Proposals

Zuzana Dočkalová	PhD	"Evolution, reproductive strategy and population dynamics in the Pilosella echioides agg."
Proposal: The project is focused on two closely interrelated topics: A) Diversity of the Pilosella echioides group in the Pannonian Basin (and surrounding hillsides). The Pannonian Basin is well-known for a high diversity of this group, at least partly caused by introgressive hybridization with Pilosella officinarum and P. piloselloides. Four taxa of still unclear taxonomic value can be recognized here. Besides morphology, they differ in chromosome number, genome size, mode of reproduction (apomixis vs. sexuality), ecology (sands, rocks, grasslands, man-made habitats), and distribution pattern. Main objectives are (i) to determine ploidy, genome size, intra- and inter-population genetic variation, habitat preferences of particular taxa and to improve the knowledge about their distribution, (ii) to compare habitat preferences and dynamics of the distribution pattern with the genetic diversity/structure, (iii) to detect the phylogeographic pattern and elucidate the origin of polyploids, (iv) to investigate hybrid/hybridogeneous origin and parental combination in morphologically intermediate taxa. The multidisciplinary approach includes molecular methods (AFLP, cpDNA, isozymes), flow cytometry, morphometric analysis and vegetation analysis (phytosociological relevés of vegetation with P. echoides agg.). The results will enable us to better understand the causes of Pilosella diversity in the Pannonian Basin and, generally, to gain better insight into evolutionary processes in polyploid and partly apomictic complexes and relations between genetic diversity, mode of reproduction, distribution pattern and habitat preferences. B) Population structure and dynamics of mixed-ploidy populations of the P. echoides agg. in Southwest Moravia (Czech Republic), escpecially at the Havraníky heathland with a unique co-existence of four ploidy levels (di- to pentaploids). The main objectives are (i) to detect the small-scale spatial pattern of plants of particular ploidy levels, (ii) to determine fecundity and ploidy level diversity in the seed set of maternal plants of particular ploidy levels with respect to the ploidal composition in the neighborhood (including tests of pollen preferences and foraging strategies of insect pollinators), (iii) to detect in a simultaneous garden experiment the ploidal composition of the progeny from inter-cytotype crosses (in seeds, young and established seedlings) and to compare these data with the germination of seeds in a field sowing experiment. The synthesis of these data will be an important contribution to the knowledge of population dynamics in mixed-ploidy populations.
Zita Ferreira	PhD	"Biosystematics of the genus Andryala L. (Asteraceae)"
Proposal: The main goal of this thesis is to reconstruct the evolutionary history of the genus Andryala L., with special emphasis on relationships between the Mediterranean Basin and Macaronesian taxa, history of colonization, and adaptive radiation. With this study we intend to clarify morphology, taxonomy, and nomenclatural aspects of Andryala L. taxa in its entire distribution area (Europe, North Africa, Mediterranean region and Macaronesia), as well as chromosome numbers. Furthermore, we intend to clarify the origin and phylogenetic relationships among Andryala L. taxa along with a phylogeographic reconstruction of speciation and colonization events, using two chloroplast DNA markers (trnT-trnL and trnV-ndhC), two multicopy nuclear markers (ITS, ETS), and three low-copy nuclear markers (sqs, shmt and gsh1). The morphological analysis will be performed upon a bibliographic revision and a biometrical study of specimens from various herbaria and material collected during field work, mainly at centres of diversity. The biometrical study includes vegetative and reproductive characters with taxonomic value. The numerical analysis of the data will be performed on the complete matrix and on different subsets of the original one, using different similarity or dissimilarity measures and coefficients (Gower similarity coefficient, Correlation coefficient simple matching and Jaccard) according to the character type (binary, multistate and quantitative). Principal Component and Principal Coordinate Analyses will be applied as ordination methods and UPGMA as a cluster analysis method. For each recognized taxon, a list of synonyms, a full description (illustrated with line drawings and SEM images), as well as a discussion on chromosome numbers, geographical distribution (illustrated with maps), ecology and conservation state, taxonomical comments and a list of the studied material, will be included. Diagnostic keys for the taxa studied will be provided.
Karol Krak	PhD	"Molecular phylogeny and evolutionary trends in Hieracium (Asteraceae, Lactuceae)"
Proposal: The genus Hieracium L. is one of the most species rich groups in the plant kingdom. The genus is well known for its taxonomic complexity caused by extensive past and present hybridization in association with variation in ploidy levels and breeding systems, which gave rise to a big variety of morphological forms. Focusing on the subgenera Chionoracium and Hieracium s. str. to complement previous studies dealing with subgen. Pilosella, the principal aim of this work is to establish a molecular phylogeny of Hieracium. We will attempt to cover the entire genetic diversity at a coarse level as a prerequisite for further, more detailed studies. For this purpose sequencing of the chloroplast trnT-trnL intergenic spacer and nuclear ribosomal ITS region will be performed. According to the nowadays-existing trend to use single or low copy genes for phylogenetic analysis, there is an effort to establish such system also for Hieracium. As soon as it will be available, it shall be used in our study as a third marker. Overall genetic vs. morphological variability and results obtained from different genetic markers (cpDNA vs. nuclear DNA) will be compared. The role and impacts of different breeding systems on speciation events and the origin of polyploids shall be inferred. Relationships at infrageneric and infratribal level shall be elucidated; the validity of present sectional and generic classifications and of the existing contradictory species concepts shall be assessed.
Tomáš Urfus	PhD	"Evolutionary mechanisms and relationships among taxa of Hieracium subgen. Pilosella"
Proposal: Basic and intermediate species are usually distinguished within subgenus Pilosella (Hill) Gray. While intermediate species are considered as hybridogenous in origin, the origin and relationships among basic ones is unresolved. (1) The first part of the project comprises phylogeographic study of basic species in subgen. Pilosella according to chloroplast (cp) haplotypes. Studies done till now indicate existence of two major cp-haplotypes groups (Fehrer et al. in press, Fehrer et al. 2005), which may reflect possible distribution pattern of studied basic species during glacial periods. Representatives of all species, which are considered as basic ones will be analysed through the PCR-RFLP of cp DNA. This analysis will test preliminary results based on low amount of samples. (2) The second aim of the study is to reveal the potential allopolyploid origin of basic Hieracium pilosella species by tracing back the contribution of diploid taxa from section Pilosellinae and other potential introgressants. By mean of chloroplast haplotypes and nuclear ITS regions analysis will be determined parental taxa of H. pilosella and by the way wil be studied rate of introgression of other species of section Pilosellina and whole subgenus Pilosella. (3) The variation of cp-haplotypes and nuclear ITS regions of H. pilosella will be compared with variation of diploid relatives (members of section Pilosellinae) to test the possibility of allopolyploid origin of H. pilosella.
Jaroslav Zahradníček	PhD	"Genome size variation and evolution of subtribe Hieraciinae (Asteraceae)."
Proposal: