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Search Results: 1 - 10 of 38701 matches for " Cecon Paulo Roberto "
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Indu??o floral de limeiras ácidas 'Tahiti' submetidas a baixas temperaturas
Santos, Dierlei dos;Siqueira, Dalmo Lopes de;Cecon, Paulo Roberto;
Ciência Rural , 2011, DOI: 10.1590/S0103-84782011000300006
Abstract: the research was realized to quantify the need for accumulation hours under low temperatures to the acid lime 'tahiti' flowering, without water application and beyond evaluating gas exchange and chlorophyll a fluorescence under low temperature and light. the experiment was conducted in vi?osa-mg, brazil, with plants from acid lime 'tahiti' grafted on rangpur lime grown in pots of 12 liters. the design was completely randomized with seven treatments and four replicates with one plant per plot. from 02/01/2008 until 04/30/2008, four plants were taken from each growth chamber (cc) (temperatures: 16/12°c (day/night); air humidity: 70%; photoperiod: 10 hours; photosynthetic photon flux density: 100μmol m-2 s-1) to 15 days and taken to a greenhouse (cv) without environmental control, totaling seven dates of transfer. exposure of plants to low temperatures, under controlled conditions, does not cause significant changes in the characteristics of chlorophyll a fluorescence, but caused 80% of reduction in gas exchange. this reduction does not hurt the flowering plants. plants exposed to no-induced conditions only issued vegetative shoots, while those submitted to lower temperatures, the greater was the exposure time, the greater was the number of flowers sent.
Produ??o, florescimento e frutifica??o de tangerineira 'Ponc?' submetida à aplica??o de ácido giberélico
Maia, Emanuel;Siqueira, Dalmo Lopes de;Cecon, Paulo Roberto;
Ciência Rural , 2010, DOI: 10.1590/S0103-84782010005000025
Abstract: the florescence and the production of tangerines are influenced by the last production. so, the inhibition of an excessive florescence can avoid a great production and the exhaustion of the plant reserves, contributing to a more uniform production every year. the objective of this work was to evaluate the effect of the reduction of the florescence in ponkan mandarin trees upon the production of fruits in two consecutive productions. the results demonstrated that the gibberellic acid application reduced the flower production and increased the percentage of fruit production in relation to the year with an excessive flowering. the application of the gibberellic acid around 90-150 days before the full flowering period can contribute to the reduction of the effect of the production alternance.
Níveis de significancia na identifica??o de marcadores moleculares no mapeamento gen?mico
Jangarelli, Marcelo;Euclydes, Ricardo Frederico;Cecon, Paulo Roberto;
Revista Brasileira de Zootecnia , 2011, DOI: 10.1590/S1516-35982011000200011
Abstract: different levels of genomic significance were used in assisted selection by markers to estimate the phenotypic value, the number of markers used in the selection and the percentage of favorable and unfavorable alleles fixed in a quantitative characteristic. a comparison among the levels 0.5; 1; 2; 4; 6; 8; 10; 12; 14; 16; 18 and 20 was done by using the computer system of gene simulation (genesys), used for simulation of a genome consisted of a quantitative character with heritability equal to 0.20. from the initial population, the evaluation of the twelve levels of significance by selection assisted by markers was carried out using the phenotypic values obtained for 10 generations. the cluster method by composite link was applied by using the average euclidean distance as dissimilarity measure among the genomic significances. there are similarities among the phenotypic values obtained with significance levels from 4 to 16%, which are superior to the highly significant (from 0.5 to 2%) and to the extremely suggestive levels (18 and 20%), because of the phenotypic gains obtained over generations under selections.
Sele??o de índices para o diagnóstico do estado de nitrogênio de batata-semente básica
Moreira, Marialva Alvarenga;Fontes, Paulo Cezar Rezende;Cecon, Paulo Roberto;Araújo, Roberto Fontes;
Acta Scientiarum. Agronomy , 2011, DOI: 10.4025/actasciagron.v33i2.5724
Abstract: the objective of this study was to select indexes for the diagnosis of nitrogen status of basic seed potato planted in pot and to determine the critical value of each index. the indexes, determined in the fourth leaf (qf) and old leaf, at 60 days after planting, were: green intensity (determined by color chart and spad), area, length, width, leaflet numbers, fresh and dry weight, n-no3 contents in the petiole sap and n in the dry matter. three experiments were set in pot containing substrate in a greenhouse, at university federal of vi?osa. in each experiment it was utilized one propagation material as tuber seed, mini-tuber and sprout and were evaluated six nitrogen rates (0, 25, 50, 100, 200 and 400 mg dm-3), being 10% of each rate applied at pre-planting time and the remainder was daily applied via irrigation water for 30 days. each experiment was set in randomized block design with four replications. the final tuber harvest occurred when the plant was completely senescent. spad index, n-no3 contents in the sap and dry matter in the qf significantly correlated with plant n contents and reached different critical values depending upon the propagating material.
Produtividade e qualidade de frutos de meloeiro variando número de frutos e de folhas por planta
Queiroga, Roberto Cleiton F de;Puiatti, Mário;Fontes, Paulo Cezar R;Cecon, Paulo Roberto;
Horticultura Brasileira , 2008, DOI: 10.1590/S0102-05362008000200016
Abstract: the muskmelon cultivation in southeast of brazil is possible in greenhouse but plants should be pruned. however, in this species plant growth and fruit yield are limited by both source and sink size activity. the muskmelon fruit productivity and quality in greenhouse were evaluated as affected by fruit and leaf numbers left in the plant. split plot scheme, in a randomized blocks design, with four replications were used. the plot consisted of the fruit number per plant (1 or 2). the fruits were fixed at betweenthe 6 and 80 nodes. the split-plot consisted of the leaf number left in each plant (16; 19; 22 and 25). when the plant was pruned from the 22th leaf and one fruit/plant was left, the leaf area increased as compared with plants with two fruits. independently of the number of leaves, plants with only one fruit presented larger mean fruit weight and smaller commercial yield. sink reduction (fruit number/plant) provided fruits with larger net rind, pulp thickness, length, diameter, total soluble solids, total soluble sugars and no reduced sugars. on the other hand, the number of fruits/plant did not affect the titratable acidity and the reduced sugars. except for the titratable acidity that declined and the cavity diameter of the fruit that presented quadratic answer, all the characteristics evaluated presented linear increment with the increase in the number of leaves for plant.
Características de frutos do meloeiro variando número e posi??o de frutos na planta
Queiroga, Roberto Cleiton F de;Puiatti, Mário;Fontes, Paulo Cezar R;Cecon, Paulo Roberto;
Horticultura Brasileira , 2009, DOI: 10.1590/S0102-05362009000100005
Abstract: the study was carried out in a greenhouse of the universidade federal de vi?osa, minas gerais state, brazil, from 26/09/05 to 24/01/06, to evaluate the yield and quality of the melon fruit, varying the number and position of fruits on the plant. the treatments consisted of fruit number per plant (1 and 2) and fruit position in the plant (5th - 8th node and 15th - 18th node). a randomized block design was used, in a 2 x 2 factorial scheme, with 5 replications. the 'coronado f1', variety reticulatus of the cantaloupe group was cultivated in 11.5 dm3 plastic pots with commercial coconut fiber. plants with one fruit provided higher harvest period, leaf area (la) (5th - 8th node), fruit mean mass (mmf), net rind (nr), pulp thickness (pt), fruit length (lf), diameter (df), total soluble solids, total soluble sugars (tss), no reduced sugars (snr) and smaller commercial fruit yield (pcf). fruit fixation among the 15th - 18th node led to more days to begin and to finish the harvest, la, mmf, pcf, pt, lf and df of fruits (in plants with 1 fruit), maturation index, tss, and snr and led to smaller nr and total titratable acidity and reduced sugar concentrations.
Produtividade e qualidade do mel?o cantaloupe, cultivado em ambiente protegido, variando o número e a posi??o dos frutos na planta
Queiroga, Roberto Cleiton Fernandes de;Puiatti, Mário;Fontes, Paulo Cezar Rezende;Cecon, Paulo Roberto;
Bragantia , 2008, DOI: 10.1590/S0006-87052008000400013
Abstract: muskmelon fruits are strong sink affecting assimilate distribution among the plant organs. this experiment aimed at to determine yield and quality of 'torreon' cultivar in greenhouse conditions as affected by fruit number and position in the plant. a 2 x 2 factorial was set in randomized block design, with five replications. treatments combined fruit number per plant (1 and 2) and position in the vine (among 5th - 8th node and among 15th - 18th node), planted in 11, 5 dm3 pot with coconut fiber fertilized with macro and micronutrients. compared to plants with two fruits, in plants with only one fruit there were the highest values of fruits mass (mf), netted rind (rc), fruit length, format index, flesh thickness, maturation index (im), soluble solids (ss), total soluble sugars and no reducing sugars. compared to plants with two fruits in plants with one fruit there was a reduction in the commercial productivity (pc) of 21.4% in fruits between 5th and 8th nodes had 24.9% in fruits of 15th and 18th nodes. fruits of the 15th and 18th nodes presented higher mf, im, pc and culture cycle, as well as lower rc and total titratable acidity. positive and significant correlations were obtained for leaf area per fruit (af) x mf of 0.81, af x ss of 0.79, mf x ss of 0.68, mf x rc of 0.72 and rc x ss of 0.51.
índices para avaliar o estado de nitrogênio da batata multiplicada por distintos materiais propagativos
Moreira, Marialva Alvarenga;Fontes, Paulo Cezar Rezende;Cecon, Paulo Roberto;Araújo, Roberto Fontes;
Revista Ceres , 2011, DOI: 10.1590/S0034-737X2011000300020
Abstract: improvement in the efficiency of n application can be achieved by synchronizing the plant demand with n supply during the potato cycle. the objective of this study was to determine the optimum values of nitrogen indexes over the cycle of potato grown in a greenhouse, using different propagative materials such as seed tuber, minituber, and sprout tuber, common in the pre-basic seed tuber production. the indexes, determined in the fourth (fl) and the oldest (ol) leaf, were green color intensity, measured by chlorophyll meter and color chart, and agronomic characteristics as leaflet length, width, area and number. three experiments were carried out in pots in a greenhouse at the university federal of vi?osa. in each experiment, arranged in a randomized block design with four replications, there was evaluated six nitrogen rates (0, 25, 50, 100, 200 and 400 mg dm-3). the indexes were determined every 10 days, starting 20 days after plant emergence (dae). with each propagating material, the spad index measured in both the fl and the ol responded differently to the increase in n and reached the optimal values of 41.3, 40.5, 37.0, 35.8, 36.0, 31.9 and 29.8 g.kg-1 from 20 to 80 dae, respectively when seed tuber was used. in all the propagating material, plant age significantly affected all variables except number of stems or the number of leaves, when it is used sprout tuber or minitubers, respectively. optimum values of variables over the potato cycle depended upon propagation material and time of evaluation.
Sele o de índices para o diagnóstico do estado de nitrogênio de batata-semente básica = Selection of indexes for the diagnosis of nitrogen state of basic seed potato
Marialva Alvarenga Moreira,Paulo Cezar Rezende Fontes,Paulo Roberto Cecon,Roberto Fontes Araújo
Acta Scientiarum : Agronomy , 2011,
Abstract: O objetivo deste trabalho foi selecionar índices para diagnóstico do estado de nitrogênio de batata-semente básica em vaso e determinar valor crítico de cada índice selecionado. Os índices, medidos na quarta folha (QF) e folha velha, aos 60 dias após o plantio, foram: intensidade do verde (determinado por tabela de cor e SPAD); área,comprimento, largura, número de folíolos, matéria fresca e seca; teor N-NO3 na seiva do pecíolo e N na matéria seca. Foram realizados três experimentos em vaso, em casa de vegeta o, Universidade Federal de Vi osa. Em cada experimento utilizou-se um material de propaga o que foi tubérculo-semente, mini-tubérculo e broto e foram avaliadas seisdoses de N (0; 25; 50; 100; 200 e 400 mg dm-3), sendo 10% de cada dose aplicada em préplantio e o restante via água de irriga o, diariamente por 30 dias. Cada experimento foi instalado no delineamento de blocos ao acaso, com quatro repeti es. A colheita dostubérculos ocorreu quando a planta estava totalmente seca. O índice SPAD, teor nitrato na seiva e massa seca na QF correlacionaram significativamente com conteúdo de N na planta sendo o valor crítico variável com o material de propaga o. The objective of this study was to select indexes for the diagnosis of nitrogen status of basic seed potato planted in pot and to determine the critical value of each index. The indexes, determined in the fourth leaf (QF) and old leaf, at 60 days after planting, were:green intensity (determined by color chart and SPAD), area, length, width, leaflet numbers, fresh and dry weight, N-NO3 contents in the petiole sap and N in the dry matter. Three experiments were set in pot containing substrate in a greenhouse, at University Federal ofVi osa. In each experiment it was utilized one propagation material as tuber seed, minituber and sprout and were evaluated six nitrogen rates (0, 25, 50, 100, 200 and 400 mg dm-3), being 10% of each rate applied at pre-planting time and the remainder was daily applied viairrigation water for 30 days. Each experiment was set in randomized block design with four replications. The final tuber harvest occurred when the plant was completely senescent. SPAD index, N-NO3 contents in the sap and dry matter in the QF significantly correlated with plant N contents and reached different critical values depending upon the propagating material.
índice SPAD para o diagnóstico do estado de nitrogênio e para o prognóstico da produtividade da batata
Gil, Paula Torrealba de;Fontes, Paulo Cezar Rezende;Cecon, Paulo Roberto;Ferreira, Francisco Affonso;
Horticultura Brasileira , 2002, DOI: 10.1590/S0102-05362002000400020
Abstract: the spad critical level (soil plant analysis development) in potato leaves was established to verify the possibility of its utilization in monalisa potato tuber yield prognosis. the experiment was installed in a red-yellow argisoil having 39 mg kg-1 of mineral nitrogen content. the experiment was laid out in randomized complete blocks with split plot design and four replications. in the plot were set five n rates (0; 25; 50; 100 and 200 kg ha-1), applied in the furrows before planting. in the split plot were set four side-dressed n rates (0; 90; 180 and 360 kg ha-1), applied in bands 10 cm apart plant side at 23 days after plant emergence, before hilling. spad indices were obtained from the terminal leaflet of the fourth leaf from the apex (qf) for six times. the first one (spad1) was measured three days before the side-dress n fertilization and the others at 7; 17; 27; 37 and 47 days after the side-dress n application. spad indices were also determined in leaves older (fm) than the qf. n content in the qf was determined at the first sampling time. spad1 index and n content in the qf increased as preplanting n rates increased following a quadratic function, attaining the critical values of 44.9 and 6.15 dag.kg-1, respectively. the correlation between spad1 indices and tuber yield was linear and positive, showing that spad1 could be used as a prognostic index of potato yield. at all sampling dates, spad indices in the qf and fm leaves were affected by n rates but they reached different values, showing the necessity to standardize the time and leaf to be sampled.
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