Seleção genética de progênies de irmãos completos obtidos entre espécies de Eucalyptus sp, visando a produção de carvão vegetal
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Data
2016-12-14
Autores
Henriques, Eduardo Pinheiro [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
Testes de Progênies de polinização aberta ou controlada são técnicas que permitem ao melhorista orientar o seu programa de melhoramento com base no potencial genético do material de que dispõe. Na atualidade são empregados programas computacionais avançados com base em modelos matemáticos de genética quantitativa. A partir dos dados dos parâmetros genéticos quantitativos, parâmetros moleculares calculados com dados de DNA, avaliações aos 2, 5 e 7 anos de idade dos caracteres altura das plantas (ALT) (m), diâmetro à altura do peito (DAP) (cm), volume individual das árvores (VOL) (m), genotipagem de 33 genitores femininos e 41 masculinos, quando foram analisados 14 locos microssatélites SSR, pode-se traçar a linha de trabalho de melhoramento com segurança nos resultados almejados. O objetivo deste estudo foi (i) formar um pomar de recombinação, (ii) formar um pomar de hibridação com as melhores progênies das famílias, (iii) identificar as famílias excepcionais para propagação seminal e clonal, (iv) selecionar as 10 melhores progênies para clonagem e (v) formar um Pomar de Semente Testada com as populações genitoras feminina e masculina. O delineamento experimental do teste foi de blocos casualisados com 286 tratamentos (cruzamentos), em 8 repetições de parcelas lineares de 6 plantas. O teste da razão de verossimilhança (LTR) revelou diferenças de alta significância, ao nível de 1% de probabilidade (p<0,001), entre todos os caracteres avaliados e em todas as idades de avaliação. A herdabilidade individual entre os sexos no sentido restrito (h2 a) foi de aproximadamente o dobro da herdabilidade dos efeitos de dominância entre machos e fêmeas (h2 dom). A herdabilidade individual entre os sexos nos sentido amplo, ou seja, dos efeitos genotípicos totais (h2 g) foi de 0,4 aos dois anos, 0,34 aos cinco anos e de 0,21, para o caráter altura aos sete anos de idade. Estes valores indicam sucesso na seleção dentro da população. As acurácias geral de machos (Acgm), geral de fêmeas (Acgf) e geral dos cruzamentos (Acgcruz) são altas, tendo em vista que se 2 situam acima de 0,75 para todos os caracteres em todas as idades estudadas. Isto indica que a seleção a ser realizada terá garantia de acerto acima de 70%. Os parâmetros moleculares evidenciaram não haver endogamia, coancestria e nem parentesco entre os indivíduos das populações dos genitores. A identidade genética é da ordem de 0,800 e a distância de 0,222. As populações de genitores compartilham apenas duas estruturas genéticas do genoma. Foram selecionadas (i) 32 famílias excepcionais e nelas (ii) 256 indivíduos para formação do pomar de recombinação, com produtividade média de 74,24 m³ ha-1 ano-1, (iii) 65 progênies para estabelecimento do pomar de hibridação com a mesma produtividade média. No “ranking” de indivíduos foram selecionados os melhores, para clonagem, com produtividade média de 86,08 m³ ha-1 ano-1.
Progeny tests of open or controlled pollination are techniques that allow the breeder to guide its improvement program based on the genetic material of the available material. At the present time advanced computer programs based on mathematical models of quantitative genetics are used. From data of the quantitative genetic parameters, molecular parameters calculated with DNA data, evaluations at 2, 5 and 7 years of age of characters, height of plants (HGT) (m), diameter at breast height (DBH) (cm), individual volume of trees (VOL) (m) and genotyping of 33 female and 41 male parents, when fourteen SSR microsatellite loci were analyzed, it is possible to draw the working line for safely improving the desired results. The objective of this study is (i) forming a recombination orchard, (ii) forming a hybridization orchard with the best progenies of the families, (iii) identifying exceptional families to seed and clonal propagation, (iv) selecting the 10 best progenies for cloning and (v) creating an Orchard of Tested Seeds with female progenitor population. The experimental design of the test was the one of randomized blocks with 286 treatments (crossings) in eight repetitions of linear parcels of 6 plants. The likelihood ratio test (LRT) revealed differences of high significance, at the level of 1% of probability (p<0.001), between all evaluated characters and in all evaluating ages. Individual heritability between sexes in the restricted sense (h2 a) was approximately the double or the heritability of dominance effects between males and females (h2 dom). Individual heritability between sexes in the broad sense, in other words, of total phenotypic effects (h2 g) was 0.4 at two years, 0.34 at five years and 0.21 at seven years of age. Those values indicate success of population selection. General accuracy of males (Gacm), general accuracy of females (Gafm) and general accuracy of plant breeding (Gacgcross) are high, considering that they are over 0.75 for all characters in all studied ages. This indicates that the selection to be performed will have a guaranteed accuracy over 70%. Molecular parameters evidenced that there are no endogamy and no relatedness between individuals from the genitors’ 4 populations. Genetic identity is in the order of 0.800 and distance 0.222. Genitors’ populations shared only two genetic structures of the genome. Thirty-two exceptional families (i) were selected and from them (ii) 256 individuals for formation of recombination orchard, with mean production of 74.24 m³ ha-1 year-1, (iii) 65 progenies for establishment of hybridization orchard with the same average production. In the ranking of individuals, the best ones were selected, for cloning, with mean productivity of 86.08 m³ ha-1 year-1.
Progeny tests of open or controlled pollination are techniques that allow the breeder to guide its improvement program based on the genetic material of the available material. At the present time advanced computer programs based on mathematical models of quantitative genetics are used. From data of the quantitative genetic parameters, molecular parameters calculated with DNA data, evaluations at 2, 5 and 7 years of age of characters, height of plants (HGT) (m), diameter at breast height (DBH) (cm), individual volume of trees (VOL) (m) and genotyping of 33 female and 41 male parents, when fourteen SSR microsatellite loci were analyzed, it is possible to draw the working line for safely improving the desired results. The objective of this study is (i) forming a recombination orchard, (ii) forming a hybridization orchard with the best progenies of the families, (iii) identifying exceptional families to seed and clonal propagation, (iv) selecting the 10 best progenies for cloning and (v) creating an Orchard of Tested Seeds with female progenitor population. The experimental design of the test was the one of randomized blocks with 286 treatments (crossings) in eight repetitions of linear parcels of 6 plants. The likelihood ratio test (LRT) revealed differences of high significance, at the level of 1% of probability (p<0.001), between all evaluated characters and in all evaluating ages. Individual heritability between sexes in the restricted sense (h2 a) was approximately the double or the heritability of dominance effects between males and females (h2 dom). Individual heritability between sexes in the broad sense, in other words, of total phenotypic effects (h2 g) was 0.4 at two years, 0.34 at five years and 0.21 at seven years of age. Those values indicate success of population selection. General accuracy of males (Gacm), general accuracy of females (Gafm) and general accuracy of plant breeding (Gacgcross) are high, considering that they are over 0.75 for all characters in all studied ages. This indicates that the selection to be performed will have a guaranteed accuracy over 70%. Molecular parameters evidenced that there are no endogamy and no relatedness between individuals from the genitors’ 4 populations. Genetic identity is in the order of 0.800 and distance 0.222. Genitors’ populations shared only two genetic structures of the genome. Thirty-two exceptional families (i) were selected and from them (ii) 256 individuals for formation of recombination orchard, with mean production of 74.24 m³ ha-1 year-1, (iii) 65 progenies for establishment of hybridization orchard with the same average production. In the ranking of individuals, the best ones were selected, for cloning, with mean productivity of 86.08 m³ ha-1 year-1.
Descrição
Palavras-chave
Eucalyptus, Teste de progênies, Parâmetros genéticos, Seleção, Endogamia, Coancestria e estrutura genética, Progeny test, Genetic parameters, Selection, Inbreeding, Coancestry and genetic structure