Relationship between genetic and phenotypic variations in natural
populations of perennial and biennial sagebrush
Abstract
Plant responses to environmental heterogeneity depend on life-history
traits, which could relate to phenotypical and genetic characteristics.
To elucidate this relationship, we examined the variation in population
genetics and functional traits of short- and a long-lived Artemisia
species that are co-occurring in the steppes of Mongolia. Mongolian
steppes represent stressful, waterlimited habitats demanding phenotypic
modifications in the short term and/or genetic adaptation in the long
term. However, detailed knowledge is missing about both plant phenotypic
and genetic differentiation and their inter-relationships in temperate
grasslands. Here, we investigated 21 populations of the widely
distributed subshrub A. frigida and the herbaceous biennial A. scoparia.
Genetic variation was assessed with newly developed Simple Sequence
Repeats (SSRs) markers. Functional trait data was collected from each
individual, and data on environmental variables was collected for each
population. We detected significantly higher genetic diversity in the
biennial species (H E =0.86) compared to the perennial (H E =0.79). For
both species, the largest share of genetic variation was partitioned
within populations (96%). Population genetic structure in the biennial
A. scoparia was weak, while the perennial A. frigida showed some spatial
genetic structure, which was impacted by geographical factors, soil
nutrients, and precipitation. Morphology-related functional traits
(i.e., plant height) were predominantly associated with environmental
variables rather than with genetic variation, while physiology-related
traits (i.e., specific leaf area) were partly genetically determined.