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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
91

Inoculação via foliar de bactérias diazotróficas em milho cultivado sob diferentes manejos de solo /

Santos, Tatiana da Silva January 2018 (has links)
Orientador: Ricardo Antonio Ferreira Rodrigues / Resumo: O manejo eficiente do solo pode provocar mudanças benéficas na qualidade física, química e microbiológica do solo refletindo em alta produtividade de grãos de milho. O nitrogênio (N) é o nutriente mais exigido pela planta de milho. A aquisição de fertilizantes nitrogenados pode ser responsável por 50% dos custos variáveis da lavoura. Dessa forma, a utilização de bactérias diazotróficas é considerado uma fonte alternativa economicamente viável e sustentável para aquisição desse nutriente por meio da fixação biológica de N por esses microrganismos. Em vista do exposto, o objetivo deste trabalho foi verificar o desenvolvimento, componente produtivo e produtividade de grãos de milho sob diferentes manejos de solo e inoculado via foliar por Azospirillum brasilense e/ou Bacillus amyloliquefaciens. O experimento foi conduzido durante o ano agrícola de 2016/17 em um Latossolo Vermelho distroférrico localizado na Fazenda de Ensino, Pesquisa e Extensão (FEPE) – Setor de Produção Vegetal pertencente à Faculdade de Engenharia de Ilha Solteira, município de Selvíria - MS. O delineamento experimental utilizado foi o de blocos casualizados, esquema de faixas. Foram estabelecidos 12 tratamentos com 4 repetições. Os tratamentos foram constituídos por 3 tipos de sistemas de manejo do solo: Sistema convencional (SC), cultivo mínimo (CM) e sistema plantio direto (SPD). Os tratamentos de inoculação via foliar de bactérias diazotróficas consistiram em: Azospirillum brasilense (AB), Bacillus amylol... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Efficient soil management can lead to beneficial changes in the physical, chemical and microbiological quality of the soil, reflecting high yields of corn grains. Nitrogen (N) is the nutrient most required by the corn plant. The acquisition of nitrogen fertilizers can account for 50% of the variable costs of the crop. Thus, the use of diazotrophic bacteria is considered an economically viable and sustainable alternative source for the acquisition of this nutrient through the biological fixation of N by these microorganisms. In view of the above, the objective of this research was to verify the development, productive component and productivity of corn grains under different soil management and foliar inoculation by Azospirillum brasilense and / or Bacillus amyloliquefaciens. The experiment was conducted during the agricultural year of 2016/17 in a Distroferric Red Oxisol located at the Teaching, Research and Extension Farm (FEPE) - Vegetable Production Sector belonging to the Faculty of Engineering of Ilha Solteira, Selvíria - MS. The experimental design was a randomized complete block design. Twelve treatments with four replicates were established. The treatments were constituted by 3 types of soil management systems: Tillage (SC), minimum tillage (CM) and notillage (SPD). The treatments of foliar inoculation of diazotrophic bacteria consisted of: Azospirillum brasilense (AB), Bacillus amyloliquefaciens (BA), Azospirillum brasilense + Bacillus amyloliquefaciens (AB + BA) and... (Complete abstract click electronic access below) / Mestre
92

Nitrogen Cycling in Leucaena Alley Cropping

Xu, Zhihong, n/a January 1991 (has links)
Field experiments were conducted on an Alfisol in the semi-arid tropics of northern Australia to investigate nitrogen (N) cycling in the leucaena (Leucaena leucocephala) alley cropping system. This is a farming system in which maize (Zea mays L.) is grown in alleys formed by leucaena hedgerows spaced 4.5 metres apart. Mineralization of N from Ieucaena (prunings) and maize residues was studied under field conditions. Response of maize growth to addition of N fertilizer and plant residues was evaluated both in field plot and microplot experiments. The fate of fertilizer N and leucaena N was examined over four consecutive seasons. The decomposition (loss of mass) of dry, cut 15N-labelled leucaena residues differed from that of intact fresh leucaena prunings in the first cropping season although no difference was detected after one year. At the end of one cropping season, 3 months after application, 58-72% of 15N-labelled leucaena had decomposed compared to only 34-36% of fresh leucaena prunings. Similar trends occurred at 20 and 52 days after application. The extent of decomposition of fresh leucaena prunings (28-33%) was similar at two loading rates (2.4 and 4.7 t DM ha -1) by 3 months after addition. About 72% of young 15N labelled maize residues was decomposed by 3 months after addition in the presence of fresh leucaena prunings. Decomposition of 15N-labelled leucaena residues and unlabelled fresh prunings was 91% and 88% respectively 14 months after addition. After 2 years the corresponding values were 96% and 94%. When N content of the recovered residues was taken into account, the values were 95% and 94% after 14 months, and the same (97%) after 2 years. Maize yield and N uptake were significantly increased following addition of either unlabelled fresh leucaena residues or 15N-labelled thy Ieucaena residues. Application of N ferilizer produced a thither increase in the presence of the residues. The maize yield and N uptake with the 15N-labelled leucaena were not different from those with the unlabelled residues. There was a significant positive interaction between N fertilizer and leucaena prunings which increased maize production. Addition of maize residues decreased the yield and N uptake of maize compared with that obtained in the presence of N fertilizer at 40 kg N ha~1 and leucaena residues (2.4 t DM ha-1). There was a marked residual benefit of N fertilizer applied in the first season at 36 kgN hat in the presence of leucaena prunings on the second maize crop yield and N uptake, but not on the third crop. However, a significant residual benefit of leucaena prunings added in the first season was found in DM yield and N uptake of the second and third maize crop. The short-term fate of 15N applied in plant residues was examined during two separate cropping seasons. By 20 days after application of separate 15N-labelled leucaena leaves, stems and petioles, 3-9% of the added 15N could be found in maize plants, 33-49% was in surface residues, 36-48% in the 2 m soil proffle and 0.3-22% unaccounted for. In a separate experiment when leucaena components were not separated, 5% of 15N applied in leucaena residues was taken up by maize 52 days after addition, 45% was in residues, 25% was in soil and 25% was unaccounted for. Jn another experiment, maize recovered 6% of added leucaena 15N after 2 months, 39% remained in residues, 28% was in soil and 27% was not recovered. Incorporation of 15N-labelled leucaena residues in the soil did not increase recoveiy of leucaena 15N by maize compared with placement of the residues on the soil surface. By the end of one cropping season (3 months after application), 9% of added 15N was recovered by maize from 15N-labelled leucaena. There was a similar 15N recoveiy from 15N-labelled maize residues applied as mulch at 1.7 t DM ha1 together with unlabelled leucaena prunings at 2.4 t DM ha ~. In both cases, 30-32% of added 15N was detected in soil, 28% in residues, and 31-34% apparently lost. The short-term fate of fertilizer 15N was different from that of 15N added in plant residues. In a 52-day experiment, maize recovered 65-79% of fertilizer 15N applied at low rates (6.1 and 12.2 kg N ha -1) in the presence of leucaena prunings, 21-34% was present in soil, and less than 1% was not recovered. By 2 months after application, recoveiy of fertilizer 15N by maize was 41% from N fertilizer added at 80 kg N ha -1, 35% from N fertilizer at 40 kg N ha -1 in the presence of leucaena prunings, and 24% from N fertilizer at 40 kg N ha -1 in the presence of maize residues and leucaena prunings. The corresponding deficits (unaccounted-for 15N) were 37%, 38% and 47% respectively. A small but significant amount of the fertilizer 15N was present in the unlabelled leucaena residues (3%) and in the mixture of unlabelled leucaena and maize residues (7%) present on the soil surface. However, application of the plant residues did not affect recoveiy of the fertilizer 15N in soil (21-24%). When N fertilizer was applied at 40 kg N hi1 in the presence of leucaena prunings, 43% of fertilizer 15N was recovered by maize at the end of cropping season, 20% in soil, 2% in residues, and 35% unaccounted for. The long-term fate of fertilizer 15N was compared with that of leucaena 15N in an experiment over four cropping seasons. In the first season, maize tops recovered 50% of the fertilizer 15N but only 4% of the leucaena 15N. In the second, third and fourth seasons, maize (tops + roots) recovered 0.7%, 0.4% and 0.3% of the initial fertilizer 15N compared with 2.6%, 1.8% and 1.4% of the initial leucaena 15N. In the second, third and fourth seasons, recovery of the initial fertilizer 15N (12-14%) in soil was much lower than that of the initial leucaena 15N (38-40%). There was no further loss of the fertilizer 15N after the first season. However, the cumulative 15N deficit for the leucaena 1N in the first two seasons was 50%--thissuggested an additional loss of 23% since the end of the first season. There was no further loss of 15N from either residual fertilizer 15N or residual leucaena 15N in the third and fourth seasons. In conclusion, application of leucaena prunings could substantially increase maize yield and N uptake although some supplementary N fertilizer may be required to achieve maximum crop yield. Maize recovered only a small amount of added leucaena N in the first year. Most of the leucaena residue N was present in the soil and remaining residues after one season. This residue N would be gradually available for plant uptake by subsequent crops. Of course, annual additions of leucaena prunings would appreciably increase the pool of available N over time. Thus, application of leucaena prunings could substantially improve soil fertility in the long term.
93

Seletividade de nicosulfuron isolado e em mistura com atrazine para trinta híbridos comerciais de milho /

Espanhol, Melina. January 2009 (has links)
Resumo: Estudou-se a seletividade do herbicida nicosulfuron, isolado e em mistura com atrazine, a trinta híbridos comerciais de milho, no ano agrícola 2006/2007, em área da UNESP, Campus de Jaboticabal (SP). O delineamento experimental foi o de blocos ao acaso, com quatro repetições, em esquema fatorial 5 x 30. Foram avaliados cinco herbicidas: nicosulfuron isolado (0, 50 e 60 g ha-1) e em mistura com atrazine (20 g ha-1 + 1,5 kg ha-1; 40 g ha-1 + 3,0 kg ha-1). O nicosulfuron isolado e em mistura com atrazine foi seletivo a 23 híbridos (A015, AG 2040, AG 8060, AGN 30A06, BM 1115, BRS 1035, BX 974, CDXS 012, CDXT 295, MAXIMUS, NB 3234, NB 4214, NB 8304, P 30K 73, P 30F36, P32R48, P30S40, SHS 5080, SHS 7070, SHS 7080, XB 6010, XB 6012, XB 7116), com base na produtividade de grãos. Dentre os trinta híbridos estudados, doze apresentaram efeito significativo de fitointoxicação, sendo eles: AG 2040, AG 8060, AGN 30A06, CDXS012, CDXT 295, NB 3234, NB 7324, SHS 5090, SHS 7070, XB 6010, XB 6012, XB 7116. A injúria visual causados pela aplicação de 50 e 60 g ha-1 nicosulfuron foi mais pronunciada do que as doses em mistura com atrazine. Os híbridos que sofreram perda na produção de grãos pela aplicação de nicosulfuron, isolado ou em mistura com atrazine, foram AGN 30A05, BRS 1015, BRS 1031, BX 981, NB7324, SHS 5090, P 30R32. / Abstract: Aiming selectivity studying the nicosulfuron herbicide, isolated and in mixture with atrazine, on thirty corn hybrids, in the agricultural year of 2006/2007, at UNESP, Campus of Jaboticabal, (São Paulo State). The experimental design was completely randomized blocks, four replications, in a factorial scheme 5 x 30. Five herbicides treatments were evaluated; isolated nicosulfuron (0, 50 and 60 g ha-1) and in mixture with atrazine (20 g ha-1 + 1.5 kg ha-1 and 40 g ha-1 + 3.0 kg ha-1). Nicosulfuron isolated and in mixtures with atrazine was selectivy to 23 hybrids (A015, AG 2040, AG 8060, AGN 30A06, BM 1115, BRS 1035, BX 974, CDXS 012, CDXT 295, MAXIMUS, NB 3234, NB 4214, NB 8304, P 30K 73, P 30F36, P32R48, P30S40, SHS 5080, SHS 7070, SHS 7080, XB 6010, XB 6012, XB 7116) based in grain yield. Among thirty hybrids studied, only twelve hybrids show significant effect of phytotoxicity, which were: AG 2040, AG 8060, AGN 30A06, CDXS012, CDXT 295, NB 3234, NB 7324, SHS 5090, SHS 7070, XB 6010, XB 6012, XB 7116. The visual damage caused by the application of 50 e 60 g ha-1 nicosulfuron were more pronounced than the nicosulfuron doses in combination with atrazine. The hybrids that suffered losses in its production by the application of nicosulfuron alone or in combination with atrazine were hybrids AGN 30A05, BRS 1015, BRS 1031, BX 981, NB7324, SHS 5090 and P30R32. / Orientador: Julio Cezar Durigan / Coorientadora: Núbia Maria Correia / Banca: Pedro Luis da Costa Aguiar Alves / Banca: Fernando Tadeu de Carvalho / Mestre
94

Potencial das populações Isanão-VF1 e Isanão-VD1 para seleção recorrente recíproca /

Garcia, Fabiana Queiroz. January 2009 (has links)
Orientador: João Antonio da Costa Andrade / Banca: Mário Luiz Teixeira de Moraes / Banca: Orivaldo Arf / Banca: José Branco de Miranda Filho / Banca: Pedro Mário de Araújo / Resumo: O milho é uma planta cultivada no mundo todo e de importância econômica mundial. Em função de sua importância, amplos programas de melhoramento são realizados nesta cultura. Das várias técnicas utilizadas, a seleção recorrente recíproca tem sido importante na melhoria do cruzamento entre duas populações e, consequentemente, na obtenção de melhores híbridos entre linhagens extraídas das mesmas. No entanto o sucesso da seleção recorrente recíproca depende da existência de variabilidade genética interpopulacional e heteroze. O objetivo deste trabalho foi verificar a existência de variabilidade genética nas populações de milho de porte baixo Isanão-VF1 e Isanão-VD1, em condições de espaçamento reduzido e alta densidade de plantas, visando o início de um programa de seleção recorrente recíproca. Foram estimados parâmetros genéticos para oito caracteres, avaliando-se 80 progênies de meios irmãos interpopulacionais Isanão-VF1 e 72 Isanão-VD1, semeadas na Fazenda de Ensino, Pesquisa e Extensão da Faculdade de Engenharia, Campus de Ilha Solteira (UNESP), em Selvíria/MS. Foi encontrada variabilidade genética interpopulacional, expressa através dos caracteres florescimento feminino (FF), altura de plantas (AP), altura de espigas (AE) e rendimento de grãos (RG), com herdabilidades (em nível de médias de progênies) de 68,8%, 76,9%, 75,0% e 54,78%, respectivamente. Os índices de variação (coeficiente de variação genético/coeficiente de variação experimental) foram de 0,9; 1,1; 1,0 e 0,6, respectivamente para FF, AP, AE e RG. Espera-se um ganho de 10,76%/ciclo de seleção no RG do híbrido interpopulacional, 19 qualificando as populações Isanão-VF1 e Isanão-VD1 para serem submetidas a um programa de seleção recorrente recíproca. Com uma heterose de 38,2% do híbrido interpopulacional sobre as populações... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Maize is a cultivated crop around the globe, and of worldwide economic importance. Due to its importance, wide genetic breeding programs are constantly applied upon it. Among the techniques employed, reciprocal recurrent selection has been important in improving the cross between two populations and in obtaining superior hybrids of inbred lines originated from them. However, the success of reciprocal recurrent selection is dependent of interpopulation genetic variability. The objective of this research was to verify the presence of genetic variability in brachytic populations Isanão-VF1 and Isanão-VD1 maize, cultivated in reduced row spacing and high plant density, aiming at beginning a reciprocal recurrent selection breeding program. Were Genetic parameters estimated for eight traits, evaluated in 80 interpopulation half-sib progenies of Isanão-VF1 and 72 of Isanão-VD1, at the UNESP Research Farm, located in Selvíria, state of Mato Grosso do Sul, Brazil. Interpopulational genetic variability was expressed in the traits silk emergence (FF), plant height (AP), ear height (AE) and grain yield (RG). The coefficients of heritability progeny mean basic were 68.8%, 76.9%, 75.0% and 54.8%, respectively. Estimates of the index of variation (genetic variation coefficient/experimental variation coefficient) were 0.9, 1.1, 1.0 and 0.6, for SE, PH, EH and GY, respectively. A gain of 10.76%/cycle on GY is expected on the interpopulation hybrid, indicating Isanão-VF1 and Isanão-VD1 populations as base for a reciprocal recurrent selection progr am. The heterosis of 38.2% of the interpopulation hybrid over the parental populations qualify the latter as a sources of inbred lines, to be used us hybrid crosses more adapted the condition of high plant density and reduced row spacing. / Doutor
95

Associação micorrízica arbuscular com genótipos de milho /

Aquino, Sueli da Silva. January 2003 (has links)
Orientador: Ana Maria Rodrigues Cassiolato / Banca: Sandra Maria Gomes da Costa / Banca: João Antonio da Costa Andrade / Resumo: O milho é uma das culturas mais cultivadas no mundo, e constitui a base alimentar para milhões de pessoas, sendo uma das espécies mais estudadas e melhoradas atualmente. Devido ao seu rápido crescimento, esta cultura apresenta elevada demanda de nutrientes, especialmente nitrogênio e fósforo, podendo assim beneficiar-se da associação com microrganismos do solo, entre estes, os fungos micorrízicos arbusculares. O benefício destes é reconhecido cientificamente, e abrange um vasto número de culturas economicamente importantes, podendo destacar-se de um modo geral as gramíneas, como beneficiadas neste processo de associação simbiótica. O estudo foi conduzido em condições de campo, na Fazenda Experimental da Faculdade de Engenharia, Campus de Ilha Solteira - UNESP, localizada em Selvíria-MS, no ano agrícola de 2001/2002. O objetivo do trabalho foi verificar variações na associação micorrízica arbuscular com diferentes genótipos de milho, utilizando fungos micorrízicos arbusculares autóctones, em condições de campo com baixo nível tecnológico. Os caracteres estudados foram: número de esporos/100 g de solo, porcentagem de colonização micorrízica, altura de inserção de espiga, altura de planta, produção de matéria seca e rendimento de grãos, em linhagens endogâmicas e seus híbridos. O delineamento experimental foi em blocos casualizados, com 2 repetições e 30 tratamentos. Para a porcentagem de colonização micorrízica foram detectadas diferenças significativas entre linhagens, híbridos e para o contraste linhagens versus híbridos. Para o rendimento de grãos, ocorreram diferenças significativas entre híbridos e para o contraste. A análise qualitativa de fungos micorrízicos arbusculares autóctones constatou a presença de 12 espécies, sendo Scutellospora calospora... (Resumo completo, clicar acesso eletrônico abaixo). / Abstract: Corn is one of the most cultivated crops in the world, and constitutes the alimentary basis for millions of people. Due to its faster growth, the corn crop presents high demand for nutrients, mainly nitrogen and phosphorus. Thus, the association with soil microorganisms, among these the arbuscular mycorrhizal fungi (AMF) could be very beneficial to the crop. This beneficial symbiotic association is recognized scientifically, and it embraces a vast number of cultures economically important. The present study was conducted in field conditions, in the Experimental Farm of UNESP - Campus de Ilha Solteira, located in Selvíria-SP, in the agricultural year of 2001/2002. The objective was to verify the of autochthonous association arbuscular mycorrhizal fungi with different corn genotypes in field conditions. The following characters were studied: number of spores/100 g of soil, percentage of mycorrhizal colonization, height of corn ear insert, plant height, dry matter production and grain yield in inbred lines and their hybrids. The experimental design was complete randomized blocks, with 2 repetitions and 30 treatments. For the percentage of mycorrhizal colonization significant differences were detected among inbred lines, hybrids and for the contrast inbred lines versus hybrids. For the grain yield, there was significant differences between hybrids and for the contrast. The qualitative analysis of autochthonous arbuscular mycorrhizal fungi indicated the presence of 12 species. Scutellospora calospora, Entrophospora colombiana and Scutellospora pellucida were the most abundant ones. There were qualitative and quantitative changes in the composition of AMF and preferential associations among AMFs and genotypes. In general, the characters were positively correlated with production of dry matter and productivity of grains. For percentage... (Complete abstract, click electronic address below). / Mestre
96

Modelo de transformação de funções de produção água-cultura / Transformation model of water-culture production functions

Jefery, Ana Paula Russo Schimidt 15 January 2018 (has links)
Submitted by Ana Paula Russo Schimidt Jefery (schimidt.ana@gmail.com) on 2018-06-07T12:13:39Z No. of bitstreams: 1 Tese Ana Paula Russo Schimidt Jefery.pdf: 1747996 bytes, checksum: e0875cc17829cdad5bcb572b43720a4d (MD5) / Approved for entry into archive by Maria Lucia Martins Frederico null (mlucia@fca.unesp.br) on 2018-06-07T12:21:24Z (GMT) No. of bitstreams: 1 jefery_aprs_dr_botfca.pdf: 1601762 bytes, checksum: f093397ad05508e789eca1216cb098a9 (MD5) / Made available in DSpace on 2018-06-07T12:21:24Z (GMT). No. of bitstreams: 1 jefery_aprs_dr_botfca.pdf: 1601762 bytes, checksum: f093397ad05508e789eca1216cb098a9 (MD5) Previous issue date: 2018-01-15 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O setor agrícola é o maior usuário dos recursos hídricos uma vez que a água é um elemento essencial para o cultivo de qualquer espécie vegetal. A necessidade crescente de produção de alimentos, fibras e energia tem fortalecido o uso das técnicas de irrigação no Brasil e no mundo. Para que se possa usufruir dos vários benefícios que a irrigação pode proporcionar, é importante o conhecimento da relação entre a quantidade de água aplicada aos cultivos e a produção obtida. Essa relação pode ser expressa através uma função matemática denominada função de produção, que é uma importante ferramenta de análise e tomada de decisão, mas a obtenção das funções de produção envolve experimentos de campo, caracterizando-se por ser um processo demorado e oneroso. O objetivo deste trabalho foi elaborar um modelo de transformação de funções de produção água-cultura obtidas em condições experimentais para determinada cultura e local, para ser utilizada pela mesma cultura em outra região com condições distintas da região original, desde que se conheça a lâmina de água correspondente a 100% da evapotranspiração da cultura, e a respectiva produtividade. O modelo de transformação desenvolvido e as funções de produção obtidas na literatura foram aplicados a dados coletados de lâmina total aplicada e produtividade em localidades no estado de São Paulo para as culturas de feijão e milho visando a avaliação do ajuste fornecido. Concluiu-se que as funções de produção da literatura tenderam a superestimar as estimativas, enquanto as funções transformadas minimizaram a variação dos dados, fornecendo ajuste adequado com os dados reais em praticamente todas os locais avaliados, tanto para a cultura do feijão como para a cultura do milho. / Agriculture is the main user of water resources because water is essential for any crop growing. The demand for food, fiber and energy production is increasing and has strengthened the use of irrigation techniques in Brazil and worldwide. In order to be able to take advantage of the benefits that irrigation can provide, it is worth to know the relationship between the water depth applied to the crops and the yield obtained. This relationship can be expressed through a mathematical function called production function, being an important tool of analysis and decision making. Obtaining the production functions involve field experiments, characterized as a time-consuming and costly process. The objective was to elaborate a mathematical model to generate a water-culture production functions obtained under experimental conditions for a given crop and place, to be used by the same crop in another region with different conditions of the original region, provided that at least one pair of water blade data corresponding to 100% crop evapotranspiration and productivity. The transformation model developed and production functions obtained in the literature were applied to data collected from productivity / total blade applied in some farms of São Paulo State, for bean and corn crops. We concluded that the production functions of the literature tended to overestimate the values, whereas the transformed functions minimized the variation of the data, providing adequate adjustment with the real data in practically all evaluated farms, both for the bean and corn crops.
97

The effects of high temperature stress on the enzymatic antioxidant system in Zea mays

Chetty, Kovin Ashley January 2017 (has links)
Philosophiae Doctor - PhD (Biotechnology) / High temperature stress is synonymous with the attenuation of plant growth, metabolism and eventually death resulting in major loss of crop productivity worldwide. Part of the metabolic perturbations associated with heat stress leads to the excessive formation of reactive oxygen species (ROS), which have highly deleterious effects on cellular homeostasis. Naturally, through millions of years of evolution and adjustment, plants have developed antioxidant enzymes that neutralize harmful ROS species offering a protective role in the annulment of oxidative damage in response to high temperature. The aim of this study was to measure the activity of several antioxidant enzymes in response to heat stress in Zea mays.
98

Potencial de bactérias endofíticas na promoção do crescimento em plantas de milho / Potential of endophitic bacteria in promoting growth of maize plants

Lobo, Laiana Lana Bentes 10 August 2018 (has links)
Submitted by Laiana Lana Bentes Lobo (laianabentes@gmail.com) on 2018-09-05T17:52:03Z No. of bitstreams: 2 Laiana Lana Bentes Lobo-Dissertação-PDF.pdf: 2488195 bytes, checksum: 92513af193ea5c474832fca34cc8885b (MD5) Laiana Lana Bentes Lobo-Dissertação-PDF.pdf: 2488195 bytes, checksum: 92513af193ea5c474832fca34cc8885b (MD5) / Approved for entry into archive by Neli Silvia Pereira null (nelisps@fcav.unesp.br) on 2018-09-05T19:11:48Z (GMT) No. of bitstreams: 1 lobo_llb_me_jabo.pdf: 2488195 bytes, checksum: 92513af193ea5c474832fca34cc8885b (MD5) / Made available in DSpace on 2018-09-05T19:11:48Z (GMT). No. of bitstreams: 1 lobo_llb_me_jabo.pdf: 2488195 bytes, checksum: 92513af193ea5c474832fca34cc8885b (MD5) Previous issue date: 2018-08-10 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / RESUMO – O milho é uma das culturas mais cultivadas em todo o mundo e atualmente o grande desafio na produção agrícola é manter os índices de produtividade, reduzindo o custo de produção, e ainda minimizar o impacto ambiental causado pelo uso excessivo de fertilizantes químicos. Nesse contexto a utilização das bactérias promotoras de crescimento de plantas pode ser uma estratégia eficaz para a prática de uma agricultura mais econômica e sustentável. O objetivo do presente estudo foi avaliar a ação de bactérias endofíticas do gênero Bacillus quanto a ação de promoção de crescimento de plantas de milho em casa de vegetação e no campo. O experimento foi dividido em dois. O experimento I, foi conduzido em casa de vegetação, constituído de 11 tratamentos, compostos por dez isolados de Bacillus, sendo um de B. amyloliquefaciens, um de B. velezensis, oito de B. subtilis e um controle sem inoculação, dispostos em delineamento inteiramente casualizado com três repetições. O isolado BS-320 proporcionou incremento na altura, este juntamente com o isolado BS-248 apresentou maior acúmulo em massa seca de parte aérea (MSPA) e massa seca de raiz (MSR). Em relação às concentrações de nitrogênio (N) na planta os isolados BS-290, BS-320 e BS-248 promoveram um aumento deste macronutriente nas raízes, e as concentrações fósforo (P) na parte aérea também foram aumentadas pelos isolados BA-001, BS-320. Nas avaliações no solo as maiores quantidades de P solúvel no solo foram proporcionadas pelos isolados BA-001 e BS-320, e quanto ao número de unidades formadoras de colônias (UFC) de Bacillus spp. no solo todos os tratamentos inoculados foram maiores significativamente em relação ao controle.Três isolados de B. subtilis (BS-320, BS-290 e BS-248) apresentaram melhores resultados nos parâmetros avaliados no experimento em casa de vegetação e por isso foram selecionados para o experimento II em campo, constituído de quatro tratamentos compostos pelos três isolados de B. subtilis selecionados e um controle sem inoculação, dispostos em delineamento em blocos casualizados com seis repetições. Em campo, o isolado BS-248 foi superior ao controle para concentração de N na parte aérea, BS-290 aumentou as concentrações de N e P da parte aérea, além de P solúvel no solo e também teve maior número de UFC de Bacillus spp. no solo comparado com o controle. O isolado BS-320 aumentou a concentração de P na parte aérea e promoveu aumento significativo na produtividade do milho, o que fortemente sugere sua utilização como um inoculante biológico nessa cultura. Embora o presente estudo tenha comparado oito isolados de B. subtilis, o comportamento de cada isolado foi diferente e os isolados BS-248, BS-290 e BS-320 se mostraram efetivos na promoção de crescimento do milho possibilitando de maneira efetiva uma redução do custo de produção sem reduzir a produtividade e causando menos danos ao meio ambiente. / ABSTRACT – Maize is one of the most cultivated crops in the world and the current challenge is maintain productivity rates, lowering production costs and minimizing the environmental impact of the excessive use of chemical fertilizers. In this context the use of plant growth promoting bacteria can be an effective strategy for the practice of a more economic and sustainable agriculture. The present study aimed to evaluate the growth activity of endophitic bacteria of the genus Bacillus on maize plants at greenhouse and field conditions. Two experiments were carried out. The experiment I, was conducted at greenhouse, consisting of 11 treatments, ten of them containing Bacillusstrains, one of B. amyloliquefaciens, one of B. velezensis, eight of B. subtilis and one control without inoculation, arranged in a completely randomized design with three replicates. The BS-320 increased plant height, and together BS-248 promoted an increase in shoot dry matter (SDM) and root dry matter (RDM). In relation nitrogen (N) content in shoot, BS-290, BS-320 and BS-248, increased the rates of this macronutrient in root, while the content of phosphorus (P) in the roots was increased by BA-001 and BS-320. In relation to the number of colonies forming units (CFU), all isolates presented higher numbers than the control. Three isolates of B. subtilis (BS-320, BS-290 and BS-248) showed better results for the evaluated parameters at greenhouse conditions and were selected for the experiment II in the field, consisting of four treatments, three of them containing B. subtilis and a control without inoculation, arranged in a randomized block design with six replicates. In the field, BS-248 was superior to the control for the concentration of N in shoot; BS-290 increased the shoot concentration of N and P, besides P soluble in the soil and also had a greater number of Bacillus CFU in the soil compared to control. BS-320 increased the concentration P in the shoot and the yield of gains, which is so advantageous for a biological inoculant. Although the present study compared eight isolates of B. subtilis, the behavior of each isolate was different and the isolates BS-248, BS-290 and BS-320 were effective in promoting the growth of maize enabling the reduction of costs production without decrease yield and being more environmentally friendly at the same time.
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Interfer?ncia inicial radicular de Urochloa brizantha em milho e feij?o avaliada por meio de rizotron / Initial root interference of Urochloa brizantha in maize and bean evaluated by means of rhizotrons

Freitas, Ana Fl?via de 19 August 2016 (has links)
Submitted by Jos? Henrique Henrique (jose.neves@ufvjm.edu.br) on 2017-04-03T20:28:05Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) ana_flavia_freitas.pdf: 1136034 bytes, checksum: 965afc88d55a61d59101bffaca9ad367 (MD5) / Approved for entry into archive by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2017-04-24T16:56:16Z (GMT) No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) ana_flavia_freitas.pdf: 1136034 bytes, checksum: 965afc88d55a61d59101bffaca9ad367 (MD5) / Made available in DSpace on 2017-04-24T16:56:16Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) ana_flavia_freitas.pdf: 1136034 bytes, checksum: 965afc88d55a61d59101bffaca9ad367 (MD5) Previous issue date: 2016 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico (CNPq.) / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / Universidade Federal dos Vales do Jequitinhonha e Mucuri (UFVJM) / Consider?vel redu??o na produtividade de culturas e consequente perda financeira resultam da competi??o com plantas daninhas. Essas perdas s?o muito estudadas e disponibilizadas na literatura, por meio da rela??o dos per?odos de controle. Contudo, mesmo ap?s amplos estudos sobre per?odos, as divulga??es recentes sobre a teoria do ?inicialismo?, pouco se sabe sobre o momento inicial da interfer?ncia radicular entre plantas, principalmente devido a dificuldades na visualiza??o dos eventos iniciais. Dessa forma, objetivou-se estimar a partir da semeadura em rizotrons, os primeiros sinais que levariam ? interfer?ncia entre sistemas radiculares. Foram realizados dois experimentos em casa de vegeta??o: No primeiro, os tratamentos foram arranjados em esquema fatorial 3x2, sendo, 3 esquemas de cultivo do feijoeiro (solteiro, com uma e com duas plantas de braqui?ria) com e sem aduba??o fosfatada, conduzido em um delineamento inteiramente casualizado com 4 repeti??es. Ap?s a semeadura das esp?cies, os resultados da visualiza??o foram registrados a cada 12 horas, por meio de fotografias do desenvolvimento do sistema radicular. O sistema de ra?zes do feijoeiro apresentou maior comprimento e ?rea radicular quando em defici?ncia de f?sforo e presen?a de duas braqui?rias. O segundo experimento foi arranjado em esquema fatorial 2x2, sendo cultivo do milho solteiro ou com uma planta de braqui?ria e pela submiss?o ou n?o do substrato ? esteriliza??o, conduzido em um delineamento inteiramente casualizado com 4 repeti??es. Foi observado maior comprimento radicular das pl?ntulas de milho, quando em presen?a da braqui?ria, por?m, sem efeito quanto ? esteriliza??o do substrato. Verificaram-se varia??es no ac?mulo de N, Mn, K, Ca e P, al?m da redu??o em altura, n?mero de folhas e mat?ria seca do milho em fun??o da esteriliza??o do substrato. As culturas como feij?o e milho s?o influenciadas quando est?o submetidas ? interfer?ncia da Urochloa brizantha antes da emerg?ncia. / Disserta??o (Mestrado) ? Programa de P?s-Gradua??o em Produ??o Vegetal, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 2016. / Considerable reduction in crop productivity and consequent financial loss result from competition with weeds. These losses are widely studied and made available in the literature by listing the control periods. However, even after extensive studies on periods and the recent disclosures about the ?initialism? theory, little is known about the initial moment of root interference between plants, especially due to difficulties in the visualization of the initial events. In this sense, the objective was to estimate, sowing in a rhyzotron, the first signals that would take to interference between root systems. Two experiments were conducted in a greenhouse: In the first, treatments were arranged in a 3x2 factorial arrangement, with three beans cultivation schemes (single, with one and with two Brachiaria plants) with and without P fertilization, conducted in a completely randomized design, with four replications. After sowing the species, visualization results were recorded every 12 hours by means of photographs of the development of the root system. The bean root system showed greater length and root area when under phosphorus deficiency and in the presence of two Brachiaria plants. The second experiment was arranged in a 2x2 factorial design, with cultivation of maize single or with one Brachiaria plant, and by the submission or not of the substrate to sterilization, in a completely randomized design, with four replications. After sowing the species, visualization results were recorded every 12 hours by means of photographs of the development of the root system. It was observed higher root length in maize seedlings when in the presence of Brachiaria, however, no effect of substrate sterilization. There were variations in the accumulation of N, Mn, K, Ca and P, and decreases in height, number of leaves and maize dry matter as a function of the substrate sterilization. Crops as bean and maize are influenced when subjected to interference of Urochloa brizantha before emergency.
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Eficiência no uso de nitrogênio ao longo dos estádios fenológicos e utilização de dados públicos na seleção genômica de milho tropical / Nitrogen Use Efficiency along growing stages and public dataset in genomic selection for tropical maize

Morais, Pedro Patric Pinho 24 June 2016 (has links)
Submitted by Reginaldo Soares de Freitas (reginaldo.freitas@ufv.br) on 2017-02-07T18:11:13Z No. of bitstreams: 1 texto completo.pdf: 1482756 bytes, checksum: 020874a6dbc4ae55faeacad2d2f1a8b1 (MD5) / Made available in DSpace on 2017-02-07T18:11:13Z (GMT). No. of bitstreams: 1 texto completo.pdf: 1482756 bytes, checksum: 020874a6dbc4ae55faeacad2d2f1a8b1 (MD5) Previous issue date: 2016-06-24 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Este estudo foi feito com uma população de linhagens de milho tropical, visando inferir sobre a eficiência no uso de nitrogênio (EUN), assim como a aplicação de seleção genômica (GS) nesse conjunto. Para a EUN foram avaliadas 64 linhagens, em duas disponibilidades de adubação nitrogenada (N) (ideal e baixo N), para 16 características. Estas avaliações ocorreram em três estádios fenológicos de oito folhas completamente expandidas (V8), florescimento masculino (VT) e após a maturação fisiológica (MF). Nas análises dos dados foi usado equações de modelos mistos via REML/G-BLUP. Foram observados que há possibilidade de seleção de linhagens superiores quanto a EUN. Mas,os componentes da produtividade não apresentam comportamento diferenciado em função da disponibilidade de N. Características de raiz, reprodutivos e fisiológicas não são atrativas para seleção precoce de genótipos EUN. De forma semelhante, os estádios V8 e VT não se mostraram promissores para avaliação precoce da EUN, devendo essa ser praticada em função da produtividade de grãos. Por outro lado, constatou-se que a seleção indireta para EUN pode ser feita via número de espigas (NE), ou ainda, por meio de índice de seleção considerando NE e peso de espigas (PE). No estudo de GS, visando a aplicação dessa em programas de melhoramento de pequeno porte e, ou então, iniciando suas atividades, foi proposto um panorama hipotético: orçamento limitado e necessidade de acréscimo de variabilidade genética. Para isso, foram definidos 29 conjuntos de população de treinamento (PT)através de painéis de diversidade: USP (painel a ser predito), ASSO e NCRPIS (painéis públicos externos - preditores). Estes conjuntos foram agrupados divididos em quatro cenáriosdistintos, quanto a configuração usada na formação. Nas análisesforam usados 28.260 marcadores SNP para 2748 linhagens, via modelo G-BLUP, para características de altura de planta e de espiga. Os resultados indicaram que é possível o uso de informações de bancos públicos para formação de PT. Além disso, a estrutura populacional influenciou as capacidades preditivas da GS, principalmente quando populações de treinamento e validação (PV) são divergentes. Nos quatro cenários propostos, evidenciou-se que conjuntos demasiadamente pequenos ou grandes não proporcionam as melhores capacidades preditiva para GS. Entretanto, PT compostas por 250 indivíduos, escolhidas de forma otimizada (PTO) a partir de informações de bancos públicos, conduzem a capacidades preditivas satisfatórias (0,32). Contudo, a adição da PV na PTO, é o cenário que conduz às maiores capacidades preditivas (0,59). Sendo seu uso, sempre que possível, o recomendado. / This study was proceeded with a population of tropical maize inbred lines, aiming to infer about the nitrogen use efficiency (NUE) as well as the application of genomic selection (GS) in this set. For EUN, 64 inbred lines were evaluated in two nitrogen (N) fertilizing conditions (optimum and low N), taking into account 16 traits. These evaluations were performed in three phenological stages eight fully expanded leaves (V8), tasseling stage (VT) and after physiological maturity (MF). Data analysis was performed using mixed models via REML/G-BLUP. It was observed that there is a possibility of selecting inbred lines for NUE, and the yield components do not show differential behavior according with the N condition. Root, reproductive and physiological traits are not attractive for early selection in efficient nitrogen use genotypes. Similarly, V8 and VT stages do not appear promising for early NUE estimation, it has to be done taking into account the yield. Indirect selection for NUE can be done via number of ear (NE), or with selection index considering NE and ear weight (PE). Forthe GS study, aiming to use GS in small breeding programs and, or, starting its activities, a hypothetical scenariowas proposed: a limited budget and the need for genetic variability. For that,29 training sets (PT) were developed through diversity panels: USP (panel to be predicted), ASSO and NCRPIS (external public panels - predictors); they were clustered into four scenarios with different PT. In the analysis 28.260 SNP markers for 2748 inbred lines were used, via model G-BLUP for plant height and ear height. Through the study it was found that it is possible to use information from public banks for PT formation. The population structure has the capacity of affecting GS predictive abilities, especially when training set and validation (PV) hold low genetic relationship. In the four proposed scenarios, it was shown that too small or large sets do not provide best predictive abilities. But, training sets with 250 individuals, via use of optimized training set (PTO) from public dataset banks, is enough for getting estimates up to 0.32. However, adding PV into PTO is the best scenario, it got predictive ability estimates up to 0.59.It should be used whenever possible.

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