oalib

Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99

Submit

Any time

2019 ( 110 )

2018 ( 898 )

2017 ( 889 )

2016 ( 1111 )

Custom range...

Search Results: 1 - 10 of 354064 matches for " Jefferson Luís Meirelles;Guidolin "
All listed articles are free for downloading (OA Articles)
Page 1 /354064
Display every page Item
Resposta de híbridos de milho cultivados em diferentes épocas à popula??o de plantas e ao despendoamento
Sangoi, Luís;Guidolin, Altamir Frederico;Coimbra, Jefferson Luís Meirelles;Silva, Paulo Regis Fereira da;
Ciência Rural , 2006, DOI: 10.1590/S0103-84782006000500004
Abstract: current maize hybrids are more tolerant to the increasing of plant population than the hybrids used in the past. it is possible that modern hybrid's better adaptation to crowding is related to the lower apical dominance of the tassel over the ear. this experiment was aimed at evaluating the evolution on maize hybrids commercially released in different times the increase in plant population and at detecting if this progress is related to the reduction of apical dominance. the experiment was carried out in lages, sc, during the 1999/2000 and 2000/2001 growing seasons. a split-split plot design was used. three plant populations were tested in the main plots: 50,000, 75,000 and 100,000pl ha-1. four hybrids commercially released in the 60's, 70's, 80's and 90's, respectively, were assessed in the split plots. each hybrid was analyzed with preserved tassels and with tassel removed at booting in the split-split plot. the trials were installed in 10/30/1999 and 11/02/2000. grain yield was assessed using the variance and regression analyzes. the hybrid commercially released in the 90's (ag 9012) was more demanding in plant population to maximize grain yield when the conditions were favorable to yields higher than 10,000kg ha-1 (1999/2000). at this scenario, tassel interference on ear development was small. on the other hand, grain yield of all tested hybrids was increased by tassel removal under a lower yield plateau (2000/2001).there was no association between higher tolerance to crowding and greater response to detasseling, indicating that the tested hybrid higher endurance to dense stands was not related to the reduction in apical dominance of the tassel over the ear.
Análise de trilha dos componentes do rendimento de gr os em genótipos de canola
Coimbra Jefferson Luís Meirelles,Guidolin Altamir Frederico,Almeida Milton Luiz de,Sangoi Luís
Ciência Rural , 2004,
Abstract: O caráter rendimento de gr os é uma variável de associa o complexa, de importancia econ mica. Foi conduzido um ensaio no município de Lages-SC, no ano agrícola de 1996 no qual se utilizaram 12 genótipos de canola. O objetivo foi determinar a associa o e os efeitos diretos e indiretos de alguns caracteres sobre a produ o de gr os, através do estudo das correla es fenotípicas e pela análise de trilha. Utilizou-se o delineamento experimental em blocos casualizados, com quatro repeti es. De acordo com os resultados obtidos, pode ser concluído que n o há associa o entre os caracteres estatura de planta com os caracteres massa de mil gr os e rendimento de gr os. A análise de trilha revelou que os componentes primários popula o de plantas por unidade de área e número de gr os por planta tem o maior efeito direto sobre a variável rendimento de gr os. Por outro lado, o caráter número de gr os por planta é o maior responsável pelo aumento massa de mil gr os. O coeficiente de trilha evidenciou que o componente secundário número de gr os por síliqua tem o maior efeito direto sobre o rendimento de gr os.
Resposta de híbridos de milho cultivados em diferentes épocas à popula o de plantas e ao despendoamento
Sangoi Luís,Guidolin Altamir Frederico,Coimbra Jefferson Luís Meirelles,Silva Paulo Regis Fereira da
Ciência Rural , 2006,
Abstract: Os híbridos contemporaneos de milho s o mais tolerantes à eleva o da popula o de plantas do que os híbridos antigos. é possível que a melhor adapta o da cultura ao adensamento esteja relacionada com a menor dominancia apical do pend o sobre a espiga. Este trabalho foi conduzido objetivando avaliar a evolu o na tolerancia de híbridos de milho liberados comercialmente em diferentes épocas à eleva o na popula o de plantas, bem como observar se o progresso obtido esta associado à redu o na dominancia apical. O experimento foi conduzido no município de Lages, SC, durante os anos agrícolas de 1999/2000 e 2000/2001. Utilizou-se o delineamento experimental de parcelas sub-subdivididas. Na parcela principal, foram testadas três popula es de planta: 50.000, 75.000 e 100.000pl ha-1. Nas subparcelas, foram alocados quatro híbridos: Ag 12, Ag 28, Ag 303 e Ag 9012, liberados comercialmente para cultivo nas décadas de 60, 70, 80 e 90, respectivamente. Cada híbrido de milho foi analisado com pend es intactos e integralmente removidos durante o emborrachamento nas sub-subparcelas. Os ensaios foram implantados em 30/10/1999 e 2/11/2000. A por meio de análise de variancia e de regress o polinomial. O híbrido Ag 9012, liberado comercialmente para cultivo na década de 90, foi mais exigente em popula o de plantas do que os híbridos antigos para otimizar o seu potencial produtivo em 1999/2000, quando as condi es foram favoráveis à obten o de rendimentos de gr o superiores a 10.000kg ha-1. Neste ano agrícola, a interferência do pend o sobre o desenvolvimento das espigas foi pequena. Por outro lado, o rendimento de gr os de todos os híbridos respondeu positivamente ao despendoamento em 2000/2001, sob tetos produtivos mais baixos. N o houve associa o entre maior tolerancia ao adensamento e resposta ao despendoamento, indicando que a tolerancia a altas densidades populacionais n o esteve relacionada com a redu o da dominancia apical do pend o sobre as espigas.
Uso ou abuso em testes de compara??es de média: conhecimento científico ou empírico?
Bertoldo, Juliano Garcia;Coimbra, Jefferson Luís Meirelles;Guidolin, Altamir Frederico;Miqueloto, Aquidauana;Toaldo, Diego;
Ciência Rural , 2008, DOI: 10.1590/S0103-84782008000400039
Abstract: the objective of this research was to verify which are the main mistakes and the successes in the application of mean comparison tests in scientific studies, demonstrating viable alternatives in the sense of increasing the impartiality of the results obtained by researchers. one of the researcher's largest challenges is the interpretation of the obtained results in a trustworthy way. in spite of the concern of most researchers with the data analysis, many times certain disregard is observed in the interpretation of the results. thus, the incorrect application of statistical tests leads the researchers to publish information not completely reliable. one hundred and forty-eight papers dealing with one or more than one factor were evaluated. all of them are related to the crop production major area, published from 2002 to 2006, in the 'ciência rural', a brazilian scientific journal. most of the studies (72%) were classified as incorrect due to the abuse of means comparison tests. in addition, only 4% and 24% were classified respectively as partially correct and correct.
Correla??es can?nicas: II - análise do rendimento de gr?os de feij?o e seus componentes
Coimbra, Jefferson Luís Meirelles;Guidolin, Altamir Frederico;Carvalho, Fernando Irajá Felix de;Azevedo, Roni de;
Ciência Rural , 2000, DOI: 10.1590/S0103-84782000000100005
Abstract: thirty two bean genotypes (phaseolus vulgaris l.) were evaluated in lages/sc, brazil, on the influence of seven characters of agronomic importance on the production of grains per unit of area. the experiment, in randomized blocks with four repetitions, was driven in the off season period in the agricultural year of 1995/96. this work aimed to estimate the intensity the association between the primary and secondary components of grain yield. the first group of variables (primary) was constituted by the number of grains per pod, number of pods per plant and the weight of a thousand grains. the second group (secondary) consisted of number of days from emergency to flowering, number of days from emergency to harvesting point, plant stature and the first pod insertion point. for the analysis of canonical correlations, the importance of secondary agronomic characters was evident in the traits number of pods per plant and grains per pod and also the influence of both on the final grain yield. therefore, the coefficients of canonical correlations indicate that, in programs bean genetic improvement programs, to increase the production of grains one should select plants with larger number of pods per plant in order to obtain plants with higher stature and longer cycle.
Parametros genéticos do rendimento de gr?os e seus componentes com implica??es na sele??o indireta em genótipos de feij?o preto
Coimbra, Jefferson Luís Meirelles;Guidolin, Altamir Frederico;Carvalho, Fernando Irajá Felix de;
Ciência Rural , 1999, DOI: 10.1590/S0103-84781999000100001
Abstract: thirty two genotypes of black bean (phaseolus vulgaris l.) had their field performance evaluated in the agricultural year of 1996/97 in lages/sc. the influences of three characters of agronomic importance on the production of grains for unit per area were scored. a completely randomized block design was used with four replications. the objective of the study was to estimate some genetic and phenotypic parameters of black bean. the direct selection revealed values of genetic gains superior to the ones obtained through indirect selection. the weight of a thousand grain (pmg) contributed to genetic progress through indirect selection than, the number of pods per plant (nlp) and the number of grains per pod (ngl). the results demonstrated that the tested black bean genotypes had a wide genetic variability, which was an indication of excellent germplas sources. the employment of estimates of genetic parameters such as genetic variance between pure lines and the heritability coefficient may be used as a powerful tool for bean breeders
Stratification of the state of Santa Catarina in macro-environments for bean cultivation
Juliano Garcia Bertoldo,Jefferson Luís Meirelles Coimbra,Rubens Onofre Nodari,Altamir Frederico Guidolin
Crop Breeding and Applied Biotechnology , 2009,
Abstract: The purpose of this study was to suggest a division of the State of Santa Catarina in macro-environments forexperimentation and bean production. Data of the traits grain yield and plant cycle were evaluated in 10 common beangenotypes grown in nine environments. The data were submitted to the Student-Newman Keuls test, to detect differencesbetween environments, and the Best Linear Unbiased Prediction, to predict the environmental values. The results showed: (a)differences between the regions of Santa Catarina for the traits grain yield and plant cycle, which had a significant positivecorrelation of 0.26 (b) Based on the genotypes and environments studied the state can be divided in two macro-environments(MA1 and MA2) and four micro-environments (MI1, MI2, MI3 and MI4). The state of Santa Catarina may be roughly dividedin at least two macro-environments for the recommendation of new cultivars.
Experimental error in AFLP markers: consequence and estimative Erro experimental em marcadores AFLP: consequências e estimativas
Jefferson Luís Meirelles Coimbra,Altamir Frederico Guidolin,Maurício Marini Kopp,Juliano Garcia Bertoldo
Semina : Ciências Agrárias , 2012,
Abstract: The objective of this study was to estimate and to compare the Dice coefficients of dissimilarity through experimental error estimation, from the use of replications composed by plant bulks. The estimate of this coefficient can become more reliable and robust with the use of replications in the molecular analyses. This procedure favors either the tests of hypotheses or the evaluation of the contrasts of interest, according to the objective of the experiment. Also, to compare these estimates with each other and with the genetic dissimilarity estimate based on agronomical traits measured in the field. Among the evaluated variables (genetic and morphological), the distances estimated with base in the use of molecular versus morphological data evidenced 80% of agreement in the estimated values, compared to 5% (P < 0.05) when the replications were used, in the molecular analysis. This way, it is evident that the use of replications in molecular analyses, besides supplying an estimate of the experimental error, enables an immediate gain through the tests of hypotheses, increasing both the reliability of the estimates of the genetic parameters (i.e., repeatability), and the agreement between laboratory and field data. O objetivo deste trabalho foi estimar e comparar os coeficientes de dissimilaridades de DICE por meio da estimativa do erro experimental, proveniente da utiliza o de repeti es, que foram compostas por bulks de plantas e, comparar tanto estas estimativas entre si e com a estimativa da dissimilaridade genética baseada em caracteres agron micos avaliados por meio da experimenta o a campo. A estimativa deste coeficiente pode se tornar mais confiável e robusta com a utiliza o de repeti es nas análises moleculares. O uso de repeti es em análises moleculares favorece tanto os testes de hipóteses quanto a avalia o dos contrastes de interesse. A associa o entre as medidas avaliadas (genética e morfológica), com base na utiliza o de dados moleculares versus morfológicos evidenciou 80% de concordancia nos valores estimados, (P < 0,05) quando foram utilizadas as repeti es, na análise molecular. Desta forma, fica evidente que o emprego de repeti es em análises moleculares, além de fornecer uma estimativa do erro experimental, propicia um ganho imediato por meio dos testes de hipóteses; podendo incrementar desta maneira tanto a confiabilidade das estimativas dos parametros genéticos, como por exemplo, a repetibilidade, quanto à concordancia dos valores de laboratório e de experimentos de campo.
Effects of different doses of phosphorus during cultivation and length of subsequent storage on the cooking time of beans.
Juliano Garcia Bertoldo,Jefferson Luís Meirelles Coimbra,Altamir Frederico Guidolin,Fabiani da Rocha
Biotemas , 2009,
Abstract: This work aimed to verify the cooking times for beans cultivated under different doses of phosphorus and submitted to various periods of storage. The experiment was conducted in the experimental area of Molecular Genetics and Breeding Institute (IMEGEM) at UDESC, in Lages, SC, during the harvest of 2006/07. The sowing density was 200,000 plants per hectare. The experimental unit consisted of six rows of 5x3m in length, 0.5m apart, with a useful area of 12m2 per batch. The experimental delineation employed was that of random blocks in a 4x3x3 factorial scheme with three repetitions. Four genotypes of beans (Pérola, Iapar 81, IPR Uirapuru and IPR Chopim) were planted and added three doses of phosphorus (0, 100 and 200kg.ha-1 of P2O5) in the sowing line. After harvesting, storage times of 0, 45 and 90 days were tested. The evaluation of the cooking time of the grains was carried out using a Mattson cooker, adapted by Proctor and Watts (1987). The analysis of variance disclosed a significant effect over the cooking time response for the triple interaction between the factors cultivar (C), dose of phosphorus (P) and time of storage (A) (CxPxA). The time of storage had a strong influence on the time of cooking: the longer the storage, the greater the cooking time required. However, the use of phosphorus for fertilization was not significant in reducing the cooking time, with the exception of cultivar Iapar 81 that was treated with a dose of 100kg.ha-1 of P2O5, followed by storage of 45 days. This significant exception merits further study.
Difficulties related to the use of tests of comparison of averages in scientific articles
Juliano Garcia Bertoldo,Jefferson Luís Meirelles Coimbra,Altamir Frederico Guidolin,Adelar Mantovani
Biotemas , 2008,
Abstract: The objective of this work was to verify the researcher’s main difficulties in the use of means comparison tests, as well as to propose alternatives for a better statistical inference. For a correct application of the statistical tests it is fundamental for the researcher to know the experimental design, the factors, the variables and the treatments that will constitute the work, because these are decisive in the choice of the statistical test. Two hundred and ninety-two scientific papers from plant sciences were revised. These papers were published in the Brazilian Qualis A journal, from 2000 until 2006. The papers were classified by their use of means comparison tests as i) appropriate, ii) partially appropriate, and iii) inappropriate. There were diffi culties involved in choosing the correct statistical procedure in relation to the experimental design used. The papers in which more than one factor was studied (75%) were classified as inadequate due to their abuse of the means comparison tests. On the other hand, 3% and 22% were classified as partially appropriate and appropriate, respectively.
Page 1 /354064
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.