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Hybridization and polyploidization as significant evolutional aspects in the tribe Triticeae
Urfusová, Romana ; Mahelka, Václav (advisor) ; Escudero, Marcial (referee) ; Štech, Milan (referee)
Hybridization and polyploidization, two vastly important evolutionary mechanisms, have been well studied experimentally within the Triticeae, but the specific consequences of both phenomena under natural conditions remain poorly defined. This is due to the variability of natural populations, whether in species composition, genetic and cytogenetic diversity, abiotic conditions, or their interaction. Each population is thus unique in its own way, with specific parameters of hybridization, polyploidization or reproductive mode. The latter mechanism is both influenced by and influences the former. For example, it is known that self-incompatibility can be broken by the presence of foreign pollen (a phenomenon known as the mentor effect). To study these processes, I chose Central European species of the genus Elymus: E. hispidus, E. repens, and marginally also E. caninus. All three species are allopolyploid. Whereas E. hispidus and E. repens are predominantly allohexaploid, E. caninus is allotetraploid. The former two have been found to hybridize and produce higher polyploid cytotypes. The role of E. caninus has not yet been studied. Methodologically, I have used flow cytometry (analysis of absolute and relative genome size), morphometrics, experimental hybridization, cytology (chromosome counting) and...
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