Teses / dissertações sobre o tema "Wheat Effect of temperature on"

"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.

Climate change is affecting UK agriculture, and research is needed to prepare crops for the future. Wheat is the UK’s most important crop, and needs to be protected from losses caused by disease. While direct effect of the environment on pathogen spread is often reported, effect of the environment on host defence is not. Many wheat resistance genes are temperature sensitive and these were used as a starting point to investigate defence temperature sensitivity in wheat starting with yellow rust resistance gene Yr36, previously shown to be temperature-sensitive. The effect of temperature on resistance was shown to be independent of Yr36 in breeding line UC1041, and was more likely to be due to a previously-uncharacterised background temperature sensitivity. These results suggest that temperature changes, rather than thresholds, might influence some disease resistance mechanisms. Understanding this phenomenon could enable the breeding of more stable defence in crops. In order to gain further insight into how temperature changes influence resistance, plants were grown under different thermoperiods and challenged with different types of pathogens; Results showed that resistance to multiple pathogens in one cultivar Claire was enhanced under variable temperatures, compared to constant temperatures. Taken together, the research presented revealed that defence temperature sensitivity in plants is much more complex than previously thought, considering that both temperature changes and different thermoperiods can influence aspects of wheat defence. To ascertain which research approaches will be most valuable in preparing for climate change, the effect of the environment on take-all was also investigated. Vulnerable periods for wheat from the threat of take-all development were identified by analysing historical datasets, and controlled environment experiments. Results showed a relationship between initial post-sowing temperatures and spring take-all levels in 2nd 3rd or 4th winter wheats, depending on the location. The work on yellow rust resistance and take-all both identify vulnerable periods for wheat caused by the environment, be it weakening of host defence responses, or increased threat from disease pressure. Further characterisation and understanding of vulnerable periods will be essential to control disease outbreaks under an increasingly unstable climate.

Doctor of Philosophy<br>Department of Agronomy<br>P. V. Vara Prasad<br>Increased ambient temperature and soil salinity seriously affect the productivity of wheat (Triticum aestivum L.) which is an important cereal second to rice as the main human food crop. However, wheat plant is most susceptible to high temperatures and salinity at booting and flowering stages. Several studies have documented the effects of individual stress like salinity and high temperature stress on wheat, nonetheless little is known about effects of combined salinity and high temperature at critical growth stages. Therefore, the objectives of this research were (i) to screen winter wheat germplasm for salinity tolerance at the germination stages and to determine seedling growth traits associated with salinity tolerance, (ii) to evaluate the independent and combined effects of high temperature and salinity on winter wheat genotypes at the booting stages through growth, physiological, biochemical, and yield traits, and (iii) to evaluate the independent and combined effects of high temperature and salinity on winter wheat genotypes at the flowering stages through growth, physiological, biochemical, and yield traits. In the first experiment, 292 winter wheat genotypes (winter wheat germplasm) was screened for salinity stress at germination stage under controlled environments. The seeds were subjected to three levels of salinity, 0, 60, and 120 mM NaCl to quantify the effects of salinity on seed germination and seedling growth. In the second experiment, controlled environment study was conducted to quantity the independent and combined high temperature and salinity stress effects on growth, physiological, biochemical, and yield traits of twelve winter wheat genotypes during booting stage. Plants were grown at 20/15 °C (daytime maximum/nighttime minimum) temperature with 16 h photoperiod. At booting stages, the plants were exposed to optimum (20/15 °C) or high temperature (35/20 °C) and without (0 mM NaCl) and with (60, and 120 mM) NaCl. In the third experiment, plants were exposed to optimum or high temperature and with and without NaCl levels at flowering stages. The temperature regime and salinity levels were same as experiment II. The duration of stress was 10 d and after the stress period the plants were brought to optimum temperature and irrigated with normal water (0 mM NaCl). The results indicated that, at 120 mM NaCl, the final germination percentage was decreased and the mean daily germination was delayed. Irrespective of the genotype, salinity stress significantly decreased the shoot and root length; seedling dry matter production, and seedling vigor. Based on the seedling vigor index, the genotype GAGE, OK04507, MTS0531, TASCOSA, ENDURANCE and GUYMON, were found to be most tolerant and CO04W320, 2174-05, CARSON, OK1070275, TX02A0252 and TX04M410211 were the most susceptible to salinity at germination stage. Combined stresses of high temperature and salinity decreased photosynthetic rate and grain yields. Based on grain yield, the genotype TASCOSA was found to be most tolerant (64 % decrease) to combined stresses, and AVALANCHE was the most susceptible to combined stresses (75 % decrease) at booting stages. Similarly, at flowering stage, TX04M410211 had greater tolerance to combined stresses (65 % decline) as compared to GAGE (83 % decline). In both experiments, tolerance was associated with higher spikelet number and seed set. In conclusion, there is genetic variability among winter wheat genotypes that can be used in breeding programs to improve winter wheat yield under combined high temperature and salinity stress conditions.

Doctor of Philosophy<br>Department of Agronomy<br>P.V. Vara Prasad<br>High temperature (HT) and drought are detrimental to crop productivity, but there is limited variability for these traits among wheat ([italics]Triticum aestivum[end italics] L.) cultivars. Five [italics]Aegilops[end italics] species were screened to identify HT (52 accessions) and drought (31 accessions) tolerant species/accessions and ascertaining traits associated with tolerance. Four synthetic wheats were studied to quantify independent and combined effects of HT and drought. [italics]Aegilops[end italics] species were grown at 25/19°C day/night and 18 h photoperiod. At anthesis, HT was imposed by transferring plants to growth chambers set at 36/30°C, whereas in another experiment, drought was imposed by withholding irrigation. Synthetic wheats were grown at 21/15°C day/night and 18 h photoperiod. At anthesis or 21 d after anthesis, plants were exposed to optimum condition (irrigation + 21/15°C), HT (irrigation + 36/30°C), drought (withhold irrigation + 21/15°C), and combined stress (withhold irrigation + 36/30°C). Stresses were imposed for 16 d. High temperature and drought stress significantly decreased chlorophyll, grain number, individual grain weight, and grain yield of [italics]Aegilops[end italics] species (≥ 25%). Based on a decrease in grain yield, [italics]A. speltoides[end italics] and [italics]A. geniculata[end italics] were most tolerant (~ 61% decline), and [italics]A. longissima[end italics] was highly susceptible to HT stress (84% decline). Similarly, [italics]A. geniculata[end italics] had greater tolerance to drought (48% decline) as compared to other species (≥ 73% decline). Tolerance was associated with higher grains spike [superscript]-1 and/or heavier grains. Within [italics]A. speltoides[end italics], accession TA 2348 was most tolerant to HT with 13.5% yield decline and a heat susceptibility index (HSI) 0.23. Among [italics]A. geniculata[end italics], TA 2899 and TA 1819 were moderately tolerant to HT with an HSI 0.80. TA 10437 of [italics]A. geniculata[end italics] was the most drought tolerant accession with 7% yield decline and drought susceptibility index 0.14. Irrespective of the time of stress, HT, drought, and combined stress decreased both individual grain weight and grain yield of synthetic wheats by ≥ 37%, 26%, and 50%, respectively. These studies suggest a presence of genetic variability among [italics]Aegilops[end italics] species that can be utilized in breeding wheat for HT and drought tolerance at anthesis; and combined stress of drought and high temperature on synthetic wheats are hypo-additive in nature.

Doctor of Philosophy<br>Department of Agronomy<br>P. V. Vara Prasad<br>Drought and high temperature are major detriments to global wheat production. Wheat varies in its susceptibility to drought and high temperature stress. Three experiments were performed to address the challenges of drought and high temperature stress in wheat. The first experiment consisted of 256 genotypes of spring wheat and 301 genotypes of winter wheat, field screened for yield traits related to drought tolerance, in irrigated and dryland experiments. The experimental designs for the first experiment were both augmented incomplete block designs with one-way or row-column blocking. This experiment was performed at the Ashland Bottom Research Farm, south of Manhattan, KS, between 2011-2013. From this experiment, three conclusions were made: wheat genotypes vary widely in their responses between dryland and irrigated treatments and this variation can be used in future experiments or breeding tolerant genotypes. The number of seeds per unit of area, total biomass per unit area, and the average weight of one thousand seeds, were the best yield traits for predicting yield in both irrigated and dryland environments. Twenty genotypes were selected for future research based on their susceptibility or tolerance to drought. The second experiment was performed in the greenhouse facilities to observe the source-sink relationship of spring wheat genotype Seri 82 under drought and defoliation. The experiment was a randomized complete block design with a split-plot treatment arrangement. Post-anthesis cessation of watering and defoliation were the treatments. Both water stress and defoliation affected seed yield and total biomass. The major effect of post-anthesis water stress was a decrease in single seed weight. Defoliation affected the source-sink relationship by reducing the source strength of the leaves. This caused the stem to contribute more to overall yield. The defoliation also caused the remaining leaves to compensate for the removed leaves. The final experiment evaluated the changes in seed-filling rate and duration of three winter wheat genotypes during high temperature stress. High temperature stress reduced the duration of seed fill and increased the rate, differently in each genotype. Higher yields in the winter wheat growing regions, susceptible to post-anthesis high temperature stress, may be possible through selection of cultivars with faster seed-filling rates and/or duration of seed filling.

Human induced climate change is predicted to increase mean surface air temperature by 2 to 4 degrees C with significant drying in some regions by the end of this century which will affect wheat production and billions of people who depend on the crop for their livelihood. Factorial pot experiments were conducted to compare the responses of GA-sensitive and GA-insensitive reduced height (Rht) alleles in wheat for susceptibility to heat and drought stress during booting and anthesis. Grain yield, grain set (grains/spikelet) and grain quality of near-isogenic lines (NILs) were assessed following three day transfers to controlled environments imposing day temperatures from 20 to 40 degrees C at the Plant Environmental Laboratory (PEL), University of Reading, UK.

L'effet des traitements hydrothermiques et l’effet des arômes sur la structure de l'amidon et de ses propriétés physiques ont été étudiés. L’amidon de blé natif a été traité à 2 hydratations différentes (rapports eau-amidon: 50/50 et 80/20 g/g) et à 2 températures (65 et 85 °C) en présence d’ arômes (hexanoate d'éthyle et de 2-hexanone). Les échantillons fraîchement préparés ont été soumis à l’analyse calorimétrique (AED) et au dosage d’ arôme. Aucun complexe d'inclusion entre amidon et arôme n’a pu être détecté par AED cependant le résultat de l'analyse aromatique a prouvé qu'il y avait des interactions arôme-amidon. Les deux composés d’arôme (hexanoate d'éthyle et 2-hexanone) ont interagi avec l'amidon à des teneurs comparables. Les pertes d’arômes ont été trouvées les plus élevées dans les échantillons traités aux plus hautes hydratation et température . La perte d’arôme était principalement liée à l’évaporation lors des traitements hydrothermiques. Après les traitements hydrothermiques, les échantillons ont été lyophilisés ont montré une stabilité d’arôme à la lyophilisation. Les échantillons lyophilisés ont été soumis à diverses études: DSC (Tg), RVA, la taille des granules, XRD, WAXS, SAXS étude et de stockage. Les traitements hydrothermiques ont conduit à des échantillons avec des propriétés différentes. A haute hydratation, la température influence la taille des granules et des propriétés rhéologiques à la cuisson (pasting). Les échantillons chauffés à 65 °C présentaient des tailles de granules significativement plus importantes, une viscosité maximale (en RVA) inférieure à celles des échantillons chauffés à 85 °C mais de significative différence en % de cristallinité. A faible hydratation, la température de chauffage n’avait pas d’influencer significative sur la taille des granules, mais un effet significatif sur les propriétés rhéologiques à la cuisson, le degré de cristallinité et le profil SAXS. Les échantillons chauffés à 65°C avaient une viscosité maximale supérieure , un degré de cristallinité plus élevé et des pics SAXS plus importants qu’après un chauffage à 85 °C. La teneur résiduelle en arôme n'a eu aucune influence significative sur la structure, mais semble affecter les propriétés rhéologiques à la cuisson. En ce qui concerne l'étude à la conservations, les échantillons ont été stockés à 58 et 75% d'humidité relative et étudiés par analyse SPME, par extraction d’arôme et par AED pour un suivide relaxation d’enthalpie après de 2, 4 et 14 semaines de stockage. Les échantillons avaient une plus grande libération de l'arôme à 75% HR et l’hexanoate d’éthyle montré une plus grande libération de 2-hexanone. Les échantillons ont montré une augmentation de relaxation d'enthalpie de lors d'un stockage<br>The effect of hydrothermal treatments and flavours addition on starch structure and its physical properties were studied. Native wheat starch was treated at 2 different hydrations (water-starch ratios: 50/50 and 80/20 g w/w) and temperatures (65 and 85 °C) in the presence of flavours (ethyl hexanoate and 2-hexanone). The freshly prepared samples were subjected to DSC and flavour analysis. Flavour inclusion complex could not be detected by DSC, however the result of flavour analysis proved that there were flavours interactions with starch. Both ethyl hexanoate and 2-hexanone interacted with starch at similar rates. The highest flavour loss was found in the samples at high hydration and heated at 85 °C. The loss of flavour was mainly due to vaporisation during hydrothermal treatments. After hydrothermal treatments, the samples subjected to freeze-drying and they showed flavour stability upon freeze-drying. The freeze-dried samples were subjected to various studies: DSC (Tg), RVA, granule size, XRD, WAXS, SAXS and storage study. The hydrothermal treatments resulted in samples with different properties. At high hydration, temperature influenced granule size and pasting properties. The samples heated at 65 °C had significantly greater granule diameter, lower peak viscosity than samples heated at 85 °C and no significantly difference in % crystallinity. At low hydration, heating temperature had no significantly influence on granule diameter but significantly affected pasting properties, % crystallinity and SAXS profile. The samples heated at 65 °C had a greater peak viscosity, % crystallinity and greater peak on SAXS than after a treatment at 85 °C. The residual flavour contenthad no significant influence on structure but affected pasting properties. Regarding storage study, the samples were stored at 58 and 75 % RH and withdrawn for SPME, flavour residual extraction and DSC (enthalpy of relaxation) at 2, 4 and 14 weeks of storage. The samples had greater flavour release at 75% RH and ethyl hexanoate showed greater release than 2-hexanone. The samples showed increasing of enthalpy relaxation upon storage

Understanding and optimising the response of crops to climate change is of central importance in enhancing food security. A better understanding of how wheat genes influence traits is required to allow breeders to respond to socioeconomic issues. One aspect concerns adjusting flowering phenotypes to match predicted future climates. It is therefore crucial to understand this vernalisation process. The identification of the genes involved in the vernalisation response will be important for breeding crops able to cope with the effects of climate change. In this research project, bioinformatics methods were used to investigate the effects of decreasing temperatures and photoperiods on the transcriptomes of three different wheat varieties. The Affymetrix probe-sets associated with the known vernalisation genes and their expression profiles were characterised. Further analyses showed that gene expression varied significantly between wheat varieties. Genes involved in cold stress, cold acclimatisation, sugar / lipid metabolism and disease resistance have been identified. Probe-set Ta.17293.2.S1_at was a potential biomarker for vernalisation. In Arabidopsis, hundreds of vernalisation-related genes have been investigated. These were compaired to the probe-sets present on the Affymetrix wheat GeneChip® and a total of 184 putative wheat vernalisation-related genes were identified. As a step towards understanding the vernalisation process, a putative wheat network was constructed, of which several interactions were substantiated using co-expression correlation analysis. These results indicated that histone modification may be taking place, suggestive of an epigenetic switch. In addition, Artificial Neural Network inference was used to identify several novel candidate vernalisation genes. Of specific note was SPK1, a GTP binding protein. This was putatively associated with the expression of CDF2, a DOF-type transcription factor. In order to test the functions of CDF2 and SPK1, shRNAi constructs were developed to silence these genes in vivo. Transgenic wheat plants were analysed with T0 plants.

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.

There are about 40 durum wheat varieties registered in Turkey. Around 10 varieties are being commonly cultivated. Amanos 97, &Ccedil<br>esit 1252, Ege 88, Firat 93, Fuatbey 2000, Burgos, Kiziltan 91, Sari&ccedil<br>anak 98, Svevo and Zenith durum wheat varieties were used in this study. Semolina and pasta have been produced in an industrial plant under constant process conditions from these varieties. In general, pasta quality is determined by three main factors, the raw materials, the production recipe and the production process. In this study, the production recipe and the production process were fixed and only durum wheat varieties were variable. So, the effects coming from the production recipe and the production process on pasta quality were eliminated. Physical, chemical and sensory properties of these pasta were determined and the effect of different durum wheat varieties on pasta quality has been investigated to give a clear idea to the Turkish pasta industry about the most commonly grown durum wheat varieties in Turkey, hoping that Turkish pasta in domestic and international Markets will continue to grow with the help of clear understanding about the quality characteristics of the durum wheat they are using. v The important criteria of acceptability of pasta products is its cooking quality and cooking quality of pasta products is of importance to consumers and also to wheat producers, breeders and manufacturers. The pasta samples produced from Svevo, Zenith and Firat 93 varieties got the higher scores than others in pasta cooking quality while those produced from Sari&ccedil<br>anak 98, &Ccedil<br>esit 1252, Kiziltan 91, and Fuatbey 2000 durum wheat were evaluated as relatively low. The main reasons of cooking quality differences can be interpreted as a result of the difference in protein quantity and quality of the varieties. The bright yellow color of pasta products, rather than cooking behavior taste, is reported to be one of the most important considerations in assessing durum wheat quality. In this study, the pasta samples produced from Svevo, Zenith and Burgos varieties got the higher scores than others in pasta color (yellowness) while that produced from Firat 93 had the lowest yellow color. The main reasons of yellow color differences can be interpreted as a result of the differences in carotenoid pigments, lipoxygenase and peroxidase enzymes contents of the varieties.

Les gibbérellines (GAs) sont des phytohormones régulant divers aspects de la croissance et du développement de la plante en réponse aux signaux endogènes et exogènes. Au niveau moléculaire, les GAs stimulent la dégradation des protéines DELLA, répresseurs nucléaires de croissance. L’azote (N), macronutriment essentiel au développement de la plante, représente un des facteurs les plus limitant pour la productivité agricole. Le nitrate (NO3-), principale source de N pour les plantes cultivées, est une molécule soluble dont la disponibilité varie dans l’espace et le temps. Depuis la Révolution Verte des années 1960, l’application d’engrais azotés et l’utilisation de variétés de céréales semi-naines (altérées dans leurs réponses aux GAs) à forts rendements ont permis d’augmenter significativement la productivité agricole. Récemment, il a été rapporté que des transporteurs NO3 - appartenant à la famille des NPF (NITRATE TRANSPORTER 1/PEPTIDE TRANSPORTER FAMILY) étaient capables de transporter des GAs. Malgré les liens historiques et scientifiques établis entre les GAs et le NO3-, peu d’études se sont intéressées à l’effet du nitrate sur la biosynthèse, le transport et la signalisation GA chez les plantes. A l’aide d’approches génétiques, moléculaires et biochimiques réalisées chez Arabidopsis et le bl, ce travail de thèse démontre que le nitrate augmente la production et le transport acropète de GA12 (un intermédiaire de biosynthèse de GAs) et en conséquence, stimule la dégradation des répresseurs DELLAs. La diminution de l’abondance des DELLAs active la division cellulaire et donc la croissance de la plante. Par ailleurs, à l’aide de micro-greffes et de tests d’import de GAs réalisés dans des oocytes de Xenopus laevis, nous montrons que NPF2.12 et NPF2.13 facilitent le transport basipète de GA12 et du nitrate. Enfin, nous montrons que le transport acropète de GA12 est accru en réponse à une élévation de la température ambiante. Pris dans leur ensemble, ces résultats révèlent que la biosynthèse et le transport de GAs sont finement régulés en réponse à la disponibilité en nitrate et aux fluctuations de la température, permettant une croissance adaptée et optimale de la plante<br>The phytohormones gibberellins (GAs) regulate major aspects of plant growth and development in response to endogenous and exogenous signals. GAs promote growth by stimulating the degradation of nuclear growth repressing DELLA proteins. Nitrogen (N), a macronutrient essential for plant development, is one of the most limiting factors for agricultural productivity. Nitrate (NO3-) represents the main N source for cultivated plants but its availability fluctuates in both time and space due to its high solubility. Since the Green Revolution in the 1960’s, the use of N-fertilizers associated with high-yielding semi-dwarf cereal varieties, altered in GA responses, led to impressive yield increases. Recently, it has been reported that some NO 3 - transporters belonging to the NPF family (NITRATE TRANSPORTER 1/PEPTIDE TRANSPORTER FAMILY), were able to transport GAs. Despite these observations, the effect of nitrate on GA biosynthesis, transport and signaling pathway is still unknown. Using genetics, molecular and biochemical approaches performed in Arabidopsis and wheat, this thesis work demonstrates that nitrate activates GA biosynthesis and GA12 transport (an inactive GA precursor), and as a consequence, DELLA protein degradation. The reduction in DELLA abundance increases cell division rate and thus plant growth. Moreover, through micrograftings and GA import assays in Xenopus laevis oocytes, we show that NPF2.12 and NPF2.13 facilitate the basipetal transport of GA12 and nitrate. Finally, we show that GA12 transport is enhanced by a small elevation of the ambient temperature. Altogether, these results reveal that GA biosynthesis and transport are tightly regulated in response to nitrate availability and temperature changes, enabling adaptive and optimal growth of the plant

Thesis advisor: Richard McGowan<br>Subsidies have played a significant role in the production of agriculture during the 20 century. While the western world gradually phased out protectionist policies for industrialized sectors of the economy following World War II, agriculture continued to receive significant support from the state until efforts were made to establish more laissez-faire markets in the 1990’s by the World Trade Organization. This paper aims to judge the effectiveness of these policies on one program in particular: export credit guarantees. By examining the effects of credit guarantees on US wheat exports through panel data regressions, this paper hopes to provide evidence of the effectiveness of recent policy in creating egalitarian and free markets for agricultural commodities<br>Thesis (BA) — Boston College, 2011<br>Submitted to: Boston College. College of Arts and Sciences<br>Discipline: Economics Honors Program<br>Discipline: Economics

Forests affect climate by absorbing CO₂ but also by altering albedo, latent heat flux, and sensible heat flux. In this study we used the Community Earth System Model to assess the biophysical effect of North American temperate forests on climate and how this effect changes with location, tree type, and forest management. We calculated the change in annual temperature and energy balance associated with afforestation with either needle leaf evergreen trees (NET) or broadleaf deciduous trees (BDT) and between forests with high and low leaf-area indices (LAI). Afforestation from crops to forests resulted in lower albedo and higher sensible heat flux but no consistent difference in latent heat flux. Forests were consistently warmer than crops at high latitudes and colder at lower latitudes. In North America, the temperature response from afforestation shifted from warming to cooling between 34° N and 40° N for ground temperature and between 21° N and 25° N for near surface air temperature. NET tended to have lower albedo, higher sensible heat flux and warmer temperatures than BDT. The effect of tree PFT was larger than the effect of afforestation in the south and in the mid-Atlantic. Increasing LAI, a proxy for increased management intensity, caused a cooling effect in both tree types, but NET responded more strongly and albedo decreased while albedo increased for BDT. Our results show that forests' location, tree type, and management intensity can have nearly equal biophysical effects on temperature. A forest will have maximum biophysical cooling effect if it is in the south, composed of broadleaf PFT, and is managed to maximize leaf area index.<br>Master of Science

Worldwide production of wheat in 2007 was 787 million (IGC 2008). Due to its importance in the world commodity market, there has been much research into the potential problems of weather damage to wheat, particularly with reference to bread making. The current project aimed to address three major research areas. Firstly, the effects of heat treatment in relation to the nutritional value of weather damaged wheat were investigated. It appears that drying at 100°C may increase Coefficient of Apparent Digestibility of starch (CAD). Some flour samples that were heated to 100°C failed to demonstrate expected hydration properties that would normally be associated with increased digestibility. They also appear to maintain their crystalline order. Therefore, an increase in CAD is not necessarily related to changes in starch structure and is probably more likely due to modification of non-starch components such as protein. A hypothesis is discussed, that proteins may form a film that protects the starch until the protein is digested by endogenous chick proteases. The precise drying temperature is critical, as at 85°C, digestibility may be decreased, possibly due to crystalline perfection. Apparent Metabolisable Energy (AME) did not follow starch digestibility. Secondly, it was hypothesised that the Rapid Visco Analyser (RVA) may be able to quantify amylase activity and predict nutritional value of wheat samples. Interestingly, unexpectedly high levels of amylase were observed in some wheat samples. This activity remained despite two years in ambient storage and temperature treatment of up to 100°C. These high levels of amylase activity did not appear to affect CAD, presumably due to deactivation in the acidic conditions of the proventriculus. There were some highly significant relationships between in vivo parameters and in vitro RVA parameters, particularly between Peak Viscosity (with an amylase inhibitor) and Coefficient of Duodenal Digestibility or AME (P<O.OOI in both cases). This suggests there is potential for the RV A to indicate nutritional value. Lastly, the nutritional value of wheat after storage for up to four months was investigated. There was no significant difference in AME, CAD or FI.

An ultra-centrifugal mill was evaluated by determining the effect of mill configuration and seed conditioning on particle size distribution and quality of whole-wheat (WW) flour. Ultra-centrifugal mill configured with rotor speed of 12,000 rpm, screen aperture of 250 ?m, and seed conditioning moisture of 9% resulted in a fine WW flour where 82% of particles were <150 ?m, starch damage was 5.9%, and flour temperature was below 35?C. The single-pass and multi-pass milling systems were evaluated by comparing the quality of WW flour and the subsequent WW spaghetti they produced. Two single-pass mill configurations for an ultra-centrifugal mill were used (fine grind: 15,000 rpm with 250 ?m mill screen aperture and coarse grind: 12,000 rpm with 1,000 ?m mill screen aperture) to direct grind durum grain or to regrind millstreams from roller milling to make WW flour and WW spaghetti. Particle size, starch damage, and pasting properties were similar for direct fine grind WW flour and multi-pass reconstituted flour:fine bran blend and for direct coarse grind WW flour and multi-pass reconstituted semolina:coarse bran blend. Semolna:fine bran or semolina:coarse bran blends made spaghetti with high cooked firmness, while spaghetti made from direct coarse grind or from semolina:fine bran or coarse bran blends had low cooking loss. Nineteen durum wheat (Triticum turgidum L. var. durum) cultivars and 17 breeding lines grown at 19 environments in North Dakota were evaluated for physical and cooking qualities of WW and traditional spaghetti. Of the 36 genotypes evaluated, 21 and 3 genotypes produced good and poor qualities of WW and traditional spaghettis, respectively, while other 12 genotypes produced good traditional spaghetti but produced poor quality WW spaghetti. These data indicate the need to select genotypes specifically for their WW pasta quality. Raw material traits (grain, semolina and WW flour characteristics) were evaluated to identify raw material traits capable of predicting WW spaghetti quality. Grain protein content had significant positive correlation with cooking quality of WW spaghetti. Stepwise multiple regressions showed grain protein content and mixogram break-time and wet gluten were the predominant characteristics in predicting cooking quality of WW spaghetti.

Bibliography: leaves 234-256. Genetic studies of tolerance of durum wheat (Triticum turgidum L. var durum) to high concentrations of boron (B) were undertaken to identify genetic variation in response to B, the mode of gene action, number of genes and chromosomal locations of genes controlling tolerance. Results demonstrated that tolerance to B is under simple genetic control as observed in bread wheat. High levels of tolerance can be transferred into sensitive commercial varieties via backcrossing and selection can be performed during seedling growth at early generations.

Doctor of Philosophy<br>Department of Agronomy<br>P. V. Vara Prasad<br>High temperature is a major environmental factor that limits wheat productivity. Climate models predict greater increases in night temperature than in day temperature. The objectives of this research were to quantify the effects of high day and night temperatures during anthesis on physiological (chlorophyll fluorescence, chlorophyll concentration, leaf level photosynthesis, lipid peroxidation and membrane damage), biochemical (reactive oxygen species [ROS] concentration and antioxidant capacity in leaves) and yield traits and membrane lipid profile and identify the lipids that are associated with high temperature response in wheat. Winter wheat genotypes Ventnor (heat tolerant) and Karl 92 (heat susceptible) were grown at optimum temperatures (25/15°C, maximum/minimum) until the onset of anthesis. Thereafter, plants were exposed to high night (HN, 25/24°C), high day (HD, 35/15°C), high day and night (HDN, 35/24°C) or optimum temperatures. Compared with optimum temperature, HN, HD and HDN increased ROS concentration, lipid peroxidation and membrane damage and decreased antioxidant capacity, photochemical efficiency, photosynthesis, seed set, grain number and grain yield. Impact of HN and HD was similar on all traits, when stress was imposed for seven days. High day and night temperatures resulted in significant changes in the amount of plastidic and extra-plastidic lipids and lipids with oxidized acyl chains (ox-lipids) in both genotypes. The decrease in lipid unsaturation levels of complex lipids at high temperatures was predominantly due to decrease in 18:3 fatty acid and increase in 18:1 and 16:0 fatty acids. We identified novel odd-numbered long-chain fatty acid-containing phospholipids, which were highly responsive to high temperature stress. Ventnor had higher amounts of sterol glycosides (SG) and lower amounts of ox-lipids at high temperatures than Karl 92; thus SGs and ox-lipids may be potential biomarkers for heat tolerance and susceptibility, respectively, in wheat. Co-occurring lipids, which are up-or-down-regulated together through time under high day and night temperatures formed groups, which were experiencing coordinated metabolism. These results suggest that high day and night temperatures during anthesis cause damage of a similar magnitude to wheat, if stress is imposed for a short term (seven days) and compositional changes in lipid profile in response to high temperature contribute to heat tolerance.

Planting dates are known to affect wheat yields. Previous research has shown that the optimum planting date in Yuma is December 15 to January 15. Wheat is sometimes sown later than this in the Yuma area, and earlier planting dates have not been tested. To test a wide range of planting dates, six varieties(Duraking, Havasu, Joaquin, Kronos, WB-Mead, and Yecora Rojo) were planted at two seeding rates (160 and 240 lbs/A) and six planting dates at the beginning of each month from November through April at the Yuma Valley Agricultural Center. Grain yield averaged 6517 (Nov 4), 6339 (Dec 6), 6096(Jan 4), 5712 (Feb 1), 4962(Mar 1), and 3590(Apr 5). The late-flowering varieties performed relatively better at the earlier planting dates. Seeding rates of 160 and 240 lbs/A had no measureable effect on yield overall.

Tese (doutorado) - Universidade Federal de Santa Catarina, Centro de Ciências Agrárias, Programa de Pós-Graduação em Ciência dos Alimentos, Florianópolis, 2017.<br>Made available in DSpace on 2017-08-01T04:15:06Z (GMT). No. of bitstreams: 1 348596.pdf: 2480210 bytes, checksum: 254174b55dd985fe8496c68ad4b4058e (MD5) Previous issue date: 2017<br>Abstract : Wheat is worldwide utilized as a food grain since the late Stone Age and cultivated since 5000 b.c.. From wheat flour a diversity of baked products can be made because the unique ability of form a viscoelastic dough, characteristic controlled mainly by gluten proteins. Gluten proteins are among the most complex protein networks in nature due to numerous different components and distinct size, and due to variability caused by genotype, growing conditions and technological processes. On the other hand, Celiac disease (CD), the most common wheat intolerance worldwide, is a complex immune-mediated disease trigged by gluten ingestion. Assume a strictly gluten-free diet represents the only effective medical treatment for CD patients. On the other hand, treatments that involve time, temperature and pressure can change protein structure. The heat treatments can affect technological properties and reduce the allergenicity to varying extents in wheat flours and breads. Also, nowadays, there is growing interest in ancient wheats, such as einkorn, emmer, Khorasan (Kamut), faro, and spelt because might these varieties could be nontoxic to celiac and helthier than modern wheat. The aim of this project was to study the effect of wheat treatment and the different varieties of wheat on the gluten proteins and the implications in the immune response in vitro. This work was divided in 3 parts. I ? Brazilian commercial wheat flour was subjected to to spray drying, oven heating, ultrasound and microwave radiation. Solubility, monomeric and polymeric proteins and glutenin and gliadin profile were analyzed. Also, digestibility and the amount of potential celiac disease immune stimulatory epitopes were measured with the R5 monoclonal antibody and G12 ELISA assays. Heat treatment leads to unfolding of peptide chains, changes in hydrophobicity and susceptibility to the action of proteolytic enzymes. The treatments affected solubility, and with exception of ultrasound, all treatment showed low solubility of polymercis and monomerics proteins. Also, treatments affected glutenins and gliadins profile, the amount of the HMW-GS (High Molecular Weigh ? glutenin) decrease after spray-dry, oven and extrusion and the amount of the LMW-GS (Low Molecular Weigh ? glutenin) decrease too after spray-drying, microwave, oven and extrusion. Wheareas for gliadin, the amount of ?-gliadin increase after spra-drying and ultrasound treatments, and the amount of a/ß- gliadin decrease after all treatments, while the treatment to do not affected ?-gliadins amount. Also, digestibility decrease after spray-dryier and ultrasound. This changes with decrease of solubility and changes in profile of proteins is results of rearrange of proteins during the treatments, resulting in a higher complex structure. And, finally, the potential celiac disease immune stimulatory epitopes were measured, and showed lower amount after spray-drying treatment by R5 monoclonal antibody and lower amounts after spray-drying and microwave treatment by G12 ELISA test in relation to control flour. At last, even with the alteration on the gluten structure and complexicity, these changes do not allow to produce a safe product to celiacs, the amount of the potential celiac disease immune stimulatory epitopes still were too high. II ? Modern and ancients? wheat varieties are being tested against anti-Gliadin antibody. If aim to found a wheat nontoxic to celiacs, we tested pools of different wheats varieties, two of them with AA genome - T. monococcum ssp monococcum and T. urartu. Due agronomical caracteristic and comercial appeal, we used five T. turgidum wheat variety as follow: T. turgidum ssp durum (AABB), T. turgidum ssp polonicum (AABB), T. turgidum ssp turgidum (AABB) and T. turgidum ssp turanicum (AABB). All wheat flours were extracted, purified, separated using 2D gel eletrophoresis, stained with Comassie blue or were run a western blot with Gliadin antibody and Skeritt antibodies, and pictures of them were overlapping. All wheat varieties tested contained gluten proteins recognized by anti-gluten Skerritt and Gliadin antibodies related to T-cell stimulatory epitopes, at distinct levels. Einkorn and durum species tested here differ in toxicity depending on the sub-species. Eikorn tested showed higher immunogenicity that durum varaities. So, it is not safe for all celiacs to consume the wheat varieties tested, that include ancients? varieties. III - Additionally, this study verified if food products commercialized in Brazil were correctly labeled in relation to the presence or absence of gluten by using the ELISA R5 method. In relation to products sold in Brazil, the results show for the celiac population that companies are testing their food products to verify if labeling is correct to provide products that are safe and to accurately identify potential gluten levels. However, if 89% of gluten-free food products are correctly labeled, this means that 11% represent a risk for the health of the celiac population. To improve this amount, routine auditing is necessary to verify the correct labeling about gluten in food products and adopt good manufacturing practices. Brazil is becoming a global economic player, so it is important to be aligned with global legislation concerning gluten presence and ensure that the label can be trusted. This results in greater confidence in both the global market and consumers and represents one more step toward health maintenance for celiacs.<br><br>Introdução: O glúten é uma proteína encontrada nos grãos de trigo, centeio e cevada. Neste trabalho, considerar-se-á o trigo como a fonte de glúten, pelo fato desta matéria prima ser amplamente utilizada tecnologicamente no mundo, em pães, biscoitos, bolos e massas. Se, por um lado o consumo de pães é tido não somente como uma questão cultural, mas também religiosa através do mundo e do tempo, por outro lado, atualmente há discussões sobre o consumo de glúten. A adoção e indicação de dietas sem glúten, mesmo para quem não apresenta sintomas clínicos e fisiológicos de uma intolerância alimentar levou a Sociedade Brasileira de Alimentação e Nutrição a publicar um artigo sobre o posicionamento da mesma, esclarescendo que dietas sem glúten devem ser recomendadas apenas para indivíduos com alguma desordens relacionada ao glúten. Por outro lado, com esse debate, os casos de indivíduos que apresentam alguma disfunção ao ingerirem glúten, são mais facilmente identificados. Atualmente, o unico tratamento é a adoção de uma dieta sem gluten. Ainda hoje, o diagnóstico pode demorar, pois os sintomas podem ser diferentes de indivíduo para indivíduo, além disso, os sintomas se sobrepoem aos de outras doenças, o que leva médicos a investigarem outras doenças. Para facilitar o entendimento, diagnóstico e classificação, as desordens relacionadas ao glúten foram recentemente classificadas de acordo com a resposta em: autoimune, alérgica e de sensibilidade. Sendo que o presente trabalho é focado nas respostas autoumines provocadas pela ingestão de glúten, que são a doença celíaca, ataxia provocada pelo glúten e dermatite herpetiforme. A indentificação destas se dá por teste clínicos (sintomas), histológicos (danos no intestino), sorológicos (presença no soro dos anticorpos anti-gliadina, anti-endeomisio e anti- transglutaminase) e genéticos (presença dos genes DQ 2/8). Acredita-se que no Brasil dois milhões de indivíduos são celíacos ou possuem alguma desordem relacionada ao gluten. Como o único tratamento é a exclusão do glúten da dieta, acaba movimentado um mercado de produtos alimentícios sem glúten. No Brasil, o número de empresas de alimentos que comercilizam produtos sem glúten e o volume de vendas tem aumentando exponencialmente. Nos Estados Unidos, o mercado de produtos sem glúten movimentou 8,8 bilhões de dólares até 2014. Devido à importância econômica do trigo em nível nacional e mundial, fazem-se necessários mais estudos, não apenas em relação à doença celíaca, mas também em relação ao glúten de trigo e suas variedades, e como o tratamento térmico deste cereal, pode afetar ou influenciar na resposta imune de indivíduos com pré disposição genética. Além disso, surgem especulações sobre o consumo de trigo de diferentes variedades, as quais poderiam ser não ser tóxicas, umas vez que não passaram por tantos processos de hibridização e manipulação gênica como o trigo hexaplóide moderno. Objetivos: O principal objetivo deste trabalho foi estudar o efeito do tratamento térmico do trigo e as diferentes variedades de trigo sobre as proteínas do glúten e quais as implicações na resposta imune in vitro. Neste contexto, os seguintes objetivos específicos foram estabelecidos: Submeter farinha brasileira comercial aos tratamentos de extrusão, spray-dry, ultrassom, microondas e forneamento. Analisar as alterações em relação as características tecnológicas das proteínas que formam o glúten na farinha do trigo antes e após os tratamentos quanto à: solubilidade, proporção entre proteínas monoméricas e poliméricas, perfil de gliadinas e gluteninas. Analisar se houve aumento ou diminuição da digetibilidade, e se os tratamentos térmicos afetam a quantidade de epitopos estimuladores de células T em celíacos pelo teste de ELISA R5 e G12. Obter e analisar diferentes variedades de trigo sendo elas: Triticum monococcum ssp monococcum, Triticum urartu, Triticum turgidum ssp durum, Triticum turgidum ssp polonicum, Triticum turgidum ssp turgidum, Triticum turgidum ssp turanicum, Triticum aestivium ssp spelta. Analisar se houve diferença entre as variedades na quantidade de epitopos estimuladores de células T em celíacos in vitro, usando western blott e anticorpos comerciais específicos. Verificar se os produtos ?sem glúten? comercializados no Brasil estão corretamente rotulados.

Master of Science<br>Department of Entomology<br>James F. Campbell<br>Thomas W. Phillips<br>Knowing the factors that influence the distribution patterns, establishment and persistence of stored product insects aids in the development of a more effective pest management program in grain storage structures. This research focuses mainly on the insect communities of stored wheat and stored rice in two different geographical locations, their temporal relationships and the most important or abundant species within that community. Stored wheat was sampled for one season in Manhattan, KS and for rice stored in Beaumont, TX was sampled for two seasons. Hairy fungus beetle, Typhaea stercorea (Coleoptera: Mycetophagidae) was one of the most abundant species and was present in every bin of either wheat or rice and appeared to move into and out of the grain mass. In wheat bin, Indianmeal moth, Plodia interpunctella (Lepidoptera: Pyralidae) was a predominant species captured in the bin headspace, but was not frequently recovered in the grain mass. Headspace temperatures tended to be warmer than grain temperatures and outside temperatures. Other major insects recovered in wheat bin included the following groups or species: Anthicidae, Lathridiidae, Cryptolestes, foreign grain beetle Ahasverus advena (Coleoptera: Silvanidae), sawtoothed grain beetle Oryzaephilus surinamensis (Coleoptera: Silvanidae), red flour beetle Tribolium castaneum (Coleoptera: Tenebrionidae), smalleyed flour beetle (Coleoptera: Tenebrionoidea) and minute pirate bug Xylocoris favipes (Hemiptera: Anthocoridae). In rice bins, the predominate species were hairy fungus beetle, foreign grain beetle and Angoumois grain moth Sitotroga cerealella (Lepidoptera: Gelechiidae). Angoumois grain moth was one of the most abundant species in rice, and was captured in the headspace as well as below the grain surface. Rice bins varied considerably in the relative abundance of different species between bins within a season and between seasons. Foreign grain beetle and hairy fungus beetle were especially variable among bins. Two species of weevil (Coleoptera: Curculionidae) that are not grain pests, the sugar cane rootstock weevil, Apinocis deplanata and rice water weevil, Lissorhoptrus oryzophilus (Coleoptera: Curculionidae), were present in high numbers in rice bins from September-December 2009.

The present project aimed at measuring plant heavy metal uptake as a function of transpiration rates and dissolved heavy metal level in the soil solution. Two experiment was conducted separately in two season (Spring and Fall 2000). In these two experiments, young wheat plants ( Triticum aestivum) were irrigated with nine different solutions containing Cd and Zn. The study was conducted in two chambers where relative humidity was controlled to obtain two different levels of transpiration rates. Each control chambers contained 27 pots filled with sand and seeded with wheat plants, each nine triplicated pots receiving a different treatment: three Cd treatments with levels of 0.01, 0.10, and 0.50 mg/L; one Zn treatment with level of 25mg/L and four treatment combinations of Cd/Zn with levels of 0.01 Cd/25Zn, 0.10Cd/25ZN, 0.50Cd/25Zn and 0.50Cd/50Zn mg/L. The transpiration rate of the plants was monitored over a period of 30 days, measured from the emergence of the plants by weighing the pots daily. On day 15 and 30, three plants were removed from each pot, to weigh their dry matter production and to analyze their heavy metal uptake. (Abstract shortened by UMI.)

Copy of author's previously published work inserted. Bibliography: leaves 147-189. This project examines the uptake of mineral N from the subsoil after anthesis and its effect on grain protein concentration (GPC) of wheat. The overall objective is to examine the importance of subsoil mineral N and to investigate the ability of wheat to take up N from the subsoil late in the season under different conditions of N supply and soil water availability. Greenhouse experiments investigate the importance of subsoil mineral N availability on GPC of wheat and the factors that contribute to the effective utilisation of N. The recovery of N from subsoil, the effect of split N application on GPC and short term N uptake by the wheat at different rooting densities are also studied.

Master of Science<br>Department of Grain Science and Industry<br>Jon M. Faubion<br>Rebecca Miller<br>Water absorption tolerance is an important parameter in commercial bread production. Hard winter wheat (HWW) flours have shown different water absorption tolerance behaviors in routine wheat quality analysis. Flours with high water absorption tolerance allow broader variation in water addition without affecting optimum dough conditions. Although studies have demonstrated that genotype and environmental factors affect optimum water absorption, mixing time and dough strength, there is no research defining or quantifying water absorption tolerance behavior or explaining reasons and factors affecting such behavior and its correlation with end product quality. Using the mixograph®, this study identified high and low absorption tolerance behaviors in five HRW varieties (Jagger, Jagalene, Fuller, 2137 and Overley) grown in six locations (Finney, Labette, Republic, Thomas, Riley and Sumner Counties) in Kansas, during crop year 2009. Milling, wheat and flour quality tests, Solvent Retention Capacity (SRC), damaged starch, protein composition and identification, flour and starch particle size distribution and bread baking tests were conducted and analyzed. Jagger grown at Finney County possessed the largest water absorption tolerance range while the smallest range was observed for Fuller grown at Riley and Sumner Counties. A positive high correlation was observed between water absorption tolerance and the following parameters: protein content, kernel hardness, extractable polymeric proteins, unextractable polymeric proteins, gliadins and flour particle size (41-300 μm). SDS PAGE and proteomic analyses determined that γ-gliadins were present in a significantly higher concentration in the high tolerance sample suggesting that these proteins play a primary role in water absorption tolerance behavior. The five wheat varieties grown at locations with high and low water absorption tolerance were blended together by location and test baked at three different absorption levels. Loaf volume varied between flours but did not vary between different water levels. It is unclear if this was an effect of the differing protein contents of the blends, water tolerance or both. However, a negative effect on crumb grain characteristics was observed when lower water levels were used.

Nitrogen is essential to obtain high yields of winter wheat in south coastal British Columbia, which includes Vancouver Island and the lower Fraser Valley. An accurate recommendation for N application is required to keep input costs down for most economical returns and to limit environmental problems related to leaching of excess N. The questions are how much, when and which form of N should be applied to winter wheat. The general objective of this study is to improve our understanding of winter wheat growth and N uptake. This study monitors the soil N supply and characterizes the plant development, dry matter accumulation, and N uptake of winter wheat in South Coastal B.C.. Also, it compares the effectiveness of conventional and intensive crop N management and urea and ammonium nitrate sources of fertilizer N under intensive crop management. A series of field experiments was conducted in 1986-87 and 1987-88 with winter wheat to evaluate conventional and intensive N management in the area. Additionally, a N source study was carried out in the latter year to compare ammonium nitrate and urea. Soil N supply for winter wheat ranged from 52 to 151 kg N/ha through the two years of field experiments at five sites. Available N in the 0-50 cm soil depth varied from 10 to 100 kg N/ha through the growing season in the different treatments. An accurate estimate of N behavior involves N accumulation in the crop. During the early spring until harvest, the crop dry matter yield and N uptake patterns were plotted. The grain yields ranged from 4 to 9 t/ha for the conventional management (75 kg N/ha), and from 4 to 11 t/ha for the intensive crop management (I.CM. 225 kg N/ha) system. Between the conventional and I.CM., there was no significant difference in grain yield but there was in quality, specifically grain protein. Grain protein ranged from 8.2 to 9.7% for the conventional and from 10 to 13.7% for the I.CM. treatment. Also, there was no difference in grain yield or quality between ammonium nitrate and urea fertilized plots at final harvest. However, in the early stage at GS31, crop took up more N from ammonium nitrate (97 kg N/ha) than from urea (75 kg N/ha) and soil mineral N levels with urea were higher than with ammonium nitrate.<br>Land and Food Systems, Faculty of<br>Graduate