Análise de trilha usando valores fenotípicos e genotípicos para componentes do rendimento na seleção de famílias de cana-de-açúcar
Arquivos
Data
2012-01
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Editor
Ciência Rural
Resumo
O objetivo deste trabalho foi investigar o uso de valores fenotípicos e genotípicos na análise de trilha envolvendo
características agronômicas em cana-de-açúcar, nos estágios
de cana-planta e cana-soca. Sob esses dois enfoques, foram
computados os efeitos diretos e indiretos dos componentes de
produção – número de colmos por parcela, diâmetro médio
de colmos e altura média de colmos – sobre a produtividade
de colmos por hectare. Para garantir uma melhor consistência
nos resultados, os dados foram obtidos em dois experimentos,
no delineamento em blocos casualizados com cinco repetições.
Os experimentos foram alocados no Centro de Experimentação
em cana-de-açúcar da UFV, em Oratórios, MG, Brasil. Cada
experimento foi constituído de 22 famílias de irmãos completos
de cana-de-açúcar. Os coeficientes de determinação foram
elevados em todas as análises de trilha, indicando que os
componentes avaliados explicam grande parte da variação
existente na produção de colmos. Praticamente não houve
diferença de interpretações e conclusões entre as análises
baseadas nas matrizes de correlações fenotípicas ou genotípicas. Pela análise dos efeitos diretos fenotípicos e genotípicos, o número de colmos foi o caractere que melhor se correlacionou com toneladas de cana por hectare, em ambos os experimentos e estágios. Isso demonstra a possibilidade de obtenção de ganhos significativos por meio da seleção indireta para toneladas de cana por hectare via número de colmos. Houve variação em relação às estimativas de correlação na
comparação entre os experimentos, o que provavelmente se
deve à origem diferenciada das famílias avaliadas em cada
experimento.
The aim of this study was to investigate the use of phenotypic and genotypic values in the path analysis involving agronomic characteristics in sugarcane at the stages of plant cane and ratoon cane. Under these two approaches it was calculated the direct and indirect effects of yield components - number of stalks per plot, diameter of stalk and average height of stalk - on sugarcane yield per hectare. To ensure a better consistency of results, data were obtained in two experiments in randomized blocks with five replications. The experiments were carried out at the Center of Sugarcane Experimentation of the UFV, Oratórios, MG, Brazil. Each experiment consisted of 22 full-sib families of sugarcane. The coefficients of determination were high in all path analysis, indicating that the evaluated components explain most of the variation in straw yield. Practically there was no difference in interpretations and conclusions from the analysis based on arrays of genotypic or phenotypic correlations. From the analysis of the direct phenotypic and genotypic effects, number of stalks was the variable that best correlated with sugarcane yield per hectare in both experiments and harvest stages, demonstrating the possibility of obtaining significant gains by means of indirect selection of sugarcane yield per hectare using number of stalks. There was variation in the estimates of correlation in the comparison between experiments, probably due to different origin of the families surveyed in each experiment.
The aim of this study was to investigate the use of phenotypic and genotypic values in the path analysis involving agronomic characteristics in sugarcane at the stages of plant cane and ratoon cane. Under these two approaches it was calculated the direct and indirect effects of yield components - number of stalks per plot, diameter of stalk and average height of stalk - on sugarcane yield per hectare. To ensure a better consistency of results, data were obtained in two experiments in randomized blocks with five replications. The experiments were carried out at the Center of Sugarcane Experimentation of the UFV, Oratórios, MG, Brazil. Each experiment consisted of 22 full-sib families of sugarcane. The coefficients of determination were high in all path analysis, indicating that the evaluated components explain most of the variation in straw yield. Practically there was no difference in interpretations and conclusions from the analysis based on arrays of genotypic or phenotypic correlations. From the analysis of the direct phenotypic and genotypic effects, number of stalks was the variable that best correlated with sugarcane yield per hectare in both experiments and harvest stages, demonstrating the possibility of obtaining significant gains by means of indirect selection of sugarcane yield per hectare using number of stalks. There was variation in the estimates of correlation in the comparison between experiments, probably due to different origin of the families surveyed in each experiment.
Descrição
Palavras-chave
Correlação, Seleção precoce, Seleção indireta, Correlation, Early selection, Indirect selection