Crescimento, adaptação e qualidade da madeira em progênies de duas populações de myracrodruon urundeuva procedentes de áreas antropizadas
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Data
2020-02-18
Autores
Riva, Lara Comar
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Universidade Estadual Paulista (Unesp)
Resumo
As ações antrópicas no bioma Cerrado levaram a perturbações do seu ecossistema e a fragmentação das florestas, colocando em risco de extinção a espécie Myracrodruon urundeuva. O objetivo do estudo foi avaliar os caracteres silviculturais para estimar os parâmetros genéticos nos bancos de germoplasma provenientes de populações naturais em Bauru-SP e Selvíria-MS, a fim de adquirir informações que possibilitem a formação de pomares de sementes melhoradas visando a qualidade da madeira. Aos 31 anos de idade, analisou-se os caracteres altura total (ALT), diâmetro médio da copa (DMC), diâmetro na altura do peito (DAP), forma do fuste (FOR), densidade básica da madeira (DBM), relação cerne/alburno (RC/Ab) e sobrevivência (SOB). Utilizou-se o procedimento REML/BLUP via metodologia dos modelos lineares mistos para estimar os componentes de variância, os parâmetros genéticos e as estimativas de correlações genéticas entre os caracteres. Para as análises de divergência genética foi utilizado o programa Genes. Os testes de progênies de ambas as populações apresentaram variação genética. Os caracteres referentes a qualidade de madeira (DBM e RC/Ab) foram os que apresentaram maiores herdabilidades, com cerca de 0,80 e coeficiente de variação genética (16,57% a 70,10%). As correlações genéticas mostraram diferentes resultados em ambas as populações, com Selvíria sendo a população com maiores correlações positivas significativas, permitindo o uso de seleção direta e indireta tanto para os caracteres de crescimento quanto para os de qualidade de madeira. Nas análises de dissimilaridade a população de Selvíria foi a que apresentou mais agrupamentos (12), sugerindo maior diferenciação genética entre suas progênies. A predição de ganho, com intensidade de seleção de 30% das progênies, propiciou ganhos com cerca de 11% para a DBM em ambas as populações e ganhos de 53% para a RC/Ab para população de Bauru e 32,10% para a população de Selvíria. A razão sexual foi próxima ao esperado na natureza (1♂:1♀) e o tamanho efetivo apresentou cerca de 50% dos indivíduos dos testes de progênies de ambas as populações contribuíram nesse evento reprodutivo. Dessa forma, é possível transformar os dois testes de progênies em futuro pomar de sementes visando qualidade da madeira e conservação ex situ a longo prazo.
Anthropic actions in the Cerrado biome led to disturbances of its ecosystem and the fragmentation of forests, putting the species Myracrodruon urundeuva at risk of extinction. The objective of the study was to evaluate the silvicultural traits to estimate the genetic parameters in the germplasm banks from natural populations in Bauru-SP and Selvíria-MS, in order to acquire information that allows the formation of improved seed orchards aiming at the quality of the wood. At 31 years of age, the characters total height (ALT), average crown diameter (DMC), diameter at chest height (DAP), stem shape (FOR), basic wood density (DBM), ratio heartwood / sapwood (RC / Ab) and survival (SOB). The REML / BLUP procedure was used via mixed linear models methodology to estimate the components of variance, genetic parameters and estimates of genetic correlations between the characters. For the genetic divergence analyzes, the Genes program was used. The progeny tests of both populations showed genetic variation. The characters referring to wood quality (DBM and RC / Ab) were those with the highest heritability, with about 0,80 and coefficient of genetic variation (16,57% to 70,10%). The genetic correlations showed different results in both populations, with Selvíria being the population with the highest significant positive correlations, allowing the use of direct and indirect selection for both growth and wood quality characters. In the dissimilarity analyzes, the Selvíria population was the one with the most clusters (12), suggesting greater genetic differentiation between their progenies. The prediction of gain, with selection intensity of 30% of the progenies, provided gains of about 11% for the DBM in both populations and gains of 53% for the RC / Ab for the population of Bauru and 32,10% for the population. Selvíria population. The sex ratio was close to what was expected in nature (1♂: 1♀) and the effective size presented about 50% of the individuals in the progeny tests of both populations contributed to this reproductive event. In this way, it is possible to transform the two progeny tests into a future seed orchard, aiming at wood quality and long term ex situ conservation.
Anthropic actions in the Cerrado biome led to disturbances of its ecosystem and the fragmentation of forests, putting the species Myracrodruon urundeuva at risk of extinction. The objective of the study was to evaluate the silvicultural traits to estimate the genetic parameters in the germplasm banks from natural populations in Bauru-SP and Selvíria-MS, in order to acquire information that allows the formation of improved seed orchards aiming at the quality of the wood. At 31 years of age, the characters total height (ALT), average crown diameter (DMC), diameter at chest height (DAP), stem shape (FOR), basic wood density (DBM), ratio heartwood / sapwood (RC / Ab) and survival (SOB). The REML / BLUP procedure was used via mixed linear models methodology to estimate the components of variance, genetic parameters and estimates of genetic correlations between the characters. For the genetic divergence analyzes, the Genes program was used. The progeny tests of both populations showed genetic variation. The characters referring to wood quality (DBM and RC / Ab) were those with the highest heritability, with about 0,80 and coefficient of genetic variation (16,57% to 70,10%). The genetic correlations showed different results in both populations, with Selvíria being the population with the highest significant positive correlations, allowing the use of direct and indirect selection for both growth and wood quality characters. In the dissimilarity analyzes, the Selvíria population was the one with the most clusters (12), suggesting greater genetic differentiation between their progenies. The prediction of gain, with selection intensity of 30% of the progenies, provided gains of about 11% for the DBM in both populations and gains of 53% for the RC / Ab for the population of Bauru and 32,10% for the population. Selvíria population. The sex ratio was close to what was expected in nature (1♂: 1♀) and the effective size presented about 50% of the individuals in the progeny tests of both populations contributed to this reproductive event. In this way, it is possible to transform the two progeny tests into a future seed orchard, aiming at wood quality and long term ex situ conservation.
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Palavras-chave
Pomar de sementes, Variação genética, Tamanho efetivo, Seed orchard, Genetic variation, Effective size