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| Registros recuperados: 44 | |
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| Oliveira,Eder Jorge; Pádua,Juliano Gomes; Zucchi,Maria Imaculada; Vencovsky,Roland; Vieira,Maria Lúcia Carneiro. |
| Microsatellites, or simple sequence repeats (SSRs), have been the most widely applied class of molecular markers used in genetic studies, with applications in many fields of genetics including genetic conservation, population genetics, molecular breeding, and paternity testing. This range of applications is due to the fact that microsatellite markers are co-dominant and multi-allelic, are highly reproducible, have high-resolution and are based on the polymerase chain reaction (PCR). When first introduced, the development of microsatellite markers was expensive but now new and efficient methods of repetitive sequence isolation have been reported, which have led to reduced costs and microsatellite-technology has been increasingly applied to several species,... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Microsatellites; Molecular genetics; Genetic structure of populations. |
| Ano: 2006 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572006000200018 |
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| Miranda Filho,José B.; Vencovsky,Roland. |
| The partial circulant diallel cross mating scheme of Kempthorne and Curnow (Biometrics 17: 229-250, 1961) was adapted for the evaluation of genotypes in crosses at the interpopulation level. Considering a random sample of n lines from base population I, and that each line is crossed with s lines from opposite population II, there will be ns sampled crosses that are evaluated experimentally. The means of the ns sampled crosses and the remaining n(n - s) crosses can be predicted by the reduced model <img src="http:/img/fbpe/gmb/v22n2/0291e1.gif" align="absmiddle"> where Yij is the mean of the cross between line i (i = 1,2,...,n) of population I and line j (j = 1',2',...,n') of population II; µ is the general mean, and gi and gj refer to general... |
| Tipo: Info:eu-repo/semantics/article |
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| Ano: 1999 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47571999000200020 |
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| Souza Jr.,Cláudio Lopes de; Geraldi,Isaias Olívio; Vencovsky,Roland. |
| A formula was derived for the prediction of the response to recurrent selection when the effective population size (Ne) is small. Usually, responses to selection have been estimated by Rs = icsigma²A/sigmaPh, where i, c, sigma²A, and sigmaPh stand for standardized selection differential, parental control, additive variance, and phenotypic standard deviation, respectively. This expression, however, was derived under the assumption of infinite population size. By introducing the effects of finite population size, the expression derived was Rs = [ic(sigma²A + deltaFD1)/sigmaPh] - DFID, where deltaF, ID and D1 are the changes in the inbreeding coefficient, the inbreeding depression, and the covariance of additive and homozygous dominance effects, respectively.... |
| Tipo: Info:eu-repo/semantics/article |
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| Ano: 2000 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572000000400023 |
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| Braga,Gilberto U.L.; Vencovsky,Roland; Messias,Claudio L.. |
| Chitinolytic activity and dry mass production were determined in culture filtrates from 17 Metarhizium anisopliae strains grown in liquid medium containing chitin as the only carbon source. The objectives were to estimate parameters such as genetic variance among strains, heritability and expected gain from selection, as well as correlations between tested traits. Wide genotypic variability was observed among strains in chitinolytic activity, permitting the exploitation of this property in selection. The high heritability suggests that progress can be made through phenotypic selection. The genotypic correlation coefficient between dry mass production and chitinolytic activity detected in the filtrates was negative (<img... |
| Tipo: Info:eu-repo/semantics/article |
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| Ano: 1998 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47571998000200001 |
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| Carlini-Garcia,Luciana Aparecida; Vencovsky,Roland; Coelho,Alexandre Siqueira Guedes. |
| We presented an alternative way to verify the relative contribution to the total variance, of the sources of variation due to populations (P), individuals within populations (I), the (P*I) interaction, and the standard error of the following parameter estimates: total (F) and intrapopulation (f) fixation indices, and divergence among populations (q). The knowledge of this relative contribution is important to establish sampling strategies of natural populations. To attain these objectives, the bootstrap method was used to resample simultaneously populations and individuals, considering different combinations of P and I. This procedure was repeated five times for a given combination of each analyzed data set. For each data set, five estimates of these... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Population structure; Resampling; Natural populations. |
| Ano: 2006 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572006000200019 |
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| Barroso,Paulo Augusto Vianna; Geraldi,Isaias Olívio; Vieira,Maria Lúcia Carneiro; Pulcinelli,Carlos Eduardo; Vencovsky,Roland; Dias,Carlos Tadeu dos Santos. |
| In order to verify whether genetic distance (GD) is associated with population mean (PM), genetic variance (GV) and the proportion of superior progenies generated by each cross in advanced generations of selfing (PS), the genetic distances between eight soybean lines (five adapted and three non-adapted) were estimated using 213 polymorphic RAPD markers. The genetic distances were partitioned according to Griffing's Model I Method 4 for diallel analysis, i.e., GDij = GD+ GGDi+ GGDj + SGDij. Phenotypic data were recorded for seed yield and plant height for 25 out of 28 populations of a diallel set derived from the eight soybean lines and evaluated from F2:8 to F2:11 generations. No significant correlation for seed yield was detected between GD and GV, while... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Soybean; Genetic distance; Molecular markers; RAPD; Prediction. |
| Ano: 2003 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572003000300020 |
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| Bearzoti,Eduardo; Vencovsky,Roland. |
| Estimation of the proportion of genetic variance explained by molecular markers (p) plays an important role in basic studies of quantitative traits, as well as in marker-assisted selection (MAS), if the selection index proposed by Lande and Thompson (Genetics 124: 743-756, 1990) is used. Frequently, the coefficient of determination (R2) is used to account for this proportion. In the present study, a simple estimator of p is presented, which is applicable when a multiple regression approach is used, and progenies are evaluated in replicated trials. The associated sampling distribution was obtained and compared with that of R2. Simulations indicated that, when the number of evaluated progenies is small, the statistics are not satisfactory, in general, due to... |
| Tipo: Info:eu-repo/semantics/article |
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| Ano: 1998 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47571998000400025 |
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| Ribeiro,Francisco E.; Baudouin,Luc; Lebrun,Patricia; Chaves,Lázaro J.; Brondani,Claudio; Zucchi,Maria I.; Vencovsky,Roland. |
| Coconut palms of the Tall group were introduced to Brazil from the Cape Verde Islands in 1553. The present study sought to evaluate the genetic diversity among and within Brazilian Tall coconut populations. Samples were collected of 195 trees from 10 populations. Genetic diversity was accessed by investigating 13 simple sequence repeats (SSR) loci. This provided a total of 68 alleles, ranging from 2 to 13 alleles per locus, with an average of 5.23. The mean values of gene diversity (He) and observed heterozygosity (Ho) were 0.459 and 0.443, respectively. The genetic differentiation among populations was estimated at θ = 0.1600 and the estimated apparent outcrossing rate was t a = 0.92. Estimates of genetic distances between the populations varied from... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Coconut; Genetic diversity; Genetic variability; Molecular markers; SSR. |
| Ano: 2010 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572010000400016 |
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| Ferreira,Maria Aldete J.F.; Queiróz,Manoel Abílio de; Braz,Leila T.; Vencovsky,Roland. |
| Foram estimadas as correlações genotípicas, fenotípicas e de ambiente entre os caracteres número de dias para o aparecimento da primeira flor feminina (FF); número de frutos por planta (NF); peso de frutos por planta (PF); cor (CP) e espessura (EP) da polpa; diâmetro longitudinal (DL) e transversal (DT) de frutos; teor de sólidos solúveis (TS); número de sementes (NS) e peso de 100 sementes (PS) por fruto. As populações de melancia B9, 'Charleston Gray', 'Crimson Sweet', 'New H. Midget', M7, P14 e B13, os 21 híbridos F1, em dialelo, e seus recíprocos foram avaliados em campo, de acordo com o delineamento em blocos ao acaso completos, com quatro repetições. Houve grande similaridade entre as estimativas das correlações genotípicas e fenotípicas... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Citrullus lanatus; Correlações; Caracteres; Pré-melhoramento; Dialelo. |
| Ano: 2003 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0102-05362003000300004 |
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| Rosse,Leonardo Novaes; Vencovsky,Roland; Ferreira,Daniel Furtado. |
| O objetivo deste trabalho foi comparar dois métodos de regressão empregados para avaliar a estabilidade fenotípica em plantas de cana-de-açúcar, o linear, de Cruz et al., e o não-linear, de Toler & Burrows. Utilizaram-se as informações do ensaio de caracterização de 1994 do programa de melhoramento genético da Copersucar, compreendendo 13 locais e 20 genótipos de cana-de-açúcar no Estado de São Paulo. Os resultados permitiram concluir que ambos os modelos se ajustaram satisfatoriamente aos dados. As estimativas da qualidade ambiental pelos dois modelos mostraram diferenças entre seus valores, porém foram concordantes para inferir sobre os melhores e piores ambientes. Ao classificar os genótipos com base na produtividade e no padrão de resposta, no... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Saccharum; Interação genótipo-ambiente; Modelos; Análise de regressão. |
| Ano: 2002 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2002000100004 |
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| Raizer,Arnaldo José; Vencovsky,Roland. |
| Cinco novas variedades de cana-de-açúcar (Saccharum officinarum L.), recomendadas para cultivo comercial pelo Programa de Melhoramento da Copersucar em 1997, foram avaliadas quanto ao nível de produtividade, estabilidade produtiva e adaptação ambiental, mediante metodologia para estimativa da estabilidade fenotípica. Os dados foram comparados com a variedade-padrão RB72454. Observou-se alta linearidade da produção em relação à melhoria ambiental, além de ótima estabilidade e nível de resposta nas variedades SP80-185, SP80-1816 e SP80-3280. A variedade SP83-5073, precoce e de alto teor de sacarose, também foi bastante estável. A variedade SP80-3480 apresentou maior dispersão dos dados, porém com alta produtividade. A variedade SP80-185 passa a ser indicada... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Saccharum officinarum; Melhoramento vegetal; Clones; Adaptação ambiental. |
| Ano: 1999 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X1999001200010 |
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| Hoogerheide,Eulália Soler Sobreira; Farias,Francisco José Correia; Vencovsky,Roland; Freire,Elêusio Curvêlo. |
| Foram avaliados oito genótipos de algodoeiro herbáceo, sendo três linhagens e cinco cultivares, com o objetivo de estimar a adaptabilidade e estabilidade fenotípica para o caráter produtividade de algodão em caroço, pelo método Eberhart e Russell. Foram conduzidos 12 experimentos em 11 locais no Estado do Mato Grosso, sob um delineamento de blocos ao acaso com oito repetições, no ano agrícola 2000/2001. Praticamente todos os genótipos apresentaram coeficiente de determinação acima de 85%, exceto Delta Opal. As estimativas de adaptabilidade indicam que todos os genótipos apresentaram adaptação ampla (b i = 1). Quanto à estabilidade, os genótipos CNPA ITA 90, BRS Antares, CNPA 96-124, CNPA 96-283 e BRS Aroeira revelaram-se estáveis (S²d i= 0). Os melhores... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Adaptabilidade; Produtividade; Interação genótipo x ambiente. |
| Ano: 2007 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2007000500012 |
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| Zucchi,Maria Imaculada; Pinheiro,José Baldin; Chaves,Lázaro José; Coelho,Alexandre Siqueira Guedes; Couto,Mansuêmia Alves; Morais,Lizz Kezzy de; Vencovsky,Roland. |
| This study was carried out to assess the genetic variability of ten "cagaita" tree (Eugenia dysenterica) populations in Southeastern Goiás. Fifty-four randomly amplified polymorphic DNA (RAPD) loci were used to characterize the population genetic variability, using the analysis of molecular variance (AMOVA). A phiST value of 0.2703 was obtained, showing that 27.03% and 72.97% of the genetic variability is present among and within populations, respectively. The Pearson correlation coefficient (r) among the genetic distances matrix (1 - Jaccard similarity index) and the geographic distances were estimated, and a strong positive correlation was detected. Results suggest that these populations are differentiating through a stochastic process, with restricted... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Myrtaceae; Cerrado; Tropical species; Genetic diversity. |
| Ano: 2005 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2005001000005 |
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| Hoogerheide,Eulália Soler Sobreira; Vencovsky,Roland; Farias,Francisco José Correia; Freire,Elêusio Curvêlo; Arantes,Eurípedes Maximiano. |
| O objetivo deste trabalho foi avaliar as relações entre os caracteres tecnológicos (variáveis independentes explicativas) e a produtividade de fibra do algodão (variável dependente) e identificar seus efeitos diretos e indiretos pela análise de trilha. Os caracteres tecnológicos foram: finura, resistência, comprimento, uniformidade de comprimento, alongamento e índice de fiabilidade do fio. Avaliaram-se 12 cultivares de algodoeiro herbáceo, no Estado do Mato Grosso, no ano agrícola 2000/2001. Estimaram-se as correlações, e fez-se a análise de trilha pelo método proposto por Wright. O caráter finura apresenta o maior efeito direto sobre a produtividade da fibra. A resistência, o comprimento e o alongamento têm efeito secundário. A uniformidade de... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Gossypium hirsutum; Seleção; Finura. |
| Ano: 2007 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2007001000005 |
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| Registros recuperados: 44 | |
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