Produtividade, estabilidade, adaptabilidade e diversidade genética em testes de progênies de Pinus caribaeae var. hondurensis e Pinus tecunumanii
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Data
2017-08-24
Autores
Moreira, Juliana Prado
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Universidade Estadual Paulista (Unesp)
Resumo
P. caribaea var. hondurensis e P. tecunumanii são as espécies mais utilizadas em florestamentos na região tropical do Brasil, porém o melhoramento genético dessas espécies ainda é muito incipiente. Assim, o objetivo do trabalho foi estimar os parâmetros genéticos; ganho genético; interação genótipo x ambiente (G×A); e identificar genótipos de alta produtividade, estabilidade e adaptabilidade em progênies de Pinus caribaea var. hondurensis e Pinus tecunumanii. Os experimentos com ambas as espécies foram implantados em Selvíria-MS, Itapeva-SP e Luiz Antônio-SP. O delineamento experimental adotado foi em blocos completos ao acaso contendo de 35 a 40 progênies (tratamentos), uma planta por parcela. Em todos os testes, adotou-se o espaçamento 3m x 3m. Os caracteres avaliados foram a altura total, o diâmetro a altura do peito e o volume. Os parâmetros genéticos e componentes de variância foram obtidos pelo procedimento REML/BLUP (máxima verossimilhança restrita/melhor predição linear não viciada). Variação significativa (p< 0,05) entre progênies para os caracteres avaliados foi observada somente em Selvíria e Luiz Antônio. As herdabilidades com base em média de progênies e no sentido restrito individual foram altas e significativas para maioria dos caracteres avaliados, tanto para P. caribaea var. hondurensis quanto para P. tecunumanii. A estratégia baseada na seleção individual a 50% foi mais eficiente para manutenção da variabilidade genética. A interação G×A com base no volume foi significativa para as duas espécies, sendo do tipo simples para o P. tecunumanii e complexa para P. caribaea var. hondurensis. A correlação do tipo b para P. tecunumanii foi acima de 0,70, e já para o P. caribaea var. hondurensis foi muito baixa (0,32). Existe divergência genética entre as progênies de P. caribaea var. hondurensis e P. tecunumanii, que deve ser utilizada para se definir futuras estratégias de seleção e cruzamento, visando o aumento de ganho esperado com a seleção e conservação da variabilidade genética ao longo dos ciclos de melhoramento.
P. caribaea var. hondurensis and P. tecunumanii are the most used species in the arborization in the tropical region of Brazil, but the genetic improvement of these species is still very incipient. Thus, the objective of the study was to estimate the genetic parameters; genetic gain; genotype x environment interaction (G × A); and to identify genotypes of high productivity, stability and adaptability in the progenies of Pinus caribaea var. hondurensis and Pinus tecunumanii. The experiments with both species were implanted in Selvíria-MS, Itapeva-SP and Luiz Antônio-SP. The experimental design was a complete randomized block containing 35 to 40 progenies (treatments), one plant per plot. In all tests, spacing of 3m x 3m was adopted. The evaluated characters were total height, diameter at height and breast volume. The genetic parameters and the variance components were obtained by the REML / BLUP procedure (restricted linear prediction of maximum likelihood / best not vitiated). The significant variation (p <0.05) among the progenies for the evaluated characters was observed only in Selvíria and Luiz Antônio. The heritabilities based on medium progenies and in the individual restricted sense were high and significant for most of the evaluated characters, both for P. caribaea var. hondurensis and P. tecunumanii. The strategy based on individual selection by 50% was more efficient to maintain genetic variability. The volume-based G × A interaction was significant for both species, being of the simple type for P. tecunumanii and complex for P. caribaea var. hondurensis. The correlation of type b with P. tecunumanii was above 0.70, and already for P. caribaea var. hondurensis was very low (0.32). There is a genetic divergence among the progenies of P. caribaea var. hondurensis and P. tecunumanii, which should be used to define future selection and crossing strategies, in order to increase the expected gain with the selection and conservation of genetic variability throughout the breeding cycles
P. caribaea var. hondurensis and P. tecunumanii are the most used species in the arborization in the tropical region of Brazil, but the genetic improvement of these species is still very incipient. Thus, the objective of the study was to estimate the genetic parameters; genetic gain; genotype x environment interaction (G × A); and to identify genotypes of high productivity, stability and adaptability in the progenies of Pinus caribaea var. hondurensis and Pinus tecunumanii. The experiments with both species were implanted in Selvíria-MS, Itapeva-SP and Luiz Antônio-SP. The experimental design was a complete randomized block containing 35 to 40 progenies (treatments), one plant per plot. In all tests, spacing of 3m x 3m was adopted. The evaluated characters were total height, diameter at height and breast volume. The genetic parameters and the variance components were obtained by the REML / BLUP procedure (restricted linear prediction of maximum likelihood / best not vitiated). The significant variation (p <0.05) among the progenies for the evaluated characters was observed only in Selvíria and Luiz Antônio. The heritabilities based on medium progenies and in the individual restricted sense were high and significant for most of the evaluated characters, both for P. caribaea var. hondurensis and P. tecunumanii. The strategy based on individual selection by 50% was more efficient to maintain genetic variability. The volume-based G × A interaction was significant for both species, being of the simple type for P. tecunumanii and complex for P. caribaea var. hondurensis. The correlation of type b with P. tecunumanii was above 0.70, and already for P. caribaea var. hondurensis was very low (0.32). There is a genetic divergence among the progenies of P. caribaea var. hondurensis and P. tecunumanii, which should be used to define future selection and crossing strategies, in order to increase the expected gain with the selection and conservation of genetic variability throughout the breeding cycles
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Melhoramento florestal, MHPRVG, Parâmetros genéticos