Wheat (Triticum aestivum L.) grown in controlled environments with a 24-hour photoperiod was analyzed for phenylpropanoid and amino acid metabolites. Discrete spectral environments, including a metal halide, high-pressure sodium and low-pressure sodium lamps, provided both photosynthetically active radiation and phenylpropanoid inducing fluences of light . A greenhouse spectral environment supplemented with fluorescent lamps was also used to culture wheat . All. four spectral envi ronments were used to culture wheat to maturity separately. The activities of phenylalanine and tyrosine ammonia-lyase were photoinduced in wheat tissue obtained from plants grown in the metal halide, high -pressure sodium and greenhouse spectral environments. These enzyme activities are the committed catalytic step in phenylpropanoid biosynthesis and were induced in wheat tissue by fluences of light in the ultraviolet and blue regions of the spectrum. The low-pressure sodium lamp , which does not provide strong irradiance in these wavelengths , produced significantly lower ammonia-lyase activities than were observed in wheat grown within the metal halide , high-pressure sodium, or greenhouse spectral environments. These effects were not caused by phytochrome, since calculation of PfrfPtotal for the low-pressure sodium lamp was higher than the ratio obtained from metal halide or high-pressure sodium lamps. Lignin was also significantly reduced in wheat grown with low-pressure sodium lamps . Several essentialamino acids were in lower molar concentration in protein from wheat grown under low-pressure sodium lamps. However, phenylalanine and tyrosine were in significantly higher concentration in wheat grain produced in this spectral environment, and amino acid concentrations of wheat cultured with the low-pressure sodium lamp are regarded as a direct result of the spectral properties of this light source.

Doctor of Philosophy / In this thesis, a set of wheat varieties (Triticum aestivum L.) produced by the Value Added Wheat Cooperative Research Centre with lower swelling power as compared to commercial Australian wheat varieties were studied to enhance our understanding of the role of amylose in starch functionality. These starches originated from a heterogeneous genetic background and had a narrow range of elevated amylose content (35 to 43%) linked with diverse functional properties. Small-angle X-ray scattering together with complementary techniques of differential scanning calorimetry and X-ray diffraction have been employed to investigate the features of starch granular structure at the nanometer scale. Starch chemical structure was characterized in terms of amylose content and amylopectin chain length distribution. Starch functionality was studied by a series of swelling, pasting and enzymic digestion methods. This study showed that swelling power of flour is a simple test that reflects a number of industrially relevant characteristics of starch, and therefore can be used as an indicator of amylose content and pasting properties of starch. In contrast to waxy starches and starches with normal amylose content, wheat starches with increased amylose content displayed characteristic pasting properties that featured decreasing peak, breakdown and final viscosities with increasing amylose contents. Existence of a threshold value in amylose content, above which final viscosity of starch paste does not further increase with increasing amylose content, was proposed. Variability in amylopectin chain length distribution was shown to have an additional effect on the swelling and pasting properties of the starches. On the molecular level, increased amylose content was correlated with increased repeat spacing of the lamellae present in the semicrystalline growth rings. In agreement with current understanding of starch synthesis, amylose was shown to accumulate in both crystalline and amorphous parts of the lamella. Using waxy starch as a distinctive comparison with the other samples confirmed general trend of increasing amylose content being linked with the accumulation of defects within crystalline lamellae. Amylose content was shown to directly influence the architecture of semicrystalline lamellae, whereas thermodynamic and functional properties were proposed to be brought about by the interplay of amylose content and amylopectin architecture. Subjecting starch granules with varying amylose content to pancreatic α-amylase showed differences in their digestion patterns. Pancreatic α-amylase preferentially attacked amorphous regions of waxy starch granules, whereas these regions for initial preferential hydrolysis gradually diminished with increasing amylose content. Observed variations in the extent of enzymic digestion were concluded to be primarily determined by the level of swelling of amorphous growth rings, which can also explain observed morphologies of partly digested granules with varying amylose content. It was confirmed that access to the granular components is not a function of the extent of crystallinity but rather the spatial positioning of the crystalline regions within the granule. Digestion kinetics is governed by factors intrinsic to starch granules, whereas influence of enzyme type was shown to be critical in determining the absolute rate of hydrolysis. Wheat starches with increased amylose content offer the potential to be used as slow digestible starch, mostly in their granular form or when complexed with lipids. Differences among varieties largely diminished when starches were gelatinized or allowed to retrograde demonstrating the importance of granular structure on starch hydrolysis. Wheat varieties used in this study displayed widely differing pasting properties in a Rapid Visco Analyser (RVA) and textural characteristics of the respective retrograded starch gels. Varietal differences in starch chemical composition among wheat varieties were shown to have significant effect on the extent of the response of starch viscoelastic characteristics to the addition of monopalmitin. Amylose content was positively correlated with the increase in final viscosity, which was attributed to the presence of more amylose in non-aggregated state contributing to higher apparent viscosity of the starch paste. Comparison of stored gels obtained from amylose-rich starches with gel prepared from waxy wheat varieties confirmed the critical role of amylose on the formation of starch network and thus providing the strength of the gel. Lack of correlation between textural properties of stored gels with amylose content or rheological characteristics measured by the RVA indicated that subtle differences in starch structure may have far-reaching consequences in relation to the strength of the gels, although these differences may have only limited effect on pasting properties in the RVA Viscoelastic properties of starch paste prepared from commercial wheat starch were significantly altered depending on the chain length and saturation of the fatty acid of the monoglyceride added during repeated heating and cooling in the Rapid Visco Analyser. Varying effects of different monoglycerides on the paste viscosity were attributed to different complexation abilities of these lipids with starch. It was proposed that stability and structure of the starch-lipid complexes formed affect the viscosity trace of the paste subjected to multiple heating and cooling. Our study indicated that differing monoglycerides in combination with the number of heat-cool cycles can be used to induce form I or form II starch-lipid complexes and thus manipulate paste rheology, gel structure and resistant starch content.

Vete, Triticum aestivum är en mycket viktig matgröda. Under historiens gång har arten fått anpassa sig till många vitt skilda miljöer. I Nordeuropa har frost-resistens varit extra viktigt. En viktig gen för frostresistensen är VRN1som kontrollerar vernaliseringen d.v.s. övergången från vegetativt till aktivt tillstånd som sker på våren. Olika varianter av denna gen leder till skillnader frostresistens under våren. I detta arbete undersöktes hur variationer i promotorn till VRN1A i accessioner från norra Europa påverkar frostresistensen. Alla sorter som kunde sekvenseras visade sig ha samma promotor trots varierande frost-resistens. Detta kan bero på att promotorn till VRN1 inte är det enda som påverkar genens utryck. Även variationer i intron1 är betydelsefulla och det är därför rimligt att variationen mellan sorterna ligger där istället. En annan förklaring kan även vara att variationen ligger på ett annat genom då T. aestivum är hexaploid. Att alla sorter har samma promotorsekvens kan också tyda på ett selektivt svep. Detta selektiva svep har i så fall förekommit innan vete kom till Nordeuropa då även de franska och tyska sorterna har samma promotor som de finska och svenska. / Bread wheat, Triticum aestivum is an important crop. As history has progressed the species has been forced to adapt to different environments. In Northern Europe, frost resistance has been especially paramount. An important gene for frost resistance is VRN1 that controls vernalization, i.e. the transition from vegetative state to active state during spring. Different variants of this gene confer differences in frost resistance during spring. In this study I examined how the promotor region of VRN1A affects frost resistance in accessions of landraces of wheat from Northern Europe. All accessions from which the promotor region could be sequenced shared the same promotor sequence even though they had very varied frost resistance. This could be because the expression of VRN1 is not only affected by the promotor. Variations in intron one is also important, and so it is reasonable to assume that the variation between these landraces lies there instead. The variations could also be on one of the other genomes, because bread wheat is hexaploid. The fact that all the accessions shared the same promotor sequence indicates that a selective sweep has taken place. This selective sweep could have occurred before bread wheat arrived in Northern Europe because landraces from Germany and France shares the same promotor as Nordic Landraces.

No description available.

Considerable research has been concentrated on the foliage application of Cycoce, whereas little attention has focused on its use in seed application. Imbibition of caryopses of wheat (Triticum aestivum L.) in (2-chloroethyl) trimethylammonium chloride (Cycocel/CCC) resulted in a reduction in germination rate and a stunting of seedling growth. This was consistent with the appearance of a thicker stem, with shorter leaves than the control. Chlorophyll content per unit weight of leaf and numbers of tillers initiated both increased in comparison to controls. However, Cycocel treatment was accompanied by an enhanced survival capacity of seedlings when they were subjected to water limitation under growth room conditions. Seedlings grown from caryopses imbibed in 0.4 % Cycocel and exposed to a 7-day cycle of watering remained green and turgid beyond the time when the controls had wilted and died. Seedlings, at the fourth leaf stage, showed no wilting 23 days after watering had been withheld totally. Enhanced survival was also noted in seedlings when caryopses had been imbibed in Cycocel for 24 hours followed by a period of dry storage for up to 2 weeks prior to sowing. Enhanced survival was also detected as a carryover into the tillers, and the subsequent GEN2 seedlings, derived from GEN1plants. Cycocel pre-treatment did not alter Stomatal Index to an extent which could lead to enhanced water use efficiency, nor to the accumulation of proline to bring compatible solutes into equilibrium. However, the pre-treatment with Cycocel was found to enhance growth as a counter to water stress, and maintained fresh and dry weight of shoots when examined under the polyethylene glycol (PEG) induced stress. At the anatomical level the microscopic investigation of the GEN2 leaf tissues, derived from GENl plant, revealed a fully turgid cell structure, cells did not collapse and tissues were not distorted after the extraction of chlorophyll when compared with the control of the continuous watering as well as the moderate watering regime. Additionally, the cortex of GENl plants derived from pre-treated caryopses, showed a bright fluorescing unidentified deposition under Nutrient Solution (NS). This was more much greater when sampled from the NS + PEG treatments. From the results achieved Cycocel pre-treatment of caryopses appeared to have potential in manipulating wheat plants against water limitation. However, the mechanism (s) by which this can be achieved was not fully resolved in this study. Further investigations are required at the biochemistry and molecular level, particularly in relation to potential carryover effects between generations.

Doctor of Philosophy / In this thesis, a set of wheat varieties (Triticum aestivum L.) produced by the Value Added Wheat Cooperative Research Centre with lower swelling power as compared to commercial Australian wheat varieties were studied to enhance our understanding of the role of amylose in starch functionality. These starches originated from a heterogeneous genetic background and had a narrow range of elevated amylose content (35 to 43%) linked with diverse functional properties. Small-angle X-ray scattering together with complementary techniques of differential scanning calorimetry and X-ray diffraction have been employed to investigate the features of starch granular structure at the nanometer scale. Starch chemical structure was characterized in terms of amylose content and amylopectin chain length distribution. Starch functionality was studied by a series of swelling, pasting and enzymic digestion methods. This study showed that swelling power of flour is a simple test that reflects a number of industrially relevant characteristics of starch, and therefore can be used as an indicator of amylose content and pasting properties of starch. In contrast to waxy starches and starches with normal amylose content, wheat starches with increased amylose content displayed characteristic pasting properties that featured decreasing peak, breakdown and final viscosities with increasing amylose contents. Existence of a threshold value in amylose content, above which final viscosity of starch paste does not further increase with increasing amylose content, was proposed. Variability in amylopectin chain length distribution was shown to have an additional effect on the swelling and pasting properties of the starches. On the molecular level, increased amylose content was correlated with increased repeat spacing of the lamellae present in the semicrystalline growth rings. In agreement with current understanding of starch synthesis, amylose was shown to accumulate in both crystalline and amorphous parts of the lamella. Using waxy starch as a distinctive comparison with the other samples confirmed general trend of increasing amylose content being linked with the accumulation of defects within crystalline lamellae. Amylose content was shown to directly influence the architecture of semicrystalline lamellae, whereas thermodynamic and functional properties were proposed to be brought about by the interplay of amylose content and amylopectin architecture. Subjecting starch granules with varying amylose content to pancreatic α-amylase showed differences in their digestion patterns. Pancreatic α-amylase preferentially attacked amorphous regions of waxy starch granules, whereas these regions for initial preferential hydrolysis gradually diminished with increasing amylose content. Observed variations in the extent of enzymic digestion were concluded to be primarily determined by the level of swelling of amorphous growth rings, which can also explain observed morphologies of partly digested granules with varying amylose content. It was confirmed that access to the granular components is not a function of the extent of crystallinity but rather the spatial positioning of the crystalline regions within the granule. Digestion kinetics is governed by factors intrinsic to starch granules, whereas influence of enzyme type was shown to be critical in determining the absolute rate of hydrolysis. Wheat starches with increased amylose content offer the potential to be used as slow digestible starch, mostly in their granular form or when complexed with lipids. Differences among varieties largely diminished when starches were gelatinized or allowed to retrograde demonstrating the importance of granular structure on starch hydrolysis. Wheat varieties used in this study displayed widely differing pasting properties in a Rapid Visco Analyser (RVA) and textural characteristics of the respective retrograded starch gels. Varietal differences in starch chemical composition among wheat varieties were shown to have significant effect on the extent of the response of starch viscoelastic characteristics to the addition of monopalmitin. Amylose content was positively correlated with the increase in final viscosity, which was attributed to the presence of more amylose in non-aggregated state contributing to higher apparent viscosity of the starch paste. Comparison of stored gels obtained from amylose-rich starches with gel prepared from waxy wheat varieties confirmed the critical role of amylose on the formation of starch network and thus providing the strength of the gel. Lack of correlation between textural properties of stored gels with amylose content or rheological characteristics measured by the RVA indicated that subtle differences in starch structure may have far-reaching consequences in relation to the strength of the gels, although these differences may have only limited effect on pasting properties in the RVA Viscoelastic properties of starch paste prepared from commercial wheat starch were significantly altered depending on the chain length and saturation of the fatty acid of the monoglyceride added during repeated heating and cooling in the Rapid Visco Analyser. Varying effects of different monoglycerides on the paste viscosity were attributed to different complexation abilities of these lipids with starch. It was proposed that stability and structure of the starch-lipid complexes formed affect the viscosity trace of the paste subjected to multiple heating and cooling. Our study indicated that differing monoglycerides in combination with the number of heat-cool cycles can be used to induce form I or form II starch-lipid complexes and thus manipulate paste rheology, gel structure and resistant starch content.

This thesis was aimed on the elaboration of literature review and a on the practical assessment of the field trial with a mixtures of varieties. The first part of the literature review was devoted to crop diversification in agriculture, which is closely related to mixtures of varieties. In the other part were characterized advantages of mixed varieties, such as better yield of mixed varieties in comparison with component varieties. We have also described some of the mechanisms for the creation of income (and mechanisms against pathogens). Another part was devoted to quality of mixed varieties. The last part was devoted to disadvantages resulting from the cultivation of mixed varieties. In the year 2013 it was founded field trial in Žabčice -- Nova obora, which was investigated in practical part. It was investigated effect of three binary mixtures. These mixtures were identified as : Elan + Golem, Viriato + Tobak Baletka and Annie. Each of pure component varieties were planted for checking and comparison. The main examined factors were yield, weight of thousand seeds, sedimentation index, wet gluten, gluten index, falling number, nitrogenous substances, weight and height of the plant. The best yield reached mixture Elan + Golem (average yield was 9.61 t / ha), it's yield reached the yield of the best variety Elan (9.92 t / ha). The mixture Tobak + Annie had higher average value of the falling number and nitrogenous substances than the pure varieties, average results this mixture reached in values of sedimentation index and wet gluten. In the total evaluation this mixture was recommended as the best one. The holder of the quality in this mixture was the Annie variety. This mixture has fulfilled requirements for baking quality and reached Czech elite level.

Powdery mildew caused by <i>Blumeria graminis</i> f. sp. <i>tritici</i> is one of the most devastating diseases in wheat (<i>Triticum aestivum</i>) worldwide. Hypersensitive, race specific genes primarily have been deployed to control the disease, however recent efforts have shifted to breeding for more durable resistance, such as "adult plant resistance" (APR). Molecular markers and quantitative trait loci (QTL) associated with APR to powdery mildew must first be validated and QTL effects evaluated in different genetic backgrounds and breeding populations to be useful in marker-assisted selection (MAS) programs. Eighteen simple sequence repeat (SSR) markers previously mapped near the three QTL in Massey for APR to powdery mildew were evaluated for association with APR for powdery mildew in a recombinant inbred line (RIL) breeding population derived from a cross between USG 3209 and a moderately susceptible cultivar Jaypee, wherein Massey is the resistance source for APR in USG 3209. Thirteen new SSR markers were added to the pre-existing genetic linkage maps near the three QTL associated with APR in the Becker by Massey (BM) population. Interval mapping analysis of mildew severity data collected in 2002 (F_5:6) and 2003 (F_6:7) field experiments with marker genotype data obtained in 2003 (F_6:7) confirmed the presence of three QTL for APR on chromosomes 1B, 2A, and 2B in the USG 3209 by Jaypee (UJ) population. The QTL on chromosomes 1B, 2A, and 2B explained 12% to 13%, 59% to 69%, and 22% to 48% of the phenotypic variance for powdery mildew severity in the UJ RIL populations, respectively, in the two field experiments. The efficiency of MAS was examined using powdery mildew data collected in 2002 and 2003 field experiments and also from a greenhouse experiment in 2004 (F_7:8), wherein adult plants of the 293 RILs were evaluated for disease severity using a composite of five different isolates of <i>B. graminis</i>. Selection of RILs possessing the QTL on chromosome 2A and to a lesser extent the one on chromosome 1B was effective in identifying powdery mildew resistance in both greenhouse and field experiments, whereas the effect of the QTL on chromosome 2B was insignificant in the greenhouse. Overall, selecting RILs with QTL on chromosomes 2A and 2B was most successful in identifying highly resistant RILs compared to selecting RILs having other combinations of two or three QTL combinations. The RILs possessing both QTL on chromosomes 2A and 2B had mean mildew severities of 4.4% and 3.2% in 2002 and 2003 field experiments, respectively. Breeders implementing MAS programs for APR to powdery mildew via selection of RILs containing the two QTL on chromosomes 2A and 2B likely will obtain RILs having high levels of resistance in the field. However, combining all three QTL may ensure greater durability of APR, on the basis that resistance conferred by QTL on chromosome 2A and 1B are genetically stable across all environments in this study. / Master of Science

Frente ao aumento populacional e consequente incremento na demanda por alimentos, é importante estabelecer um melhor aproveitamento da área de cultivo, objetivando a colheita de produtos agrícolas em maior quantidade e de melhor qualidade. O aumento da concentração de micronutrientes nos produtos colhidos, especialmente de zinco é um desafio crescente para a agricultura, com possibilidade de trazer benefícios à saúde humana e à produtividade da cultura. Nesse sentido, a aplicação foliar de zinco realizada periodicamente, à partir da antese floral, é uma técnica capaz de incrementar o teor do micronutriente nas sementes e biofortificar os grãos de feijão e trigo, causando melhoria de aspectos agronômicos (crescimento vegetativo e produtividade da cultura) de plantas provenientes dessas sementes, além de resultar proveitos para a saúde humana daqueles que se alimentam de produtos biofortificados, e ainda com potencial para produzir grãos e sementes como produtos de maior valor comercial no mercado, valendo-se de inovação tecnológica. Porém, atualmente pouco se conhece sobre os diversos aspectos desta técnica. Assim sendo, objetivou-se: (i) elucidar o efeito da aplicação foliar de zinco, à partir da antese floral, como método para incrementar o teor do micronutriente nos grãos de feijão (Phaseolus vulgaris L.) e de trigo (Triticum aestivum L.), em substrato com teor adequado do micronutriente (ii) utilização de diferentes fontes de zinco aplicadas via foliar visando estabelecer a melhor fonte para o aumento do teor do micronutriente no grão de feijoeiro e (iii) determinação das doses de zinco mais adequadas a serem aplicadas através de pulverização foliar visando o aumento do teor do nutriente no grão de plantas de feijão e de trigo. Com base nos resultados obtidos, concluiu-se que (i) a aplicação foliar de zinco realizada periodicamente, à partir da antese floral é capaz de aumentar o teor do micronutriente em grãos de feijão e de trigo; (ii) a fonte mais viável para o enriquecimento de grãos de feijão é o sulfato de zinco; (iii) e todas as doses testadas (125, 250, 375 e 500 g Zn ha-1) aplicadas via foliar na forma de sulfato de zinco foram efetivas para o enriquecimento de grãos de feijão e de trigo, em relação ao controle (0 g Zn ha-1). / In view of the population increase and consequent growth of food demand, it is important to establish a better utilization of the cultivation area, aiming the harvest of agricultural products in greater quantity and of better quality. The increased concentration of micronutrients in products harvested, especially zinc, is a growing challenge for agriculture, with potential to bring benefits to human health and crop productivity. In this matter, the foliar zinc application performed periodically starting at floral anthesis is a technique capable of increasing the micronutrient content in the seeds and biofortifying grains of common bean and wheat, causing agronomic aspects improvement (vegetative growth and crop productivity) of plants derived from these seeds, in addition to bringing benefits to human health of those who feed on biofortified products, and still with potential to produce grains and seeds as products of greater commercial value in the market, being a technological innovation. However, currently little is known about the aspects that circumvent this technique. The objective of this study was: (i) elucidate the effect of foliar application of zinc, starting at floral anthesis, as a method to increase the micronutrient content of common bean (Phaseolus vulgaris L.) and wheat (Triticum aestivum L.) (ii) the use of different sources of zinc applied in a foliar way, in order to establish the best source for increasing the micronutrient content in common bean grains, and (iii) the determination of the most suitable zinc doses, applied by foliar spraying to increase the nutrient content of common bean and wheat plants. Based on the results obtained, it was concluded that (i) the periodic application of zinc foliar application starting at floral anthesis is capable of increasing the micronutrient content in common bean and wheat grains; (ii) the most viable source for the enrichment of bean grains is zinc sulphate; (iii) and all the doses tested (125, 250, 375 and 500 g Zn ha-1) applied via foliar in the form of zinc sulfate were effective for the enrichment of common bean and wheat grains, in relation to the control (0g Zn ha-1).

Made available in DSpace on 2017-07-25T19:29:38Z (GMT). No. of bitstreams: 1 henriquec.pdf: 216448 bytes, checksum: e0d1c9ae923e6c3eb7de206691047710 (MD5) Previous issue date: 2006-08-10 / The use of nitrogen in the culture of the wheat seeks the increase of the productivity.However, it also increases the probability of occurrence of the lodgnign. That can be avoided with the application of growth regulators. In that sense, he took place a field experiment, in the city of Castro, PR, seeking to evaluate the effects of the application of the trinexapac-ethyil in different times and of doses of nitrogen on wheat, cultivars (VANTE and BRS 77). The experimental field was blocks at random in factorial outline 4x4 with four repetitions. The treatments consisted of the combination of 100 g i.a ha -1 of applied trinexapac-ethyl among the 1º and 2º visible knot of the wheat, 2º and 3º visible knot, sequential application on half of the dose between the 1º and the 2º visible knot and half between the 2º and 3º visibleknot, besides the witness without trinexapac-ethyl apllication. The doses of nitrogen were of 90, 135, 180 and 225 kg.ha - 1 fot to AVANTE and 60,90, 120 and 150 kg.ha - 1 for to BRS 177. They were certain the stand, tillers numbers for plant, height of plants, diameter of the stem, lengthof the stem, length of thes stem among the leaf flag unitl the insert of the erar, lodging in the antesis and in the pre-cropo haverst, tenor of nitrogen in the leaves, yield and yield componentes and industrial quality of thewheat. The trinexapac-ethyl was efficient in reducing the length of the he/she enters us, reducidng the height of the plants and lodging percentage, being the moment of application of hte trinexapac-ethyl that promotes larger effects in the height of plants in between the 2º and 3º visible knot. The application of hte trinexapac - ethyl mainly in the phase of 1º and 2º visivle knot or 2º and 3º visible knot promoted significant increase of the ears number and in the productivity of grains when compared to the treatment without application of the growth regulator in cultivar AVANTE, what didn t happen for to cultivar BRS 177. The increase of the dose of nitrogen increases the tenor of the element in the plant and it promotes larger lodging factor that can be mininmized by the application of the growth reducer. It didn t happen earnings about the production components and productivity for the increase of the doses of nitrogen, showing that the recommended doses assistg the demands of the cultivars. The industrial quality of hte wheat was not influenced by the trinexapac-ethyl application, except for to cultivate BRS 177 that presented increase of theweight hectolitric in the treatments with trinexapac-ethyl. The increase of the dose of nitrogen increased the amount of gluten humid, dry and of the Force of Gluten (W) and it reduced the weight hectolitric and Falling Number to cultivar BRS 177, in cultivar AVANTE the doses of N didn t influence the parameters regarding the industrial quality / O uso de nitrogênio na cultura do trigo visa o aumento da produtividade. No entanto, aumenta também a probabilidade de ocorrência do acamamento. Que pode ser evitado com a aplicação de reguladores de crescimento. Nesse sentido, realizou-se um experimento de campo, no município de Castro, PR, visando avaliar os efeitos de doses de nitrogênio nas cultivares de trigo AVANTE e BRS 177. O delineamento experimental foi blocos ao acaso em esquema fatorial 4X4 , com quatro repetições para cada cultivar. Os tratamentos constaram da combinação de 100 g i.a ha-1 de trinexapac-ethyl aplicado entre o 1º e o 2º nó visível e metade entre o 2º e o 3º nó visível, além da testemunha sem aplicação. As doses de nitrogênio em cobertura foram de 90, 135, 180 e 225 kg.ha-1 para a cultivar AVANTE e 60,90, 120 e 150 kg.ha-1 para a cultivar BRS 177. Foram avaliados o stand, números de perfilhos por planta, estatura de plantas, diâmetro de colmo, comprimento dos entre-nós, comprimento do caule do último nó e a inserção da espiga, acamamento no florescimento e na pré-colheita, teor de nitrogênio nas folhas, componentes da produção, produtividade e qualidade industrial do trigo. O Trinexapac-ethyl foi eficiente em reduzir o comprimento dos entre-nós, diminuindo a estatura das plantas e a porcentagem de acamamento, sendo o momento da aplicação do trinexapac-ethyl que promove maiores efeitos na estatura de plantas é entre o 2º e 3º nó visível. A aplicação do trinexapac-ethyl principalmente na fase de 1º e 2º nó visível ou 2º e 3º nó visível promoveu aumento significativo do número de espiguetas e na produtividade de grãos quando comparado ao tratamento sem aplicação do regulador de crescimento na cultivar AVANTE, o que não ocorreu para a cultivar BRS 177. O aumento da dose de nitrogênio aumenta o teor do elemento da planta e promove maior acamamento, fator que pode ser minimizado pela aplicação do redutor de crescimento. Não ocorreu ganho sobre os componentes de produção e produtividade pelo aumento das doses de nitrogênio, mostrando que as doses recomendadas atendem as exigências das cultivares. A qualidade industrial do trigo não foi influenciada pela aplicação de trinexapac-ethyl, com exceção da cultivar BRS 177 que apresentou aumento do peso hectolitrico nos tratamentos com trinexapac-ethyl. O aumento da dose de nitrogênio aumentou a quantidade de glúten úmido, seco e da Força de Glúten (W) e diminuiu o peso hectolitrico (PH) e Falling Number (FN) para cultivar BRS 117, na cultivar AVANTE as doses de N não influenciaram os parâmetros referentes à qualidade industrial.