RESUMO
In common bean (Phaseolus vulgaris L.) breeding, plant selection that associate erect plant architecture, high yield, and grains with good commercial acceptance has been the choice of breeders. Thus, this study aimed to evaluate potential parents, to obtain promising segregating populations that associate high yield, erect plant architecture and carioca grain type, as well as to obtain information on heterosis, general and specific combining ability of these parents regarding grain yield and traits related to plant architecture. Fourteen common bean lines were crossed under a partial diallel scheme. Group 1 was composed by eight erect plant lines and group 2 by six carioca grain type lines. The F1's plants from the crosses and the 14 parents were evaluated during spring (Mar. sowing) for plant architecture grade, diameter of the hipocotyl, plant mean height, and grain yield. Predominance of additive effects was observed for plant architecture grade and diameter of the hypocotyls. For grain yield and plant mean height, there was a greater contribution of the dominance effects. Thus, selection of erect plants, with a larger diameter of the hypocotyl can be carried out in early generations; while for grain yield and plant mean height, it must be delayed, preferably, to later generations.
RESUMO
In common bean (Phaseolus vulgaris L.) breeding, plant selection that associate erect plant architecture, high yield, and grains with good commercial acceptance has been the choice of breeders. Thus, this study aimed to evaluate potential parents, to obtain promising segregating populations that associate high yield, erect plant architecture and carioca grain type, as well as to obtain information on heterosis, general and specific combining ability of these parents regarding grain yield and traits related to plant architecture. Fourteen common bean lines were crossed under a partial diallel scheme. Group 1 was composed by eight erect plant lines and group 2 by six carioca grain type lines. The F1's plants from the crosses and the 14 parents were evaluated during spring (Mar. sowing) for plant architecture grade, diameter of the hipocotyl, plant mean height, and grain yield. Predominance of additive effects was observed for plant architecture grade and diameter of the hypocotyls. For grain yield and plant mean height, there was a greater contribution of the dominance effects. Thus, selection of erect plants, with a larger diameter of the hypocotyl can be carried out in early generations; while for grain yield and plant mean height, it must be delayed, preferably, to later generations.
RESUMO
The repeatability coefficient is widely used by geneticists as a measure of the upper limit of the heritability and as an efficient tool for predicting genotype value from successive measurements on individuals. It also allows to estimate whether the number of evaluations is sufficient to determine genotype superiority within a certain degree of reliability. The purpose of this research was to evaluate the coefficient of repeatability of crude protein concentration on stems and leaves, in 77 accesses of the Embrapa's Elephantgrass Germplasm Active Bank. The experimental design consisted of was randomized blocks, with two replicates. Forage was cut on 30, 45, 60 and 75 days of croping, using 15 sprouts of each experimental unit. ANOVA was performed for each trait data set, and genetic and environmental parameters were determined. The repeatability coefficients were estimated by the methods: Analysis of variance, principal components - correlation matrix, principal components - co-variance matrix and structural analysis - correlation matrix. Genetic variability was found among the genotypes for the appraised traits, which allowed the identification of genetically superior material that can be used in breeding programs. The coefficients of estimated repeatability were not different for the traits studied. Four cuts were enough for a coefficient of determination of 0.80, for all the methods. The use of seven cuts may enable predictions with 0.90 reliability for the studied traits, using any method.
O coeficiente de repetibilidade é amplamente usado pelos geneticistas como medida do limite superior da herdabilidade e da eficiência da predição do valor genotípico a partir de sucessivas medições no indivíduo. Pelo seu conhecimento pode-se avaliar se o número de avaliações realizadas é suficiente para se inferir sobre a superioridade genotípica com determinado grau de certeza. Estimou-se o coeficiente de repetibilidade das características forrageiras proteína bruta do colmo e da folha, em 77 acessos do Banco Ativo de Germoplasma de Capim-Elefante da Embrapa. O delineamento experimental foi em blocos ao acaso com duas repetições. Os cortes foram realizados aos 30, 45, 60 e 75 dias de idade, em 15 perfilhos, tomados ao acaso dentro de cada parcela. Foi realizada análise de variância dos dados obtidos para cada característica, como também estimados os parâmetros genéticos e ambientais. Os coeficientes de repetibilidade foram estimados através dos métodos: análise de variância, componentes principais - matriz de correlação, componentes principais - matriz de covariância e análise estrutural - matriz de correlação. Constatou-se variabilidade genética entre os genótipos para as características avaliadas, possibilitando a identificação de materiais genéticos superiores que podem ser utilizados em programas de melhoramento. Os coeficientes de repetibilidade estimados não apresentaram diferenças discrepantes com relação às características estudadas. Os quatro cortes foram suficientes para obter um coeficiente de determinação de 0,80, para todos os métodos. O acréscimo de três cortes, totalizando sete, torna possível obter predições com uma confiabilidade em torno de 0,90 para as características estudadas, utilizando-se qualquer dos métodos.
RESUMO
The repeatability coefficient is widely used by geneticists as a measure of the upper limit of the heritability and as an efficient tool for predicting genotype value from successive measurements on individuals. It also allows to estimate whether the number of evaluations is sufficient to determine genotype superiority within a certain degree of reliability. The purpose of this research was to evaluate the coefficient of repeatability of crude protein concentration on stems and leaves, in 77 accesses of the Embrapa's Elephantgrass Germplasm Active Bank. The experimental design consisted of was randomized blocks, with two replicates. Forage was cut on 30, 45, 60 and 75 days of croping, using 15 sprouts of each experimental unit. ANOVA was performed for each trait data set, and genetic and environmental parameters were determined. The repeatability coefficients were estimated by the methods: Analysis of variance, principal components - correlation matrix, principal components - co-variance matrix and structural analysis - correlation matrix. Genetic variability was found among the genotypes for the appraised traits, which allowed the identification of genetically superior material that can be used in breeding programs. The coefficients of estimated repeatability were not different for the traits studied. Four cuts were enough for a coefficient of determination of 0.80, for all the methods. The use of seven cuts may enable predictions with 0.90 reliability for the studied traits, using any method.
O coeficiente de repetibilidade é amplamente usado pelos geneticistas como medida do limite superior da herdabilidade e da eficiência da predição do valor genotípico a partir de sucessivas medições no indivíduo. Pelo seu conhecimento pode-se avaliar se o número de avaliações realizadas é suficiente para se inferir sobre a superioridade genotípica com determinado grau de certeza. Estimou-se o coeficiente de repetibilidade das características forrageiras proteína bruta do colmo e da folha, em 77 acessos do Banco Ativo de Germoplasma de Capim-Elefante da Embrapa. O delineamento experimental foi em blocos ao acaso com duas repetições. Os cortes foram realizados aos 30, 45, 60 e 75 dias de idade, em 15 perfilhos, tomados ao acaso dentro de cada parcela. Foi realizada análise de variância dos dados obtidos para cada característica, como também estimados os parâmetros genéticos e ambientais. Os coeficientes de repetibilidade foram estimados através dos métodos: análise de variância, componentes principais - matriz de correlação, componentes principais - matriz de covariância e análise estrutural - matriz de correlação. Constatou-se variabilidade genética entre os genótipos para as características avaliadas, possibilitando a identificação de materiais genéticos superiores que podem ser utilizados em programas de melhoramento. Os coeficientes de repetibilidade estimados não apresentaram diferenças discrepantes com relação às características estudadas. Os quatro cortes foram suficientes para obter um coeficiente de determinação de 0,80, para todos os métodos. O acréscimo de três cortes, totalizando sete, torna possível obter predições com uma confiabilidade em torno de 0,90 para as características estudadas, utilizando-se qualquer dos métodos.