Variabilidade genética e conservação de Stryphnodendron adstringens (leguminosae)
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2020-03-23
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Universidade Federal de Goiás
Resumo
Barbatimão (Stryphnodendron adstringens) is a Cerrado’s native tree that has multiple uses, especially medicinal. In view of its ethnobotanical and socioeconomic importance, it is pertinent that this genetic resource be characterized, in order to outline more effective strategies for its use and conservation. In this context, this work had the general objective of evaluating the magnitude and distribution of genetic variability among subpopulations of S. adstringens, aiming at the conservation of the species. The presence of genetic clusters and levels of genetic differentiation and gene flow were evaluated in order to test the hypothesis of isolation by distance (IBD). In addition, the influence of climatic components on the distribution of the genetic variability of barbatimão in future scenarios was tested. For this, nine microsatellite loci were genotyped with 605 individuals from 19 local populations in the Cerrado. Based on the results, it was found that barbatimão has a moderate genetic diversity (
e = 0.594) and a high genetic structure among the subpopulations (
ST = 0.165; p < 0.01), with low levels of inbreeding in most of the subpopulations (
IS = 0.029, p > 0.05). Clonality was detected in ten subpopulations, most frequently in the TERGO subpopulation, characterizing the mixed reproductive system of the species. It was found that geographic distance has a significant influence on the genetic differentiation of subpopulations, as in a model of isolation by distance (rm = 0.569, p < 0.01). Temperature, precipitation and altitude are components that influence the distribution of genetic variability, and consequent structuring, in S. adstringens (R²aju = 0.081, p <0.001). In addition, the simulations warned of changes in the composition of genetic groups in the face of climate change in the future. A genetic discontinuity was identified in the Araguaia River region, possibly isolating CHGMT from other subpopulations, which was corroborated by Bayesian analyses. Low gene flow rates were detected, with a reduction in the connection between subpopulations in the recent context, which were not able to neutralize the effects of genetic drift. There was evidence of a recent bottleneck in four subpopulations, which showed lower levels of genetic diversity. Based on the degree of irreplaceable, six priority subpopulations were indicated for the conservation in situ of barbatimão, or for the collection of seeds as a way to complement the ex situ conservation of S. adstringens genetic resources and guarantee the long-term genetic variability of the species.
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GONÇALVES, A. R. Variabilidade genética e conservação de Stryphnodendron adstringens (leguminosae). 2020. 129 f. Tese (Doutorado em Genética e Melhoramento de Plantas) - Universidade Federal de Goiás, Goiânia, 2020.