Periódicos
URI permanente desta comunidadehttps://thoth.dti.ufv.br/handle/123456789/3352
Navegar
6 resultados
Resultados da Pesquisa
Item Repeatability and number of harvests required for selection in robusta coffee(Crop Breeding and Applied Biotechnology, 2004) Fonseca, Aymbiré Francisco Almeida da; Sediyama, Tocio; Cruz, Cosme Damião; Sakiyama, Ney Sussumu; Ferrão, Romário Gava; Ferrão, Maria Amélia Gava; Bragança, Scheilla MarinaThis study aimed to estimate the repeatability coefficient of the grain yield in Coffea canephora by three methods: to quantify the precision of the measurements; to predict the real value of an individual based on n evaluations; and to determine the number of phenotypic measures required in each plant to obtain an adequate precision level for an efficient discrimination of the genotypes. The coefficients of repeatability and determination were estimated based on four harvests of 80 genotypes. Highest estimates of the repeatability coefficient were obtained by the method of the principal components derived from the matrix of covariances, which expresses the correlation between each measurement pair. The prediction precision of the real individual value ranged from 65.32 to 81.59%, and remained practically unchanged from the sixth harvest on.Item Prediction of genetic gains from selection in Arabica coffee progenies(Crop Breeding and Applied Biotechnology, 2011-09-08) Oliveira, Antonio Carlos Baião de; Pereira, Antonio Alves; Silva, Felipe Lopes da; Rezende, Juliana Costa de; Botelho, César Elias; Carvalho, Gladyston RodriguesGains from selection for yield were estimated in Arabica coffee progenies carrying rust-resistance genes. The experiment in augmented block design was installed in Três Pontas, state of Minas Gerais. Three blocks were established with six plants per plot, spaced 3.50 x 0.90 m, in 96 regular (F2 progenies) and two control treatments. The plant response to rust was evaluated on a grade scale in 2008. Yield (bags per hectare) was estimated in the growing seasons 2005 to 2008. Significant differences between treatments for yield were observed in all harvests, except 2005. The presence of genetic variability among progenies allowed significant gain from selection for yield. Under the experimental conditions of this study, selection for yield can be performed in the first high-yield year, without major losses compared to genetic gain from selection for yield when based on the mean of four harvests.Item Inter-trait relations for direct and indirect selection in coffee(Crop Breeding and Applied Biotechnology, 2008-06-09) Ferrão, Romário Gava; Ferreira, Adésio; Cruz, Cosme Damião; Cecon, Paulo Roberto; Ferrão, Maria Amélia Gava; Fonseca, Aymbiré Francisco Almeida da; Carneiro, Pedro Crescêncio de Souza; Silva, Marcia Flores daThe purpose of this study was to verify the possibility of using direct selection in nine traits underlying indirect selection for yield and determine which traits should participate in the selection process. Data of 40 Conilon coffee genotypes were analyzed in two experiments in the growing seasons of 1996, 1998, 1999, 2000 and 2001 in random blocks with four and six replications. The significance of phenotypic associations was evaluated by the t test and the genotypic and environmental associations by bootstrap resampling. The genotypic associations were higher than the phenotypic, indicating a prevailing influence of the genotypic over the environmental effects in the relationship between significant traits; equal signs indicated a lack of contrary action among the effects. The traits related to cycle; yield; ratio of fresh ripe cherries to clean coffee; empty or flat grains; and sieve 17 should be maintained in the selection, evaluation and study of genetic divergence. The estimated gains in grain yield by indirect selection for any trait studied are not satisfactory.Item Genetic divergence in Conilon coffee revealed by RAPD markers(Crop Breeding and Applied Biotechnology, 2009) Ferrão, Maria Amélia Gava; Fonseca, Aymbiré Francisco Almeida da; Ferrão, Romário Gava; Barbosa, Wellington Marota; Souza, Elaine Manelli RivaThis study aimed to evaluate the genetic variability of 49 Coffea canephora clones of the breeding program of the Capixaba Institute of Research, Technical Assistance and Rural Extension (Incaper) based on RAPD markers. Thirty-one primers were used with polymorphism patterns that generated 333 markers, of which 231 (69.4%) were polymorphic. The group of genotypes based on the UPGMA algorithm and Tocher optimization methods detected high divergence in the genotypes. It was found that the component clones of each clone variety recommended by Incaper are distributed in various genetically dissimilar groups, in spite of common phenotypic traits. The relatively wide genetic diversity observed here demonstrates the importance of hybridizations between these germplasms. The RAPD markers efficiently estimated the genetic divergence in the 49 C. canephora genotypes studied.Item Genetic determination of characteristics related to semi-mechanized coffee harvests(Crop Breeding and Applied Biotechnology, 2020) Dias, Rodrigo Elias Batista Almeida; Dias, Rafael Antônio Almeida; Botelho, César Elias; Abrahão, Juliana Costa de Rezende; Rezende, Tiago Teruel; Carvalho, Gladyston RodriguesBrazilian coffee cultivation was boosted over the last few decades by the mechanization of various field operations. Considering the influence of genetic factors on coffee harvesting efficiency, we aimed to evaluate the use of mechanized harvesting characteristics as a criterion to select progenies derived from ‘Icatu’ germplasm, previously evaluated for agronomic characteristics, resistance to rust and cercosporiosis. We also investigated genotypic and phenotypic correlations between semi-mechanized harvesting characteristics. Ten progenies of Coffea arabica L. were analyzed in two experimental farms during two consecutive harvests. Genetic parameters were evaluated to trace selection strategies. Four progenies that were suitable for mechanization were selected, supporting our hypothesis of the use of harvest characteristics as selection criteria.Item Prediction of genetic gains from selection in arabica coffee progenies(Crop Breeding and Applied Biotechnology, 2011-06) Oliveira, Antonio Carlos Baião de; Pereira, Antonio Alves; Silva, Felipe Lopes da; Rezende, Juliana Costa de; Botelho, César Elias; Carvalho, Gladyston RodriguesGains from selection for yield were estimated in Arabica coffee progenies carrying rust-resistance genes. The experiment in augmented block design was installed in Três Pontas, state of Minas Gerais. Three blocks were established with six plants per plot, spaced 3.50 x 0.90 m, in 96 regular (F 2 progenies) and two control treatments. The plant response to rust was evaluated on a grade scale in 2008. Yield (bags per hectare) was estimated in the growing seasons 2005 to 2008. Significant differences between treatments for yield were observed in all harvests, except 2005. The presence of genetic variability among progenies allowed significant gain from selection for yield. Under the experimental conditions of this study, selection for yield can be performed in the first high-yield year, without major losses compared to genetic gain from selection for yield when based on the mean of four harvests.