Viabilidade de aplicação da seleção precoce e tamanho de parcelas em testes clonais de Eucalyptus spp
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Data
2008-12-01
Autores
Massaro, Renata Alves Meira [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
Com o objetivo de avaliar a eficiência da seleção precoce e tamanho ótimo de parcelas em Eucalyptus spp., foram usados dados de dois testes clonais avaliados quanto ao crescimento em altura (ALT), diâmetro à altura do peito (DAP) e volume individual de madeira (VOL) aos 25, 50 e 72 meses de idade. O delineamento experimental nos dois testes clonais foi o de blocos casualizados, com 30 tratamentos (clones), seis repetições, sendo um deles com seis plantas por parcelas (teste clonal 1) e o outro com 10 plantas (teste clonal 2). Foram obtidas as estimativas de coeficiente de determinação genotípico e de correlações genotípicas entre os caracteres nas idades juvenis e na idade de rotação. Para verificar a viabilidade da aplicação da seleção precoce foi simulada a seleção de 30% dos clones nas idades juvenis e na idade de rotação, para cada um dos caracteres e idades avaliadas, obtendo-se as estimativas de ganhos com a seleção direta e indireta. Para verificar o tamanho de parcelas, foi utilizado o coeficiente de repetibilidade calculado através dos métodos: Análise de Variância, dos Componentes Principais e o de Análise Estrutural, os dois últimos calculados através da matriz de correlação. Houve diferenças significativas entre os clones avaliados nos dois experimentos para todos os caracteres e idades. Com os resultados obtidos, recomenda-se a seleção precoce sobre DAP praticada em torno de dois anos de idade. O uso de seis repetições constituídas de pelo menos quatro plantas por parcela e a avaliação em apenas uma idade proporciona coeficiente de determinação superior a 80%.
Aiming evaluate the Eucalyptus spp. early selection efficiency and optimum size of plots, were used data of height, diameter at breast height and individual wood volume evaluated in two clonal tests at 25, 50, and 72 months old. The experimental design in both clonal tests was randomized blocks, using 30 treatments (clones), 6 replications, at 3.0 x 3.0m spacing and linear plots, and one of them with 6 plants per plot (clonal test 1) and the other with 10 plants (clonal test 2). Variance analysis to each trait and age was done to each experiment. The estimates of genotypic determination coefficient and the correlation between the early and mature age traits were obtained. To check the viability of early selection, was simulated the selection in young and mature age, adopting 30% of selection to each one of the traits and ages evaluated, estimating the gains by the direct and indirect selection. To check the size of plots, we used the repeatability coefficient calculated by the methods: Analysis of Variance, and the Principal Components of Structural Analysis, the last two calculated through the matrix of correlation. There were significant differences among clones evaluated in the two experiments to all traits and ages. From the results obtained is suggested the practice of early selection from 2 years old age to eucalyptus clonal tests. The use of six replications consisting of at least four plants per plot and evaluation at one age provides a coefficient of determination more than 80%.
Aiming evaluate the Eucalyptus spp. early selection efficiency and optimum size of plots, were used data of height, diameter at breast height and individual wood volume evaluated in two clonal tests at 25, 50, and 72 months old. The experimental design in both clonal tests was randomized blocks, using 30 treatments (clones), 6 replications, at 3.0 x 3.0m spacing and linear plots, and one of them with 6 plants per plot (clonal test 1) and the other with 10 plants (clonal test 2). Variance analysis to each trait and age was done to each experiment. The estimates of genotypic determination coefficient and the correlation between the early and mature age traits were obtained. To check the viability of early selection, was simulated the selection in young and mature age, adopting 30% of selection to each one of the traits and ages evaluated, estimating the gains by the direct and indirect selection. To check the size of plots, we used the repeatability coefficient calculated by the methods: Analysis of Variance, and the Principal Components of Structural Analysis, the last two calculated through the matrix of correlation. There were significant differences among clones evaluated in the two experiments to all traits and ages. From the results obtained is suggested the practice of early selection from 2 years old age to eucalyptus clonal tests. The use of six replications consisting of at least four plants per plot and evaluation at one age provides a coefficient of determination more than 80%.
Descrição
Palavras-chave
Eucalipto, Teste clonal, Seleção antecipada, Repetibilidade, Correlação juvenil-adulto, Melhoramento genético florestal, Tamanho da parcela, Juvenile-adult correlation, Forest tree breeding, Early selection, repeatability, Size of plot, Clonal test
Como citar
MASSARO, Renata Alves Meira. Viabilidade de aplicação da seleção precoce e tamanho de parcelas em testes clonais de Eucalyptus spp. 2008. iii, 51 f. Dissertação (mestrado) - Universidade Estadual Paulista, Faculdade de Ciências Agrárias e Veterinárias, 2008.