Relationship between fruit phenotypes and domestication in hexaploid populations of biribá (Annona mucosa) in Brazilian Amazonia.

Background: Biribá (Annona mucosa Jacq.) is a fruit tree domesticated in Amazonia and has polyploid populations. The species presents ample phenotypic variation in fruit characteristics, including weight (100-4,000 g) and differences in carpel protrusions. Two cytotypes are recorded in the literature (2n = 28, 42) and genome size records are divergent (2C = 4.77, 5.42 and 6.00 pg). To decipher the role of polyploidy in the domestication of A. mucosa, we examined the relationships among phenotypic variation, chromosome number and genome size, and which came first, polyploidization or domestication. Methodology: We performed chromosome counts of A. mucosa from central and western Brazilian Amazonia, and estimated genome size by flow cytometry. We performed phylogenetic reconstruction with publicly available data using a Bayesian framework, time divergence analysis and reconstructed the ancestral chromosome number for the genus Annona and for A. mucosa. Results: We observed that variation in fruit phenotypes is not associated with variation in chromosome number and genome size. The most recent common ancestor of A. mucosa is inferred to be polyploid and diverged before domestication. Conclusions: We conclude that, when domesticated, A. mucosa was already polyploid and we suggest that human selection is the main evolutionary force behind fruit size and fruit morphological variation in Annona mucosa.

A set of plastid microsatellite loci for the genus Dyckia (Bromeliaceae) derived from 454 pyrosequencing.

PREMISE OF THE STUDY: Phylogeographical analyses of Dyckia (Bromeliaceae) suffer from low levels of sequence variation. Plastid microsatellite markers were developed to achieve a better-resolved genus-wide plastid genealogy of Dyckia. • METHODS AND RESULTS: Approximately 84% of the D. marnier-lapostollei plastome was sequenced using 454 technology. Flanking primer pairs were designed for 34 out of 36 chloroplast simple sequence repeats (cpSSRs) detected, and 12 loci were further characterized by genotyping Dyckia samples at the level of populations and species. Three, five, and six cpSSRs were polymorphic among four individuals of D. limae, 12 individuals of D. dissitiflora, and 12 of D. pernambucana, respectively, with two to three alleles per locus and species. All loci were polymorphic among 19 different Dyckia species, with three to 10 alleles per locus. Ten primer pairs cross-amplified with bromeliad genera from five subfamilies. • CONCLUSIONS: The set of 12 cpSSR markers provides a toolbox to analyze phylogeographical patterns of Dyckia species.