Caracterização genética de áreas de produção de sementes de Araucaria angustifolia (BERT.) o. ktze para produção de pinhão e madeira
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2016-08-11
Autores
Silva, Janaína Rodrigues [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
Em função da importância ecológica, econômica e do alto grau de degradação das Florestas com araucária, informações sobre genética de populações envolvendo a Araucaria angustifolia são essenciais para programas de conservação ex situ e o melhoramento genético. A conservação ex situ de populações na forma de testes de procedências e progênies permite monitorar os níveis de variabilidade genética e verificar a eficácia de estratégia de amostragem utilizadas nas populações. Dentro deste contexto, o objetivo foi realizar a caracterização genética e estimar o ganho com a seleção em três testes de procedências e progênies de A. angustifolia em Colombo-PR visando a produção de madeira e de sementes. Essas áreas experimentais foram estabelecidas sob delineamento experimental em blocos de progênies compactadas. O número de progênies e repetições em cada área variou da seguinte forma: 25, 110 e 50 progênies e 16, 2 e 6 repetições, nas áreas 1, 2 e 3, respectivamente. Os caracteres avaliados foram: o diâmetro a altura do peito (DAP), altura total (ALT), volume total (VOL), diâmetro médio de copa (DMC) e espessura da casca (ESP) aos 30, 32 e 33 anos de idade e os caracteres de produção de pinhão. Os parâmetros genéticos e componentes de variância foram obtidos pelo procedimento REML/BLUP. Os resultados deste trabalho permitiram concluir que há variação genética significativa entre procedências e progênies para a maioria dos caracteres avaliados. Verificou-se que a maior parte da variação genética encontra-se entre progênies para 67% dos caracteres avaliados e 33% entre procedências. O diâmetro a altura do peito aos 32 anos foi o mais indicado para a seleção dos indivíduos nas áreas experimentais. As correlações fenotípicas e genéticas entre os caracteres silviculturais foram moderadas a altas, positivas e significativas, variou de 0,95 a 0,98. As procedências Telêmaco Borba-PR e Irati- PR apresentam melhor desempenho em DAP 32. A correlação entre as distâncias genotípicas e geográficas foram positivas em todas as áreas experimentais, confirmando que a variabilidade genética está estruturada no espaço. Com base na distância de Mahalanobis, os acessos de araucária foram separados em grupos distintos. Esses foram formados, principalmente, pelas procedências geograficamente mais próximas. Com a análise descritiva das pinhas e pinhões obteve-se ligeira superioridade na capacidade produtiva das árvores matrizes da área 1 comparada as árvores matrizes da área 2. Correlações fenotípicas moderadas negativa a moderadas positiva foram observadas para os caracteres de crescimento associados aos da produção de pinhão. Com base no diâmetro à altura do peito aos 32 anos foram simuladas duas intensidades de seleção em nível individual. A intensidade de seleção de 41%, 38% e 27% foi a mais adequada visto que proporcionaram ganhos por seleção de 8,27% 7,63% e 7,59% nas áreas 1, 2 e 3, respectivamente. Esta estratégia evitará a perda excessiva de variabilidade genética e ganhos genéticos modestos.
Due to both ecological and economic importance, as well as the high degree of degradation of Araucarian Forests, it can be important to obtain genetic information about genetic of Brazilian pine (Araucaria angustifolia) population is essential to ex situ conservation programs and genetic improvement. The ex situ population conservation, in the configuration of provenance and progeny tests allow monitoring the genetic variability levels and checking the efficiency of sampling strategies used in population. In this context, the aim of this work was to perform the genetic characterization and estimate gain with selection in three provenance and progeny tests of A. angustifolia in Colombo-PR, Brazil, more specifically, and analysis will focus on its wood and seed production. Those trial areas were established by experimental design in compacted blocks of progeny. The number of replicates and progenies in each area varied as follows: 25, 110 and 50 progenies and 16, 2 and 6 replicates, respectively, in the areas 1, 2 and 3. The evaluated traits were: diameter at breast height (DBH), total height (ALT), total volume (VOL), average crown diameter (DMC) and bark thickness (ESP) at 30, 32 and 33 years old beyond the traits related to pine nut production. Genetic parameters and variance components were obtained by REML/BLUP procedure. The results of this study indicated a significant genetic variation among provenances and progenies for the majority of evaluated traits. It was determined that most of the genetic variation was found among progenies up to 67% of the analysed traits and 33% among of provenances. The DBH at age 32 was the most suitable for the selection of individuals in the experimental areas. Phenotypic and genetic correlations between growth traits were observed from moderate to high, positive and significant, varying from 0,95 to 0,98. Provenances Telêmaco Borba-PR and Irati-PR presented best performances for the trait for DBH 32. The correlation between genotypic and geographical distances were positive in all experimental areas, confirming that genetic variability is structured in space. Based on the Mahalanobis distances, the araucaria accesses were separated into different groups. These were clustered, especially by the geographically closest provenances. With the descriptive analysis of pine cones and pine nuts, it gave a slight superiority in the productive capacity of trees in the Area 1 compared to trees of Area 2. Moderate negative to moderate positive phenotpic correlation were observed for growth traits associated to variables of pine nut production. Based on DBH trait at 32 years old were simulated two selection intensities at individual level. The selection intensity of 41%, 38% and 27%, leads genetic gains 8.27%, 7.63% and 7.59% in areas 1, 2 and 3, respectively. This strategy will avoid an excessive loss of genetic variability and modest genetic gains.
Due to both ecological and economic importance, as well as the high degree of degradation of Araucarian Forests, it can be important to obtain genetic information about genetic of Brazilian pine (Araucaria angustifolia) population is essential to ex situ conservation programs and genetic improvement. The ex situ population conservation, in the configuration of provenance and progeny tests allow monitoring the genetic variability levels and checking the efficiency of sampling strategies used in population. In this context, the aim of this work was to perform the genetic characterization and estimate gain with selection in three provenance and progeny tests of A. angustifolia in Colombo-PR, Brazil, more specifically, and analysis will focus on its wood and seed production. Those trial areas were established by experimental design in compacted blocks of progeny. The number of replicates and progenies in each area varied as follows: 25, 110 and 50 progenies and 16, 2 and 6 replicates, respectively, in the areas 1, 2 and 3. The evaluated traits were: diameter at breast height (DBH), total height (ALT), total volume (VOL), average crown diameter (DMC) and bark thickness (ESP) at 30, 32 and 33 years old beyond the traits related to pine nut production. Genetic parameters and variance components were obtained by REML/BLUP procedure. The results of this study indicated a significant genetic variation among provenances and progenies for the majority of evaluated traits. It was determined that most of the genetic variation was found among progenies up to 67% of the analysed traits and 33% among of provenances. The DBH at age 32 was the most suitable for the selection of individuals in the experimental areas. Phenotypic and genetic correlations between growth traits were observed from moderate to high, positive and significant, varying from 0,95 to 0,98. Provenances Telêmaco Borba-PR and Irati-PR presented best performances for the trait for DBH 32. The correlation between genotypic and geographical distances were positive in all experimental areas, confirming that genetic variability is structured in space. Based on the Mahalanobis distances, the araucaria accesses were separated into different groups. These were clustered, especially by the geographically closest provenances. With the descriptive analysis of pine cones and pine nuts, it gave a slight superiority in the productive capacity of trees in the Area 1 compared to trees of Area 2. Moderate negative to moderate positive phenotpic correlation were observed for growth traits associated to variables of pine nut production. Based on DBH trait at 32 years old were simulated two selection intensities at individual level. The selection intensity of 41%, 38% and 27%, leads genetic gains 8.27%, 7.63% and 7.59% in areas 1, 2 and 3, respectively. This strategy will avoid an excessive loss of genetic variability and modest genetic gains.
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Palavras-chave
Conífera, Caracteres quantitativos, Melhoramento genético, Ganho genético por seleção, Conifers, Quantitative trait, Genetic improvement, Genetic gain by selection