Lodging is a key agronomic problem in E. tef. due to morpho-physiological features, such tall and slender phenotype of the plant. Gibberellins metabolic genes are key targets in the control of plant height. Plant growth regulators (PGRs) that inhibit GA biosynthesis are used to shorten stem length thereby increasing lodging resistance. E. tef responded to treatment with PGRs such as GA, chlormequat chloride (CCC) and paclobutrazol (PBZ). Both PGRs reduced E. tef plant height but CCC treatment did not affect grain yield. Stem diameter was not affected by PGR treatment and also not the poor tapering (acropitally increasing diameter). Putatively transformed E. tef plants carrying a bean GA 2-oxidase (PcGA2ox) coding sequence were further produced via embryogenic callus after Agrobacterium-mediated transformation and plants were successfully grown into mature fertile plants. Eight putative transformed plants were finally generated carrying the insert (PcGA20 ox or nptII gene sequence) at the T0 generation. Constitutive expression of the GA 2-oxidase (PcGA2ox) coding sequence in E. tef resulted in phenotypic changes such as reduction in culm height, change in biomass, reduction in amount of GA in putative transformant semi-dwarf plants. The challenges found in the transgene detection in the T1 generation has been highlighted. Pheno-morphic changes occurred with little or no effect on yield. Genes involved in height control (orthologs to the rice sd-1 gene) and signaling (Rht) in E. tef were also identified and characterized. Activity of the protein for the putative rice sd-1 orthologs was further confirmed by heterologous expression. The three putative sequences in E. tef were named EtGA20ox1a, EtGA20ox1b and EtGA20ox2. Expression analysis showed that EtGA20ox2 were much less transcribed compared to the others and EtGA20ox1b could be the functional equivalent to the rice sd-1 (OsGA20ox2) gene in E. tef. Further, E. tef mutants with a semi-dwarf phenotype could be developed through mutagenesis and TILLING. However, regardless of height, grain yield was severely reduced in all mutants except in the semi-dwarf mutant GA-10. This line also had significantly higher diameter in most internodes which might contribute to the stiffness of stem. G-10 is therefore a promising line for further investigations. / Thesis (PhD)--University of Pretoria, 2012. / Plant Science / unrestricted

Plant breeders often examine leaf size, plant height and photosynthetic capacity in an effort to increase wheat yield. This study was concerned with the relationship between these parameters in dwarf and semidwarf wheat cultivars (Triticum aestivum L.) with a wide range in flag leaf size. Photosynthetic capacity was measured at anthesis using photosynthesis versus intercellular CO2 response curves to determine maximum photosynthetic rate and ribulose-1,5- bisphosphate carboxylase efficiency. Leaf area, chlorophyll concentration, stomatal density, interveinal distance and dry mass partitioning were also examined. Smaller flag leaves had greater carboxylation efficiency and closer vein spacing. Dwarf wheat had higher chlorophyll concentrations and maximum photosynthetic rates at anthesis than the taller semi-dwarfs. Dwarf cultivars had lower photosynthetic rates before anthesis, suggesting preanthesis feedback inhibition of photosynthesis, possibly due to a smaller sink capacity of its stem.

In this thesis, we develop algorithms to estimate crop heights as well as to detect plots infarms. Plant height estimation is needed in precision agriculture to monitor plant health andgrowth cycles. We use a 3D LiDAR mounted on an Unmanned Aerial Vehicle (UAV) anduse the LiDAR data for height and plot estimation. We present a general methodology forextracting plant heights from 3D LiDAR with two specific variants for the two environments:row-crops and pasture. The main algorithm is based on ground plane estimation from 3DLiDAR scans, which is then used to determine the height of plants in the scans. For rowcrops, the plot detection uses a K-means clustering algorithm to find the bounding boxes ofthese clusters, and a voting scheme to determine the best-fit width, height, and orientationof the clusters/plots. This best-fit box is then used to create a grid over the LiDAR dataand the plots are extracted. For pasture, relative heights are estimated using data collectedweekly. Both algorithms we evaluated using data collected from actual farms and pasture.The accuracy in plot height estimation was +/- 5.36 % and that for growth estimates was+/- 7.91 %. / Master of Science / Plant height estimation and measurement is a vital task when it comes to farming. Knowing these characteristics help determine whether the plants are growing healthy and when to harvest them. On similar lines, accurate estimates of the plant heights can be used to prevent overgrazing and undergrazing of pastures. However, as farm and plot size increases, getting consistent and accurate measurements becomes a more time-consuming and manually intensive task. Using robots can help solve this problem because they can be used to estimate the height. With sensors that are already available, such as the 3D LiDAR that we use, we can use aerial robots to fly over the farm and collect plant data. This data can then be processed to estimate the plant height, eliminating the need to go out and manually measure every single plant. This thesis discusses a methodology of doing exactly this, as well as detecting plots within a farm. The algorithms are evaluated using data collected from actual farms and pasture.

Made available in DSpace on 2014-06-11T19:22:15Z (GMT). No. of bitstreams: 0 Previous issue date: 2007-06-20Bitstream added on 2014-06-13T19:48:24Z : No. of bitstreams: 1 oliveira_ij_me_botfca.pdf: 275488 bytes, checksum: 3122975d714c1de04cce8ee601eeec51 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / The castor bean (Ricinus communis L.) is high social economic value oil plant and a resource source to Brazil. To attend the increasing necessity of the raw material and the difficulty of production in industrial scale, it is essential the genetic material development in adequate size to facilitate the harvest, with precocious and uniform maturation, purposing the utilization of high technology and becoming possible the oil plant production in higher scale. The objective of this work was to evaluate the recurrent selection efficiency for height s reduction of the castor bean plants Guarani cultivar, adequating its size to facilitate the harvest. Were developed four cycles of recurrent selection through the utilization of self-pollinated progenies in the Guarani cultivar for height s reduction of plants, in edaphclimatic condictions of the São Manuel-SP and Botucatu-SP cities. The evaluations of plant s height and grain s productivity (kg.ha-1) of the four selection cycles and of the original cycle (cycle 0) were realized at São Manuel-SP and Botucatu-SP cities, under a casualised blocks design with five repetitions and useful parcels of 30 m2. The variance s analysis for the characteristics plant s height and grain s productivity was made apart to each place and together for the two places and, afterwards it was realized the comparison of the averages by the Tukey test using 5% of probability. Were estimated for the two places, by the regression s analysis... (Complete abstract click electronic access below)

Orientador: Maurício Dutra Zanotto / Banca: Norberto da Silva / Banca: José Geraldo Carvalho do Amaral / Abstract: The castor bean (Ricinus communis L.) is high social economic value oil plant and a resource source to Brazil. To attend the increasing necessity of the raw material and the difficulty of production in industrial scale, it is essential the genetic material development in adequate size to facilitate the harvest, with precocious and uniform maturation, purposing the utilization of high technology and becoming possible the oil plant production in higher scale. The objective of this work was to evaluate the recurrent selection efficiency for height’s reduction of the castor bean plants Guarani cultivar, adequating its size to facilitate the harvest. Were developed four cycles of recurrent selection through the utilization of self-pollinated progenies in the Guarani cultivar for height’s reduction of plants, in edaphclimatic condictions of the São Manuel-SP and Botucatu-SP cities. The evaluations of plant’s height and grain’s productivity (kg.ha-1) of the four selection cycles and of the original cycle (cycle 0) were realized at São Manuel-SP and Botucatu-SP cities, under a casualised blocks design with five repetitions and useful parcels of 30 m2. The variance’s analysis for the characteristics plant’s height and grain’s productivity was made apart to each place and together for the two places and, afterwards it was realized the comparison of the averages by the Tukey test using 5% of probability. Were estimated for the two places, by the regression’s analysis... (Complete abstract click electronic access below) / Mestre

Made available in DSpace on 2017-07-25T19:29:37Z (GMT). No. of bitstreams: 1 melissa.pdf: 22685399 bytes, checksum: 52613e711bdb2207d8ee610ea5bcd520 (MD5) Previous issue date: 2006-08-10 / Trinexapac-ethyl is a growth reducer used in winter cereals that promote height plant reduction, preventing the lodging. With the aim of determine the rate and the time of ethyltrinexapac (Moddus) application in wheat cultivars of different lodging answers an experiment was established at the UEPG School Farm in Ponta Grossa, PR, in 2005, in a clay soil. The experimental design was complete randomized blocks, in a factorial design 2 x 2 x 6, with three repetitions for four wheat cultivars. The treatments consisted of two nitrogen rates (50 and 240 kg/ha), two times of trinexapac-ethyl application (between 1º and 2º knot and between 2º and 3º perceivable knot) and six trinexapac-ethyl rates (0; 31,2; 62,5; 93,7; 125,0 and 156,2 g/ha), applied in four wheat cultivars of different answers to the lodging (CD-104 - resistant), (Vanguarda - moderately resistant), (Supera - moderately susceptible) and (CEP-24 - susceptible). It evaluated agronomicals characteristics, diseases severity, yield components and yield. The nitrogen rate affected some plant characteristics and the yield for CEP-24. The application time of trinexapac-ethyl affect the yield of CD-104; the plant height that was lesser how much more delayed was the application in cultivars CEP-24 and CD-104; trinexapac-ethyl reduced the plants height of all the cultivars with changeable intensity with the port of the same ones. For all the cultivars the adjustment equation of the yield in relation to the trinexapac-ethyl rates was quadratic, occurring an increase of the yield with the increase of the reducer rate, until a changeable limit with the cultivar. However, for all cultivars occurred increase of the yield with the trinexapac-ethyl application. For the cultivar majority it had reduction of rust severity, head blight and foliar spots with the increase of the trinexapac-ethyl rate. / O trinexapac-ethyl é um redutor de crescimento utilizado em cereais de inverno que promove redução na altura das plantas, evitando o acamamento. Visando determinar a dose e a época de aplicação de trinexapac-ethyl (Moddus) em cultivares de trigo de diferentes respostas ao acamamento realizou-se um experimento na Fazenda Escola da Universidade Estadual de Ponta Grossa (UEPG), no ano de 2005, em um Cambissolo distrófico de textura argilosa. O delineamento experimental foi de blocos ao acaso, em esquema fatorial 2 x 2 x 6 com três repetições para quatro cultivares de trigo. Os tratamentos constaram de duas doses de nitrogênio (50 e 240 kg/ha), duas épocas de aplicação de trinexapac-ethyl (entre o 1º e o 2º nó e entre o 2º e o 3º nó perceptível) e de seis doses de trinexapac-ethyl (0; 31,2; 62,5; 93,7; 125,0 e 156,2 g/ha), aplicadas em quatro cultivares de trigo de diferentes respostas ao acamamento (CD-104 – resistente), (Vanguarda – moderadamente resistente), (Supera – moderadamente suscetível) e (CEP-24 – suscetível). Avaliou-se características agronômicas, severidade de doenças, componentes da produção e produtividade. As doses de nitrogênio afetaram algumas características da planta e a produtividade de apenas da cultivar CEP-24. A época de aplicação do trinexapac-ethyl afetou de forma substancial a produtividade apenas na CD-104; a altura das plantas foi menor quanto mais tardia foi a aplicação do redutor nas cultivares CEP-24 e CD-104; o trinexapac-ethyl reduziu a altura das plantas de todas as cultivares com intensidade variável com o porte das mesmas. Para todas as cultivares a equação de ajuste da produtividade em relação às doses de trinexapac-ethyl foi quadrática ocorrendo um aumento da produção com o aumento da dose do redutor, até um limite variável com a cultivar. No entanto, para todas as cultivares ocorreu aumento da produtividade com a aplicação do trinexapac-ethyl, e para a maioria delas houve redução da severidade de giberela e manchas foliares com o aumento da dose de trinexapac-ethyl.

Submitted by Claudia Rocha (claudia.rocha@udesc.br) on 2018-02-27T14:02:19Z No. of bitstreams: 1 PGPV16MA204.pdf: 1612999 bytes, checksum: f5d52d475f7cbba62f4aaa7c3ecc2278 (MD5) / Made available in DSpace on 2018-02-27T14:02:19Z (GMT). No. of bitstreams: 1 PGPV16MA204.pdf: 1612999 bytes, checksum: f5d52d475f7cbba62f4aaa7c3ecc2278 (MD5) Previous issue date: 2016-07-19 / Capes / The increase in plant density is an alternative to enhance maize grain yield. However, the increment of plant population also accentuates intraspecific competition, leading to a high percentage of stem lodging and breaking. The use of growth regulators can mitigate the negative effects derived from crowded sowings. This work was carried out aiming to evaluate the effects of the growth regulator ethyl trinexapac on maize response to the increase of plant density at different sowing dates. A field experiment was set in the city of Lages, SC, during the growing seasons of 2014/2015 and 2015/2016. The randomized block design, disposed in split-split plots, was used. Two sowing dates were tested in the main plots: second half of October (recommended sowing date) and first half of December (late sowing date). Four plant densities were assessed in the split plots: 5, 7, 9 and 11 pl m-2. At the split-split plots the treatments with and without growth regulator trinexapac ethyl were evaluated. Ethyl trinexapac was sprayed over the canopy two times, when the crop was at the growth stages of V5 and V10, in a rate of 150 g i.a. on each application. The hybrid P30F53YH was sown under no-till system with a row spacing of 0,7m. Morphological traits, grain yield and its components were determined. The application of ethyl trinexapac decreased plant height an increase stem diameter at both growing seasons. The percentage of lodged 16 and broken plants was lower than 8% in all treatments. It was not affected by sowing date, plant density and growth regulator application. Grain yield ranged from 11,422 to 14,805 kg ha-1. It was higher when maize was sown in October than in December and increased in a quadratic trend with the elevation of plant density, regardless of the presence or absence of growth regulator. The application of ethyl trinexapac did not affect grain yield and decrease 1,000 kernels mass at both sowing times. The spraying of ethyl trinexapac was not an effective management strategy to enhance the response of maize grain yield to the increase in plant population, at the recommended and late sowing times / O aumento na densidade de plantas é uma alternativa para incrementar o rendimento de grãos do milho. Entretanto, densidades excessivas elevam a competição intraespecífica, resultando no aumento da percentagem de plantas acamadas e quebradas. A utilização de reguladores de crescimento pode mitigar os efeitos negativos advindos de semeaduras adensadas. Este trabalho objetivou avaliar os efeitos da aplicação do regulador de crescimento etil trinexapac na resposta do milho ao incremento na densidade de plantas em duas épocas de semeadura. O experimento foi implantado a campo, no município de Lages, SC, durante os anos agrícolas 2014/15 e 2015/16. O delineamento experimental utilizado foi de blocos casualizados dispostos em parcelas sub-subdivididas. Duas épocas de semeaduras foram testadas na parcela principal: segunda quinzena de outubro (recomendada) e primeira quinzena de dezembro (tardia). Quatro densidades de plantas foram avaliadas nas sub-parcelas: 5, 7, 9, 11 plantas m-2. Nas sub-subparcelas foram avaliados os tratamentos com e sem o regulador de crescimento etil trinexapac. O produto foi aplicado duas vezes, quando a cultura se encontrava nos estádios V5 e V10, na dose de 150 g i.a. em cada aplicação. O híbrido P30F53YH foi implantado, no sistema de semeadura direta, com espaçamento entre linhas de 0,7 m. Avaliaram-se características morfológicas, o rendimento 12 de grãos e os seus componentes. A aplicação do regulador de crescimento etil trinexapac diminuiu a altura de plantas e incrementou o diâmetro de colmo nos dois anos de estudo. A percentagem de plantas acamadas e quebradas foi inferior a 8% em todos os tratamentos e não foi influenciada pela época de semeadura, densidade de plantas e aplicação do regulador de crescimento. O rendimento de grãos variou de 11.422 a 14.805 kg ha-1. Ele foi maior na semeadura de outubro do que na de dezembro e aumentou de forma quadrática com a elevação da densidade de plantas, independentemente da presença ou ausência do regulador de crescimento. A aplicação de etil trinexpac não interferiu no rendimento de grãos e diminuiu a massa de 1.000 grãos nas duas épocas de semeadura. A utilização do regulador de crescimento etil trinexapac não foi uma estratégia de manejo efetiva para aumentar a reposta do rendimento de grãos do milho ao adensamento, tanto na época recomendada quanto na semeadura tardia

Made available in DSpace on 2017-07-10T17:48:22Z (GMT). No. of bitstreams: 1 Fernando_Henrique_de_Souza.pdf: 1096434 bytes, checksum: 5d8e7789a9e24f55a440b9f9c7615b45 (MD5) Previous issue date: 2010-08-19 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / In the tropics, livestock production is virtually dependent on pasture. In Brazil, the exploitation of pastures extraction is done by providing in this way, the progressive degradation of pastures. As a result there is a continuing search for new and even miraculous grasses to replace those that were used, without bothering to correct the problems that led to a drop in pasture productivity. Probably, the problems of reduced productivity are linked to soil fertility and pasture management. The use of nitrogen fertilizers, in animal production systems in grazing, aims to increase the sustainability of the business, by increasing the longevity of the pasture. In systems with low management level / input, the replacement of nitrogen (N) primarily aims to ensure the sustainability of plant communities. Already in production systems and improved management uprighted, N, besides working on the sustainability of grazing, becomes the main nutrient controlling the plant and animal productivity, as the increased availability of N in the medium interferes positively on the factors morphology of grasses, stimulating its growth and, consequently, contributing to increased productivity of the pasture. The aim of this study was to evaluate the morphogenesis, production and nutritional Panicum maximum cv. Millennium IPR 86 fertilized with increasing doses of nitrogen at different cutting heights. The forages studied responded very well to nitrogen fertilization showing the best response at the highest dose applied, and the height of 90 cm was obtained the best yield response, which is the recommended height for the management of this forage. However if the goal is to provide a forage with a higher nutritional value it should be handled at the height of 80 cm. / Nas regiões tropicais, a produção animal é, praticamente, dependente de pastagens. No Brasil a exploração das pastagens é feita de forma extrativista, proporcionando dessa maneira, a degradação progressiva das pastagens. Em decorrência disso observa-se uma busca continua de novas e até milagrosas gramíneas forrageiras para substituir aquelas que foram utilizadas, sem no entanto preocupar-se em corrigir os problemas que levaram à queda da produtividade da pastagem. Provavelmente, os problemas dessa queda de produtividade estão ligados a fertilidade dos solos e ao manejo das pastagens. O uso de fertilizantes nitrogenados, em sistemas de produção animal em pastejo, tem o objetivo de aumentar a sustentabilidade do negócio, por meio do aumento na longevidade da pastagem. Em sistemas com baixo nível de manejo/insumo, a reposição de nitrogênio (N) visa prioritariamente garantir a sustentabilidade da comunidade vegetal. Já em sistemas de produção verticalizados e de melhor manejo, o N, além de atuar sobre a sustentabilidade da pastagem, torna-se o principal nutriente regulando a produtividade vegetal e animal, pois o aumento na disponibilidade de N no meio interfere positivamente sobre os fatores morfológicos da planta forrageira, estimulando seu crescimento e, conseqüentemente, concorrendo para o aumento da produtividade da pastagem. O objetivo do presente estudo foi avaliar as características morfogênicas, produtivas e nutricionais do Panicum maximum cv. Milênio IPR 86 adubado com doses crescentes de nitrogênio em diferentes alturas de corte. A planta forrageira estudada respondeu muito bem a adubação nitrogenada apresentando a melhor resposta na maior dose aplicada, sendo que na altura de 90 cm se obteve as melhores respostas produtivas, sendo esta a altura recomendada para o manejo desta forrageira. No entanto se o objetivo for o fornecimento de uma forragem com um maior valor nutricional este devera ser manejado na altura de 80 cm

Groat oil content and composition are important quality traits in oats (Avena sativa L). These traits are controlled by many genes with additive effects. The chromosomal regions containing these genes, known as quantitative trait loci (QTL), can be discovered through their close association with markers. This study investigated total oil content and fatty acid components in an oat breeding population derived from a cross between high oil ('Dal') and low oil ('Exeter') parents. A genetic map consisting of 475 DArT (Diversity Array Technology) markers spanning 1271.8 cM across 40 linkage groups was constructed. QTL analysis for groat oil content and composition was conducted using grain samples grown at Aberdeen, ID in 1997. QTL analysis for multiple agronomic traits was also conducted using data collected from hill plots and field plots in Ottawa, ON in 2010. QTLs for oil content, palmitic acid (16:0), stearic acid (18:0), oleic acid (18:1), linoleic acid (18:2) and linolenic acid (18:3) were identified. Two of the QTLs associated with oil content were also associated with all of the fatty acids examined in this study, and most oil-related QTL showed similar patterns of effect on the fatty acid profile. These results suggest the presence of pleiotropic effects on oil-related traits through influences at specific nodes of the oil synthesis pathway. In addition, 12 QTL-associated markers (likely representing nine unique regions) were associated with plant height, heading date, lodging, and protein content. The results of this study will provide information for molecular breeding as well as insight into the genetic mechanisms controlling oil biosynthesis in oat.

Groat oil content and composition are important quality traits in oats (Avena sativa L). These traits are controlled by many genes with additive effects. The chromosomal regions containing these genes, known as quantitative trait loci (QTL), can be discovered through their close association with markers. This study investigated total oil content and fatty acid components in an oat breeding population derived from a cross between high oil ('Dal') and low oil ('Exeter') parents. A genetic map consisting of 475 DArT (Diversity Array Technology) markers spanning 1271.8 cM across 40 linkage groups was constructed. QTL analysis for groat oil content and composition was conducted using grain samples grown at Aberdeen, ID in 1997. QTL analysis for multiple agronomic traits was also conducted using data collected from hill plots and field plots in Ottawa, ON in 2010. QTLs for oil content, palmitic acid (16:0), stearic acid (18:0), oleic acid (18:1), linoleic acid (18:2) and linolenic acid (18:3) were identified. Two of the QTLs associated with oil content were also associated with all of the fatty acids examined in this study, and most oil-related QTL showed similar patterns of effect on the fatty acid profile. These results suggest the presence of pleiotropic effects on oil-related traits through influences at specific nodes of the oil synthesis pathway. In addition, 12 QTL-associated markers (likely representing nine unique regions) were associated with plant height, heading date, lodging, and protein content. The results of this study will provide information for molecular breeding as well as insight into the genetic mechanisms controlling oil biosynthesis in oat.