Examinando por Materia "Apiaceae"

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Assessment of the genetic structure and diversity of arracacha (Arracacia xanthorrhiza) using genotyping-by-sequencing
(International Society for Horticultural Science, 2024-04-13) Arbizu Berrocal, Carlos Irvin; Saldaña Serrano, Carla Lizet; Lazo, E.; Suca Damiano, Esther Stefany; Santa Cruz Padilla, Angel Esteban; Chávez Cabrera, Alexander; Cabrera Hoyos, Héctor Antonio; Guerrero Abad, Juan Carlos; Maicelo Quintana, Jorge Luis
Arracacha, also known as “Peruvian carrot”, is a native crop from the Andean region, and is considered an unexplored root. To date, studies on this crop were mainly focused at the morphological and agronomic level. However, its genetics remains unclear. Today it is feasible to study the genetic composition of this Andean root by next-generation sequencing techniques such as genotyping-by-sequencing (GBS). We here for the first time employed 183 accessions of arracacha from six Andean localities of Peru and identified 8976 SNP markers. STRUCTURE analysis revealed this Andean crop is clustered into four populations, and with few accessions intermingled. A dendrogram was generated using the UPGMA clustering algorithm, and, similar to the principal coordinate analysis (PCoA), it showed four groups. Genetic diversity estimation was conducted considering the four populations identified, revealing very high expected heterozygosity (0.432). AMOVA revealed the greatest variation within populations (89.66%) and indicated that variability between populations is 10.34%. Population divergence (Fst) ranged from 0.02 (cluster 1 vs. cluster 3) to 0.036 (cluster 1 vs. cluster 4). Negative Fis values were also detected for all populations of arracacha, indicating it depends on cross-pollination. We hope this work stimulates the development of additional molecular tools for this orphan crop in order to establish a modern breeding program and conservation strategies of this important Andean crop.
Morphometrics of Daucus (Apiaceae): A counterpart to a phylogenomic study
(John Wiley & Sons, 2014-11-01) Arbizu Berrocal, Carlos Irvin; Reitsma, Kathleen R.; Simon, Philipp W.; Spooner, David M.
•Premise of study: Molecular phylogenetics of genome‐scale data sets (phylogenomics) often produces phylogenetic trees with unprecedented resolution. A companion phylogenomics analysis of Daucus using 94 conserved nuclear orthologs supported many of the traditional species but showed unexpected results that require morphological analyses to help interpret them in a practical taxonomic context. •Methods: We evaluated character state distributions, stepwise discriminant analyses, canonical variate analyses, and hierarchical cluster analyses from 40 morphological characters from 81 accessions of 14 taxa of Daucus and eight species in related genera in an experimental plot. •Key results: Most characters showed tremendous variation with character state overlap across many taxa. Multivariate analyses separated the outgroup taxa easily from the Daucus ingroup. Concordant with molecular analyses, most species form phenetic groups, except the same taxa that are problematical in the molecular results: (1) the subspecies of D. carota, (2) D. sahariensis and D. syrticus, and (3) D. broteri and D. guttatus. •Conclusions: Phenetic analyses, in combination with molecular data, support many Daucus species, but mostly by overlapping ranges of size and meristic variation. The subspecies of D. carota are poorly separated morphologically, are paraphyletic, and all could be recognized at the subspecies rank under D. carota. Daucus sahariensis and D. syrticus are so similar morphologically that they could be placed in synonymy. Combined molecular and morphological data support three species in accessions previously identified as D. broteri and D. guttatus. Molecular and morphological results support the new combination Daucus carota subsp. capillifolius.
Phylogenomics of the Carrot Genus (Daucus, Apiaceae)
(John Wiley & Sons, 2014-10-01) Arbizu Berrocal, Carlos Irvin; Ruess, Holly; Senalik, Douglas; Simon, Philipp W.; Spooner, David M.
•Premise of the study: We explored the utility of multiple nuclear orthologs for the taxonomic resolution of wild and cultivated carrot, Daucus species. •Methods: We studied the phylogeny of 92 accessions of 13 species and two subspecies of Daucus and 15 accessions of related genera (107 accessions total) with DNA sequences of 94 nuclear orthologs. Reiterative analyses examined data of both alleles using ambiguity codes or a single allele with the highest coverage, trimmed vs. untrimmed homopolymers; pure exonic vs. pure intronic data; the use of all 94 markers vs. a reduced subset of markers; and analysis of a concatenated data set vs. a coalescent (species tree) approach. •Key results: Our maximum parsimony and maximum likelihood trees were highly resolved, with 100% bootstrap support for most of the external and many of the internal clades. They resolved multiple accessions of many different species as monophyletic with strong support, but failed to support other species. The single allele analysis gave slightly better topological resolution; trimming homopolymers failed to increase taxonomic resolution; the exonic data had a smaller proportion of parsimony‐informative characters. Similar results demonstrating the same dominant topology can be obtained with many fewer markers. A Bayesian concordance analysis provided an overall similar phylogeny, but the coalescent analysis provided drastic changes in topology to all the above. •Conclusions: Our research highlights some difficult species groups in Daucus and misidentifications in germplasm collections. It highlights a useful subset of markers and approaches for future studies of dominant topologies in Daucus.