Dialelo parcial circulante interpopulacional em milho (Zea mays L.): efeito do número(s) de cruzamentos

Fuzatto, Sandro Ricardo

doi:10.11606/t.11.2003.tde-17062003-144900

Cited by 3 publications

(5 citation statements)

References 33 publications

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“…These results denote that the reduced model that employs the GCA estimates is better than the model that uses constant effects. These findings also show that the use of s = 4 allowed a good prediction of the means of the nonevaluated single hybrids, corroborating the data presented by Miranda and Vencovsky (1999), Araújo (2000), andFuzatto (2003).…”

Section: Tablesupporting

confidence: 88%

“…The V(A 12 ) mean estimates for grain yield were between 0.287 (t ha -1 ) 2 (93.0 g plant -1 ) 2 and 4.310 (t ha -1 ) 2 (1396.5 g plant -1 ) 2 (Table 1). These results reveal that the synthetics used in this study have the potential for the extraction of lines with high performance per se, especially if we consider the results described by Andrade (1995) [40.85 (g plant -1 ) 2 for the selfing system and 72.25 (g plant -1 ) 2 for sib-crosses]; Souza (1983) [260.50 (g plant -1 ) 2 in half-sib progenies]; Nass et al (2000) [99.20 (g plant -1 ) 2 and 134.60 (g plant -1 ) 2 in maize compounds]; Araújo (2000) [111.55, 165.3, and 63.09 (g plant -1 ) 2 for populations IAPAR 26 and BR 106 in three locations, using the PCDCI scheme]; and Fuzatto (2003) [38.44 (g plant -1 ) 2 to 120.56 (g plant -1 ) 2 for two populations].…”

Section: Tablementioning

confidence: 99%

“…In this regard, it is important to determine the size s of combinations of each line, which will provide an adequate estimation of the GCA and SCA effects and indicate the value of each line in the production of hybrids. Different studies have shown high genetic correlations between observed and estimated means of hybrids when s values between three and five were used (Andrade, 1995;Araújo, 2000;Fuzatto, 2003).…”

Section: Introductionmentioning

confidence: 99%

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Dialelo parcial circulante interpopulacional na identificação de linhagens elites e predição de híbridos de milho

Duarte,

Fregonezi,

Lucena

et al. 2023

Sem. Ci. Agr.

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A proposta do Cruzamento Dialelo Parcial Circulante Interpopulacional (CDPCI) foi desenvolvida com a finalidade de explorar melhor a heterose, ao combinar linhagens de diferentes grupos heteróticos, e viabilizar a avaliação do potencial combinatório de um maior número de linhagens (n), que participam em s cruzamentos, com um número reduzido de combinações híbridos avaliadas (ns), com a possibilidade de estimação de [n(n-s)] híbridos não avaliados. Os objetivos foram determinar o potencial do CDPCI para identificar linhagens elites e combinações superiores nos híbridos avaliados e predizer o desempenho dos híbridos não avaliados, por meio de um modelo reduzido. Foram obtidos quatro dialelos CDPCI’s, envolvendo seis sintéticos de milho, empregando grupos de 20 linhagens S5 por sintético, sendo cada linhagem combinada com quatro linhagens do grupo contrastante (s=4), em cada dialelo, dando um total de 80 combinações híbridas por dialelo, utilizadas para predição do desempenho de 320 outras combinações não avaliadas. As 80 combinações híbridas e quatro testemunhas comerciais foram avaliados para produtividade de grãos, utilizando o delineamento de blocos casualizados com duas repetições, em duas safras. As análises de variâncias individuais e conjuntas foram realizadas com base nas médias de tratamentos, sendo as análises dialélicas e estimativas de efeitos dos parâmetros genéticos realizadas pelo método dos quadrados mínimos ordinários. Os efeitos significativos de capacidade geral e específica de combinação e suas interações com safras, mostram que tanto os efeitos aditivos quanto de dominância foram importantes para a produtividade. Os modelos reduzidos para estimação de médias de híbridos tiveram elevada correlação com as médias observadas, com estimativas entre 0,75 e 0,93. O emprego do CDPCI’s é eficiente para predição dos híbridos não avaliados nos dialelos e permite identificar linhagens elites para síntese de híbridos.

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Section: Tablesupporting

confidence: 88%

Section: Tablementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Dialelo parcial circulante interpopulacional na identificação de linhagens elites e predição de híbridos de milho

Duarte,

Fregonezi,

Lucena

et al. 2023

Sem. Ci. Agr.

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“…Andrade (1995), using s = 3, found correlation coefficients varying from 0.82 to 0.96. On the other hand, Araújo (2000), using s = 4, found a correlation of 0.86, and Fuzatto (2003) observed correlations between 0.685 and 0.925, using values of s from 6 to 2. The correlation increased as the value of s decreased.…”

Section: Introductionmentioning

confidence: 98%

Prediction of hybrid means from a partial circulant diallel table using the ordinary least square and the mixed model methods

et al. 2005

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By definition, the genetic effects obtained from a circulant diallel table are random. However, because of the methods of analysis, those effects have been considered as fixed. Two different statistical approaches were applied. One assumed the model to be fixed and obtained solutions through the ordinary least square (OLS) method. The other assumed a mixed model and estimated the fixed effects (BLUE) by generalized least squares (GLS) and the best linear unbiased predictor (BLUP) of the random effects. The goal of this study was to evaluate the consequences when considering these effects as fixed or random, using the coefficient of correlation between the responses of observed and non-observed hybrids. Crossings were made between S 1 inbred lines from two maize populations developed at Universidade Federal de Goiás, the UFG-Samambaia "Dent" and UFG-Samambaia "Flint". A circulant inter-group design was applied, and there were five (s = 5) crossings for each parent. The predictions were made using a reduced model. Diallels with different sizes of s (from 2 to 5) were simulated, and the coefficients of correlation were obtained using two different approaches for each size of s. In the first approach, the observed hybrids were included in both the estimation of the genetic parameters and the coefficient of correlation, while in the second a cross-validation process was employed. In this process, the set of hybrids was divided in two groups: one group, comprising 75% of the original group, to estimate the genetic parameters, and a second one, consisting of the remaining 25%, to validate the predictions. In all cases, a bootstrap process with 200 resamplings was used to generate the empirical distribution of the correlation coefficient. This coefficient showed a decrease as the value of s decreased. The cross-validation method allowed to estimate the bias magnitude in evaluating the correlation coefficient using the same hybrids, to predict the genetic parameters and the correlation evaluation. The bias was shown to be greater when the OLS method was used. When the correlation coefficients of the observed and estimated hybrid means were obtained through the mixed instead of the fixed model, this decrease was less marked. The selection of hybrids superior to the checks, in terms of grain weight, also differed in the two different approaches. Nineteen percent of the hybrids were shown to be superior to the checks in the fixed models, while only 1.8% of them were superior in the mixed model.

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“…In this step, early selection of these genotypes in the first generations of self-pollination is common, based on their combining ability with an elite tester line whose performance is already known by the breeder (Guimarães et al, 2012). This substantially reduces the number of lines before reaching homozygosity (Fuzatto, 2003), as well as the cost of carrying out the breeding program.…”

Section: Introductionmentioning

confidence: 99%

Selection of S0:2 maize progenies using a mixed-model approach

Cancellier¹,

Pires²,

Júnior³

et al. 2016

Afr. J. Agric. Res.

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In breeding programs, obtaining breeding lines was important, and first selfing selection generations is common. In addition, an analytic approach through mixed models can lead to more success in genotype selection because it lends flexibility in analysis of unbalanced data and provides more precise genotypic values in regard to progenies evaluated. The goal of this study was to make early selection (in the S 2 generation) of progenies evaluated in top crosses, using a mixed-model approach. Five hundred S 2 progenies were plant derived from three populations using selection intensity (40%), which were crossbreeding with three testers. The hybrids obtained, together with control treatments, were set up in five experiments in Brazil: three in Minas Gerais, one in Santa Catarina, and one in Paraná, which evaluated grain yield. The REML method was used for calculation of variance components, and means were predicted through BLUP. The BLUPs of general combining ability (GCA) and specific combining ability (SCA) were also predicted, and the Spearman correlation coefficients among BLUPs were estimated. The dominance effects had a bigger influence on yield expression, as seen from wider amplitude in SCA values. There was an 86% coincidence considering strategy in which selection index was carried out within three populations, in relation to selection by the overall value of GCA. Considering superior hybrids, the progenies of population C exceeded the quantity of hybrids expected by 24.6%, whereas there was a reduction of 30.8% for A and 20% for B. The hybrids that exhibited the highest BLUP means were derived from crosses between progenies of population C together with the tester LE84. The low correlation among testers, both for SCA and for BLUPs, indicates that there is progeny per tester interaction.

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Dialelo parcial circulante interpopulacional em milho (Zea mays L.): efeito do número(s) de cruzamentos

Abstract: Estimativas dos parâmetros do modelo utilizado para o caráter peso de espigas (t/ha) dos 30 melhores híbridos, avaliados no DPCI (B) com s igual a 6.

Cited by 3 publications

References 33 publications

Dialelo parcial circulante interpopulacional na identificação de linhagens elites e predição de híbridos de milho

Dialelo parcial circulante interpopulacional na identificação de linhagens elites e predição de híbridos de milho

Prediction of hybrid means from a partial circulant diallel table using the ordinary least square and the mixed model methods

Selection of S0:2 maize progenies using a mixed-model approach

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