Location: Vegetable Crops Research Unit
Project Number: 3655-21000-058-00
Start Date: Mar 12, 2013
End Date: Mar 11, 2018
For objective 1, information about boundaries of carrot species will be obtained from taxonomic treatments. Characters used for carrot descriptions will be obtained from the literature and used to reassess taxonomic boundaries. For molecular analyses, next-generation “targeted” sequencing technology will begin with a collection of 100 accessions of Daucus and outgroups with 90 orthologous DNA markers to 1) determine the generic limits of Daucus, 2) determine the interspecific relationships within the genus, and 3) determine the genetic diversity within and among the species. The data will be analyzed with concatenated analyses and analyses of individual loci with Bayesian analyses. As this project progresses we will be able to select a subset of the DNA and morphological markers that provide maximum discrimination of the species of carrot (and generic ingroups) that can then be used for more rapid assessment of phylogeny and diversity of a high-confidence, statistically well-supported phylogeny of many more carrot genetic resources present in the US National Plant Germplasm System. This will incorporate additional material collected in field explorations that are of problematic identity. Two monographic treatments are planned, one for wild potatoes of northern South America (Venezuela, Colombia, Ecuador, Peru). For Daucus, a shorter taxonomic treatment is planned to include keys and distribution maps. For objective 2, if germplasm collecting regulations are relaxed for Peru, Solanum collections will be attempted in central and northern Peru. For Daucus, we will inquire of some of the larger world genebanks (VIR, IPK, PGRC, Vegetable centre in Taiwan) which may have Daucus germplasm not yet incorporated into the US collection. Herbarium specimens will be examined for species differences and locality data. Contacts will be made with floristic workers or germplasm curators in foreign countries to initiate collecting for Daucus. Collecting goals and analyses of distributional patterns will be made with GIS software to analyze distributional data to indicate gaps in the collections. The carrot collection has very poor herbarium specimen representation and this plan is to collect 100 herbarium specimens/year with a focus on the wild species. Collecting expeditions will involve cooperators at the National Germplasm Resources Laboratory (NGRL) to identify legal requirements and permit possibilities in different countries and obtain in-country contacts. The PI will present a collecting plan and seek their concordance and support from the root and bulb CGC, and submit collecting proposals to the NGRL and conduct collecting expeditions based on available permits and funding. For objective 3, the PI will accumulate a literature database of references on core collections and diversity assessments of germplasm evaluations, with a primary focus on those relying primarily on neutral molecular markers but also including non-neutral markers, breeders’ opinions or genetic traits, as criteria to establish core collections. He also will assemble literature on the history and development of the core collection concept to reassess the core collection concept.