Systematics Section / ASPT
Bruneau, Anne , Joly, Simon , Starr, Julian R. , Drouin, Josée Nadia .
What do RAPD, ISSR and AFLP markers suggest about the taxonomic status of two rare North American roses, Rosa rousseauiorum and Rosa williamsii?.
Rosa rousseauiorum Boivin and R. williamsii Fern. (sect. Cinnamomeae) are two taxa endemic and rare in eastern Québec whose taxonomic status is controversial. Morphological characters alone do not clearly differentiate these two taxa from each other nor from their close relative, the widespread R. blanda. Using molecular markers that potentially can differentiate closely related taxa or within species variants, we evaluated the taxonomic status of R. rousseauiorum and R. williamsii, as well as of R. johannensis Fern. and R. subblanda Rydb., two other rarely recognised eastern North American segregates of R. blanda s.l. A total of 88 individuals were studied using five RAPD, four ISSR and three AFLP primer combinations. Despite a high degree of polymorphism, Principal Coordinates Analysis suggests no grouping of individuals that corresponds to taxonomic boundaries, although R. palustris from the closely related sect. Carolinae is clearly differentiated. Mantel tests indicate a significant east-west North American geographical pattern within R. blanda s.l. However, within the province of Québec, no clear grouping is noted based on geographical location and an analysis of molecular variation (AMOVA) indicates that most genetic variation occurs within taxa or within populations, rather than among taxa and among populations. We conclude that R. rousseauiorum and R. williamsii may best be considered glandular varieties of R. blanda that are restricted to the lower St Lawrence, rather than good taxonomic species.
1 - Université de Montréal, Institut de recherche en biologie végétale, 4101 rue Sherbrooke est, Montréal, Québec, H1X 2B2, Canada
2 - University of Mississippi, Department of Biology, University, Mississipp, 38677, U. S. A.
Presentation Type: Paper
Location: Cottonwood A (Snowbird Center)
Date: Wednesday, August 4th, 2004
Time: 2:15 PM