1000 resultados para Cana-de-açúcar - Efeito do stress
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Pós-graduação em Agronomia (Agricultura) - FCA
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Pós-graduação em Ciências Biológicas (Microbiologia Aplicada) - IBRC
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Pós-graduação em Agronomia (Proteção de Plantas) - FCA
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Este trabalho teve como o objetivo, verificar o efeito da freqüência da irrigação subsuperficial por gotejamento no desenvolvimento inicial da cana-de-açúcar. Os tubos gotejadores foram instalados sob a linha da cultura, a uma profundidade de 0,3 m. A cana-de-açúcar foi plantada no dia 03/03/2000 e a partir de 01/04/2000 iniciaram os tratamentos nas parcelas irrigadas. O delineamento experimental foi inteiramente casualizado, com quatro tratamentos, e quatro repetições, definidos por regimes de freqüência da irrigação. O sistema de irrigação era acionado quando a evapotranspiração da cultura atingisse 10 mm, 20 mm, e 30 mm, para os tratamentos 1, 2, e 3 respectivamente. O tratamento 4 foi definido como testemunha (não irrigado). A colheita foi realizada no dia 05/12/2000 e através da avaliação de produção de massa fresca, diâmetro e comprimento do colmo, e produção de massa seca, observou-se que não houve diferença estatística entre os diferentes regimes de freqüência de irrigação. Todavia, quando comparado com a testemunha, as irrigações proporcionaram um aumento médio maior que 45 % na produção de massa fresca e seca final dos colmos.
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The soil is one of the main C pools in terrestrial ecosystem, capable of storing significant C amounts. Therefore, understanding the factors that contribute to the loss of CO2 from agricultural soils is critical to determine strategies reducing emissions of this gas and help mitigate the greenhouse effect. The purpose of this study was to investigate the effect of soil tillage and sugarcane trash on CO2 emissions, temperature and soil moisture during sugarcane (re)planting, over a study period of 15 days. The following managements were evaluated: no-tillage with crop residues left on the soil surface (NTR); without tillage and without residue (NTNR) and tillage with no residue (TNR). The average soil CO2 emission (FCO2) was lowest in NTR (2.16 µmol m-2 s-1), compared to the managements NTNR (2.90 µmol m-2 s-1) and TNR (3.22 µmol m-2 s-1), indicating that the higher moisture and lower soil temperature variations observed in NTR were responsible for this decrease. During the study period, the lowest daily average FCO2 was recorded in NTR (1.28 µmol m-2 s-1), and the highest in TNR (6.08 µmol m-2 s-1), after rainfall. A loss of soil CO2 was lowest from the management NTR (367 kg ha-1 of CO2-C) and differing significantly (p<0.05) from the managements NTNR (502 kg ha-1 of CO2-C) and TNR (535 kg ha-1 of CO2-C). Soil moisture was the variable that differed most managements and was positively correlated (r = 0.55, p<0.05) with the temporal variations of CO2 emission from NTR and TNR. In addition, the soil temperature differed (p<0.05) only in management NTR (24 °C) compared to NTNR (26 °C) and TNR (26.5 °C), suggesting that under the conditions of this study, sugarcane trash left on the surface induced an average rise in the of soil temperature of 2 ºC.
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Pós-graduação em Agronomia (Agricultura) - FCA
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The objective of this study was to evaluate the responses of sugar cane subject to water stress by photosynthetic pigments (chlorophylls a, b, total a + b, ratio chlorophylls a/b and carotenoids) and verify the use of SPAD index as a cultivar differentiation tool. The experiment was carried out in a greenhouse, where four cultivars (IACSP95-5000, RB835054, RB928064 and SP80-3280) were grown in pots. After 65 days of planting, two treatments were implemented, i.e., with no stress (-D) and with water stress (D +). Cultivars of sugar cane respond differently in relation to photosynthetic pigments when subjected to water deficit. Cultivars IACSP95-5000 and RB928064 have less effect of drought, that is attributed to the ability of maintaining the chlorophyll and carotenoid content, as well as higher SPAD index values under this condition. Water stress affects with more intensity the cultivars RB835054 and SP80-3280 due to higher reductions in photosynthetic pigments and SPAD index. SPAD index is correlated with chlorophyll and carotenoid content in sugar cane and can be used as a technique for selecting tolerant cultivars to drought in breeding programs.
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Pós-graduação em Agronomia (Produção Vegetal) - FCAV
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Pós-graduação em Zootecnia - FCAV
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Pós-graduação em Agronomia (Ciência do Solo) - FCAV
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Aiming qualitative improvements in the mass rearing of Cotesia flavipes (Cameron, 1891) (Hymenoptera: Braconidae) in laboratory, tests were conducted with adults feed before parasitism on Diatraea saccharalis (Fabricius, 1794) (Lepidoptera: Crambidae) larvae, using 14 artificial diets based on sucrose, brewer yeast and honey. The design was completely randomized with 15 treatments and five replications. The biological parameters evaluated in F1 and F2 generations were: number of adults emerged; sex ratio; adult emergence percentage; weight of pupae mass; and male and female longevity. The highest average of emerged adults were 85 in diet with sucrose 5% for F1 generation, and 91 in diet with sucrose 5% + yeast brewer 2,5% for F2; the smaller average of adult emergency were 63.60 in diet with honey 5% + yeast brewer 2.5 % for F1 generation and 66.80 in diet with honey 5% for F2. Diets that produced more females were honey 5% + yeast brewer 2.5%, showing the sex ratio of 0.82 for F1 generation, and sucrose 10% + 2.5% yeast brewer 2.5% (0.75) for F2, while sucrose 10% + yeast brewer 2.5% (0.60 for F1) and honey 2.5% (0.59) provided fewer females for F2 generation. The highest percentage of adult emergence were 93.90% with the diet containing sucrose 2.5% + yeast brewer 2.5%) and 93.89 % with honey 5% + yeast brewer 2.5%, and the lowest 81.71% (honey 5% + yeast brewer 2.5%) for F1 and 78.96 % (honey 5%) to F1 and F2, respectively. The diet with Mel 2.5% produced greater weight of pupae mass. The adult longevity did not differ significantly for all diets in F1 and F2 generations. Diets containing 5% or 10% of sucrose or honey provide, in general, improve the qualitative development of C. flavipes in mass rearing.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)