Genetic Diversity and Tests of the Hybrid Origin of the Endangered Yellow Larkspur.

Abstract: Delphinium luteum ( Ranunculaceae), an endangered larkspur, is restricted to two wild populations near Bodega Bay, California. The total number of individuals in these two populations is estimated to be <100. We used allozyme and random amplified polymorphic DNA ( RAPD) markers to (1) assess levels and patterns of genetic diversity in one wild population and two cultivated populations and (2) test the hypothesis that D. luteum is of hybrid origin between D. decorum and D. nudicaule. These data will be used to aid in developing a management plan to conserve the species. The wild population maintains high levels of genetic diversity. Genetic data indicate that both cultivated populations, especially the north Sonoma population, have several allozymes and RAPD markers not found in the wild population and could be used to establish new populations of D. luteum or to enhance the diversity and size of the wild population. The allozyme data did not reveal any fixed differences between D. decorum and D. nudicaule, although allele frequencies of the putative parental populations differed. At these loci, D. luteum resembled D. nudicaule more than D. decorum . Many unique RAPD markers distinguish each of the three species. The diagnostic markers from populations of D. nudicaule and D. decorum were not additive in the putative hybrid, and these data indicate that D. luteum is not of recent hybrid origin. Conservation of the yellow larkspur should include strategies that use the cultivated populations of D. luteum, but hybridizing D. decorum and D. nudicaule to “recreate” D. luteum is not recommended. [ABSTRACT FROM AUTHOR]