Phenotypic differentiation of Rhododendron ferrugineum populations in European mountains

Abstract

Rhododendron ferrugineum occurs in the mountains of the Central Europe with large disjunction in geographic range between Pyrenees and Alps and between Alps and Sudetes. We expect that these discontinuities in the species occurrence should involved their phenotypic differentiation, similar as described on the studies of molecular markers. The aim of the study was verification of phenotypic differences between the species populations from the Pyrenees, Alps and Sudetes. We examined characters of leaves and capsules from 13 populations, each represented by 25–30 individuals, using ANOVA, discrimination analysis, principal components analysis and agglomeration on the closest Euclidean distances. Every from examined characters of leaves and capsules except of apex angle of a capsule valve and capsule valve shape differentiated between populations at P≤0.001. Despite, range of character variation differentiating even at the highest level overlapped between populations. The analysis of discrimination, principal component analysis and agglomeration gave similar results indicating differences between populations from Pyrenees, Alps and Sudetes. However, the differences between individuals did not allow distinguish regions. The morphological characteristics of the leaves and capsules allowed to distinguish among populations of R. ferrugineum from the Pyrenees, Alps and Sudetes, and the pattern of their phenotypic differentiation was similar to that described based on genetic markers. The relict population from the Sudetes is phenotypically more similar to the populations from the Pyrenees and the Western Alps than to the spatially closest populations from the Eastern Alps.