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Search Results: 1 - 10 of 9733 matches for " Giovani;Vieira "
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Verifica??o da adaptabilidade e estabilidade de popula??es de cenoura pelos métodos AMMI, GGE biplot e REML/BLUP
Silva, Giovani Olegario da;Carvalho, Agnaldo Donizete Ferreira de;Vieira, Jairo Vidal;Benin, Giovani;
Bragantia , 2011, DOI: 10.1590/S0006-87052011005000003
Abstract: the aim of this study was to verify the adaptability and stability of carrot populations for organic and conventional production systems and to draw a comparison among the used statistical methodologies. the study was carried out during 2007 and 2008, at five sites: conventional cultivation was performed in sao gotardo (mg), irece (ba) and gama (df); and organic production system was performed in pad-df and gama (df). the experiment was arranged in complete randomized block design with tree replications and plots of 1 m2. seven carrot populations from the brasilia group were evaluated: 0912545, 0912532, 0912520, brs planalto, esplanada, brasilia and alvorada. one-hundred days after sowing, the root mass with commercial value was evaluated in each plot. the methodologies ammi, gge biplot and reml/blup were applied for evaluating the adaptability and stability. ammi and gge biplot obtained very similar results regarding adaptability and stability of carrot populations; however gge biplot grouped the more favorable and unfavorable environments more clearly. the reml/blup analysis did not group of the most similar areas; however, it presented the results as function of genotypic values taking into account the parameters of adaptability and stability. the populations that presented the best adaptability and stability were 0912532, brs planalto and 0912520.
Componentes genéticos e fenotípicos para caracteres de importancia agron?mica em popula??o de cenoura sob sele??o recorrente
Silva, Giovani Olegário da;Vieira, Jairo Vidal;
Horticultura Brasileira , 2008, DOI: 10.1590/S0102-05362008000400011
Abstract: the objective of this work was to estimate the genotypic and phenotypic parameters for traits of carrot populations among characters in carrot populations, in order to guide the choice of selection strategies. the experiments were performed at two locations (lap?o, bahia state and brasília, brazil) in the summer of 2004. nine carrot hybrid populations were evaluated in randomized complete block design with 4 replications and 2 m2 treatments. 90 days after sowing, 15 competitive plants per plot were harvested and evaluated individually for the characters yield, root length, green shoulder length, tip type, shoulder type, root diameter, xylem root diameter, relationship among xylem diameter/root diameter, and both xylem and phloem a* color (color parameter determined by colorimetry, varying from green to red). the data were submitted to variance analyses and the heritability in the wide sense of plot average was estimated by medium square and the correlation among the characters. according to the heritability values, for the characters xylem diameter (0.92 and 0.87), color of a* xylem (0.96 and 0.95) and ratio among xylem diameter and root diameter (0.87 and 0.91), strong selection pressure can be applied in the two evaluation places. larger root yield was associated with larger root diameter and larger xylem diameter, as well as by larger values of the ratio among xylem diameter and root diameter. thicker roots are associated with smaller a* (content of β-carotene), mainly in relation to the part constituted by the xylem. therefore, through the correlation values, there exist an indication that selection for larger carotene content cannot be carried out without considering the characters of root diameter, which are important yield components.
Genetic parameter and correlation estimates of processing traits in half-sib progenies of tropical-adapted carrot germplasm
Vieira, Jairo V;Silva, Giovani Olegario da;Boiteux, Leonardo S;
Horticultura Brasileira , 2012, DOI: 10.1590/S0102-05362012000100002
Abstract: the estimate of the genetic parameters associated with processing (fresh-cut) traits, including root length (rl), is crucial for carrot breeding programs in tropical areas. the cultivar alvorada is an important germplasm due to its resistance to nematodes, leaf blight, heat-tolerance, and high carotenoid content. seventy-four 'alvorada' half-sib progenies were evaluated during the summer of 2005 in the federal district, brazil, in a randomized complete block design with three replications. thirteen competitive plants in each block were randomly selected and evaluated and/or classified for rl and for number of leaves (nl), leaf length (ll), root tip type (rt), root mass (rw), crown shape (cs), root diameter (rd), and xylem diameter (xd). the pearson's correlation coefficients and the heritability values were estimated for all traits. the path analysis was also used considering the rl trait as dependent variable. the heritability for rl ranged from 12 to 44%. for the other traits, the values ranged from 3% (rd) to 79% (ll). phenotypic and genotypic correlations among all traits were low to intermediate. path analysis indicated positive direct relationship between rl and rw, whereas rd and xd displayed negative direct effect on rl. longer roots had narrow diameter and narrow xd. recurrent selection based upon either half-sib or s1 families would be more effective than mass phenotypic recurrent selection in increasing rl and to develop populations expressing multiple desirable processing traits in tropical-adapted carrot germplasm.
Ganhos realizados com a sele??o para caracteres de importancia agron?mica em cenoura
Silva, Giovani Olegário da;Vieira, Jairo V;
Horticultura Brasileira , 2009, DOI: 10.1590/S0102-05362009000400009
Abstract: the genetic progress estimative is an important aspect in breeding programs, in order to evaluate the breeding selection methods efficiency for the characteristics of interest in the populations under selection. in this research, the gains obtained from the selection of agronomic traits were evaluated in a carrot population through successive generations. the experiment was performed at embrapa hortali?as, brasília, brazil. a carrot population was selected every summer during six consecutive generations from 1999 to 2004. in the summer of 2005, samples of seeds harvested in the previous years were sown in plots of 1 m2 in randomized blocks design with five replications. the plants were evaluated for severity of leaf blight at 60 and 90 days after sowing and harvested at 90 days after sowing when each plot was evaluated for the characters of number and mass of waste roots, number and mass of marketable roots with green shoulder, number and mass of marketable roots without green shoulder, number, mass and average mass of total roots and number, mass and average mass of marketable roots. the data were submitted to analyses of variance, and comparisons of treatment means by scott-knott, and the gain obtained with selection was calculated. superior gains occurred only in the first cycles of selection towards the decrease of refused roots and increase of resistance to leaf blight. the selection for leaf blight resistance was efficient only when performed at 90 days after sowing, because the disease severity was low at 60 days. the amount of roots classified as marketable with and without green shoulder increased during all the selection cycles, although the gains were higher for the roots without green shoulder.
Tamanho mínimo de parcela para avalia??o de caracteres de raiz em cenoura
Vieira, Jairo Vidal;Silva, Giovani Olegário da;
Bragantia , 2008, DOI: 10.1590/S0006-87052008000400029
Abstract: the estimate of the optimal number of plants per plot for the evaluation of carrot populations is important in order to reduce the experimental error and to enhance the accuracy of the information obtained in breeding experiments. additionally, it contributes to reduce the research costs. the objective of the present work was to estimate the minimum number of plants per plot for evaluation of root characters in carrot populations using the modified maximum curvature and the stabilization of the average and genetic variance methods. the essays were conducted in the summer of 2004 at three representative areas for carrot production in brazil, respectively: brasília, df; s?o gotardo, mg and lap?o, ba, in randomized blocks design with four replications, and plots with 2 m2. harvesting took place 90 days after sowing. in each plot of nine populations, 15 competitive plants were harvest and roots evaluated for mass, length, green shoulder length, tip shape, shoulder shape, diameter, xylem diameter, relationship among xylem diameter / root diameter and the l* a* b* color caracters for the xylem and phloem. the procedures of re-sampling and the modified maximum curvature method were used to estimate the minimum plant number to represent each plot. the results obtained for each procedure indicated that a sample of 13 plants per plot is enough to guarantee an appropriate evaluation of carrot populations for the group of studied characters.
Rela??es entre caracteres de cenoura para sistemas de cultivos organico e convencional
Silva, Giovani Olegário da;Vieira, Jairo Vidal;
Revista Ceres , 2010, DOI: 10.1590/S0034-737X2010000500016
Abstract: the selection strategy and the gain that it will provide allow, in a more efficient way, to direct a breeding program and to predict the success of the chosen selective scheme. the aim of this work was to evaluate the stability of the relationships among phenotypic characteristics of carrot populations cultivated in organic and conventional production systems. the experiments were conducted at embrapa vegetables, df, brazil. two breeding lines and four commercial cultivars were planted in november 2007 in both production systems, in a randomized block design with four replications and plots of 1m2. ninety days after planting, twenty roots per plot were harvested and evaluated for phenotypic characteristics. the analysis of variance was performed to determine the interaction between treatments and production systems, as well as phenotypic correlations and path analysis. the direct and correlated selection gains were also determined. almost all of the median correlations above 0.30 and the largest direct effects of path analysis and direct and indirect gains estimated were repeated in both systems, indicating that the systems are very similar in the expression of the relationship among the characteristics. thus, breeding for these traits do not need to be carried out in areas of both organic and conventional systems.
Ganhos genéticos após seis ciclos de sele??o em três popula??es de cenoura
Silva, Giovani Olegário da;Vieira, Jairo Vidal;
Revista Ceres , 2010, DOI: 10.1590/S0034-737X2010000600011
Abstract: the objective of this work was to evaluate the genetic gain with selection for root traits in three carrot populations. the experiment was conducted at embrapa hortali?as, brasília -df, brazil. three carrot populations derived from cultivar brasília and of common origin until 2001, were selected in six consecutive generations in the summers of 1998 to 2003. in the summer of 2004, seed samples of each year were sowed in the field in a randomized block design with five replications and plots of 1m2. ninety days after sowing, 25 roots per plot were harvested and evaluated for: length, xylem and phloem diameter, green shoulder length, mass, presence of halo, shape of tip and shoulder, and l* a* b* parameters of xylem and phloem. analysis of variance, comparisons among treatment means and estimation of genetic gain with selection were performed. in the last six years of selection, visual selection for color traits was not successful, probably due the low genetic variability, because the roots of these populations are already deep in color, indicating higher β-carotene content. increase in mass and root length was seen in both populations, with a proportional decrease in mean diameter of root and phloem.
Sele??o e número mínimo de famílias para avalia??o de parametros de cor em uma popula??o meio-irm? de cenoura
Silva, Giovani Olegário da;Vieira, Jairo Vidal;
Revista Ceres , 2010, DOI: 10.1590/S0034-737X2010000100012
Abstract: the use of the number of families not superior to what may be considered as sufficient for a good representation of a certain crossing is recommended, but taking into account the relationship between cost of experiment implementation and the progress obtained from the breeding program. thus, the aim of this work was to estimate the minimum number of half-sibling families of carrot necessary to represent the genetic characteristics of a population, as well as to identify the best families and the best plants inside families as to color features. the experiment was carried out at embrapa vegetable crops, gama-df, during the summer of 2004. a hybrid population with 71 half-sibling families of carrot plus two standard cultivars were evaluated in a experiment arranged in a complete randomized block design with 2 replications, with plots measuring 2,0 m2. ninety days after planting, 10 plants per plot were harvested and evaluated as to xylem and phloem l* a* b* parameters. the analysis of variance was performed and the minimum number of families to represent the population as well as the gains from the selection of 10% of the best families and plants inside families were estimated. it was observed that the selection among and inside families provided similar βcarotene level increases for faboth root parts. higher gains with the selection were obtained for the xylem characteristics. for xylem l* a* b*, both standard cultivars were surpassed by the selected families. only families 71, 7, 61 and 20 should be selected for phloem l* a* b*. for the evaluation of xylem and phloem color parameters, 52 and 42 families are necessary, respectively.
Strategies of selection for carrot seed germination at high temperatures Estratégias de sele o para germina o de sementes de cenoura em altas temperaturas
Giovani Olegario da Silva,Jairo Vidal Vieira,Warley Marcos Nascimento
Semina : Ciências Agrárias , 2011,
Abstract: Among the carrot cultivars developed for summer cultivation, stand out those from the “Brasilia” group. These cultivars present higher performance in relation to the others commercialized in the country due to their productivity, resistance to leaf-blight diseases and higher adaptation to the Brazilian summer conditions. However, it is necessary to increase, by selection, the potential for carrot seed germination at high temperatures (above 35oC), resulting in seed economy and more uniform plant establishment, especially during warm weather conditions. Thus, the objective of this study was to select carrot populations with seeds able to germinate under conditions of high temperature. The experiment was carried out in Brasília, DF, in the year of 2007. Four replications of fifth seeds from forty-seven carrot half-sib families were incubated at 20oC and 37oC in a randomized block design. The data were submitted to the analysis of variance, application of selection indexes and estimation of gains with the selection. The selection for germination of carrot seeds at high temperatures (37oC) were not effective. The values of vigor and germination at 37°C were low, suggesting that this temperature is approaching the biological limit of the populations of the carrot group Brasilia. At 20°C it is possible to differentiate the genotypes regarding to physiological quality of seeds. Dentre as cultivares de cenoura desenvolvidas para o cultivo durante o ver o, destacam-se aquelas do grupo Brasilia. Estas cultivares apresentam desempenho superior em rela o às outras comercializadas no país quanto a produtividade, resistência à queima-das-folhas e adapta o às nossas condi es de cultivo durante o ver o. Entretanto, há necessidade de se fazer sele o para aumentar o potencial de germina o da cenoura sob temperaturas elevadas (acima de 35oC), propiciando assim uma economia de sementes e estandes mais uniformes, principalmente em regi es quentes. Desta forma, o objetivo do trabalho foi verificar a possibilidade de sele o de popula es de cenoura com sementes capazes de germinar sob condi es de temperaturas elevadas. O experimento foi realizado em Brasília, DF, no ano de 2007. Foram avaliados germina o e vigor a 20oC e 37oC de sementes provenientes de 47 famílias de meio-irm os, utilizando-se delineamento inteiramente casualizado com 4 repeti es de 50 sementes para cada família. Os dados foram submetidos à análise de variancia, aplica o de índices de sele o e estimativas de ganhos com a sele o. A sele o para germina o de sementes de cenoura em altas temperatur
Dissimilarity among families and correlated selection response for root characters of carrots grown in two agroecologic production systems in Distrito Federal Dissimilaridade entre famílias e resposta correlacionada à sele o para caracteres de raiz de cenoura cultivada em dois sistemas de produ o agroecológicos no Distrito Federal
Giovani Olegario da Silva,Jairo Vidal Vieira,Michelly Souza Villela
Semina : Ciências Agrárias , 2012,
Abstract: The objective of this work was to calculate the dissimilarity among families and the correlated selection response in a carrot population grown in two agroecologic production systems. The experiments were conducted in Brasília, in the summer of 2006/2007. A hundred half-sib families of carrot were evaluated in a complete randomized block design with two replications. Twenty plants were harvested individually per plot and were evaluated for root characters. Joint and separated variance analyses for the two systems were performed. The dissimilarity among and between families and the correlated selection response were calculated. It was mainly verified that inside of the population, in both production systems, it is possible to select for more dissimilar families to be used in a next recurrent selection cycle, providing gains with heterosis. In selecting among or within families, for larger root mass, gains superior to 2% per selection cycle could be expected, for longer roots and with larger xylem diameter. Selection for higher levels of carotenoids, mainly in the xylem cannot be made separately from the yield components, length, measures of diameter and average root weight. O objetivo deste trabalho foi calcular a dissimilaridade entre famílias e a resposta correlacionada à sele o em uma popula o de cenoura cultivada em dois sistemas agroecológicos de produ o. Os ensaios foram conduzidos em Brasília, no ver o de 2006/2007. Foram avaliadas 100 famílias de meioirm os de cenoura em delineamento de blocos casualizados com duas repeti es. Foram colhidas individualmente 20 plantas por parcela e avaliadas para caracteres de raiz. Foi realizada análise de variancia conjunta e para cada sistema. Foram calculadas a dissimilaridade entre e dentro de famílias, e a resposta correlacionada à sele o. Verificou-se principalmente que dentro da popula o, em ambos os sistemas de produ o, é possível selecionar famílias mais dissimilares para serem utilizadas num próximo ciclo de sele o recorrente, proporcionando ganhos com heterose. Ao se fazer sele o tanto entre quanto dentro de famílias, para maior massa de raízes, ganhos superiores a 2% por ciclo de sele o poderiam ser esperados, para raízes mais compridas e com maior diametro de xilema. A sele o para maior teor de carotenóides, principalmente no xilema, n o pode ser efetuada em separado dos caracteres componentes do rendimento, comprimento, medidas de diametro e massa média de raiz.
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