Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Aiming to characterize the main transgenic soybeans cultivars used in Rio Grande do Sul, experiments were conducted during the 2007/2008 season, in Santa Maria/RS. In the field, the cultivars Relmo Anta RR 82, A 6001 RG, A 8000 RG, FUNDACEP 53 RR, FUNDACEP 54 RR, FUNDACEP 56 RR, BRS 244 RR, and CD 214 RR CD 219 RR, drilled at seeds rates of 250, 400 and 550 thousand seed ha-1 and at row spacing of 0.30, 0.45 and 0.60m. The variables were: grain yield, yield components, distribution of income in different strata of the plant, morphological characteristics, rate of soil covering and amount of light incident on the canopy. The experimental design was a randomized blocks, with 4 repetitions in trifatorial outline (9 cultivars x 3 seed rates x 3 row spacing). In laboratory, tests of peroxidase reaction had been carried through only using the tegument of the seeds or the entire seeds and also seedling color for 50 soybean cultivars. For the grain yield cultivars CD 214 RR and FUNDACEP 53 RR had the best results (3589 and 3530 kg ha-1, respectively). For the distribution of income in the plant strata, there is interaction between density of planting and row spacing, which indicate the trends for each cultivar. For the amount of light incident on the canopy, the interactions between the factors of planting density, row spacing, timing of the cycle of development and level of the canopy, combined with the architecture of each cultivar define the amount of light intercepted, after flowering. The morphological response of each cultivar is different for every situation tested, indicating the need for understanding the behavior of each material, to select the practices to maximize the yield. The use of the test of reaction of peroxidase used the entire seed can be used of so efficient form how much the traditionally used method (tegument). The identification of the seedling color may be an early way to identify varietal blend. / Com o objetivo de caracterizar as principais cultivares transgênicas de soja utilizadas no Rio Grande do Sul, foram realizados experimentos durante a safra agrícola 2007/2008, em Santa Maria/RS. Em campo, as cultivares Relmo Anta 82 RR, A 6001 RG, A 8000 RG, FUNDACEP 53 RR, FUNDACEP 54 RR, FUNDACEP 56 RR, BRS 244 RR, CD 214 RR e CD 219 RR foram submetidas às densidade de semeadura de 250, 400 e 550 mil semente ha-1 e aos espaçamentos entre linhas de 0,30, 0,45 e 0,60m. As variáveis avaliadas foram: rendimento de grãos, componentes do rendimento, distribuição do rendimento em diferentes estratos da planta, características morfológicas, taxa de cobertura do solo e quantidade de luz incidente no dossel. O delineamento experimental utilizado foi o de blocos ao acaso, com 4 repetições, no esquema trifatorial (9 cultivares x 3 densidades de semeadura x 3 espaçamentos entre linhas). Em laboratório, foram realizados testes de reação da peroxidase utilizando somente o tegumento das sementes ou as sementes inteiras e também coloração do hipocótilo para 50 cultivares de soja. Para o rendimento de grãos as cultivares CD 214 RR e FUNDACEP 53 RR apresentaram os melhores resultados (3589 e 3530 kg ha-1, respectivamente). Para a distribuição do rendimento nos estratos da planta, existe interação entre densidade de semeadura e espaçamento entre linhas, os quais indicam as tendências para cada cultivar. Para a quantidade de luz incidente no dossel, as interações entre os fatores densidade de semeadura, espaçamento entre linhas, época do ciclo de desenvolvimento e nível do dossel, aliados à arquitetura de cada cultivar definem a quantidade de luz interceptada, após o florescimento. A resposta morfológica de cada cultivar é diferenciada para todas as situações testadas, indicando a necessidade do conhecimento do comportamento de cada material, para a escolha das práticas que visem maximizar o rendimento de grãos. O uso do teste de reação da peroxidase utilizando a semente inteira pode ser utilizado de forma tão eficiente quanto o método tradicionalmente utilizado (tegumento). A identificação da coloração do hipocótilo pode ser uma forma precoce de identificar mistura varietal.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The no-tillage system (SPD) was one of the main innovations in Brazilian agriculture, but there are still discussions about how to achieve and maintain its quality and sustainability. The management of SPD areas through management zones presents great potential for this purpose, since it integrates different variables in order to facilitate and increase the technical and computerized management of agricultural practices and consequently the reduction of polluting potencies in environments. Among the main variables used to delimit management zones are the chemical attributes, yield maps and recently the NDVI index. In this sense, with Article I, the objective was to delimit management zones through yield maps and NDVIs derived from satellite images in historical series. To do this, in an area of 118 ha, three yield maps of different cultures between the years of 2010 to 2015 were selected and for each yield map we searched for the images from the Landsat 5 and 8 satellite that included a date in of the cycle of the crop in question from which the NDVI was calculated and also with the intention of verifying the stability of the NDVI generated in different crop cycles, four other satellite images were selected for four crops according to the historical of the study area, between the years 2007 and 2013. In article II, the objective was to verify the variability caused by the winter cover crop in the summer crop and if the NDVI index performed by land and with a RPAS is able to evidence this variability in the summer crop. In an area 73.96 there was applied a sampling grid of 70.71 x 70.71 m (0.5 ha), where soil sampling for chemical analysis and dry matter nutrients accumulated in the winter cover crop of black oats where soybean was sown in the summer, in which in the R5 and R5.5 stages evaluations were carried out with a portable sensor "by land" and with a RPAS for obtaining of the NDVI index and finally the grain yield of the soybean was determined, as well as the final population of plants. With the results, NDVI from satellite images can replace and/or compose the yield maps (article I) and that the dry mass and accumulated nutrients in the winter crop interfere with the yield of the summer crop and the NDVI index performed by land or with a RPAS was effective in expressing this variability (article II). / O Sistema Plantio Direto (SPD) foi uma das principais inovações na agricultura brasileira, contudo ainda há discussões sobre como alcançar e manter sua qualidade e sustentabilidade. A gestão de áreas sob SPD por meio de zonas de manejo, apresenta grande potencial para essa finalidade, pois integra diferentes variáveis afim de facilitar e incrementar a gestão tecnificada e informatizada das práticas agrícolas, e em consequência a redução de potencias poluidores no ambiente. Entre as principais variáveis utilizadas para delimitar zonas de manejo estão os atributos químicos, mapas de rendimento e recentemente o índice NDVI. Nesse sentido, com o artigo I objetivou-se delimitar zonas de manejo por meio de mapas de rendimento e NDVI oriundos de imagens de satélite em series históricas. Para isso, em uma área de 118 ha, selecionou-se três mapas de rendimento de diferentes culturas compreendidas entre os anos de 2010 a 2015 e para cada mapa de rendimento buscou-se selecionar as imagens satélite oriundas série Landsat que compreendessem uma data dentro do ciclo da cultura em questão a partir das quais procedeu-se o cálculo do NDVI e ainda com o intuito de verificar a estabilidade do NDVI gerado em diferentes ciclos de cultivo, foram selecionadas outras quatro imagens de satélites referentes a quatro cultivos, segundo o histórico de cultivo da área de estudo, compreendidos entre os anos de 2007 a 2013. Já no artigo II, o objetivo foi verificar a variabilidade causada pela cultura de cobertura de inverno na cultura de verão e se o índice de NDVI realizado “por terra” e com um RPAS é capaz de evidenciar essa variabilidade na cultura de verão. Em uma área 73,96 ha, aplicou-se uma malha amostral de 70,71 x 70,71 m (0,5 ha), onde realizou-se a amostragem de solo para a análise química e as avaliações de matéria seca e os nutrientes acumulados na cultura de cobertura inverno da aveia preta onde sobre esta, foi semeada no verão a cultura da soja, na qual nos estágios R5 e R5.5 foram realizadas avaliações com um sensor portátil “por terra” e com um RPAS para a obtenção do índice de NDVI e por final determinou-se o rendimento de grãos da soja, bem como, a população final de plantas. Com os resultados, constatou-se que O NDVI foi um bom parâmetro para delimitar duas zonas de manejo de alto e baixo potencial (artigo I) e que a matéria seca e os nutrientes acumulados na cultura de inverno interferem o rendimento da cultura de verão, sendo que o índice de NDVI realizado “por terra” ou com um RPAS foi eficaz em expressar essa variabilidade (artigo II).

Submitted by Gabriela Lopes (gmachadolopesufpel@gmail.com) on 2016-10-03T17:58:28Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Dissertação Diego Baretta oficial.pdf: 4294007 bytes, checksum: af5d209b7d453630ed4e62113be77952 (MD5) / Approved for entry into archive by Aline Batista (alinehb.ufpel@gmail.com) on 2016-10-11T19:59:16Z (GMT) No. of bitstreams: 2 Dissertação Diego Baretta oficial.pdf: 4294007 bytes, checksum: af5d209b7d453630ed4e62113be77952 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2016-10-11T19:59:16Z (GMT). No. of bitstreams: 2 Dissertação Diego Baretta oficial.pdf: 4294007 bytes, checksum: af5d209b7d453630ed4e62113be77952 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2013-10-29 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / No melhoramento de milho (Zea mays L.) a utilização de cruzamentos dialélicos visando combinações híbridas promissoras é prática comum, assim como o conhecimento da inter-relação entre rendimento de grãos e seus componentes, visando uma maior eficiência nos programas de melhoramento. Desta forma o objetivo deste trabalho foi estimar a capacidade geral (CGC) e específica (CEC) de combinação, utilizando o esquema de dialelo parcial entre linhagens endogâmicas de milho, assim como estimar os coeficientes de correlações fenotípicas entre caracteres de rendimento em milho e o desdobramento em efeitos diretos e indiretos pela análise de trilha. As combinações híbridas oriundas dos dois grupos heteróticos foram avaliadas em cinco ambientes de cultivo, utilizando -se delineamento de blocos casualizados. Avaliaram-se os caracteres: altura de plantas (AP), altura de inserção de espiga (AE), rendimento de grãos de parcela (RG), diâmetro de espiga (DE) e comprimento de espiga (CE). Realizou-se a análise dialélica, seguindo o método IV, modelo I adaptado para dialelos parciais para múltiplos ambientes. Detectaram-se diferenças significativas para cruzamentos entre todos os caracteres. O ambiente revelou significância entre todos os caracteres, com exceção de DE. A interação cruzamento e ambiente foi significativa para os caracteres AP e RG. As CGC's e CEC's foram significativas para todos os caracteres, revelando importância dos efeitos aditivos (CGC) e não-aditivos (CEC) na expressão dos caracteres, revelando predominância dos efeitos não-aditivos da CEC. Os genitores que apresentaram elevados valores de CGC foram 14 e 8 (grupo I) e 6' e 7' (grupo II) para os caracteres AE e AP, assim como dos genitores 15 e 4 (grupo I) e 3' e 4' (grupo II) para os caracteres RG, DE e CE. As combinações híbridas 10x4', 2x4', 12x4', 11x4', 10x3', 7x3', 9x3', 8x3', 14x3' e 15x7' se destacaram-se para os caracteres AE e AP apresentando elevadas magnitudes de CEC. Para os caracteres RG, DE e CE evidenciou-se elevados valores de CEC entre as combinações 3x1', 4x7', 1x1', 4x6', 15x2', 15x5' e 15x8'. Para as estimativas de correlação e análise de trilha foram mensurados caracteres primários e secundários envolvidos nos componentes do rendimento de grãos em milho em cinco locais distintos. Os resultados indicaram que rendimento de grãos de parcela apresentou estimativas positivas e significativas entre os caracteres diâmetro da espiga, peso de espiga, peso de grãos e massa de cem grãos nos ambientes classificados como desfavoráveis. Da mesma forma, evidenciou-se associação significativa e positiva com prolificidade de plantas e rendimento de grãos de parcela em todos os locais analisados, e revelou elevado efeito direto positivo, indicando ser um caráter promissor via seleção indireta visando ganho genético para o rendimento de grãos na cultura. / For maize (Zea mays L.) using diallel hybrids order promising is common practice, as well as knowledge of the inter-relationship between grain yield and its components in order to achieve greater efficiency in breeding programs. Thus the aim of this study was to estimate the general (CGC) and specific (CEC), using the scheme of partial diallel among maize inbred lines as well as estimate the coefficients of correlations between traits in maize yield and unfolding direct and indirect effects in path analysis. The hybrid combinations stemming from two heterotic groups were assessed in five cultivation environments, using a randomized block design. Characters were evaluated: plant height (AP), ear insertion height (AE), grain yield plot (RG), ear diameter (DE) and ear length (CE). The intersection and environment interaction was significant for the characters AP and RG. The CGC's and CEC's were significant for all the characters, revealing the importance of additive (CGC) and non -additive (CEC) in the expression of the characters, noting the predominance of non -additive effects of CEC. The parents who had high values were CGC 14 and 8 (group I) and 6 'and 7' (group II) for AE and AP chara cters, as well as parents of 15 and 4 (group I) and 3 'and 4' (group II) for the characters RG, DE and CE. The hybrid combinations 10x4 ', 2x4' 12x4 ', 11x4', 10x3 ', 7x3', 9x3 ', 8x3' 14x3 'and 15x7' can be up to the characters AE and AP presenting high magnitudes of CEC. For characters RG, DE and CE showed up high CEC values between combinations 3x1', 4x7', 1x1', 4x6', 15x2', 15x5' and 15x8'. For the correlation coefficients and path analysis were measured characters involved in primary and secondary components of grain yield in maize in five different locations. The results indicated that grain yield plot showed positive and significant estimates between characters ear diameter, ear weight, grain weight and weight of hundred grains in environments classified as unfavorable. Likewise, there was a significant positive association with prolificacy of plants and grain yield of the plot at all sites analyzed, and showed high positive direct effect and could be a promising character through indirect selection targeting genetic gain for grain yield in culture.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The common bean is a basic food of Brazilian diet, with great importance in many regions of the country because of economic and/or nutritional reasons. Genetic variability related to the grain yield, morphologic, phenologic and nutritional traits, and others, makes possible the use of genetic improvement and gain genetic can be maximized when adequate methodologies are used to obtain segregant populations and selection of lines. So, the purposes of this study were to evaluate the efficiency of the Genealogic and Single Seed Descent (SSD) methods in the obtained of segregating populations and evaluate direct selection, indirect selection, classical index (SMITH, 1936; HAZEL, 1943), base index (WILLIANS, 1962), parameter and weight free index (ELSTON, 1963), desired gains index (PESEK; BAKER, 1969), multiplicative index (SUBANDI et al., 1973) and rank summation index (MULAMBA; MOCK, 1978) in the identification of common bean families with higher grain yield, morphologic and phenologic desirable traits and higher calcium and iron contents in the seeds. For that, an amount of 272 families from F7 generation 136 families obtained by the Genealogic method with selection in segregant generations for grain yield, 136 families obtained by the SSD method, and 17 registered cultivars to be grown in Rio Grande do Sul state were evaluated in simple lattice model 17 x 17. Through the Genealogic method we obtained a higher number of families with high grain yield, early cycle and a lower general adaptation note (better adaptation). The SSD method was efficient by selection the higher grain yield, higher number of families with the lowest lodging grade (erect type), higher insertion height of first pod and higher calcium and iron contents in seeds. Correlations unfavorable to the interests of improvement were observed between the characters grain yield and height insertion of first pod and calcium and iron content in seeds. The classical index (SMITH, 1936; HAZEL, 1943), the base index (WILLIANS, 1962) and the multiplicative index (SUBANDI et al., 1973) can provide higher genetic progress common bean lines showing high similarity between the selected lines. / O feijão é um alimento básico na dieta dos brasileiros, com importância significativa em diversas regiões do país por razões econômicas e/ou nutricionais. Variabilidade genética com relação à produtividade de grãos, aos caracteres morfológicos, fenológicos e nutricionais possibilita a utilização do melhoramento genético e ganhos podem ser obtidos quando forem utilizadas metodologias adequadas na condução das populações segregantes e na seleção de linhagens. Desta forma, os objetivos deste trabalho foram avaliar a eficiência dos métodos Genealógico e Descendente de uma Única Semente (SSD) na condução das populações segregantes e avaliar a seleção direta, seleção indireta, índice clássico (SMITH, 1936; HAZEL, 1943), índice base (WILLIANS, 1962), índice livre de peso e parâmetros (ELSTON, 1963), índice baseado nos ganhos desejados (PESEK; BAKER, 1969), índice multiplicativo (SUBANDI et al., 1973) e índice baseado em soma de ranks (MULAMBA; MOCK, 1978) na identificação de famílias de feijão com maior produtividade de grãos, com caracteres morfológicos e fenológicos desejáveis e maior teor de cálcio e de ferro nas sementes. Para tanto, um total de 272 famílias em geração F7 - 136 famílias conduzidas pelo método Genealógico com seleção nas gerações segregantes para a produtividade de grãos e 136 famílias conduzidas pelo método SSD, além de 17 cultivares registradas para cultivo no Estado do Rio Grande do Sul, foram avaliadas em delineamento látice simples 17 x 17. Pelo método Genealógico se obteve maior número de famílias com alta produtividade de grãos, de ciclo precoce e com menor nota geral de adaptação (melhor adaptação). O método SSD foi eficiente para a seleção de maior número de famílias com as menores notas de acamamento (porte ereto), as maiores alturas de inserção de primeira vagem e os maiores teores de cálcio e de ferro nas sementes. Correlações desfavoráveis ao interesse do melhoramento foram observadas entre os caracteres produtividade de grãos, altura de inserção da primeira vagem e teores de cálcio e de ferro nas sementes. O índice clássico (SMITH, 1936; HAZEL, 1943), o índice base (WILLIANS, 1962) e o índice multiplicativo (SUBANDI et al., 1973) podem propiciar progresso genético superior na seleção de linhagens de feijão apresentando elevada coincidência entre as linhagens selecionadas.

The objectives of this study were to evaluate whether advanced common bean lines differ in phenological, morphological, grain yield and cooking quality characters; to study the linear correlations between these characters; and to select superior lines for these characters for use in breeding programs. For this purpose, 14 common bean lines of trial Use and Cultivation South -Brazilian Bean (VCU - SB) were growing in normal rainy 2012/2013 and in dry season 2013 in Santa Maria, Rio Grande do Sul, Brazil. Data were subjected to analysis of individual and joint variance, using the F test at 5 % probability. If the effect of line and control was significant, the stratification of averages was performed by the Scott-Knott test at 5 % probability. Interaction line x growing season significant was observed for the characters: number of days from emergence to flowering, reproductive period, cycle, lodging, stay green, number of lateral branches, number of pods per plant, number of grains per plant, number of grains per pod, weight of 100 grains, grain yield, grain length and width. The line and control evaluated differed significantly among the characters: number of days from emergence to flowering, cycle, number of nodes on main stem, width and thickness of grains, grain brightness and time of cooking, allowing you to select improved lines for these characters. Positive linear correlation of high magnitude was observed between grain yield and number of pods per plant (r = 0.632) and weight of 100 grains (r = 0.942), while the grain yield and the number of days from emergence to flowering (r = -0.857) and the cycle (r = -0.677) had high negative linear correlation. The LP 09-40 line and BRS Valente control have the lower note of lodging in the two growing seasons, allowing the use of these blocks of crosses to obtain lines with erect architecture. The CNFP 10794 and DF 06-17 lines may be used as parents in hybrid combinations for presenting high yield and reduced cooking time and high yield and early cycle, respectively. / Os objetivos deste trabalho foram avaliar se as linhagens avançadas de feijão diferem quanto aos caracteres fenológicos, morfológicos, de produção e de qualidade de cozimento; estudar as correlações lineares entre esses caracteres; e selecionar linhagens superiores para esses caracteres para uso em programas de melhoramento. Para tanto, foram avaliadas 14 linhagens de feijão do Ensaio de Valor Cultivo e Uso Sul-brasileiro de Feijão (VCU-SB) em cultivo de safra 2012/2013 e de safrinha 2013 em Santa Maria, Rio Grande do Sul, Brasil. Os dados obtidos foram submetidos à análise de variância individual e conjunta, usando o teste F a 5% de probabilidade. Sendo o efeito de linhagens significativo, a estratificação das médias obtidas foi realizada pelo teste de Scott-Knott a 5% de probabilidade. Interação linhagem x época de cultivo significativa foi observada para os caracteres: número de dias da emergência a floração, período reprodutivo, ciclo, acamamento, stay green, número de ramos laterais, número de vagens por planta, número de grãos por planta, número de grãos por vagem, massa de 100 grãos, produtividade de grãos, comprimento e largura de grãos. As linhagens e as testemunhas avaliadas diferiram significativamente para os caracteres: número de dias da emergência a floração, ciclo, número de nós no ramo principal, largura e espessura dos grãos, luminosidade dos grãos e tempo de cozimento dos grãos, possibilitando a seleção de linhagens superiores para esses caracteres. Correlação linear positiva de alta magnitude foi observada entre a produtividade de grãos e o número de vagens por planta (r = 0,632) e a massa de 100 grãos (r = 0,942), enquanto que a produtividade de grãos e o número de dias da emergência a floração (r = -0,857) e o ciclo (r = -0,677), apresentaram alta correlação linear negativa. A linhagem LP 09-40 e a testemunha BRS Valente apresentam as menores notas de acamamento nas duas épocas de cultivo, o que possibilita o uso dessas em blocos de cruzamentos para a obtenção de linhagens com porte ereto. As linhagens CNFP 10794 e DF 06-17 poderão ser utilizadas como genitores em combinações híbridas por apresentarem alta produtividade de grãos e reduzido tempo de cozimento e alta produtividade de grãos e ciclo reduzido, respectivamente.

MSCAGR (Plant Production) / Department of Plant Production / Smallholder farmers in Sub-Saharan Africa still obtain low grain yields in maize largely due to low soil fertility. The soils are inherently low in nitrogen (N) that is required for the proper development of the maize plant. Currently there are no commercial cultivars for low N tolerance locally. The combining ability approach can be used as a tool for breeding desirable cultivars. In order to improve grain yield in maize, it is important to consider ear prolificacy which is a major yield component. Therefore this study was designed to estimate combining ability in maize. Exotic germplasm from the International Maize and Wheat Improvement Center and the Institute of Tropical Agriculture as well as the local germplasm from the Agricultural Research Council was used in the study to generate crosses. One hundred and two crosses were evaluated together with a standard commercial check under low N and optimum N conditions. The specific objectives of the study were to determine general and specific combining ability for prolificacy among local and exotic inbred lines and evaluate the response of prolific hybrids to low N conditions. The hybrids were planted in the 2014/2015 summer season under irrigation in Potchefstroom, Cedara and Taung in field plots consisting of 0.75m x 0.25m spacing in a 0.1 alpha lattice design replicated twice. Data for agronomic attributes were recorded and subjected to analysis of variance using SAS version 9.1.3. Genetic correlations were analyzed using the Principal Components Analysis and factor analysis based on the correlation analysis and major traits. The results showed variation in agronomic performance among the inbred lines and their F1 hybrids. Inbred lines including TZEI63, T1162W, L15 and L17 showed positive GCA estimates for ear prolificacy at the different locations. Specific combining ability for prolific hybrids was positive at all locations and environments. The GCA:SCA ratio was close to unity; indicating that the number of ears per plant showed highly significant (P<0.01) correlation with grain yield. The hybrids showed ear prolificacy under the low N conditions. This trait can be used effectively in stress tolerance maize breeding programmes. / NRF

Langzeitdüngungsversuche (LTFE) sind für die Agrarforschung von entscheidender Bedeutung, da sie dokumentieren, überwachen, lernen und zeigen können, was in der Vergangenheit geschehen ist, und mit Hilfe von Vorhersagemodellen vorhersagen und simulieren können, was in Zukunft geschehen wird. Diese Modelle dienen dazu, zukünftiges Pflanzenwachstum unter verschiedenen Klima- und Bewirtschaftungsszenarien abzuschätzen und so Entscheidungsprozesse zu unterstützen. In diese Studie wurden die Reaktionen der Getreideerträge auf das Düngermanagement in Sandböden in einem LTFE (1971 bis 2016) in Nordostdeutschland analysiert. Die Ziele dieser Studie waren a) die Analyse der Ertragsreaktionen von Sommergerste, Winterroggen und Winterweizen auf das Düngemanagement, b) die Analyse der Sensitivität der Ertragsreaktionen auf den Zeitpunkt von Wetterereignissen und c) der Vergleich verschiedener Analysemodelle. Die Studie ergab, dass die Reaktion der Getreideerträge auf das Düngermanagement von komplexen Beziehungen zwischen Klimaabhängigkeit, Vorfrucht und Bodeneigenschaften beeinflusst wurde. Die Witterungsbedingungen bei der Aussaat und in den frühen Wachstumsstadien des Getreides beeinflusste den Kornertrag. Bei Wintergetreide waren die Intensität und Dauer der extremen Temperaturen im Sommer, insbesondere die Anzahl der Tage mit einer Höchsttemperatur von über 30°C im Juli, eine wichtige Variable für den Ertrag. Unter den untersuchten Modellen zeigte das LMM-Modell eine bessere Vorhersageleistung als das M5P-Modell, und beide hatten umfangreichere Regressoren als die ANOVA und die BMA. Das M5P-Modell bot eine intuitive Visualisierung wichtiger Variablen und ihrer kritischen Schwellenwerte und offenbarte andere Variablen, die vom LMM-Modell nicht erfasst wurden. Die Ergebnisse dieser Analyse tragen zu umfassenden Strategien für eine nachhaltige Pflanzenproduktion im Hinblick auf den zukünftigen Klimawandel bei. / Long-term fertilizer experiments (LTFEs) are essential for agricultural research as they provide necessary information and data to build predictive models. These models can be used to estimate future plant growth under different climate and management scenarios to support decision-making processes. The current study analyzed cereal grain yield responses to fertilizer management in sandy soil in a LTFE (1971 to 2016) in Northeast Germany. The objectives of this study were to a) analyze yield responses of spring barley), winter rye, and winter wheat to fertilizer management, b) analyze the sensitivity of yield responses to timing of weather events, and c) compare different analysis models. The study revealed that cereal yield response to fertilizer management was influenced by complex relationships among climatic dependence, preceding crop, and soil characteristics. Weather conditions at seeding and early growth stages of cereal were found to be sensitive to grain yield. For winter cereals, the intensity and duration of extreme temperatures in the summertime (harvest year), especially the number of days recorded with a maximum temperature above 30°C in July was an important variable for the yield. Among the investigated models, LMM-model had a better predictive performance compared to M5P-model and both had richer regressors than the ANOVA and BMA-model. The M5P-model presented an intuitive visualization of important variables and their critical thresholds, and revealed other variables that were not captured by the LMM-model. The findings of this analysis contribute to comprehensive strategies for sustainable crop production with regard to future climate change.

Les associations d'espèces sont définies comme la culture simultanée d'au moins deux espèces sur la même parcelle pendant une période significative de leur croissance. Ce système permettrait d'améliorer l'utilisation des ressources du milieu (eau, azote, lumière…) et ainsi d'augmenter le rendement et la qualité des grains par rapport aux cultures monospécifiques. L'objectif de notre travail était d'analyser le fonctionnement et d'évaluer la performance des associations blé dur - pois d'hiver et blé dur - féverole d'hiver pour aider à la conception d'itinéraires techniques adaptés à différents objectifs de production. Pour cela nous avons testé, au cours de trois années d'expérimentations, différentes combinaisons de variétés de blé dur, disponibilités en azote, structures de couverts et densités de plantes. Nos résultats ont confirmé l'intérêt de ces systèmes pour améliorer le rendement et la teneur en protéines du blé dur comparativement aux cultures monospécifiques mais également pour la réduction des ravageurs, maladies et de l'enherbement dans certaines conditions. Ces systèmes sont ainsi particulièrement bien adaptés aux situations à faible disponibilité en azote en raison de la complémentarité entre céréale et légumineuse pour l'utilisation de l'azote (minéral du sol et fixation symbiotique) mais aussi pour la captation de l'énergie lumineuse. In fine, ce travail a permis de proposer des prototypes d'itinéraires techniques d'associations adaptés à différents objectifs de production, grâce notamment à l'analyse dynamique des compétitions et complémentarités entre espèces au sein du couvert et en particulier de l'élaboration du rendement du blé dur en association. / Intercropping is the simultaneous growing of two or more species in the same field for a significant period. Such systems are known to use available resources (water, light, nitrogen…) more efficiently than their corresponding sole crops and consequently to increase yield and grain protein concentration particularly in low N input systems. The aim of our work was to analyse the functioning of durum wheat - winter pea and durum wheat - winter faba bean intercrops. A 3-year field experiment was carried out with different fertilizer-N levels, wheat cultivars and plant densities. The intercrop efficiency was studied in order to further design low inputs cropping systems for specific objectives. Our results confirm that intercropping is more suited to low-N-input systems because it takes advantage of complementary N sources (soil mineral N and N2 fixation) and light use between species of the intercrop. Thus, intercrops were more efficient than sole crops for yield, they increased durum wheat grain protein concentration and in certain cases reduced weeds, pests and diseases. Finally, our work indicates that intercrops can be optimized for specific objectives by the choice of crop species, cultivars, N fertilization and plant densities in order to maximize resource capture and minimize competition. Indeed, intercrop efficiency is determined by the complementary resource use between the two species as well as the relative strength of the intra- and interspecific dynamic competitive interactions.

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Cereal rye (CR), the most common and effective nitrogen (N) scavenging cover crop option in the Midwest, is often utilized in cropping systems to reduce nitrate loss for environmental benefits. To increase environmental efficiency in Midwest corn cropping systems, we must increase the overall adoption of CR. However, due to the yield reduction potential (6%) for corn planted after CR termination, CR is primarily recommended before soybean. To increase CR adoption, we must develop adaptive fertilizer management practices that achieve competitive grain yields relative to cropping systems where CR is not adopted. Therefore, the objectives of this study are to determine (1) the effect of CR and starter nitrogen rate on corn growth and nitrogen content. (2) the optimum starter nitrogen rate to achieve agronomic optimum corn yield following CR. (3) the impact of phosphorus (P) at starter on plant growth, nitrogen content, and yield with the inclusion of CR. For our study, five starter N rates were applied in a 5x5 cm band to both CR and non-CR plots, concentrations ranged from 0-84 kg N ha^-1in 28 kg N ha^-1 intervals. Total N applied was the same for each treatment, relative to its location, and was split between starter N at planting and sidedress applied at growth stage V6 relatively. Although CR termination took place at least two weeks before planting, CR decreased corn grain yield at one of three locations by an average of 8%, nitrogen recovery efficiency (NRE) by 27%, and R6 total N content by 23%, relative to the conventional control (non-CR 0N), when no starter N was applied. At one of three locations, starter N rates of 56 kg N ha^-1, 56 kg N ha^-1plus 17 kg P ha^-1, and 84 kg N ha^-1 increased corn grain yield, in CR plots, and 56 kg N ha^-1 plus 17 kg P ha^-1 increased corn grain yield in non-CR plots. Phosphorus increased corn grain N content at growth stage R6 in one of three locations and did not impact corn grain yield at all locations. We conclude that the inclusion of starter N at planting has the potential to increase agronomic productivity in CR corn cropping systems in soil environments with a high capacity to mineralize soil N. However, further research is required to refine our starter N results to find an optimum starter N rate to apply before planting corn following CR.