Pomar de sementes por mudas em Eucalyptus camaldulensis e Hymenaea stigonocarpa: uma opção para o melhoramento e a conservação genética em espécies arbóreas exóticas e nativas
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Data
2020-02-27
Autores
Zaruma, Darlin Ulises Gonzalez [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
As espécies florestais possuem grande importância econômica, pois oferecem diversos produtos fundamentais para a sociedade, mas dada a impossibilidade de se separar ações de melhoramento das de conservação de recursos genéticos, técnicas como os testes combinados de progênies e procedências, tanto para espécies exóticas ou nativas, visam a seleção de árvores pelo valor genético e a transformação dos experimentos em PSM (pomares de semente por mudas). Os pomares de sementes são os vetores de produção de sementes de alta qualidade genética, que ligam as atividades de melhoramento das árvores às práticas de conservação. No anterior contexto, sementes de polinização aberta provenientes de uma população base de Eucalyptus camaldulensis e de um fragmento de Cerrado com Hymenaea stigonocarpa, foram coletadas e plantadas na Faculdade de Engenharia de Ilha Solteira (FEIS/UNESP), em Selvíria-MS. O objetivo deste trabalho foi verificar a variação genética e ganhos genéticos a partir do desbaste dentro de progênies de E. camaldulensis aos 10 anos de idade e estimar parâmetros genéticos populacionais, por meio de marcadores moleculares do tipo microssatélites para H. stigonocarpa, com vistas ao melhoramento genético e conservação, respectivamente. Para análise quantitativa, os caracteres altura (ALT), diâmetro a altura do peito (DAP), volume (VOL), densidade básica (DBM) e sobrevivência (SOB) foram utilizados. Assim os valores observados para sobrevivência (>90%) de E. camaldulensis indicam boa adaptação da espécie ao local e estimativas consideradas de alta magnitude para o coeficiente de variação genética aditiva individual, herdabilidade em nível de medias de progênies e acurácia. A estratégia de seleção dentro de progênies, com desbaste de 40% dos indivíduos com base no caráter DAP, revelou baixos ganhos com seleção. Em quanto H. stigonocarpa mostrou altos níveis de diversidade genética para adultos (54 alelos) e progênies (40 alelos), e uma estrutura genética espacial de até 75 m. o sistema de reprodução foi pôr cruzamento (0,99) entre parentes (0,125), resultando em um coeficiente de coancestria de 0,140, com progênies de meios-irmãos. Em conclusão, este estudo gerou informações sobre a variabilidade genética e permite orientar ações para transformá-los em pomares de sementes por mudas.
Forest species are of great economic importance, as they offer several fundamental products for society, but given the impossibility of separating actions to improve those from the conservation of genetic resources, techniques such as the combined testing of progenies and provenances for both exotic and native species, aim at the selection of trees by their genetic value and the transformation of the experiments in PSM (seed orchards by seedlings). Seed orchards are the vectors of seed production of high genetic quality, which link tree improvement activities to conservation practices. In the previous context, open pollination seeds from a base population of Eucalyptus camaldulensis and a fragment of Cerrado with Hymenaea stigonocarpa, were collected and planted at the Faculty of Engineering of Ilha Solteira (FEIS/UNESP), in Selvíria-MS. The objective of this work was to evaluate the genetic variation and genetic gains from thinning within E. camaldulensis progeny at 10 years of age, and to estimate population genetic parameters, using microsatellite molecular markers for H. stigonocarpa, with a view to genetic improvement and conservation, respectively. For quantitative analysis, the characters height (H), diameter at breast height (DBH), volume (VOL), basic density (DBM) and survival (SUR) were used, thus the values observed for survival (> 90%) indicate good adaptation of the species to the place. Estimates considered to be of high magnitude were obtained for the coefficient of individual additive genetic variation, heritability of the mean of progenies and accuracy. The selection strategy within progenies, with thinning of 40% of the individuals based on the DAP character, revealed gains in the selection. High levels of genetic diversity for adults (54 alleles) and progenies (40 alleles) have been recorded, and a spatial genetic structure of up to 75 m. The average crossing rate was 0.99, indicating a breeding system for breeding the species. The crossing rate between relatives was 0.125, resulting in a coancestry coefficient of 0.140, with half-sib progenies. This study generated information on genetic variability and allows guiding actions to transform them into seed orchards for seedlings.
Forest species are of great economic importance, as they offer several fundamental products for society, but given the impossibility of separating actions to improve those from the conservation of genetic resources, techniques such as the combined testing of progenies and provenances for both exotic and native species, aim at the selection of trees by their genetic value and the transformation of the experiments in PSM (seed orchards by seedlings). Seed orchards are the vectors of seed production of high genetic quality, which link tree improvement activities to conservation practices. In the previous context, open pollination seeds from a base population of Eucalyptus camaldulensis and a fragment of Cerrado with Hymenaea stigonocarpa, were collected and planted at the Faculty of Engineering of Ilha Solteira (FEIS/UNESP), in Selvíria-MS. The objective of this work was to evaluate the genetic variation and genetic gains from thinning within E. camaldulensis progeny at 10 years of age, and to estimate population genetic parameters, using microsatellite molecular markers for H. stigonocarpa, with a view to genetic improvement and conservation, respectively. For quantitative analysis, the characters height (H), diameter at breast height (DBH), volume (VOL), basic density (DBM) and survival (SUR) were used, thus the values observed for survival (> 90%) indicate good adaptation of the species to the place. Estimates considered to be of high magnitude were obtained for the coefficient of individual additive genetic variation, heritability of the mean of progenies and accuracy. The selection strategy within progenies, with thinning of 40% of the individuals based on the DAP character, revealed gains in the selection. High levels of genetic diversity for adults (54 alleles) and progenies (40 alleles) have been recorded, and a spatial genetic structure of up to 75 m. The average crossing rate was 0.99, indicating a breeding system for breeding the species. The crossing rate between relatives was 0.125, resulting in a coancestry coefficient of 0.140, with half-sib progenies. This study generated information on genetic variability and allows guiding actions to transform them into seed orchards for seedlings.
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Palavras-chave
Cerrado, Sementes florestais, Endogamia, Diversidade genética, Parâmetros genéticos, Forest seeds, Inbreeding, Genetic diversity, Parameters genetics, Savanna