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Integrated molecular and morphological studies of Daucus
- C. I. Arbizu, H. Ruess, D. Senalik, M. Iorizzo, P. W. Simon, D. M. Spooner, K. Reitsma
- Acta horticulturae 2017 no.1153 pp. 265-272
- DNA, Daucus, USDA, carrots, domestication, genotyping by sequencing, germplasm, marine environment, monophyly, morphometry, single nucleotide polymorphism, transcriptome, Central Asia
- We here summarize and integrate results from recent publications examining the species boundaries, phylogeny, and domestication in the genus Daucus, and outline our future research goals directed towards the goal of producing a taxonomic monograph of the genus. In one study, 94 nuclear orthologs were used to analyze phylogenetic structure in 92 accessions of 13 Daucus species, and an additional 15 accessions of related genera. The cladograms grouped multiple accessions of many different species as monophyletic with strong support, but failed to support some other taxa. Similar phylogenetic results demonstrating the same topology can be obtained with many fewer markers. A near parallel set of accessions were used for morphological analyses of all available Daucus species in the USDA germplasm collection in a common garden, with the data analyzed by morphometric methods. Molecular and morphological analyses separated the 15 accessions of related genera designated as outgroup taxa easily from the Daucus ingroup but, concordant with the DNA results problems are shown in the recognition of 1) the subspecies of D. carota and D. capillifolius; 2) D. sahariensis and D. syrticus; and 3) D. broteri and D. guttatus, with the present data supporting three clades. In a separate study, we investigated the structure of wild and cultivated D. carota with SNPs from transcriptomes, a goal of determining the place of domestication of carrot. The results supported Central Asia as the site of domestication of carrot. Currently, we are using genotyping by sequencing (GBS) data to investigate support for the recognition of the wild subspecies in D. carota, to compliment a recent morphological study that could support only two subspecies. We seek collaborations to expand this study of D. carota by sharing germplasm and DNA, and performing a replicated morphological study in a maritime environment where D. carota subspecies gummifer (sensu lato) grows.