This thesis concerns quantitative genetic aspects of the conservation biology of two rare plants, Scabiosa canescens and Silene diclinis. Particular attention was given to the effects of genetic drift on the structuring of variation in allozymes and quantitative characters, the association between (current) population size and quantitative genetic variation, the level of inbreeding depression in fitness characters and morphology in a small, isolated population, and the effect of inbreeding and intraspecific hybridization on developmental instability. Some of the Scabiosa studies included the more common and widespread Scabiosa columbaria as a reference species. The quantitative genetic structure within Scabiosa canescens and Silene diclinis — low between-population variance combined with high within-population variation — suggests that the current number of individuals is a poor predictor of the adaptive potential of a population and that it takes many generations before random genetic drift reduces the quantitative genetic variation of small, isolated populations. A majority of the allozyme and quantitative characters in Scabiosa canescens and Silene diclinis showed similar levels of population subdivision, suggesting some overlap between the structure of variation in monogenic and polygenic characters. However, there is no reason to believe that this pattern is general. For example, the Silene data indicated a tendency for some characters (leaf size) to be more strongly differentiated than the allozymes, and S. columbaria, a close relative of S. canescens, showed higher population differentiation for phenotypic traits than for allozymes. Hence, as long as high resolution QTL-analyses cannot be performed, conservation strategies based on variation at marker loci may be misleading. The observation that flower fluctuating asymmetry (FA) is sensitive to inbreeding suggests that measures of developmental instability could serve as an early warning system for monitoring the effects of genetic stress in rare, threatened species. However, given the low statistical power in studies of developmental instability, I urge caution in the use of FA as a measure of genetic stress at the individual level, unless several measurements on repeated organs from each individual are available.
Place: Östra Vallgatan 14 (Murbeckssalen Gula huset) Lund
Name: Fenster, Charles B.
Affiliation: Botanisk Institutt, NTNU, Trondheim, N-7034, Norway
The information about affiliations in this record was updated in December 2015.
The record was previously connected to the following departments: Department of Ecology (Closed 2011) (011006010)
- conservation biology
- quantitative genetics
- Scabiosa canescens
- Silene diclinis