bread wheat with cultivated emmer wheats (had gone through early screening), subsequently backcrossing with bread wheat to increase bread wheat characteristics and producing doubled haploid (DH) from BC1F1 is one possible solution for increasing the yield stability of wheat in drought prone areas. The key point of this research study was to evaluate physiological and agronomic traits among the DH lines in optimum conditions for them to fully express their highest potential in 2013. Subsequently, selection was made among the DH lines for two years of trials under irrigated and rainfed conditions (to mimic drought) in 2014-2015 to evaluate genotypes that use water efficiently under drought stress. The relationship of physiology, phenology, and yield components in high water use efficiency genotypes revealed aspects of adaptation in northwestern NSW. The comparisons of bread wheat parents and their respective progenies (DH lines) were explored and diverse responses to soil water stress were observed. Biplot genotype main effect plus genotype by environment interaction (G+GE) of the multi-environment trials (METs) identified ideal genotypes that are stable cultivars across environment. These findings were also strengthened with GWAS analysis that revealed marker trait associations (MTAs) in water deficit conditions were not observed under the irrigated environments. Such lines would allow farmers to maintain income during drought years, as well as increase their income during wet years. The outcomes from this study should be worthwhile to the wheat industries in Australia and India, as some of domesticated bread wheat parents used were commercial cultivars in India.

Estilos ABNT, Harvard, Vancouver, APA, etc.

39

Morrison, Elizabeth. "The contribution of Australian wheat and wheat products essential trace mineral intake". Thesis, Queensland University of Technology, 1996. https://eprints.qut.edu.au/36731/1/36731_Morrison_1996.pdf.

Texto completo da fonte

Resumo:

Nutrition authorities' current recommendations include an increased consumption of whole grain cereal products, including wheat products, in order to increase consumption levels of dietary .fibre. However, the essential trace mineral contribution of such products tends to be underestimated. The trace mineral data for Australian wheat and wheat products, moreover, tends to be lacking or out-of-date. Consequently, a survey was conducted to obtain information on the nutritional value of wheat and wheat products with regard to trace minerals. Wheat grain samples were procured from around Australia, over two seasons in most cases. A method was developed utilising a microwave digestion procedure and inductively-coupled plasma atomic emission spectroscopy (ICP-AES) to analyse these samples for the following minerals (mean result of 233 samples in parenthesis): magnesium (1160mg/kg), zinc (18mg/kg), iron (30mg/kg), manganese (33mg/kg), copper (3.2mg/kg), nickel (0.30mg/kg), chromium (0.04mg/kg), cobalt (0.03mg/kg), cadmium (less than detection limit) and aluminium (3.7mg/kg). Mineral content was, generally, strongly correlated (positively) with protein content. Significant geographical and seasonal variations in the mineral content of wheat grain were identified. A number of wheat products were also analysed as above. An assessment of the contribution of wheat and wheat products to the mineral intake of a general adult Australian population was explored and concluded to be significant.

Estilos ABNT, Harvard, Vancouver, APA, etc.

40

Selvatico, Elisa. "A biochemical approach to study wheat products digestibility and wheat allergens degradation". Doctoral thesis, Università degli studi di Padova, 2010. http://hdl.handle.net/11577/3422245.

Texto completo da fonte

Resumo:

This thesis is focused on wheat digestibility, particularly referring to proteins, starch and fibre nutrients, which can plays a crucial role in several fields as in food allergic reactions, glycemic index assessment and in the fibre degradation. Wheat is one of the most important crops in the world, used to make a vast range of food products, such as bread, pasta and cakes. Allergic reactions to food, including wheat products, are becoming more common in Western countries affecting up to 2% of the adult population and 6% of children (Sotkovsky et al., 2008). The stability of proteins to the gastro-intestinal digestion process after heat treatment may contribute to their allergenic potential. It is thought that resistance to digestion plays an important role in the development of sensitisation, and it is postulated that resistance to gastric conditions (low pH and pepsinolysis) may have a significant impact on the solubility and allergenic potential of food proteins. Indeed, both intact proteins and digested polypeptides have the potential to elicit an allergic reaction. In order to better understand how chemical and biochemical changes induced by food processing (such as cooking) affect digestibility of wheat flour proteins, one dimensional (1D) and two-dimensional electrophoresis (2-DE) digestion maps of heated and unheated flour have been produced. Experiments were carried out using an in vitro static system with an additional ‘chewing’ step including human salivary amylase, in order to study oral degradation of wheat flour proteins. Afterwards, an in vitro dynamic model of digestion has been performed to gain a more reliable comprehension on protein degradation. Besides, as known, starch is the main constituent in cereal food and it influences the rate and the extent of digestion and, consequently, its nutritional and health properties. Foods having a low glycemic index have been suggested from FAO/WHO organisations (1998) since it promotes the slow release of glucose in the body. This work involved also the study of three types of pasta which were subjected to in vitro and in vivo digestions in order to assess their glycemic index. Finally, another crucial nutrient component in wheat is represented by arabinoxylans (AX) which are hemicellulose belonging to the fibre group. This fibre have been described as resistant to gastrointestinal digestion, since it is usually degraded in the colon tract, by macrobiota. However in vitro simulated digestions of arabinoxylans, extracted from wheat dough, were performed, and the effect on arabinose substitution level was investigated. Results mainly showed a reduced protein degradation in heated flour, suggesting that heat treatment can modify protein susceptibility to digestion. Results concerning the glycemic index study gave evidence that the wheat genotype can affect the rate of starch hydrolysis due to some nutrients, as proteins, which may vary among wheat varieties. Finally, concerning the arabinoxylans digestions, interesting findings showed that enzymes and surfactants and either the acid gastric pH, were able to affect AX region IR spectra.
Il lavoro sviluppato in questa tesi riguarda la digeribilità dei nutritivi del frumento, con particolare riferimento a proteine, amido e fibra. La digestione dei nutritivi gioca un ruolo chiave nelle reazioni allergiche agli alimenti, nella valutazione dell’indice glicemico e infine nella degradazione della fibra. Il frumento è una tra le più importanti produzioni cerealicole mondiali e viene utilizzato per la produzione di svariati prodotti: pane, pasta, dolci. Le reazioni allergiche agli alimenti, incluse quelle indotte dal frumento, stanno diventando sempre piu’ diffuse nei paesi occidentali, colpendo circa il 2% degli adulti e il 6% dei bambini (Sotkovsky et al., 2008). Tra i fattori che contribuiscono al potenziale allergenico di un alimento si deve considerare la stabilità delle proteine in seguito al processo digestivo e di cottura. Infatti è noto che la resistenza degli allergeni al trattamento di digestione è tra i parametri coinvolti nello sviluppo della sensitizzazione individuale, e le condizioni ambientali gastriche possono influenzare la solubilità di potenziali allergeni. È altresi’ noto che proteine o polipeptidi non digeriti hanno la potenzialità di scaturire una reazione allergica. In questo lavoro è stato studiato l’effetto del trattamento termico e della digestione, in farine di frumento cotta e non, attraverso l’analisi di profili proteici 1D e di mappe bidimensionali 2D. Questi esperimenti sono stati effettuati utilizzando un sistema di digestione statico simulando la fase orale, gastrica e intestinale. Inoltre, successivamente, è stato messo a pun to un sistema di digestione dinamico, per lo studio della degradazione delle proteine in farina cotta. Inoltre, è noto che l’amido è il principale componente dei prodotti cerealicoli e ne influenza le proprietà salutistiche nutrizionali. Alimenti con basso indice glicemico sono stati suggeriti dalle organizzazioni FAO/WHO. Questo lavoro ha coinvolto l’utilizzo di tre varietà di pasta, ove, esperimenti di digeribilità dell’amido in vitro e in vivo, hanno permesso di fornire una valutazione del loro indice glicemico. Infine, componenti della fibra in farine di frumento sono stati studiati attraverso la messa a punto di un sistema di digestione in vitro, per valutare l’effetto dell’ambiente gastro-intestinale sugli arabinoxilani estratti da impasti di farina. I risultati mostrano come il trattamento termico della farina di frumento modifichi la degradazione degli allergeni durante la digestione gastro-intestinale in vitro. Inoltre, lo studio delle tre varietà di pasta dimostra differenze significative nei valori di indice glicemico, imputabili al genotipo. Infine dalla digestione degli arabinoxilani, i risultati riportano sorprendentemente un effetto della digestione gastrica e intestinale, sulla parziale midificazione di queste fibre.

Estilos ABNT, Harvard, Vancouver, APA, etc.

41

Lobb, Alexandra E. "Two studies of the Australian Wheat Board : a traditional price discrimination model, and the privatisation process and pricing behaviour of a risk averse firm". University of Western Australia. School of Agricultural and Resource Economics, 2003. http://theses.library.uwa.edu.au/adt-WU2004.0071.

Texto completo da fonte

Resumo:

This thesis is motivated by the impacts of contemporary political and economic issues such as microeconomic reform and regulatory control on the Australian wheat industry. Firstly, the suggestion of whether the AWB (International) Ltd commands market power and secondly, that the objectives of the AWB Ltd have changed since semi-privatisation of the Australian Wheat Board under the Wheat Marketing Act, 1989. The AWB (International) Ltd’s ability to price discriminate is a key component to the retention of the single desk regulatory arrangement for the export of Australian wheat. Due to data restrictions the market power of the AWB (International) Ltd has not been determined within this thesis. To complement this traditional approach, a more novel proposal is developed to determine the effect of microeconomic reform on the Australian wheat industry. Conceptualising the change of the AWB Ltd’s objectives as a shift from revenue maximization to profit maximization, this study examines the impact of such a change on the pricing policies of a multi- market price-setting firm. More specifically, this study investigates, for two hypothetical objective functions, a risk averse firm’s price-setting behaviour in an “overseas” and a “domestic” market, given differing costs of supply, uncertain demand functions and differing price elasticities of demand in each market. The aim is to generate empirically testable hypotheses relating to the impact of a change of objectives on pricing behaviour.

Estilos ABNT, Harvard, Vancouver, APA, etc.

42

Khan, Imtiaz Ahmed. "Utilisation of molecular markers in the selection and characterisation of wheat-alien recombiant chromosomes". Title page, contents and summary only, 1996. http://web4.library.adelaide.edu.au/theses/09PH/09phk451.pdf.

Texto completo da fonte

Resumo:

Bibliography: leaves 137-163. his is a comprehensive study of induced homoeologous recombination along most of the complete genetic length of two homoeologous chromosomes in the Triticeae (7A of common wheat and 7Ai of Agropyron intermedium), using co-dominant DNA markers. Chromosome 7Ai was chosen as a model alien chromosome because is has been reported to carry agronomically important genes conferring resistance to stem rust and barley yellow dwarf virus on its short and long arms, respectively.

Estilos ABNT, Harvard, Vancouver, APA, etc.

43

Van, Zyl Rosetta Andrews. "Elucidation of possible virulence factors present in Russian wheat aphid (Diuraphis noxia) biotypes' saliva". Diss., Pretoria : [s.n.], 2007. http://upetd.up.ac.za/thesis/available/etd-04222008-075741/.

Texto completo da fonte

Estilos ABNT, Harvard, Vancouver, APA, etc.

44

Filbert, Seth Alan. "Comparison of drought tolerance among winter wheat hybrids and their parents using a comprehensive screening method". Thesis, Kansas State University, 2017. http://hdl.handle.net/2097/38215.

Texto completo da fonte

Resumo:

Master of Science
Department of Agronomy
Allan K. Fritz
Drought is known to be one of the most limiting abiotic stresses for wheat (Triticum aestivum L.) production, not only in the Midwest, but throughout the world. It is a complex issue and one that is difficult to screen for when breeding for new varieties. Hybrid wheat is one possible tool for breeders to use in order to make genetic gains towards better tolerance. The effectiveness of hybrid wheat as a tool to address regular periods of drought is a topic of continual discussion. The purpose of this study was to perform a comprehensive screening for drought tolerance comparing two different experimental hybrid entries to their parents. The hybrids were selected based on their good performance under drought in prior field trials. Plants were grown in PVC columns containing sensors that monitored growth media water content and matric potential. All plants were grown equally until heading. Drought treatment began 10 days post anthesis. Plants were observed until senescence/maturity. Several different agronomic characteristics were measured along with physiological traits that have previously been linked to drought tolerance. After completion of the screening, it was observed that the hybrid entries tended to fall between the two parents for a majority of the measurements. When comparing the hybrids to the parents overall, at least one parent outperformed its hybrid in every category. Parent line Parent B was one of the highest ranking genotypes for all measurements. Different drought mechanisms were observed across genotypes upon completion of the treatment. Further research is necessary to understand the hybrid response to drought when compared to pure line varieties.

Estilos ABNT, Harvard, Vancouver, APA, etc.

45

Kaehne, Ian D. "Improving wheat by composite crosses based on `cornerstone' nuclear male sterility / Ian D. Kaehne". Adelaide, 1986. http://hdl.handle.net/2440/18530.

Texto completo da fonte

Resumo:

1 v.
Title page, contents and abstract only. The complete thesis in print form is available from the University Library.
Thesis (Ph.D.)--University of Adelaide, Dept. of Agronomy, Waite Agricultural Institute, 1986

Estilos ABNT, Harvard, Vancouver, APA, etc.

46

Hogg, Andrew Charles. "Puroindolines their control over wheat grain hardness and influence on milling and bread baking traits /". Thesis, Montana State University, 2004. http://etd.lib.montana.edu/etd/2004/hogg/HoggA04.pdf.

Texto completo da fonte

Resumo:

Wheat grain is sold based upon several physiochemical characteristics, one of the most important being grain texture. Grain texture in wheat directly affects many end use qualities such as milling yield, break flour yield, and starch damage. The Hardness (Ha) locus located on the short arm of chromosome 5D is known to control grain hardness in wheat. This locus contains the puroindoline a (pina) and puroindoline b (pinb) genes. All wheats to date that have mutations in pina or pinb are hard textured, while wheats possessing both the 'soft type' pina-D1a and pinb-D1a sequences are soft. Furthermore, it has been shown that complementation of the pinb-D1b mutation in hard spring wheat can restore a soft phenotype. Here, the first objective was to identify and characterize the effect the puroindolines have on grain texture independently and together. The second objective was to determine which milling bread baking characteristics are affected by the seed specific over-expression of puroindolines. To accomplish both of these objectives a hard red spring wheat, possessing the pinb-D1b mutation, was transformed with 'soft type' pina and pinb, creating transgenic isolines that have added pina, pinb, or pina and pinb. Northern blot analysis of developing control and transgenic lines indicated that grain hardness differences were correlated with the timing of the expression of the native and transgenically added puroindolines. The addition of PINA decreased grain hardness less than the reduction seen with added PINB. Friabilin abundance was correlated with the presence of both 'soft type' PINA and PINB and did not correlate well with total puroindoline abundance. Selected T3 lines were grown in a field trial with two replications under dry and irrigated field conditions. Harvested grain was then milled and baked. Lines transformed with the puroindolines exhibited decreased total flour yields and increased break flour yields, yielding flour with lower protein and ash content. Decreases in loaf volume, mixograph absorption, and crumb grain scores were also observed in transgenic lines. These results demonstrate that the puroindolines can be used to profoundly influence grain hardness and a variety of milling and bread baking traits in wheat.

Estilos ABNT, Harvard, Vancouver, APA, etc.

47

Abdelkader, Amal Fadl. "Salt stress in wheat (Triticum aestivum) and its impact on plastid development /". Göteborg : Göteborg University, 2007. http://www.loc.gov/catdir/toc/fy0714/2007423862.html.

Texto completo da fonte

Estilos ABNT, Harvard, Vancouver, APA, etc.

48

Campbell, Jackie Bridget. "Increasing wheat hardness locus functionality by increasing puroindoline copy number and introduction of novel alleles". Thesis, Montana State University, 2007. http://etd.lib.montana.edu/etd/2007/campbell/CampbellJ0507.pdf.

Texto completo da fonte

Estilos ABNT, Harvard, Vancouver, APA, etc.

49

Tonkin, Rebecca Elizabeth. "The influence of seeding density and environmental factors on grain quality of main stems and tillers of wheat in South Australia (with special reference to prime hard quality wheat) : a thesis submitted for the degree of Doctor of Philosophy, School of Earth and Environmental Sciences, University of Adelaide /". Title page, table of contents and abstract only, 2004. http://web4.library.adelaide.edu.au/theses/09PH/09pht6654.pdf.

Texto completo da fonte

Resumo:

Thesis (Ph.D.)--University of Adelaide, School of Earth and Environmental Sciences, Discipline of Soil and Land Systems, 2004.
"November 2004" Includes bibliographical references (leaves 182-189). Also available online.

Estilos ABNT, Harvard, Vancouver, APA, etc.

50

He, Jiajing. "An economic analysis of wheat variety selection in Kansas, 1990-2016". Thesis, Kansas State University, 2017. http://hdl.handle.net/2097/38187.

Texto completo da fonte

Resumo:

Master of Science
Department of Agricultural Economics
Andrew P. Barkley
From 1990 to 2016, the Kansas wheat varieties with milling and baking quality rated as “Less Desirable” accounted for 22% of all wheat acres planted, compared with 36% during the period 1974 to 1993. Thus, wheat producers have selected wheat varieties with lower end-use quality over time. Regression analysis was used to identify and quantify the determinants of planted wheat varieties in Kansas over the time period 1990 to 2016. The results show that Kansas wheat producers make variety decisions primarily based on relative yield and previously planted varieties. Wheat producers also consider the end-use qualities on test weight and milling and baking quality. There were more varieties planted in 1990-2016 than during the 1974-1993 period, and producers have planted with a greater emphasis on yield than other production characteristics.

Estilos ABNT, Harvard, Vancouver, APA, etc.

Oferecemos descontos em todos os planos premium para autores cujas obras estão incluídas em seleções literárias temáticas. Contate-nos para obter um código promocional único!