Diversidade, estrutura genética e parentesco em populações de [Hevea brasiliensis (Willd. Ex Adr. de Juss.) Muell.- Arg.] conservadas ex situ
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Data
2019-02-28
Autores
Silva, Murilo da Serra
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Universidade Estadual Paulista (Unesp)
Resumo
Este estudo teve como finalidade conhecer a diversidade genética de duas populações de Hevea brasiliensis, conservadas ex situ em Selvíria-MS e Marabá-PA, bem como estimar os parâmetros genéticos e medidas de dissimilaridade de suas progênies. Foram utilizados15 locos microssatélites para investigar a diversidade e estrutura genética e o parentesco de 18 matrizes da POP SEL e 46 da POP MAB. No ano de 2016, foi instalado em Selvíria-MS um teste de progênies a partir de sementes das referidas matrizes. As progênies foram avaliadas por meio de cinco variáveis silviculturais e oito morfológicas. A população de Selvíria apresentou número total de alelos (100) menor do que a população Marabá (179), com a média por locos de 6,7 e 11,9, respectivamente. A heterozigosidade esperada (He ), heterozigosidade observada ( Ho) e o índice de fixação (F) foram semelhantes entre populações, mas a riqueza alélica (R ) foi maior em Selvíria. A diferenciação genética entre as populações ( = 0,28) revelou que 72% da diversidade genética está distribuída dentro das populações. O coeficiente médio de coancestria dentro de ambas as populações foi positivo, mas os valores foram próximos de zero (< 0,08) e considerando indivíduos de ambas as populações, a coancestria media foi zero (-0,001). A estimativa de parâmetros genéticos utilizando o modelo linear misto univariado aditivo REML/BLUP, demonstrou que a herdabilidade individual não foi significativa para a maioria das variáveis observadas nas progênies. Contudo, apresentaram herdabilidades das médias de progênies para variáveis silviculturais de moderada a alta (0,40 a 0,63) na POP MAB e baixa a alta (0,23 a 0,62) na POP SEL, promovendo os maiores valores de acurácia. Entre as estimativas por técnicas multivariadas, a variável perímetro do caule foi a que mais contribuiu para explicar a variação total na POP MAB e POP SEL, respectivamente 41,3% e 43,2%. As distâncias generalizadas de Mahalanobis determinaram que a maior distância genética (81,9), bem como a menor (1,1) são de combinações das progênies da POP MAB: 45 e 42 e 34 e 13 respectivamente. A técnica de agrupamento de Tocher formou 7 grupos de divergência genética na POP MAB, 9 na POP SEL e 5 considerando as duas populações. Análises moleculares e quantitativas sugerem que há diversidade, tanto nos parentais quanto nas progênies, portanto são de interesse para programas de conservação e melhoramento genético.
This study aimed to know the diversity, genetic structure and kinship of genotypes of two populations of Hevea brasiliensis, conserved ex situ in Selvíria-MS and Marabá-PA, as well as to evaluate the genetic parameters and measures of dissimilarity of their progenies. 15 microsatellite loci were used to investigate the diversity and genetic structure and kinship of 18 matrices from Selvíria-MS and 46 from Marabá-PA. In the year 2016, a progeny test was installed in Selvíria-MS from seeds of said matrices. The progenies were evaluated by means of five silvicultural variables and eight morphological variables. The population of Selvíria presented a total number of alleles (100) smaller than the Marabá population (179) with the average per locos of 6,7 and 11,9 respectively. The expected heterozygosity (eH), observed heterozygosity (oH) and fixation index (F) were similar among populations, but allelic richness (R) was higher in Selvíria. Genetic differentiation among populations (Gst = 0.28) revealed that 72% of genetic diversity is distributed within populations. The mean coefficient of coancestria within both populations was positive, but values were close to zero (<0.08) and considering individuals from both populations, mean covensis was zero (-0.001). The univariate mixed linear additive model methodology REML / BLUP showed that the individual heritability parameter was not significant for most of the variables observed in the progenies. However, they presented mean heritabilities of progenies for moderate to high silvicultural variables (0.40 to 0.63) in POP MAB and low to high (0.23 to 0.62) in POP SEL, promoting the highest values of accuracy. Estimates using multivariate techniques showed that the stem perimeter variable contributed the most to explain the total variation in POP MAB and POP SEL, respectively, 41.3 and 43.2%. The generalized distances of Mahalanobis determined that the greatest genetic distance (81.9) as well as the lowest (1.1) are combinations of the POP MAB progenies: 45 and 42 and 34 and 13. The Tocher grouping technique, formed 7 groups of genetic divergence in POP MAB, 9 in POP SEL and 5 considering both populations. Molecular and quantitative analyzes suggest that there is diversity both in the parental and in the progenies and therefore are of interest for conservation and breeding programs.
This study aimed to know the diversity, genetic structure and kinship of genotypes of two populations of Hevea brasiliensis, conserved ex situ in Selvíria-MS and Marabá-PA, as well as to evaluate the genetic parameters and measures of dissimilarity of their progenies. 15 microsatellite loci were used to investigate the diversity and genetic structure and kinship of 18 matrices from Selvíria-MS and 46 from Marabá-PA. In the year 2016, a progeny test was installed in Selvíria-MS from seeds of said matrices. The progenies were evaluated by means of five silvicultural variables and eight morphological variables. The population of Selvíria presented a total number of alleles (100) smaller than the Marabá population (179) with the average per locos of 6,7 and 11,9 respectively. The expected heterozygosity (eH), observed heterozygosity (oH) and fixation index (F) were similar among populations, but allelic richness (R) was higher in Selvíria. Genetic differentiation among populations (Gst = 0.28) revealed that 72% of genetic diversity is distributed within populations. The mean coefficient of coancestria within both populations was positive, but values were close to zero (<0.08) and considering individuals from both populations, mean covensis was zero (-0.001). The univariate mixed linear additive model methodology REML / BLUP showed that the individual heritability parameter was not significant for most of the variables observed in the progenies. However, they presented mean heritabilities of progenies for moderate to high silvicultural variables (0.40 to 0.63) in POP MAB and low to high (0.23 to 0.62) in POP SEL, promoting the highest values of accuracy. Estimates using multivariate techniques showed that the stem perimeter variable contributed the most to explain the total variation in POP MAB and POP SEL, respectively, 41.3 and 43.2%. The generalized distances of Mahalanobis determined that the greatest genetic distance (81.9) as well as the lowest (1.1) are combinations of the POP MAB progenies: 45 and 42 and 34 and 13. The Tocher grouping technique, formed 7 groups of genetic divergence in POP MAB, 9 in POP SEL and 5 considering both populations. Molecular and quantitative analyzes suggest that there is diversity both in the parental and in the progenies and therefore are of interest for conservation and breeding programs.
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Palavras-chave
Coancestria, Diferenciação genética, Endogamia, Seringueira, Coancestry, Inbreeding, Genetic differentiation, Rubber tree