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Title: Integrated molecular and morphological studies of the Daucus guttatus complex (Apiaceae)

Author
item ARBIZU, CARLOS - University Of Wisconsin
item Simon, Philipp
item MARTINEZ-FLORES, FERNANDO - Universidad De Alicante
item Ruess, Holly
item CRESPO, MANUEL - Universidad De Alicante
item Spooner, David

Submitted to: Systematic Botany
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/22/2016
Publication Date: 6/28/2016
Publication URL: http://handle.nal.usda.gov/10113/62926
Citation: Arbizu, C.I., Simon, P.W., Martinez-Flores, F., Ruess, H., Crespo, M.B., Spooner, D.M. 2016. Integrated molecular and morphological studies of the Daucus guttatus complex (Apiaceae). Systematic Botany. 41(2):479-492. doi: 10.1600/036364416X691948.

Interpretive Summary: Carrot is technically known by the Latin name Daucus carota. This cultivated plant has 20-25 wild species relatives, known by other technical Latin names, one of which is Daucus guttatus. Daucus guttatus is part of a complex of 2-4 very similar species growing from central and northern Italy to the Middle East. Because these species are so similar, no one is sure about how many species there really are, or how to tell them apart. This paper forms a pair submitted to the same journal at the same time, this paper figuring out how many species there are, and how to tell these species apart, by the use of DNA sequence data and morphological data (the outward form of the plant), and the other paper figuring out what are the proper species names of these four species. This paper discovers that there are four species, and the companion paper that the technical names of these species are Daucus bicolor, Daucus conchitae, Daucus guttatus, and Daucus setulosus. This information is needed to clarify the names of these species in germplasm collections, and for other studies using these species in breeding or other studies.

Technical Abstract: In a previous study using 94 nuclear orthologs, we reported the species status of D. broteri and D. guttatus (here referred to as the D. guttatus complex) to be unresolved, partitioned into three clades. In the present study, a subset of ten of these 94 nuclear orthologs with 10,982 bp of aligned length was used to infer the phylogeny of 83 accessions of 15 species and three subspecies of Daucus, with a focus on the D. guttatus complex. A near parallel set of accessions were used for morphological analyses of germplasm accessions planted in a common garden in Madison, Wisconsin. The molecular trees are highly resolved for most of the external and many of the internal clades, grouping accessions of the D. guttatus complex into four clades. Bayesian concordance analysis and coalescent (species tree) approach gave a slightly different topology. Morphological data likewise support four taxa of accessions previously identified as D. broteri and D. guttatus. With historical and herbarium research from a companion study, we identify these four clades as D. bicolor, D. conchitae, D. guttatus, and D. setulosus; internested in these segregates are the phenetically distinctive species D. glochidiatus, D. involucratus, D. littoralis and D. pusillus. Our research redefines species variation in the D. guttatus complex, clarifies species names, interspecific relationships, and discovered misidentifications in germplasm collections. It confirms a new useful subset of nuclear orthologs for studies of dominant topologies of Daucus and morphological characters useful to identify these four species.