Caracterização genética de Dalbergia nigra (Vell.) Allemão ex Benth em fragmentos de Floresta Atlântica: implicações à conservação e ao manejo
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Data
2021-02-25
Autores
Silva Júnior, Adelson Lemes da
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Universidade Federal do Espírito Santo
Resumo
Dalbergia nigra (Vell.) Allemão ex Benth is an arboreal species, popularly known as jacarandá-da-Bahia. Endemic to the Atlantic Forest, the species has economic and ecological importance, as it has quality wood and potential for use in the recovery of degraded areas. However, it is classified as vulnerable to extinction due to the fragmentation of the Atlantic Forest and its intense exploitation in the past, in which, little is known about the genetic consequences generated in its populations. The objective of this study was to characterize the diversity and genetic structure of the species Dalbergia nigra in the Atlantic Forest biome, within the limits of the state of Espírito Santo. The sampling was carried out in 12 populations distributed in the South, Central, Northwest and North-Coast mesoregions, being sampled 15 individuals per population, totaling 180 individuals. For the analyzes, 12 Inter Simple Sequence Repeats (ISSR) primers and 7 pairs of Simple Sequence Repeats (SSR) primers were used. Regarding the performance of the molecular markers, the PIC values for the ISSR ranged from 0.26 to 0.36, indicating moderate informativeness, whereas for the SSR the values ranged from 0.33 to 0.61, indicating moderate to high informativeness for the populations evaluated individually, and high for the joint data. The values of H* and I* calculated for the ISSR data and, mainly the HO, HE and F values obtained for the SSR data, also differentiated the populations with higher (PFP, FNP, APSE, RBS, RNV and MNPC) and minor (PEAMA, RPPNC, RBAR, FNRP, RBCV and APPE) genetic diversity, in addition to revealing moderate to high levels for genetic diversity in the joint data. The genetic distance between the pairs of individuals did not conform between the markers, however, a kinship relationship was observed by geographic proximity. Regarding genetic structuring, Amova indicated moderate genetic differentiation (ΦST = 0.1616) for ISSR data and low differentiation (ΦST = 0.1483) for SSR data, however, for both markers, the greatest genetic variation is within populations. The moderate to low genetic differentiation corroborates with the Nm data obtained from the ISSR (Nm = 1.98 to 8.78) and SSR (Nm = 1.09 to 9.21), indicating the occurrence of gene flow between populations. The Bayesian analysis carried out from the ISSR data resulted in only two groups, while the SSR data revealed that there are three genetic groups dividing into populations located in the North-Coastal region, close to or located in the Northwest region, and close or located in the South region. The Mantel test revealed a low correlation between the markers, however, according to the entanglement analysis, there was a moderate association between the matrices of genetic distances (Entanglement = 0.47), with consistency between some individuals. The satisfactory results found for the species confirm the potential of possible matrices for the collection of seeds and production of seedlings, however, the low levels of genetic diversity found for some populations, are possibly associated with the intense exploitation of D. nigra in the past and the fragmentation of the Atlantic Forest.
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Diversidade genética , estrutura genética , fragmentação florestal , jacarandá-da-Bahia , marcadores moleculares