131 resultados para SPAD


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Pós-graduação em Agronomia (Agricultura) - FCA

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Cucumber (Cucumis sativus L.) is a plant of the Cucurbitaceae family of great commercial importance and their culture is widespread throughout the country. The production of vegetables, high-quality care begins with training ranging from seedlings and shading techniques have an important role in creating environments more conducive to the production of seedlings and many researchers and producers of seedlings have opted for the use of color shading screens, making this way, the wavelength and the amount of incident energy are changed in favor of the plants. Work will be performed at the Department of Forest Sciences, Faculty of Agricultural Sciences, Universidade Estadual Paulista (UNESP), Botucatu campus. The statistical design will be in three blocks, each containing 100 plots of each treatment (seedlings covered with blue screen, red and black). Evaluations of dry mass and height will be made at 7, 14, 21 and 28 days after emergence, and 5 will be selected seedlings of each treatment. At 14 and 28 DAE was measured, and SPAD chlorophyll content at 30 DAE, was evaluated by measuring gas exchange in the second pair of leaves, fully expanded for each plant, which was put in a chamber controlled with infrared gas analyzer (IRGA LI 6400, Licor) to perform measurements of photosynthesis. Treatment with black shading showed statistically better results for total dry matter, plant height, SPAD chlorophyll content and net assimilation of CO2, showing a better quality seedlings and its use is recommended in the cultivation of cucumber Taiko

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Pós-graduação em Agronomia (Agricultura) - FCA

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Pós-graduação em Agronomia (Ciência do Solo) - FCAV

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Pós-graduação em Agronomia (Horticultura) - FCA

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The physic nut can be propagated asexually or sexually. Using cuttings have been earlier yield and more fidelity characteristics of the parent plant. However, there is less initial vegetative growth. The seeds from the plants have increased genetic variability, are more vigorous and begin production later. To get quality changes, the substrate is an important factor. With that the objective was to taste pre-germinated treatments and different substrate on seeds emergence and quality physic nut seedlings. The experimental design was completely randomized, in factorial scheme 6 x 3 (pre-germinated treatments x substrate), 18 treatments and 4 repetition, 8 seeds to each repetition. It was evaluated six pre-germination treatments: T1: witness (without treatments); T2: water immersion for 12 hours; T3: water immersion for 24 hours; T4: mechanical scarification; T5: mechanical scarification + water immersion for 12 hours; T6: mechanical scarification + water immersion for 24 hours, using as substrate: commercial, expanded vermiculite and sand washed. The mechanical scarification was realized opposite the micropyle using sandpaper n. 60. After the pre-germination treatments, the seeds were emergence in plastic cups (200mL) with substrates. We evaluated the characteristics: percentage, beginning and emergence speed index, mean length of plant, diameter of plant stem, SPAD index, fresh and dry shoot and root. The results showed that in seeds of Jatropha do not need pre-germinative treatments; and the use of commercial substrate showed seedling development.

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To achieve high wheat yield, correct management of N fertilization and the use of high yield potential cultivars are necessary. The aim of this study was to evaluate the effects of different application rates and sources of N, applied totally at sowing or in topdressing, on grain yield and yield components of two irrigated wheat cultivars under a no-till system, grown in a Cerrado (Brazilian tropical savanna) region of low altitude. A randomized block design was used in a 5 x 3 x 2 x 2 factorial arrangement with three replications, combining five levels of N (0, 50, 100, 150, and 200 kg ha(-1)), three sources of N (Entec (R), ammonium sulfate, and urea), and two application times (at sowing, near the rows, or in topdressing) in two wheat cultivars (IAC 370 and Embrapa 21). The wheat cultivars had similar grain yields. There was no difference among the sources of N for grain yield and yield components. The N applied totally at sowing did not differ from the traditional application at sowing and in topdressing for production of irrigated wheat in no-tillage. The increase in application rates of N increased the leaf N contents and chlorophyll, plant height, and the number of ears per m(2). Grain yield of the wheat cultivars IAC 370 and Embrapa 21 increased up to the application rates of 134 and 128 kg ha(-1) of N, respectively, regardless of application time and source of N. The positive correlation between chlorophyll leaf content and grain yield in accordance with N fertilization levels indicates that N fertilization in topdressing can be recommended based on SPAD readings of leaf chlorophyll performed at 38 days after wheat plant emergence.

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Strategies of cotton growth as row spacing and use of growth regulator are efficient when the knowledge of crop production potential as well as the amounts of nutrients content. The objective of this study was to evaluate the nutritional status of cotton DeltaOpal cultivar through leaf analysis of macronutrient, chlorophyll index and yield in relation to plant arrangement and managements of the growth regulator. The treatments consisted of plant arrangement: arrangement 1: 88,900 plant ha(-1) and row spacing at 0.9m, arrangement 2: 114,300 plant ha(-1) and row spacing at 0.7m, arrangement 3: 178,000 plant ha(-1) and row spacing at 0.45m; management of growth regulator (mepiquat chloride) at 1.0 L ha(-1) dose, concentration was50g L-1: a-no regulator application; b-single application at 70 days after emergency (d.a.e.); c-split application into four stages (35, 45, 55, and 65 d.a.e.). The reading reviews SPAD chlorophyll, leaf analysis of macronutrients and cotton yield were conducted in three agricultural years 2006/07, 2007/08 and 2008/09, under the experimental design of completely randomized blocks, in a 3x3 factorial scheme totaling up nine treatments with four replications. The reduction of row spacing and increasing plant density gives less absorption of potassium and sulfur by cotton crop. A single application of mepiquat chloride increase calcium leaf content. The split application of mepiquat chloride provides increased SPAD reading index, higher foliar magnesium concentration and highest seed cotton yield.

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Pós-graduação em Agronomia - FEIS

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Pós-graduação em Agronomia (Horticultura) - FCA

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Pós-graduação em Agronomia (Agricultura) - FCA

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)