Genetic Diversity and Fine-Scale Genetic Structure in Syagrus oleracea (Mart.) Becc.: A Survivor Palm Species of the Semiarid

摘要

The species Syagrus oleracea is a native palm tree, present in highly impacted environments of the Brazilian semiarid. This species is exploited for use in the manufacture of folk crafts and for human and animal feeding. The objective of this study was to characterize the diversity and genetic structure of individuals from different populations, located in anthropic regions of the Brazilian semiarid region, in the state of Minas Gerais. This information is important for species management and conservation strategies. Thus, we used ISSR molecular markers in 157 individuals in seven populations of S. oleracea. Looking at the results, one can observe that amplifications of 109 locos occurred and that an average of 18, 17 alleles were found on each primer, values that demonstrated that the ISSR technique used was highly efficient. The genetic diversity indexes were observed, showing expected heterozygosity (He) and Shannon index (I) of 0.260 and 0.383, respectively. The number of alleles observed (na) among populations was 1.954 and the effective number of alleles (ne) was 1,606. Individuals of the populations are genetically structured in groups (demes) in a random and aggregate manner. We obtained the amplification of 109 ISSR loci, with a mean of 18.2 alleles per primer. The genetic diversity indexes revealed expected heterozygosity (He) and Shannon index (I) of 0.260 and 0.383, respectively. The number of alleles observed (na) was 1.954 and the effective number of alleles (ne) was 1.606. The value of the indirect gene flow found was 1.546. Evidence of high levels of kinship in populations was found, possibly due to low migration rates and geographical barrier. In addition, we observed signs of overexploitation in the areas, which consequently leads to a low rate of gene flow, occurring inbreeding among the sampled populations of Syagrus oleracea.