Orientador: Edson Luiz Lopes Baldin / Resumo: O milho (Zea mays L.) é um dos principais cereais cultivados no mundo. O Brasil é o terceiro maior produtor deste grão ficando atrás somente da China e dos Estados Unidos da América. A cigarrinha Dalbulus maidis (DeLong & Wolcott) (Hemiptera: Cicadellidae) causa danos diretos à cultura por meio da sucção contínua de seiva, além de ser vetora de fitopatógenos como o espiroplasma Spiroplasma kunkelli Whitcomb (CSS) e o fitoplasma Candidatus Phytoplasma asteris (MBSP), molicutes responsáveis por enfezamentos nas lavouras. O uso do controle químico dessa espécie apresenta baixa eficiência por se tratar de um inseto com alto grau de dispersão. A utilização de genótipos resistentes a pragas agrícolas é uma estratégia valiosa e compatível com as demais ferramentas do manejo integrado de pragas (MIP). O presente estudo objetivou avaliar 32 genótipos de milho não-Bt e Bt sob condições de campo, visando caracterizar a expressão de antixenose e a incidência de molicutes. Foram realizados dois experimentos, sendo o primeiro na “safrinha” (2018) e o segundo na “safra de verão” (2018/2019). Para a constatação da presença do espiroplasma e do fitoplasma, foi realizada análise PCR na “safra de verão” (2018/2019). Posteriormente, avaliou-se a possível expressão de resistência por antixenose e/ou antibiose em 11 genótipos de milho previamente selecionados no ensaio conduzido a campo (Capítulo 1), sobre D. maidis em casa de vegetação. Os parâmetros biológicos avaliados foram: duração dos estádi... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Corn (Zea mays L.) is one of the main cereals grown in the world. Brazil is the third largest producer of this grain behind only China and the United States of America. The leafhopper Dalbulus maidis (DeLong & Wolcott) (Hemiptera: Cicadellidae) causes direct damage to the crop through the continuous suction of sap, in addition to being a vector of phytopathogens such as the Spiroplasma kunkelli Whitcomb (CSS) and the phytoplasma Candidatus Phytoplasma asteris (MBSP), responsible for red stunt. The use of chemical control of this species has low efficiency because it is an individual with a high degree of dispersion. The use of genotypes resistant to agricultural pests is a valuable strategy and compatible with other integrated pest management (IPM) tools. The present study aimed to evaluate 32 no-Bt and Bt corn genotypes under field conditions, aiming to characterize the expression of antixenosis and the incidence of molicutes. Two experiments were carried out, the first in the second harvest (2018) and the second in the first harvest (2018/2019). To contact the presence of spiroplasma and phytoplasma, PCR analysis was performed in the first harvest (2018/2019). Subsequently, the possible expression of resistance by antixenosis and /or antibiosis was evaluated in 11 corn genotypes previously selected in the field trial (Chapter 1), on D. maidis in a greenhouse. The biological parameters evaluated were: duration of the stages and the nymphal period, viability per instar and to... (Complete abstract click electronic access below) / Mestre

Brassinosteroids are plant hormones which are also known for their pleiotropic effects on plants exposed to various biotic and abiotic stress factors. The aim of this study was to evaluate the role of 10-8 M 24-epibrassinolide in Zea mays L. and Vicia faba L., grown under conditions of drought stress (6, 10, 14, 18 days) with an emphasis on different answer to their drought sensitive and resistant genotypes. Net photosynthetic rate (PN) and transpiration rate (E), stomatal conductance (gs), osmotic potential (ψs), proline (Pro) and malondialdehyde (MDA) content and membrane injury index (MI) were measured in stressed plants and plants grown under controlled conditions. The most important factor influencing these parameters was drought, which led to a gradual decrease of PN, E, gs, ψs and increase of Pro, MDA a MI. The effect of 24-epibrassinolid was significant rather exceptionally and in these cases, more pronounced response was observed in drought stressed plants compared with plants grown under controlled conditions. Plants showed intraspecific variability in their reactions, which in sensitive and tolerant genotypes were not clear and differed depending on the studied parameters and conditions of plant cultivation.

Transgenic plants in the US and abroad generated using genetic engineering technology are regulated with respect to release into the environment and inclusion into diets of humans and animals. For crops incorporating pharmaceuticals or industrial enzymes regulations are even more stringent. Notifications are not allowed for movement and release, therefore a permit is required. However, growing under permit is cumbersome and more expensive than open, non- regulated growth. Thus, when the genetically engineered pharmaceutical or industrial crop is ready for scale-up, achieving non-regulated status is critical. Regulatory compliance in the US comprises petitioning the appropriate agencies for permission for environmental release and feeding trials. For release without yearly permits, a petition for allowing non-regulated status can be filed with the United States Department of Agriculture with consultations that include the Food and Drug Administration and possibly the Environmental Protection Agency, the latter if the plant includes an incorporated pesticide. The data package should ensure that the plants are substantially equivalent in every parameter except for the engineered trait. We undertook a preliminary study on transgenic maize field-grown hybrids that express one of two cellulase genes, an exo-cellulase or an endo-cellulase. We performed field observations of whole plants and numerous in vitro analyses of grain. Although some minor differences were observed when comparing genetically engineered hybrid plants to control wild type hybrids, no significant differences were seen.

A single application of aerobically digested sewage sludge was applied by Rappaport et al. (1988) in 1984 at rates up to 210 dry Mt ha⁻¹ on a Davidson clay loam (clayey, kaolinitic, thermic, Rhodic KandiuduIts). The heavily contaminated sludge supplied up to 760 kg Cu and 620 kg Zn ha⁻¹, which are below current cumulative limits, but above annual loading limits for these metals (USEPA, 1993). Rappaport et al. (1988) reported an increase in DTPA extractable Cu and Zn with increasing sludge rate. They observed a linear increase in com yields with an increase in sludge rate, which was attributed to high levels of available N supplied by the sludge. In the present residual study, conducted at the same research site, DTPA extractable Cu and Zn followed the trend observed by Rappaport et at. (1988). However, a linear decrease in corn and sorghum yields was observed with increasing sludge rate. The sludge-related decrease in yields was attributed to phytotoxicity (probably a combination of Al, Cu, Mn, and Zn) induced by low soil pH levels. Whole plant tissue concentrations of eu and Zn at the high sludge rates were above the normal range, however grain concentrations were within the normal range. An adsorption study was conducted, in which soils were amended with Ca(OH)₂ and Al₂(S0₄)₃, to ascertain the effect of decreased pH on Cu adsorption on the soil. Copper adsorption maxima decreased with a reduction in soil pH in all treatments. The effect of ionic strength on Cu adsorption was also investigated. Regardless of pH or ionic strength, Cu adsorption increased with an increase in sludge rate. This adsorption increase was attributed to the higher organic matter content of the sludge treatments. The organic matter at the highest sludge rate was approximately double that of the control after 11 years. The adsorption study shows that sludge amendment has long-term effects on metal retention in soils and the field study reveals that careful management of sludge-amended soils is necessary to prevent phytotoxicity. / Ph. D.

Brassinosteroids (BRs) have been recognized to alleviate damages caused by drought stress and to enhance tolerance to water deficit. Soaking of maize kernels before the sowing in solution with different 24-epibrassinolide concentrations (especially the 10-8 M) had a positive effect on growth of plants before and after the stress period, although it did not affected relative water content and photosynthetic parameters. After the recovery under optimal conditions there were no differences among the treatments. When compared to spraying, soaking of maize kernels was not proved to have any advantages, though its positive effect on plants germination under water deficit conditions could be possible. Based on the results of the second season experiment it is not possible to deduce the role of exogenous BRs application (spraying with 24-epibrassinolide) or endogenous BRs biosynthesis (spraying with biosynthesis inhibitor - brassinazole) in maize plants subjected to water deficit. However, decrease in relative water content in contrast to chlorophylls content increase during the days following after drought stress onset in both cultivars (contrastive in drought sensitivity) challenges for further investigation of this problem. Understanding the role of BRs in plant drought tolerance and resistance is...

A ureia (UR) é atualmente o fertilizante nitrogenado mais utilizado na agricultura brasileira. No entanto, quando aplicada na superfície do solo está sujeita a perdas de nitrogênio (N) por volatilização de NH3. Uma das formas de minimizar as perdas de N-NH3 é o tratamento do fertilizante com inibidores de urease. A associação desses compostos com substâncias húmicas (SH), no tratamento da UR poderia aumentar a eficiência de uso dos nutrientes pelas plantas. O objetivo desse trabalho foi avaliar a eficiência de inibidores de urease, associados ou não com SH no revestimento da UR como fonte de N em cobertura para o milho. O experimento foi conduzido em casa de vegetação durante 62 dias em delineamento experimental de blocos ao acaso, com três repetições, no esquema fatorial completo, com UR recoberta três inibidores de urease (0,40% B + 0,15% Cu; 0,64% B; NBPT) e um tratamento adicional sem inibidor (Ausente), três doses de SH (0, 0,6, e 1,2%) e um controle. Os tratamentos com N constaram da aplicação de fonte única do nutriente [CO(15NH2)2] aplicada em faixa e em superfície na dose de 180 mg kg-1 de N no estádio fisiológico V4 das plantas de milho. As plantas foram amostradas nos estádios V8 e VT do milho, respectivamente, aos 52 e 62 dias após a semeadura, quando foram avaliados: biometria de parte aérea, área foliar, biomassa seca de raízes e da parte aérea, caracterização morfológica do sistema radicular, e a eficiência de uso do N-fertilizante (EUN) pelo método do balanço isotópico (15N). Também se quantificou as perdas de N por volatilização de NH3 por meio de coletores semi-estáticos com espuma embebida em H3PO4- para avaliação comparativa entre tratamentos. Embora a concentração mais elevada de ácido bórico na UR (0,64% B) tenha reduzido mais as perdas de NH3 por volatilização em comparação ao 0,40 % B + 0,15 % Cu, isso não resultou em maior eficiência de uso do N-fertilizante pelo milho em VT, que ocorreu somente em V8. Em ambos os estádios, o NBPT apresentou-se como melhor inibidor de urease na ausência de SH. A aplicação de SH não aumentou a EUN pelo milho em V8 ou VT quando associados com 0,40% B + 0,15% Cu, 0,64% B, ou mesmo na UR convencional. Entretanto, quando associado com o NBPT, ocorreu aumento das perdas de NH3 por volatilização e redução na EUN em VT, o que pode ter ocorrido devido ao elevado pH das SH (8,5-9) e ao seu baixo poder tampão. A aplicação da UR convencional ou revestida com inibidores de urease não aumentou a taxa de crescimento ou biomassa seca de raízes e parte aérea do milho em nenhum dos períodos avaliados quando comparado ao controle. Da mesma forma, não foram observadas diferenças expressivas entre tratamentos na caracterização morfológica do sistema radicular em V8 ou VT. A ausência de diferença entre tratamentos pode ser explicada pelo curto período de tempo entre a adubação de cobertura e as avaliações das plantas, à aplicação superficial das fontes recobertas com SH e ao método de irrigação adotado, que impediu que as SH entrassem totalmente em contato com as raízes da planta. Além disso, é possível, também, que a dose de SH empregada tenha sido muito baixa para ser efetiva. / Urea (UR) is the most widely applied nitrogen (N) fertilizer in Brazilian agriculture. However, UR is more prone to ammonia (NH3) volatilization losses than other N sources when surface-applied. One alternative to improve nitrogen use efficiency (NUE) of surface-applied UR is through application of urease inhibitors as coating materials of UR. The association of these composts with humic substances (HS) as UR coating materials may also improve nutrient recovery by plants. The aim of this study was to evaluate the efficiency of urease inhibitors, associated or not with HS, as coating materials of UR as new top-dress N sources for maize. A greenhouse pot trial was carried out over 62 days with maize (Zea mays L.), in a completely randomized block design, with three replicates in a full factorial design, with UR coated with three urease inhibitors (0,40% B + 0,15% Cu; 0,64% B; NBPT) and one additional treatment without inhibitor, three doses of HS (0, 0.6, and 1.2%), and one control treatment. All treatments imposed had CO(15NH2)2 as N source, application rate of 180 mg kg-1of N, and side-dressing application at the V4 maize growth stage. Maize plants were assessed at V8 and VT growth stages, at 52 and 62 days after sowing, respectively, when it was evaluated: above and below-ground plant dry matter weight; leaf area; root morphological traits (length, surface area, and volume); and fertilizer use efficiency by the 15N balance method. In addition, semi-open static collectors with foam discs previously soaked in H3PO4- were used to quantify comparatively the NH3 volatilized from all treatments. Although the addition of a higher dose of boric acid on UR (0,64% B) promoted lower ammonia losses by volatilization in comparison to 0,40 % B + 0,15 % Cu, it did not result in higher NUE by maize in VT, which occurred at V8. In both growth stages, NBPT presented the best performance as urease inhibitor in the absence of HS. The application of HS did not increase NUE by maize in V8 and VT when associated with 0,40% B + 0,15% Cu, 0,64% B or even conventional UR. However, when added in conjunction with NBPT, it increased ammonia volatilization and reduced NUE in VT which may have occurred due to the high pH of the HS (8.5-9) and low buffering capacity. Moreover, the application of conventional UR or UR treated with HS and urease inhibitors did not increase maize growth rate or shoot/root dry matter weight in comparison to the control treatment at both growth stages. Likewise, there was no major significant differences between treatments on root morphological traits (length, surface area, and volume) at both growth stages assessed. The lack of sizable outcome differences between treatments could be explained by the application of a single N dose, the short period of time between the side-dressing application and assessment of maize plants, and to the surface-application of the HS and method of irrigation which prevented HS to have full contact with maize roots. Furthermore, HS application rate may have been too low to be effective.

Em estudos recentes, a epistasia tem sido detectada no controle genético de caracteres quantitativos em diversas espécies. Dado o grande número de locos controlando um único caráter, é evidente que ocorram interações inter-alélicas, além de pleiotropia, que resulta do controle de mais de um caráter por um mesmo loco. Também tem sido reportada a presença de epistasia pleiotrópica em animais, que basicamente resulta do efeito da epistasia sobre locos pleiotrópicos ou sobre múltiplos caracteres, afetando a correlação genética entre esses. Desse modo, o objetivo desta pesquisa foi a análise genética de diversos caracteres de importância econômica e agronômica em milho, incluindo estimativas de componentes de variância genética e presença de efeitos epistáticos em ambientes com e sem estresse hídrico; e estimativas de epistasia pleiotrópica. Para isso foi utilizado o delineamento triple test cross (TTC), obtendo-se 300 progênies de retrocruzamentos que foram avaliadas em oito ambientes nos anos agrícolas de 2008/2009 e 2009/2010, na cidade de Piracicaba, São Paulo, Brasil. Ao longo da condução dos experimentos observou-se a ocorrência de déficit hídrico, de modo que os ambientes foram divididos em dois grupos (sem estresse - SE e com estresse - CE). Avaliou-se os caracteres da planta: dias para os florescimentos masculino (FM) e feminino (FF), intervalo entre florescimentos (IF), altura da planta (AP) e espiga (AE), posição relativa da espiga (PRE), acamamento e quebramento de plantas (ACQ), stay green (SG); produção de grãos (PG) e seus componentes de produção: número de fileiras (NF), número de grãos por fileira (NGF), peso de 300 grãos (P300), comprimento de grãos (CG) e prolificidade (PRO). Foram realizadas análises de variâncias individuais para cada ambiente; análises conjuntas de ambientes; e análises conjuntas de grupos, das quais estimaram-se as variâncias aditiva, de dominância, epistática e suas respectivas interações com ambiente; o grau médio de dominância, coeficientes de herdabilidade em nível de médias de progênies e em nível de parcelas e também os efeitos epistáticos em plantas F2. Também foram feitas análises de covariâncias considerando todos os caracteres combinados dois a dois, tendo sido estimados os coeficientes de correlações. A epistasia foi detectada para a maioria dos caracteres nos dois grupos, exceto ACQ, IF, SG e CG, no grupo SE; e ACQ, CG e PRO, no grupo CE. Porém não foi detectada interação epistasia x ambiente em nenhum dos grupos e a interação epistasia x grupos só foi detectada para IF. Os efeitos epistáticos em plantas F2 para PG variaram de -3,03 t ha-1 a 5,13 t ha-1 no grupo SE e -1,94 t ha-1 a 2,87 t ha-1 no grupo CE, mas não foram detectadas altas magnitudes dos coeficientes de correlações entre esses efeitos e as médias gerais dos retrocruzamentos. Foram detectados coeficientes de correlações epistáticas para 29,67% das combinações, indicando a presença de epistasia pleiotrópica entre caracteres. Observou-se a formação de agrupamentos entre caracteres relacionados. Em vista desses resultados, a epistasia se constituiu num componente importante no controle dos caracteres analisados, sugerindo ainda que a epistasia pleiotrópica possa ser responsável pelas interações complexas no genoma. / In recent studies, epistasis has been considered in genetic control of quantitative traits in several species. Due to a large number of loci controlling a single trait, it is evident that inter allele interactions occur in addition to pleiotropy, which results in the control of more than one trait by the same locus. Besides, the presence of pleiotropy, epistasis has been reported in animals, which basically result from the effect of epistasis on pleiotropic loci or on multiple traits, affecting the genetic correlation between them. Thus, the objective of this research was to do genetic analysis of several traits of economic and agronomic importance in maize, including estimates of genetic variance components and the presence of epistatic effects in environments with and without water stress; and estimates of pleiotropic epistasis. For this, the triple test cross (TTC) design was used to obtain 300 backcrosses progenies, which were evaluated in eight environments in the 2008/2009 and 2009/2010 agricultural seasons, in Piracicaba, Sao Paulo State, Brazil. During the conduction of the experiments, the occurrence of water deficit was observed, so that the environments were divided into two groups (without stress - WS and with stress - SS). The traits evaluated were: days to anthesis (DA), days to silking (DS), anthesis-silking interval (ASI), plant height (PH), ear height (EH), ear placement (EP), root and stalk lodging (PL) and stay green (SG), grain yield (GY), kernel rows (KR), kernels per row (KPR), 300-grain weight (300W), kernel depth (KD) and prolificacy (PRO). Individual analysis of variances were performed for each environment; joint analysis of environments; and joint analysis of groups, from which additive, dominance and epistatic variances and their respective interactions with the environment were estimated; besides average degree of dominance, heritability coefficients at level of half-sib progenies and at plots level; also epistatic effects in F2 plants were estimated. Covariance analyses were also performed considering all pairs of traits, two by two, and the correlation coefficients were estimated. Epistasis was detected for most traits in both groups except to PL, ASI, SG and KD, in WS group; and PL, KD, and PRO, in SS group. However, no epistasis x environment interaction was detected in any group and epistasis x group interaction was detected only to ASI. Epistatic effects on F2 plants were detected to GY, oscillating from -3.03 t/ha to 5.13 t/ha in WS group and from -1.94 t/ha to 2.87 t/ha in SS group. However, high magnitudes of correlation coefficients between these F2 epistatic effects and averages of backcrosses were not detected. Epistatic correlation coefficients were detected for 29.67% of pairs of traits, indicating the presence of pleiotropic epistasis. The formation of clusters was observed between related traits. In view of these results, epistasis was considered an important component in the control of traits analyzed, furthermore suggesting that pleiotropic epistasis may be responsible for complex interactions in the genome.

O melhoramento genético clássico de sementes milho (Zea mays L.) permitiu desenvolver inúmeras variedades, incluindo o milho com qualidade proteica melhorada (Quality Protein Maize, QPM), que visava aumentar os teores proteicos e as propriedades nutricionais. Por outro lado, novas variedades comerciais foram obtidas por vegetais geneticamente modificados (GM), com foco em parâmetros agronômicos. Em ambos os casos, a segurança dessas variedades para uso como alimento é uma das principais preocupações dos desenvolvedores e dos órgãos de regulamentação. A Equivalência Substancial é a base do sistema de avaliação da segurança de culturas geneticamente modificadas, no entanto alterações na expressão de proteínas não são devidamente analisadas e esclarecidas. As abordagens proteômicas complementam as técnicas de avaliação de biossegurança para alimentos GM, bem como permitem investigar possíveis efeitos indesejáveis derivados do melhoramento clássico. Os objetivos do presente estudo foram caracterizar e comparar os perfis proteicos de variedades de milhos convencionais melhorados (QPM) e geneticamente modificados (GMs), contra suas respectivas linhas convencionais utilizando técnicas proteômicas como eletroforese bidimensional (2-DE) e bottom up shotgun (gel-free). Num primeiro estudo, foram utilizadas três amostras de milho, sendo duas variedades convencionais com QPM (QP1 e QP2) e uma variedade convencional normal (CN). No segundo estudo, foram analisadas duas cultivares de milho GM (GM1 e GM2) e seus respectivos convencionais genitores (CG1 e CG2). As composições químicas de todas as amostras também foram avaliadas quanto a Equivalência Substancial. O extrato bruto proteico foi submetido à análise de eletroforese unidimensional (1-DE), bidimensional (2-DE) e bottom up shotgun (gel-free). As imagens dos mapas proteicos foram analisadas pelo software Image Master 2D Platinum 7.0 (GE). Os spots diferencialmente expressos e selecionados foram sequenciados por MS. Pela composição química das principais frações das amostras de milho foi possível identificar a equivalência substancial entre as amostras convencionais e GMs, bem como QPMs e sua convencional dentro das faixas de variabilidade esperadas da espécie. Nos géis 1-DE foram observadas bandas proteicas com perfis similares entre os grupos de amostras avaliadas para ambos estudos. Nas imagens dos géis 2-DE não houveram alterações extremas entre as amostras de milhos GMs e seus respectivos convencionais genitores (CGs), mas apenas diferenças na intensidade dos spots proteicos. As variedades QPMs e CN apresentaram diferenças devido à distribuição dos spots. Os mapas proteicos das amostras CG1 x GM1 e CG2 x GM2 apresentaram maior semelhança com porcentagens de matchings superiores a 70 %, enquanto as porcentagens de matchings entre variedades diferentes (QPMs e CN) foram menores. No total foram identificadas 219 proteínas das amostras CGs x GMs e QPMs x CN, classificadas quanto aos seus processos biológicos e função molecular. Em conclusão, foram encontradas diferenças entre os cultivares GMs e CGs, indicando uma variação normal entre variedades de milho, que não comprometem a segurança alimentar das amostras estudadas. Quanto às amostras com QPM e CN as diferenças encontradas são devido à sua distância nas linhagens ou germoplasma. / The classic genetic breeding of corn seeds (Zea mays) has enabled the development of many varieties, including corn with improved protein quality (Quality Protein Maize, QPM), which aimed to increase protein levels and nutritional properties. On the other hand, new commercial varieties have been obtained out of genetically modified (GM) vegetables, with a focus in agronomic parameters. In both cases, the safety of these varieties for food use is one of the main concerns for the developers and for the regulatory agencies. Substantial Equivalence is the basis of the safety evaluation system for genetically modified crops, however, alterations in the protein expressions are not been properly analyzed and clarified. The protein approaches complement the techniques of biosafety evaluation for GM foods, as well as allow for possible undesirable effects derived from classic improvement to be investigated. The goals of the current studies were to characterize and compare the protein profiles of the different varieties of conventionally improved (QPM) and genetically modified (GM) corn, against their respective conventional lines using proteomic techniques, such as, two-dimensional electrophoresis (2-DE), bottom up shotgun (gel-free) and masses spectrometry (MS). In a first instance of the study, three samples of corn were used, two of conventional varieties with QPM (QP1 and QP2) and one conventional normal variety (CN). In a second instance of the study, two cultures of GM corn (GM1 and GM2) were analyzed and their respective conventional genitors (CG1 and CG2). The chemical compositions of all the samples were also evaluated for their Substantial Equivalence. The protein raw extract was submitted to analysis of one-dimensional (1-DE), two-dimensional (2-DE) electrophoresis, and bottom up shotgun (gel-free). The protein image maps were analyzed by the Image Master 2D Platinum 7.0 (GE) software. The spots which were expressed and selected differentially were sequenced by MS. By the chemical composition of the main fractions of the samples of corn, it was possible to identify the substantial equivalence between the conventional samples and GMs, likewise with OPMs and their conventional in the ranges of variability which were expected for the species. On the 1-DE gel, it was observed protein bands with similar profiles amongst the groups of evaluated samples for both studies. In the images of the 2-DE gel, there were no alterations between the GM corn and their respective conventional genitors (CGs), but only differences in intensity of the protein spots. The OPM and CN varieties presented differences due to the distribution of the spots. The protein maps of samples CG1 vs. GM1 and CG2 vs. GM2 presented greater similarities with the percentages of matchings superior to 70%, while the percentage of matchings among different varieties (QPMs and CN) were smaller. In total, there were 219 proteins identified in the samples CGs vs. GMs and QPMs vs. CN, classified by the biologic processes and molecular function. In conclusion, there were found differences between the cultures of GMs and CGs, indicating a normal variation among the corn varieties, which do not affect the food security of the studied samples. As per the samples with QPM and CN, the differences found were due to the line distances or germplasm.

Made available in DSpace on 2017-07-25T19:29:44Z (GMT). No. of bitstreams: 1 Evandro H G Maschietto.pdf: 563360 bytes, checksum: 0a83cb502d668d2ed21718b29160c31d (MD5) Previous issue date: 2009-07-31 / There are doubts about the conditions in which a favorable effect of the application of gypsum on the yield of grain crops can be expected. In order to evaluate the influence of gypsum application in the soil chemical attributes, in mineral nutrition of maize (Zea mays L.) and soybean (Glycine max L. Merrill) yield in no-till system, an experiment was carried out in an clay Oxisol with high organic carbon content and low acidity in Guarapuava (PR). The treatments, arranged in randomized complete block with four replications, consisted of four of gypsum: 0, 4, 8 and 12 t ha-1. Gypsum was applied in September 2005, set on the soil satesurface. The corn, hybrid Pionner 30R50, was sown in October 2005, and the transgenic soybeans, MAGIC cultivar, was sown in November 2006 and 2007. During the autumn-winter seasons of 2005 to 2007, black oats (Avena strigosa Schreb) was sown in the experimental area. Gypsum application, after 9, 18 and 30 months, increased the content of exchangeable Ca2+ and S-SO4 2- available in the soil profile (0-60 cm) and the Ca2+/Mg2+ ratio in surface layers and subsoil. The application of gypsum caused leaching of exchangeable of Mg2+ and K+ the subsoil. There was positive and significant correlation (p < 0.01) between the content of S-SO4 2- extracted with ammonium acetate and acetic acid with calcium phosphate. The rates of gypsum increased the content of S in leaf and grain yield of maize. The maximum technical efficiency (MET) for corn occurred with a rate of 7.8 t ha-1 of gypsum. Nutrition and grain yield of soybean were not affected by the application of gypsum. The different responses of corn and soybean to the application of gypsum might have been caused by the supply of P, S and the increase in exchangeable Ca2+ and of the Ca2+/Mg2+ ratio in the soil. The application of gypsum proved to be an efficient practice to maximize corn yield, even in soil of high fertility and low acidity under notill system. / Existem dúvidas a respeito das condições em que se podem esperar efeitos favoráveis da aplicação de gesso na produção de grãos das culturas. Com o objetivo de avaliar a influência da aplicação de gesso nos atributos químicos do solo, na nutrição mineral e na produção de milho (Zea mays L.) e soja (Glycine max L. Merrill) em sistema plantio direto, realizou-se um experimento em um Latossolo Vermelho distrófico textura argilosa com alto teor de carbono orgânico e baixa acidez, em Guarapuava (PR). Os tratamentos, dispostos em blocos completos ao acaso com quatro repetições, constaram de quatro doses de gesso agrícola: 0, 4, 8 e 12 t ha-1. O gesso foi aplicado em setembro de 2005, a lanço na superfície do solo. O milho, híbrido PIONNER 30R50, foi semeado em outubro de 2005, e a soja transgênica, cultivar MAGIC, foi semeada em novembro de 2006 e de 2007. Durante a estação de outono-inverno de 2005 a 2007, a área experimental foi cultivada com aveia-preta (Avena strigosa Schreb). A aplicação de gesso, após 9, 18 e 30 meses, aumentou o teor de P na camada superficial (0–0,10 m) e os teores de Ca2+ trocável e de SSO4 2- disponível no perfil do solo (0–0,60 m), bem como a relação Ca2+/Mg2+ nas camadas superficiais e do subsolo. A aplicação de gesso ocasionou lixiviação de Mg2+ e K+ trocáveis para o subsolo. Houve correlação positiva e significativa (p < 0,01) entre o teor de S-SO4 2- extraído com acetato de amônio em ácido acético e com fosfato de cálcio. As doses de gesso aumentaram os teores de P e S no tecido foliar e a produção de grãos de milho. A máxima eficiência técnica (MET) para o milho ocorreu com a dose de 7,8 t ha-1 de gesso. A nutrição e a produção de grãos de soja não foram influenciadas pela aplicação de gesso. As respostas diferenciadas do milho e da soja à aplicação de gesso devem ter sido ocasionadas pelo fornecimento de S e pelo aumento da relação Ca2+/Mg2+ no solo. A aplicação de gesso agrícola demonstrou ser uma prática eficiente para maximizar a produção de milho, mesmo em solo de alta fertilidade e baixa acidez em subsuperfície no sistema plantio direto.

Made available in DSpace on 2017-07-25T19:29:44Z (GMT). No. of bitstreams: 1 Itacir Feldhaus.pdf: 550488 bytes, checksum: 13f0af90b9e23ee384c7dd7fe7d06acb (MD5) Previous issue date: 2006-03-17 / The effects of surface liming and nitrogen application on soil chemical attributes, on the dry matter production of black oats and on the root growth, mineral nutrition and grain yield of corn, under a no-till system, were evaluated in a field trial carried out on a loamy Typic Hapludox, in Ponta Grossa, State of Paraná, Brazil. A randomized complete block, split-plot design was employed, with three replications. The plots received four treatments of lime: no lime, 4, 8 and 12 t ha-1 of dolomitic lime applied on the surface before the sowing of the oats. In the subplots were employed four treatments of nitrogen: without nitrogen, 60, 120 and 180 kg ha-1 of nitrogen spread out manually at tillering of oat plants. After 110 days of the application, liming provided soil acidity correction to a depth of 20 cm, with effects of larger magnitude in the uppermost soil layer (0-5 cm). After 330 days of the application, liming raised pH and reduced the potential acidity (H+Al) to a depth of 20 cm, reduced Al3+ to a depth of 40 cm and raised bases saturation to a depth of 60 cm. The treatments of N promoted acidification of the uppermost soil layers and raised the levels of N-Mineral in the uppermost soil layers 60 days after the application, and in the subsoil 280 after the application. The levels of Ca2+ in the uppermost layers were reduced with N application, but there was no correlation between NO3 - leaching and the amelioration in the subsoil chemical attributes with liming. The dry matter production of oats was not affected by the treatments of liming and N. The root growth of the corn cultivated in succession was also not affected by the treatments. Liming increased the Ca and S levels in the leaves and in the grains of corn, respectively, and reduced the leaf Mn content. The treatments of N fertilization increased the content of N in the grains and of Mn in the leaves and in the grains of corn. Liming had no effect in the dry matter production, grain yield and content of oil and protein of corn. The N treatments had no effect in the dry matter production, but raised the grain yield and the content of oil and protein of corn. / Os efeitos da calagem superficial e da adubação nitrogenada nas alterações químicas do solo, na produção de massa seca de aveia preta e no crescimento radicular, nutrição mineral e rendimento de grãos da cultura do milho, em sistema plantio direto, foram avaliados em um experimento realizado em Latossolo Vermelho Distrófico textura média, em Ponta Grossa (PR). O delineamento experimental empregado foi o de blocos ao acaso em parcelas subdivididas, com três repetições. As parcelas receberam quatro tratamentos de calagem: sem calcário, 4, 8 e 12 t ha-1 de calcário dolomítico na superfície antes da semeadura da aveia. Nas subparcelas foram empregados quatro tratamentos de adubação nitrogenada: sem N, 60, 120 e 180 kg ha-1 de N aplicados a lanço no perfilhamento da aveia. Aos 110 dias após a aplicação, a calagem proporcionou correção da acidez do solo até a profundidade de 20 cm, apresentando efeito de maior magnitude na camada superficial do solo (0-5 cm). Aos 330 dias após a aplicação, a calagem elevou o pH e reduziu a acidez potencial até a profundidade de 20 cm, reduziu o Al3+ até a profundidade de 40 cm e elevou a saturação por bases até a profundidade de 60 cm. As doses de N promoveram acidificação das camadas superficiais do solo e elevaram os teores de N-Mineral nas camadas superficiais aos 60 dias após a aplicação, e nas do subsolo, aos 280 dias após a aplicação. Houve redução dos teores de Ca2+ nas camadas superficiais com a adubação nitrogenada, mas não houve correlação entre a lixiviação de NO3 - e as melhorias nos atributos químicos do subsolo pela calagem. A produção de massa seca de aveia não foi influenciada pelos tratamentos de calagem e de N. Também não houve efeito dos tratamentos sobre o crescimento radicular do milho cultivado em sucessão à aveia. A calagem aumentou a concentração de Mg e de S nas folhas e nos grãos de milho, respectivamente, e reduziu a concentração foliar de Mn. Os tratamentos de adubação nitrogenada aumentaram a concentração de N nos grãos e de Mn nas folhas e nos grãos de milho. A calagem não influenciou a produção de massa seca, o rendimento de grãos e a concentração de óleo e de proteína de milho. Os tratamentos de N não afetaram a produção de massa seca, mas aumentaram o rendimento de grãos e o teor de óleo e de proteína de milho