Caracterização e comparação da diversidade genética de populações de Eucalyptus grandis por meio de marcadores moleculares e características quantitativas
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Data
2016-09-27
Autores
Miranda, Aline Cristina [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
O objetivo desse estudo foi explorar a variabilidade genética existente entre e dentro de procedências e progênies da população estudada, conhecendo a estrutura genética da população de melhoramento, estimando parâmetros genéticos de caracteres quantitativos de crescimento e determinando a origem das populações de melhoramento de Eucalyptus grandis. O teste de progênies e procedências de Eucalyptus grandis com 153 progênies de polinização aberta, oriundas de dez procedências foi implantado em Anhembi como parte da rede experimental Projeto Cooperativo Populações Núcleo, sendo o delineamento experimental utilizado de blocos casualizados com quatro repetições e seis plantas lineares. A mensuração dos caracteres quantitativos como diâmetro à altura do peito, altura total das árvores, volume e sobrevivência ocorreram aos 12, 24, 36, 48 e 60 meses e as análises foram realizadas via RELM/BLUP. Para a avaliação do sistema de reprodução e identificação da diversidade genética existente nas procedências brasileiras, foram selecionadas 981 plantas para análise de nove locos microssatélites e para determinação das origens da espécie estudada foi realizado a genotipagem de 254 plantas de 18 populações da Austrália. Nas análises individuais em todos os períodos de avaliação, os caracteres de produção apresentaram-se significativos a um grau de liberdade pelo teste LRT, indicando a existência de variabilidade genética a ser explorada pelo melhoramento genético, tanto entre como dentro de progênies. Houve uma redução dos valores de herdabilidade individual para todas as características avaliadas aos 12 meses para 60 meses de mensuração. O valor de repetibilidade individual ( ) obtido apresentou magnitude alta (0,78). Das 20 progênies selecionadas pela média harmônica da performance relativa dos valores genéticos (MHPRVG), 14 dessas estão presentes em todas as análises mostrando que a seleção com base apenas na análise de interação genótipos x anos, pode ser errônea e/ou não capitalizar genótipos importantes. Das dez procedências avaliadas, a seleção realizada pela MHPRVG proporcionou a seleção de progênies de seis procedências. Estimativa da taxa de cruzamento multiloco foi alta (0,994), esse resultado está dentro do padrão observado para a taxa de cruzamento em outras populações, mas significativamente diferente de 1,0, sugerindo um sistema misto de reprodução, combinando autofecundações e cruzamentos, com predominância de cruzamento. As estimativas de diferenciação genética entre as populações foram significativamente diferentes de zero. A combinação da origem de diferentes procedências brasileiras associadas à seleção, indica potencial de reprodução, sendo que, os indivíduos de diferentes procedências podem ser utilizados para compor uma nova geração.
To explore the genetic variability between and within provenances and progenies of the population studied, the aim of this study was to understand the genetic structure of the population of breeding, to estimate genetic parameters of quantitative traits of growth and determine the origin of breeding populations Eucalyptus grandis. The provenances test and progenies of Eucalyptus grandis with 153 open-pollinated progenies, ten provenances, was established at Anhembi, as part of the experimental network (PCPN), the experimental design was a design randomized block with linear plots. The measurement of quantitative traits diameter at breast height, total tree height, cylindrical volume and survival were evaluates at 12, 24, 36, 48 and 60 months, the analyzes were performed by RELM / BLUP and evaluation of mating system and identification the genetic diversity of Brazilian provenances, 981 plants were selected for analysis of nine microsatellite loci and to determine the origins of studied species was conducted genotyping of 254 samples from 18 populations of Australia. In the individual analysis in all evaluation, yield traits showed a significant degree of freedom for the LRT test, indicating the existence of genetic variability to be exploited by breeding, both between and within progenies. There was a reduction of individual heritability values for all characteristics evaluated at 12 months to 60 months of measurement. The individual value of repeatability ( r ˆ ) obtained showed high magnitude (0.78). We selected the best 20 progenies classified in terms of individual genetic value by MHPRVG, 14 progenies were found are present in all analyzes showing that the selection based only on the analysis of genotype x years can be erroneous and / or to capitalize important genotypes. Of the ten evaluated provenances, the selection made by MHPRVG provided the selection of six provenances progenies. Estimated multilocus outcrossing rate was high (0.994), this result is within the pattern observed for the outcrossing rate in other populations, but significantly different from 1.0, suggesting a mixed system of reproduction, combining selfing and crosses, especially cross. Estimates of genetic differentiation among populations were significantly different from zero. The combination of different origin Brazilian origins associated with the selection, indicates reproductive potential, is that individuals of different origins may be used to compose a new generation.
To explore the genetic variability between and within provenances and progenies of the population studied, the aim of this study was to understand the genetic structure of the population of breeding, to estimate genetic parameters of quantitative traits of growth and determine the origin of breeding populations Eucalyptus grandis. The provenances test and progenies of Eucalyptus grandis with 153 open-pollinated progenies, ten provenances, was established at Anhembi, as part of the experimental network (PCPN), the experimental design was a design randomized block with linear plots. The measurement of quantitative traits diameter at breast height, total tree height, cylindrical volume and survival were evaluates at 12, 24, 36, 48 and 60 months, the analyzes were performed by RELM / BLUP and evaluation of mating system and identification the genetic diversity of Brazilian provenances, 981 plants were selected for analysis of nine microsatellite loci and to determine the origins of studied species was conducted genotyping of 254 samples from 18 populations of Australia. In the individual analysis in all evaluation, yield traits showed a significant degree of freedom for the LRT test, indicating the existence of genetic variability to be exploited by breeding, both between and within progenies. There was a reduction of individual heritability values for all characteristics evaluated at 12 months to 60 months of measurement. The individual value of repeatability ( r ˆ ) obtained showed high magnitude (0.78). We selected the best 20 progenies classified in terms of individual genetic value by MHPRVG, 14 progenies were found are present in all analyzes showing that the selection based only on the analysis of genotype x years can be erroneous and / or to capitalize important genotypes. Of the ten evaluated provenances, the selection made by MHPRVG provided the selection of six provenances progenies. Estimated multilocus outcrossing rate was high (0.994), this result is within the pattern observed for the outcrossing rate in other populations, but significantly different from 1.0, suggesting a mixed system of reproduction, combining selfing and crosses, especially cross. Estimates of genetic differentiation among populations were significantly different from zero. The combination of different origin Brazilian origins associated with the selection, indicates reproductive potential, is that individuals of different origins may be used to compose a new generation.
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Palavras-chave
Eucalipto, Germoplasma, Populações núcleo, Sistema misto de reprodução, Variabilidade genética, Eucalypts, Germplasm, Nucleus breeding, Mating system, Genetic variability