Abstract/Summary

Narcissus is a genus of well-known and widely grown garden plants that shows conflict between morphological and molecular taxa. This is compounded by complex breeding programmes that have given rise to over 30,000 registered cultivars, themselves difficult to tell apart. Current identification methods require meticulous study of morphological characters that are available only seasonally. Many of the modern cultivars are a result of hybridization of species from subsection Pseudonarcissi including the Narcissus minor group. Population-level sampling was used to study genetic variation within the N. minor group and to explore the congruence of genetic and taxonomic-morphological boundaries. More than 600 individuals were collected from 56 populations across the geographic range of the species, and a reference living collection for Narcissus established. A combination of microsatellite markers, Sanger and Next-Generation sequencing were used to generate data. Strong geographic structure to population genetics of the N. minor group is revealed using microsatellite analysis and plastid DNA sequencing, that is incongruent with the current taxonomic treatment. Further to this, microsatellite markers were applied to the study of cultivar identification. Successful transferability of microsatellites to cultivated daffodils ranged from 39-100%. Despite the complex interbreeding history of daffodil cultivars genetic patterns recovered were able to distinguish the cultivars studied. As expected, many of these cultivars did not form genetic groups that were congruent with the horticultural daffodil Divisions in which those cultivars occur. However, the utility of microsatellites is demonstrated, distinguishing most cultivars and highlighting mislabelled stocks. Ten new complete plastomes for Narcissus are presented, as a first step in quantifying levels of differences across the genus and the variation among these genomes is compared. The data gathered from genome skimming will provide a valuable resource for marker development for future classification of species and cultivar identification. Overall, both microsatellite and genomic approaches have been shown to resolve taxa however the taxa recovered do not match those currently recognised using morphology.