Métodos de seleção para otimizar o ganho e a diversidade genética em pomares de sementes por muda de Pinus caribaea var. caribaea
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Data
2017-02-09
Autores
Zulian, Daniele Fernanda [UNESP]
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Universidade Estadual Paulista (Unesp)
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Pinus caribaea var caribaea, é uma espécie de importância para regiões tropicais do Brasil, pouco exigente em solo e com boa produção de madeira. A proposta desse trabalho foi estimar a variabilidade genética em pomares de pinus caribaea var. caribaea e analisar qual melhor método de seleção. O estudo foi conduzido em dois Pomares de Sementes por Mudas de Pinus caribaea var. caribaea, o primeiro com 76 progênies e 4 testemunhas (área 1) e o segundo com 99 progênies e uma testemunha (área 2), ambos de polinização aberta. Foram avaliados os caracteres quantitativos: altura total de plantas (m); diâmetro à altura do peito - DAP (cm) e calculado o volume (m³/arv-1). A análise de deviance e as estimativas dos parâmetros genéticos foram realizadas pelo procedimento REML/BLUP. Foram propostas oitenta estratégias de seleção: quatro métodos e dez intensidades de seleção para a área 1 e quatro métodos e dez intensidades para a área 2 com base nos valores de BLUP’s individuais. Para determinar a intensidade de seleção que maximiza tanto o Ganho de seleção (GS) quanto a diversidade genética (D), foi utilizado os valores de GS e D usando uma escala relativa de 0,0 – 0,1. Equações quadráticas foram utilizadas para estimar as linhas de regressão a partir dos pontos de dados, e determinar o ponto de intersecção das linhas, o qual foi considerado como o número ideal de indivíduos para cada método de seleção nas duas áreas. Os efeitos de progênies não foram significativos para nenhum dos caracteres. Variação significativa foi observada somente entre plantas dentro de parcelas para altura na área 1 e todos caracteres na área 2. As maiores estimativas de variação genética e herdabilidade foram obtidas para a área 1. Sem a otimização da seleção, o maior ganho obtido (4,8%) foi na seleção entre e dentro com uma intensidade de seleção de 52%, para a área 1. Na área 2 o maior ganho (2,86%) foi na seleção individual, porém ambas apresentaram a menor diversidade genética, a área 1 com 0,08 e área 2 com 0,07. Em ambas as áreas, foi possível otimizar ganho de seleção e a diversidade genética em apenas três métodos de seleção. Concluímos que existe baixa variabilidade genética nos Pomares de Sementes por Mudas de Pinus caribaea var caribaea a ser explorada. O método de seleção que maximiza o ganho e a diversidade genética para a área 1 foi a seleção entre e dentro de progênies na intensidade de seleção de 30%. E para a área 2 é o método de seleção individual com uma intensidade de seleção de 8,1%. Recomenda-se a infusão de novos materiais genéticos para prosseguir com um programa de melhoramento florestal, visto que foi encontrado baixa variabilidade e baixos ganhos na seleção de Pinus caribaea var. caribaea.
Pinus caribaea var. caribaea, is a species of particular importance for tropical regions of Brazil. It is not very demanding on soil and is a good wood for production and manufacturing. The proposal of this work was to estimate the genetic variability in orchards of P. caribaea var. caribaea and to analyze the best methods of selection. This study was conducted in two Seed Orchards of P. caribaea var. caribaea. The first (area 1) consisted of 76 progenies and 4 controls and the second (area 2) was comprised of 99 progenies and one control. Both test orchards were open pollinated. Quantitative traits were evaluated: total plant height (m); Diameter at breast height - DAP (cm) and calculated volume (m³ / arv-1). Deviance analysis and estimates of genetic parameters were performed using the REML / BLUP procedure. Eighty selection strategies were proposed; four methods and ten selection intensities for area 1 and four methods and ten intensities for area 2 each based on individual BLUP values. To determine the selection intensity that maximizes both the Gain (GS) and the genetic diversity (D), GS and D values were analyzed using a relative scale of 0.0 - 0.1. Quadratic equations were analyzed to estimate the regression lines from the data points. Additionally, applying the same SigmaPlot computational methods, we were able to determine the point of intersection of the lines, which were considered as the ideal number of individuals for each selection method in the two respective areas. Progeny effects were not significant for any of the traits. Significant variation was observed only between plants within the plots for height in area 1 and all traits in area 2. The highest estimates of genetic variation and heritability were obtained for area 1. Without selection optimization, the highest gain (4.8%) was in the selection between and within with a selection intensity of 52%, for area 1. In area 2 the highest gain (2.86%) was in individual selection. But both each area showed low genetic diversity, area 1 with 0.08 and area 2 with 0.07. In both areas, it was possible to optimize selection gain and genetic diversity utilizing only three selection methods. The selection method that maximized gain and genetic diversity for area 1 was the selection between and within progenies at the selection intensity of 30%. And for area 2 is the individual selection method with a selection intensity of 8.1%. It is recommended the infusion of new genetic material to proceed with a forest improvement program, since it was found to have low variability and low gains in the selection of Pinus caribaea var. caribaea. We concluded low genetic variability exists in seed orchards by seedlings of Pinus caribaea var. caribaea; thereby identifying the need for further exploration.
Pinus caribaea var. caribaea, is a species of particular importance for tropical regions of Brazil. It is not very demanding on soil and is a good wood for production and manufacturing. The proposal of this work was to estimate the genetic variability in orchards of P. caribaea var. caribaea and to analyze the best methods of selection. This study was conducted in two Seed Orchards of P. caribaea var. caribaea. The first (area 1) consisted of 76 progenies and 4 controls and the second (area 2) was comprised of 99 progenies and one control. Both test orchards were open pollinated. Quantitative traits were evaluated: total plant height (m); Diameter at breast height - DAP (cm) and calculated volume (m³ / arv-1). Deviance analysis and estimates of genetic parameters were performed using the REML / BLUP procedure. Eighty selection strategies were proposed; four methods and ten selection intensities for area 1 and four methods and ten intensities for area 2 each based on individual BLUP values. To determine the selection intensity that maximizes both the Gain (GS) and the genetic diversity (D), GS and D values were analyzed using a relative scale of 0.0 - 0.1. Quadratic equations were analyzed to estimate the regression lines from the data points. Additionally, applying the same SigmaPlot computational methods, we were able to determine the point of intersection of the lines, which were considered as the ideal number of individuals for each selection method in the two respective areas. Progeny effects were not significant for any of the traits. Significant variation was observed only between plants within the plots for height in area 1 and all traits in area 2. The highest estimates of genetic variation and heritability were obtained for area 1. Without selection optimization, the highest gain (4.8%) was in the selection between and within with a selection intensity of 52%, for area 1. In area 2 the highest gain (2.86%) was in individual selection. But both each area showed low genetic diversity, area 1 with 0.08 and area 2 with 0.07. In both areas, it was possible to optimize selection gain and genetic diversity utilizing only three selection methods. The selection method that maximized gain and genetic diversity for area 1 was the selection between and within progenies at the selection intensity of 30%. And for area 2 is the individual selection method with a selection intensity of 8.1%. It is recommended the infusion of new genetic material to proceed with a forest improvement program, since it was found to have low variability and low gains in the selection of Pinus caribaea var. caribaea. We concluded low genetic variability exists in seed orchards by seedlings of Pinus caribaea var. caribaea; thereby identifying the need for further exploration.
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Palavras-chave
Melhoramento florestal, Parâmetros genéticos, REML/BLUP