Nitrogen is one of the most important part of nutrition of winter wheat. However, if in the crop are weeds capable of using nitrogen more efficiently, the area-wide fertilization can make competitive ability higher for weed, after that there is a reduction in the yield of wheat. Example of weed with this ability is cleavers (Galium aparine). Possibility how we can eleiminate this weed ability is using precision placement of fertilizer under the crop row. The aim of this thesis is finding out of positive effects of precision placement of nitrogen fertilizer (calcium nitrate) in comparison with area-wide fertilization for reduction competitive ability of cleavers against wheat. The experiment was containerized and was run in a growth room with controlled conditions. Based of the experiment, it was found, that competition of cleavers was decreased by precision placement of fertilizer but growth of wheat was decreased too because of higher nitrate availability in the soil. This method of fertilization does not produce the expected effect for better wheat competitive ability.

Common wheat and spelled wheat are one of the most important agricultural crops. Their use is mainly in the food industry and also in the feed industry. There is a strong interest in the differentiation of the common wheat from the spelled wheat in the last tens of years. This trend is especially in the food industry because of the adulteration of the spelled flour. This dissertation was focused on the differentiation of the common wheat from the spelled wheat by using the microscopic methods and on the detection of variability in the gene for gamma wheat gliadin by the molecular markers (RFLP method). Through the molecular analysis of the 15 tested varieties of the spelled wheat and one variety of the common wheat were obtained the results which make us able to detect the proportion of the spelled wheat in the common wheat.

Wheat (triticum aestivum, L.) plants were exposed to three different levels of phytochrome photoequilibria (φ), two different photoperiods, end-of-day far-red radiation, two different levels of blue (400-500 nm) light, three levels of photosynthetic photon flux (PPF), and two types of high intensity discharge lamp types. Tillering was reduced by lowered φ, by reduced amounts on blue light and by end-of-day far-red. Main culm development was increased by lowered φ, by increased PPF, and was reduced by shortened photoperiod and by reduced blue light. Leaf length was increased by increased PPF, lowered φ, and reduced blue light but was not affected by photoperiod, end-of-day far-red or lamp type. Dry-mass accumulation increased under increasing PPF but was unaffected by other treatment in these experiments.

The objective of this study was to determine the effect of increasing leaf area index on the photosynthetic temperature response of a wheat canopy. Hard red spring wheat (Triticum aestivum L. cv. Veery-10) was grown hydroponically in a growth chamber, which also served as the gas-exchange chamber. Gas-exchange parameters were measured on single leaves and on wheat canopies at various leaf area indices. The temperature response curves of the canopy shifted from being steeper with a high temperature optimum to being flatter with a lower temperature optimum as leaf area index increased from 0 to 20.0 m2m-2. Single-leaf and canopy measurements show that this shift was primarily a result of increasing respiration from accumulating stems and reproductive structures and, to a lesser extent, from lower temperature optimums associated with lower light levels within the canopy.

As the population continues to rise, there becomes an ever-increasing need for sustainable food production not only to produce enough food but also to ensure the feasibility of our farmland for years to come. In an effort to curb this problem, nanotechnology is an up-and-coming strategy that acts as a sustainable method of boosting a crop’s growth and yield, especially the use of nanoscale sulfur. The work included in this thesis is an investigation into the question of whether this technology has the potential to increase these parameters in Spring wheat var. Louise (Triticum aestivum L.). In order to answer this question, several application methods including soil amendment, foliar spray, and seed priming were utilized and the results of which are presented below. Methods used to compare each of the treatments include recording different growth parameters such as the Soil Plant Analysis Development (SPAD) value and ethanol assays for the chlorophyll content along with the linear electron flow and Fv/Fm (a sensitive indicator of plant photosynthetic performance or maximum quantum yield of photosystem II) values to assess plant stress. Short-term and maturity experiments were performed and after harvest, parameters such as dry biomass (straw and root), tiller number, flag leaf length, ear length, harvest index, and seed yield were recorded to further assess whether nano sulfur has beneficial impacts on wheat. The goal of this research is to provide additional insights into the use of nanosulfur in wheat agriculture and act as a supplement to other research being performed in this field. From the results, it was found that when plants were treated with the sulfur treatments using the foliar spray application method, there were many increases in the parameters being investigated for increased growth and yield. Agronomic parameters included the flag leaf length, dry straw weight, and seed weight per plant while photosynthetic parameters included SPAD, Fv/Fm, and LEF. At all three concentrations (50, 100, and 200 ppm) foliar applications, the nanosulfur (NS)and nanosulfur coated with stearic acid (NS SA) and sulfate showed a significant increase in chlorophyll 6.3-10.7%), dry biomass (7.9-14.6%), Fv/FM (2.8-3.0%) whereas the bulk sulfur was less effective. Further, 50 ppm, there are highly significant increases across all treatments (BS, sulfate, NS, NS SA, and NS PVP) with 26.9%, 26.1%, 24.5%, 18.4%, and 16.3% increases, respectively, compared to the control group. At 100 ppm application rates, there are highly significant increases in BS (24.8%), sulfate (29.5%), NS SA (15.3%), and the NS treatment (11.2%). When 200 ppm was used, there were highly significant results in BS (34.0%), sulfate (20.9%), NS SA (53.2%), and NS PVP (42.8%) treatment groups, while plants treated with NS SA had a slight but significant increase (13.5%) when compared to the control. From these, it was shown that the sodium sulfate and stearic acid coated nanosulfur had the most consistent significant increases in these parameters, leading to this conclusion. For soil amendment assay, the results were not very conclusive but overall NS and NS SA group showed significant increases in the number of tillers and the length of primary ears whereas BS and sulfate treatments caused a significant decrease in these parameters. From this research, the data that resulted from the soil amendment and seed priming experiments were somewhat inconclusive, indicating that additional research is required to further understand the mechanism for these two application methods.

Fusarium head blight (FHB) is one of the most destructive diseases of common wheat (Triticum eastivum L.) worldwide. Resistance to FHB is an ideal trait for which molecular marker assisted selection (MAS) would facilitate breeding and cultivar development efforts. Validation of quantitative trait loci (QTL) conferring FHB resistance is a prerequisite for MAS. This study was conducted to validate and evaluate the effect of two major QTL, previously reported on chromosomes 3BS and 5AS, on multiple FHB resistance components in two independent studies, one involving a mapping population derived from a cross between a known resistance source W14 and a susceptible soft red winter (SRW) wheat cultivar Pioneer2684, and the other involving seventy adapted SRW wheat lines. The first study confirmed that the 3BS and 5AS QTL were significantly associated with FHB resistance and further indicated that the 3BS QTL has a larger effect on three FHB resistance components (type II and III resistance and resistance to Fusarium Damaged kernels) evaluated in greenhouse experiments, while the 5AS QTL has a larger effect on type I resistance evaluated in a field experiment. Six simple sequence repeat (SSR) and two sequence targeted site (STS) markers associated with FHB resistance in the two QTL regions identified in the first experiment were then used to characterize FHB QTL marker haplotypes and their effect on FHB resistance in seventy wheat genotypes. Five main haplotype groups (1-5) were characterized among the elite lines on the basis of allelic differences of four marker loci linked to the 3BS QTL and two marker loci linked to the 5AS QTL. Haplotype group 5 was comprised of marker allele combinations of both 3BS and 5AS QTL and elite lines with this haplotype have improved type I and type II resistance compared to the other haplotypes. This again validated the presence of QTL on chromosomes 3BS and 5AS, and illustrated the utility of SSR and STS markers in the two QTL regions in selection of FHB resistance in elite backgrounds. Four favorable marker alleles including two (Xbarc133 and XSTS3B142) on 3BS and two (Xbarc117 and Xbarc056) on 5AS are recommended for MAS of the two QTL for improved FHB resistance in wheat. Wheat lines having favorable marker alleles identified in the current study will provide breeding programs with a source of unique and adapted FHB resistant parents and some of the lines also may have potential for release as cultivars. / Ph. D.

Fusarium Head Blight (FHB) is a devastating fungal disease of wheat (Triticum aestivum L.) and results in significant economic losses due to reductions in grain yield and the accumulation of mycotoxins, such as deoxynivalenol (DON) and nivalenol (NIV). As a result, breeding programs have been working to identify resistance genes in wheat varieties known to be resistant to FHB. Some of the major quantitative trait loci (QTL) for FHB resistance identified to date have been from exotic sources such as 'Sumai3' and the Chinese landrace Wangshuibai, and native resistance has been identified in North American cultivars such as Ernie and Truman which are being used in breeding programs. This study was conducted to characterize and map QTL for resistance to FHB in the soft red winter wheat cultivar Jamestown and to identify tightly linked DNA markers associated with those QTL so that marker-assisted selection (MAS) can be used in pyramiding these and other known QTL into elite backgrounds. Types of resistance assessed in this study include: Type I (resistance to initial infection; incidence), Type II (resistance to spread in wheat spike; severity), and decreases in mycotoxin accumulation (DON) and percentage of Fusarium damaged kernels (FDK). A population composed of 186 F5:7 recombinant-inbred lines (RILs) from the cross Pioneer Brand '25R47'/Jamestown were used to evaluate these traits in six environments (MD, NC, and VA in 2011 and 2012). This study identified a QTL for resistance to DON accumulation and FHB severity on the wheat chromosome 1B. The QTL accounted for 12.7% to 13.3% of the phenotypic variation in DON accumulation and 26.1% of the phenotypic variation in FHB severity. The most diagnostic marker for the QTL on chromosome 1B associated with resistance to FHB severity and DON accumulation is Xwmc500.6 located 7.2 cM from the QTL peak and flanked by markers Xwmc500.7 and Xgwm273.2 (28.2 cM interval). / Master of Science

Flooding is a major environmental stress that damages agricultural production worldwide. Using the key regulator of submergence tolerance in rice, SUB1A, as a model, we have advanced our understanding of how plants coordinate transcriptional, hormonal, and metabolic responses to submergence. However, the contribution of SUB1A to recovery from sublethal submergence is still unknown. This study revealed SUB1A's additional role in the recovery phase: promotion of a rapid return to normal metabolic status upon desubmergence through quick recovery of photosystem II photochemistry and carbon fixation. We also investigated how SUB1A differentially regulates adaptive responses in two functionally distinct leaves, growing and mature leaves, under submergence. This study revealed that rice plants promote rapid carbohydrate and nitrogen remobilization and transport in mature leaves, supporting quick elongation growth of growing leaves. In the presence of SUB1A, these metabolic processes were suppressed in mature leaves, resulting in the avoidance of energy starvation in the source tissues. In growing leaves, SUB1A enhanced the accumulation of abscisic acid, but repressed the level of ACC, a precursor of ethylene, contributing to the restriction of elongation growth and leaf senescence in the sink tissues. Application of nitrogen fertilizers is a necessary step to maintain high grain yield in cereals, but plants absorb only 30-50% of supplied N. Wheat, one of the most widely grown crops in the world, requires a high level of nitrogen application to maintain grain yield and protein content. In this study, we investigated how nitrogen input affects the accumulation of major N and C compounds and expression of genes associated with N and C metabolism in flag leaves of wheat. We used two genotypes with distinct nitrogen use efficiencies (NUE), VA08MAS-369 and VA07W-415. VA08MAS-369 displayed higher grain yield, stover biomass, and stover N content at low N, which results from greater N-uptake efficiency in this genotype. Consistently, high N-uptake efficiency was reflected by increased mRNA accumulation of nitrate transporters and their transcriptional regulator, NAC2, in flag leaves at the post-anthesis stage. Overall, this study advanced our knowledge of the important mechanisms in plant response to flooding and N limitation in these key staple cereals. / PHD / Flooding is a serious natural disaster that damages agricultural production worldwide. Rice is a wetland plant that adapts to flooding conditions, but its tolerance to flooding varies in cultivars. Functional characterization of a submergence tolerance gene, SUB1A, has led to our understanding of various mechanisms that regulate flooding tolerance in rice and other plants. However, the role of SUB1A in plant recovery from mild submergence stress is still unknown. This study revealed that SUB1A contributes to the maintenance of photosynthetic performance and provides protection from sudden exposure to high light after floodwater subsides. These processes aid in a quick recovery from reduced metabolic activities. We also investigated the role of SUB1A in adaptive responses in growing and mature leaves of rice plants during submergence. Mature and growing leaves looked similar, but their functional importance was distinct. In general, mature leaves serve as energy production tissues through photosynthesis. The excess carbohydrate and nitrogen reserves produced in mature leaves are transferred to growing leaves that consume a large amount of energy for rapid growth. This study revealed that SUB1A restricted the consumption and transfer of energy reserves in mature leaves to avoid an energy crisis. In growing leaves, SUB1A suppressed elongation growth and leaf senescence through the proper regulation of key hormones controlling these processes. Nitrogen (N) fertilizer application is a necessary process to improve agricultural productivity in many crops. However, crops only take up 30-50% of applied N, resulting in water and air pollution and altered ecosystems. Improvement of plant N use efficiency (NUE) is one of the ways to address this issue. This study compared two soft red winter wheat lines with contrasting NUE under low and normal N supply. It was concluded that one line, VA08MAS-369, had higher grain yield and N uptake efficiency under low N supply. Our physiological and molecular study indicated that VA08MAS-369 significantly promoted N remobilization in leaves and N transport to grains after flowering under limited N. This study advanced our understanding of NUE mechanisms in winter wheat, which may aid the development of new cultivars with enhanced NUE through modern biotechnological approaches.

Le blé est la seconde céréale la plus produite dans le monde. Il constitue une importante source de denrées alimentaires et de beaucoup d’autres usages industriels. La compréhension des mécanismes impliqués dans le développement du grain de blé est fondamentale pour développer des blés à valeur ajoutée. La physiologie du grain de blé et les mécanismes moléculaires impliqués dans son développement nécessitent d’être mieux connus et ces connaissances pourront être très utiles pour l’amélioration du blé mais aussi des autres céréales. L’approche protéomique a été aussi utilisée dans ce contexte mais aucun travail n’avait jusqu’ici été réalisé sur la totalité des phases de développement des tissus et sur des intervalles de temps très courts. La caractérisation des changements d’expressions protéiques dans les couches périphériques du grain et de l’albumen est présentée dans cette étude. Nous avons utilisé les grains de Triticum aestivum de la variété Récital, cultivés à l’INRA de Clermont-Ferrand. Les grains ont été prélevés tous les 50°C jour (°Cj) depuis la fécondation jusqu’à la maturité sur 15 stades de développement pour les couches périphériques et sur 21 stades pour l’albumen amylacé. Pour chaque échantillon, les couches périphériques des grains ont été disséquées et les protéines totales extraites. L’analyse des protéines en électrophorèse bidimensionnelle puis par spectrométrie de masse MALDI-TOF a permis d’identifier via l’interrogation des bases de données, 207 protéines différentiellement exprimées sur 15 stades de développement (0°Cj-700°Cj). Ces protéines ont ensuite été classées en 16 classes fonctionnelles. L’analyse en cluster a révélé 5 profils d’expression au cours du temps. Parallèlement, l’albumen amylacé a été isolé des grains et les protéines métaboliques de ce tissu extraites. Après électrophorèse bidimensionnelle des protéines, 487 protéines variant significativement dans l’albumen sur l’ensemble des stades de développement (0°Cj-1006°Cj) ont été identifiées par utilisation de la LC-MS. Les protéines ont été réparties sur neuf profils d’expression et 17 fonctions biochimiques. Le protéome des couches périphériques a ensuite été comparé au protéome de l’albumen dans le but de comprendre si l’évolution des processus biochimiques diffère dans chacun de ces tissus. Au final, nous avons optimisé l’intégration des données protéomiques avec celles du transcriptome (en se focalisant sur les protéines du métabolisme carboné). Seulement 32% des profils d’expression protéome/transcriptome montrent une corrélation significative au cours du développement (152°Cj-700°Cj). Les profils d’expression des enzymes ont été comparés sur les deux niveaux. Ils devraient permettre de distinguer les processus régulés au niveau du transcriptome de ceux régulés au niveau du protéome. L’ensemble de ces données pourra être compilé dans une base de données propre de la variété Récital et utilisé comme référence dans l’étude des maladies et des stress abiotiques des tissus du grain de blé en développement. / Wheat is the second most produced cereal in the world, important for food, feed and many industrial uses. Understanding of the mechanisms involved in grain development is fundamental for developing high quality wheat. In particular, detailed knowledge of the wheat grain physiology and molecular mechanisms involved in its development would help in breeding not only of wheat but also many other cereals. A proteomic approach has been used in this context but, up to now, there had been no work on developing tissues at very short temporal distances. This thesis presents, firstly, a proteomic study to characterize protein expression changes in peripheral layers and in starchy endosperm of wheat, during kernel development. We used grains of Triticum aestivum cv Récital, cultivated at INRA, Clermont-Ferrand. Grains were harvested at each 50°Cd from fertilization to maturity at fifteen stages for peripheral layers and at twenty-one stages for starchy endosperm. After grain dissection, protein extraction and 2DE- MALDI-TOF MS and data mining, we identified 207 differentially expressed proteins at fifteen stages (0°Cd-700°Cd) of peripheral layers during kernel development. These proteins were then classed in sixteen different functional classes. HCA revealed five different expression profiles during development. Similarly after obtaining starchy endosperm from dissected grains, we performed protein extraction specific to metabolic proteins. After 2DE, 487 proteins were identified from fertilization to grain maturity (0°Cd-1006°Cd), using LC-MS and data mining. Proteins were grouped in nine different expression profiles and were classed in seventeen biochemical functions. We have constructed proteome maps of these two important grain tissues during kernel development. Further, the comparison of peripheral layers and starchy endosperm proteomic data was made, with an objective to understand whether the changes in different biochemical processes differ between these tissues.Finally, we performed an integration of our proteomic data (focusing our approach on proteins involved in carbohydrate metabolism) with that of transcriptomics. Only 32% of proteome/transcriptome expression profiles showed a significant correlation during development (from 152°Cd-700°Cd). Comparison of enzyme expression profiles with those of proteome and transcriptome would help to distinguish the processes regulated at transcriptome level and those controlled at the proteome level. This comprehensive grain development data could further help in construction of a Récital databank, which may be used as reference for studies of diseased and stressed grain tissues during development.

Made available in DSpace on 2017-07-21T14:19:37Z (GMT). No. of bitstreams: 1 CLAUDIO KAPP JUNIOR.pdf: 1815678 bytes, checksum: d0a947fefc0e6b1b5a0242eb975f3cb7 (MD5) Previous issue date: 2013-03-18 / No-till systems with diversified crop rotations have stood out of the most effective strategies to improve the sustainability of farming in tropical and subtropical regions. Wheat (Triticum aestivum L.) is one of the most important crops used in this rotation during the autumn-winter season. Nitrogen (N) is uptake in larger amounts by plants, it is essential for the structure and functions in the cell, for all enzymatic reactions and is part of the chlorophyll molecules. Nitrogen fertilizers represent a significant part of the costs of production and due to the dynamics of N in soil, losses of N occur and cause economic and environmental damages. In the same agricultural area may exist changing demands for this nutrient. The attributes of the plant commonly used as indicators of N are NO3- content in stem, leaf chlorophyll content, the intensity of the green color and the N foliar content, dry biomass, and the extraction of N by plants. Lower levels of N can cause chlorophyll deficiency that is recognized by whitish or pale foliar coloration, and this changing in plant color can be identified using remote sensing techniques. This study aimed to evaluate the correlations between spectral reflectance data obtained by commercial ground sensors (Clorofilog 1030, GreenSeeker, and Crop Circle ACS-470) and attributes of wheat crop in response to N rates in top dressing under a no-till system. The efficiency of the sensors was evaluated in two ways: (i) by classical statistical methods, and (ii) through the application of Artificial Neural Networks, a machine learning technique. For the use of Artificial Neural Networks, this study compared the performance of the algorithms Resilient Propagation and Backpropagation. Because wheat plants exhibited adequate nutritional status, even without N application in top dressing, Clorofilog 1030 readings were not sensitive to variations of N rates. Thus, this sensor also did not correlate significantly with the N foliar content, dry biomass, and the extraction of N by wheat plants. The indices obtained by reflectance sensors Crop Circle and GreenSeeker had close correlation with the rates of N in top dressing, dry biomass, and the extraction of N by wheat plants. The Crop Circle and GreenSeeker sensors showed weaker correlation with the N content in leaves, and especially with the wheat grain yield. In this way, it was evident that grain yield has not followed the dry biomass production when high wheat grain yields were obtained. The correlation coefficients obtained by the Resilient Propagation and Backpropagation algorithms were similar to those found by statistical analysis. The Artificial Neural Networks technique had satisfactory behavior similar to classical statistical methods. / O sistema plantio direto com rotação diversificada de culturas tem sido apontado como uma das melhores estratégias para aumentar a sustentabilidade da agricultura em regiões tropicais e subtropicais. Uma das culturas de maior importância nessa rotação durante a estação de outono–inverno é o trigo (Triticum aestivum L.). O nitrogênio (N) é um dos nutrientes extraídos em maior quantidade pelas plantas, sendo essencial para a estrutura e funções nas células, para todas as reações enzimáticas e faz parte das moléculas de clorofila. Os fertilizantes nitrogenados representam parte significativa dos custos da produção agrícola e, em razão da dinâmica do N no solo, perdas consideráveis de N podem ocorrer e causar prejuízos econômicos e ambientais. Em uma mesma área agrícola podem existir demandas variáveis por este nutriente. Os atributos da planta mais utilizados como indicadores de N são o teor de NO3- no colmo, o teor de clorofila, a intensidade da cor verde e o teor de N na folha bandeira, a produção de matéria seca da parte aérea e a extração de N pelas plantas. Níveis baixos de N podem ocasionar deficiência de clorofila que é reconhecida pela coloração pálida ou mesmo esbranquiçada da folha, e esta variação de coloração da planta pode ser identificada por meio de técnicas de sensoriamento remoto. Este trabalho teve o objetivo de estudar as correlações entre dados de refletância espectral obtidos por sensores terrestres comerciais (Clorofilog 1030, GreenSeeker e Crop Circle ACS-470) e atributos de desempenho da cultura do trigo em resposta à doses de N aplicadas em cobertura no sistema plantio direto. A eficiência dos sensores foi avaliada de duas maneiras: (i) por meio de métodos estatísticos clássicos e (ii) por meio da aplicação de Redes Neurais Artificiais com uso da técnica de aprendizado de máquina, software MatLab. Para a utilização de Redes Neurais Artificiais, este trabalho comparou o desempenho dos algoritmos Backpropagation e Resilient Propagation. Os resultados mostraram que as leituras do Clorofilog 1030 não foram sensíveis às variações das doses de N aplicadas em cobertura na cultura do trigo, pois as plantas de trigo apresentaram bom estado nutricional, mesmo sem aplicação de N em cobertura. Logo, este sensor também não teve correlação significativa com o teor de N na folha bandeira, a produção de matéria seca da parte aérea e a extração de N pelas plantas de trigo. Os índices obtidos pelos sensores de refletância Crop Circle e GreenSeeker tiveram estreita correlação com as doses de N aplicadas em cobertura, a produção de matéria seca da parte aérea e a extração de N pelas plantas de trigo. Os sensores Crop Circle e GreenSeeker apresentaram correlação mais fraca com o teor de N no tecido foliar e, principalmente, com a produtividade de grãos de trigo. Isso aconteceu porque ficou bem evidenciado que a produtividade de grãos não acompanhou os ganhos de matéria seca da parte aérea do trigo, quando os rendimentos de grãos de trigo foram elevados. Os coeficientes de correlação obtidos pelos algoritmos Backpropagation e Resilient Propagation foram semelhantes aos encontrados pelas análises estatísticas. A técnica de Redes Neurais Artificiais teve comportamento satisfatório e similar aos métodos estatísticos clássicos.