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Genetic control of traits associated with phosphorus use efficiency in maize by REML/BLUP Controle genético de caracteres associados à eficiência no uso de fósforo em milho via REML/BLUP
Júlio César DoVale,Roberto Fritsche-Neto
Revista Ciência Agron?mica , 2013,
Abstract: The improvement phosphorus use efficiency (PUE) allows to reach satisfactory yields with lower costs. A breeding strategy for PUE is to increase its components, the phosphorus acquisiton efficiency (PAE) and phosphorus utilization efficiency (PUtE). Thus, this study aimed to identify: i) the relative importance of the components of PUE, in high and low phosphorus; ii) the relationship of root system length and shoot dry mass (SDM) with PUE and its components and; iii) the genetic control of traits associated with the PUE. Forty-one hybrid combinations were evaluated in two experimental environments representing contrasting conditions of availability of phosphorus: low (LP) and high (HP). A randomized block design with two replications were used in simple factorial (hybrid combination x availability of phosphorus) arrangement. Independently of phosphorus availability, PAE was the most important component of the PUE and non-additive genetic effects were more important to the traits associated with the PUE. It was observed that the estimates of specific combining ability for SDM and PUE, in LP and HP, showed similar behavior and magnitude, indicating that the selection based on performance of hybrid combinations for SDM, allows to obtain genotypes with high PUE. O aumento da eficiência no uso de fósforo (PUE) permite alcan ar produtividades satisfatórias com menores custos. Uma estratégia para melhorar esse caráter é elevar seus componentes, às eficiências na absor o (PUE) e na utiliza o de fósforo (PUtE). Assim, objetivou-se com esse estudo identificar: i) a importancia relativa dos componentes da eficiência no uso de fósforo (PUE), em alta e baixa disponibilidade desse nutriente; ii) a rela o do comprimento do sistema radicular (CR) e da massa de parte aérea seca (SDM) com a PUE e seus componentes e, iii) o controle genético dos caracteres associados à PUE. Foram avaliadas 41 combina es híbridas experimentais em duas condi es contrastantes de disponibilidade de fósforo: baixa (LP) e alta (HP). Foi utilizado o delineamento em blocos ao acaso com duas repeti es em esquema fatorial simples (combina o híbrida x disponibilidade de fósforo). Independentemente da disponibilidade de fósforo, a PAE foi o componente mais importante da PUE e os efeitos genéticos n o aditivos apresentaram maior importancia para os caracteres associados à PUE. Observou-se que as estimativas de capacidade específica de combina o para SDM e PUE em LP e HP, apresentam comportamento e magnitude semelhantes, indicando que sele o baseada no desempenho de combina es híbridas quant
Updating the ranking of the coefficients of variation from maize experiments
Fritsche-Neto, Roberto;Vieira, Rafael Augusto;Scapim, Carlos Alberto;Miranda, Glauco Vieira;Rezende, Luciano Moreira;
Acta Scientiarum. Agronomy , 2012, DOI: 10.4025/actasciagron.v34i1.13115
Abstract: the objective of this study was to update the ranking of the coefficients of variation (cvs) from maize experiments and evaluate the accuracy of the data from the latest brazilian publications. we rank-ordered the cvs for grain yield, plant and ear heights, number of ears per plant, and weight of commercial ears, except for the weight of 100 grains. the data were obtained from 143 scientific papers published from 2005 to 2010. the classification was based on the average (m) and standard deviation (sd) and the cvs were ranked as low, intermediate, high and very high. all of the random variables had the cvs normally distributed. for most of the traits, we observed a large difference between the ranks from scapim and pimentel gomes. in summary, the coefficients of variation have to be classified for each variable, significant improvement occurred in the accuracy of the national maize experiments in the last 15 years, and they still require periodic updating.
índice de sele??o para cultivares de milho com dupla aptid?o: minimilho e milho verde
DoVale, Júlio César;Fritsche-Neto, Roberto;e Silva, Paulo Sérgio Lima;
Bragantia , 2011, DOI: 10.1590/S0006-87052011000400008
Abstract: this study aimed to propose an index for allowing accurate selection of corn hybrids for producing both baby corn and green corn. the experiments were carried out during the 2002/2003 growing season and ten commercial corn cultivars were evaluated in two experiments, the first for evaluating the yield of baby corn and the second for the yield of green corn. both experiments were designed in randomized blocks, with three replications. the relative importance of traits was estimated by the principal components method and the cluster analysis was carried out. the following index was obtained: i = 0.031 nem + 0.013 mem + 0.207 nev + 0.243 mev - 0.16 ap - 0.058 mfp, being considered the variables: number and mass of husked ears for baby corn (nem and mem) and green corn (nev and mev), plant height (ap) and the fresh mass of tassel (mfp). this index indicated that the three-way cross hybrids dkb 350, ag 8080 and ag 6690 and the double-cross hybrids dkb 747 have the best performances for the production of baby corn and green corn.
Factor analysis and SREG GGE biplot for the genotype × environment interaction stratification in maize
Fritsche-Neto, Roberto;Miranda, Glauco Vieira;DeLima, Rodrigo Oliveira;Souza, Heraldo Namorato de;
Ciência Rural , 2010, DOI: 10.1590/S0103-84782010000500007
Abstract: the objective of this study was to evaluate the use of sreg gge biplot methodology and factor analysis to stratify the genotype×environment interaction in maize. forty-nine early maize hybrids were evaluated in nine environments. the experimental design used was a 7×7 square lattice with two replicates. each plot consisted of two 5m long rows spaced 0.90m apart. grain yield data were used to perform the analysis. the results indicated the existence of two mega-environments in the state of minas gerais, brazil, for early maize hybrids. the stratification of the environment by factor analysis was more selective to join the similarity the according with cultivar performance. however, this approach did not identify specific genotype x environment interactions, which is possible through sreg gge biplot analysis.
Efeitos gênicos de caracteres associados à eficiência no uso de nitrogênio em milho
DoVale, Júlio César;Fritsche-Neto, Roberto;Bermudez, Felipe;Miranda, Glauco Vieira;
Pesquisa Agropecuária Brasileira , 2012, DOI: 10.1590/S0100-204X2012000300010
Abstract: the objectives of this work were to determine the genetic control of nitrogen use efficiency (nue), to identify the importance of n acquisition (nae) and utilization (nute) efficiencies on its composition, and to quantify the relation between production of shoot (sdm) and root dry matter mass with nue and its components. forty-one hybrid combinations were evaluated in two n availabilities: low (ln) and high (hn). a randomized complete block design with two replicates, in a simple factorial arrangement (hybrid combination x n availability), was used. statistical analyses were done using mixed model equations. high magnitude correlations were detected between nae and nue, and between these efficiencies and sdm in ln and hn. in both n availabilities, additive genetic effects were more important for the traits associated with nue. therefore, selection based on the individual performance of inbred lines as to sdm can allow for the obtainment of genotypes with high nue. independently of n availability, nae is the most important component of nue.
Sele??o gen?mica ampla e novos métodos de melhoramento do milho
Fritsche-Neto, Roberto;Resende, Marcos Deon Vilela;Miranda, Glauco Vieira;DoVale, Júlio César;
Revista Ceres , 2012, DOI: 10.1590/S0034-737X2012000600009
Abstract: the objectives of this work were to verify the accuracy of the genome wide selection method (gws) in the maize breeding for nutritional stress conditions and propose new breeding methods based on gws. the efficiency of two components of use of nitrogen and phosphorus (absorption and utilization) was estimated in 41 single-cross hybrids assessed in two experiments under low and high availability of n and p. eighty microsatellite markers were used to genotype the base population. the estimates of genetic parameters were obtained by reml/blup and the predictions of genetic genomic values were obtained by random regression (rr), applied to genome wide selection (rr-blup/gws). gws showed high values of accuracy for the traits; it was comparable to the methods of recurrent intra and interpopulational selection. it was concluded that there is a significant increase in selective accuracy and in the genetic gains per unit of time with use of gws.
Prediction of genotypic values of maize hybrids in unbalanced experiments
Roberto Fritsche-Neto,Manoel Carlos Gon?alves,Roland Vencovsky,Cláudio Lopes de Souza Junior
Crop Breeding and Applied Biotechnology , 2010,
Abstract: The objective of this study was to evaluate whether the REML/BLUP can be useful for predicting the genotypicvalues of maize hybrids in a group of unbalanced experiments. A set of 256 single-crosses were evaluated in 13 environmentsfor grain yield, plant height and plant lodging. Sets of hybrids within environments and sets of environments were withdrawnfrom the experiments to simulate unbalanced data, and the hybrid predictions of the unbalanced data were computed by theREML/BLUP, simulated using the bootstrap resampling procedure. The coefficients of determination and percentage ofselection coincidence were computed for the predicted genotypic values of unbalanced data and their means from the balanceddata. The REML/BLUP method accurately predicted the genotypic values of missing hybrids under losses of up to 20% ofhybrids within environments or a reduction of 23% of the environments, even in the presence of significant and complexhybrid x environment interaction.
Contribution of the universities to the development of field crop cultivars
Carlos Sigueyuki Sediyama,José Eustáquio de Souza Carneiro,Roberto Fritsche-Neto,Tuneo Sediyama
Crop Breeding and Applied Biotechnology , 2012,
Abstract: Public and private research institutions employ their best efforts to produce new cultivars, which are intended to ensure productivity, reduce ecological footprint and present characteristics that meet consumer expectations. Some Brazilian universities, which are usually originated from schools of higher education in agriculture, have contributed to the breeding of some crops. These universities also aimed to solve the problems of the Brazilian agricultural sector, and became essential tool to make Brazil an important player in the agribusiness world. In the last decades, regarding the five species presented here, the universities have developed 35 oat cultivars and made the country self-sufficient in this grain; they have also developed cultivars of common beans (27), sugarcane (59), soybean (62), and wheat (03), besides countless corn hybrids, since works in this species date before the establishment of the national cultivar registration system.
NOTE - The difference between breeding for nutrient use efficiency and for nutrient stress tolerance
Ciro Maia,Júlio César DoVale,Roberto Fritsche-Neto,Paulo Cezar Cavatte
Crop Breeding and Applied Biotechnology , 2011,
Abstract: This study aimed to verify the relationship between breeding for tolerance to low levels of soil nutrients and fornutrient use efficiency in tropical maize. Fifteen inbred lines were evaluated in two greenhouse experiments under contrasting levelsof N and P. The relationship between nutritional efficiency and tolerance to nutritional stress was estimated by the Spearman rankingcorrelation between the genotypes for the traits related to N and P use efficiency and phenotypic plasticity indices. The lack ofrelationship between the traits, in magnitude as well as significance, indicates that these characters are controlled by different genegroups. Consequently, simultaneous selection for both nutrient use efficiency and tolerance to nutritional stress is possible, if themechanisms that confer efficiency and tolerance are not competitive.
Sele o gen mica ampla e novos métodos de melhoramento do milho Genome wide selection and new methods of maize breeding
Roberto Fritsche-Neto,Marcos Deon Vilela Resende,Glauco Vieira Miranda,Júlio César DoVale
Revista Ceres , 2012,
Abstract: Os objetivos deste trabalho foram verificar a acurácia do método da Sele o Gen mica Ampla (GWS) no melhoramento de milho nas condi es de estresse nutricional e propor novos métodos de melhoramento baseados em GWS. Foram estimados os dois componentes da eficiência no uso de nitrogênio e de fósforo (eficiência de absor o e de utiliza o) em 41 combina es híbridas, em dois experimentos, sob baixa e alta disponibilidades de N e P. Para a genotipagem da popula o de estima o, foram utilizados 80 marcadores microssatélites. As estimativas dos parametros genéticos foram obtidas via REML/BLUP, e a predi o dos valores genéticos gen micos, via regress o aleatória (Random Regression - RR) aplicada à sele o gen mica ampla (RR-BLUP/GWS). Para os caracteres em que a GWS apresentou altos valores de acurácia, essa foi comparada com os métodos de Sele o Recorrente Intra e Interpopulacional. Com o uso da GWS houve aumento significativo na acurácia seletiva e nos ganhos genéticos por unidade de tempo. The objectives of this work were to verify the accuracy of the Genome Wide Selection method (GWS) in the maize breeding for nutritional stress conditions and propose new breeding methods based on GWS. The efficiency of two components of use of nitrogen and phosphorus (absorption and utilization) was estimated in 41 single-cross hybrids assessed in two experiments under low and high availability of N and P. Eighty microsatellite markers were used to genotype the base population. The estimates of genetic parameters were obtained by REML/BLUP and the predictions of genetic genomic values were obtained by random regression (RR), applied to genome wide selection (RR-BLUP/GWS). GWS showed high values of accuracy for the traits; it was comparable to the methods of Recurrent Intra and Interpopulational Selection. It was concluded that there is a significant increase in selective accuracy and in the genetic gains per unit of time with use of GWS.
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