Piotr T. Bednarek

Studies on genetic changes in rye samples (Secale cereale L.) maintained in a seed bank

The aim of this study was to identify genetic changes in rye seeds induced by natural ageing during long-term storage and consecutive regeneration cycles under gene bank conditions. Genomic DNA from four rye samples varying in their initial viability after one and three cycles of reproduction was analyzed by AFLP (amplified fragment length polymorphism) fingerprinting. Seven EcoRI/MseI primer combinations defined 663 fragments, and seven PstI/MseI primer combinations defined 551 fragments. The variation in the frequency of the seventy-four EcoRI/MseI bands was statistically significant between samples. These changes could be attributed to genetic changes occurring during storage and regeneration. However, the PstI/MseI fragments appeared to be uninfluenced by seed ageing, regeneration and propagation. A combined Principle Coordinate Analysis revealed differences between samples with different initial viability. We showed that materials with low initial viability differ in their response from highly viable ones, and that the changes exhibited in the former case are preserved through regeneration cycles.

Genetic and morphological variation of Saxifraga caespitose L. from Spitsbergen (Svalbard): a preliminary study

Saxifraga caespitose is a taxonomically difficult and poorly studied circumpolar arctic–alpine species. Two different phenotypes with distinct growth habits were collected at two shared localities in Spitsbergen. The natural genetic variation of both phenotypes was tested by AFLPs in order to investigate whether the differences at the phenothypical level are reflected at the genetic level. Low level of molecular variability between “tall” and “short” plants may suggest that the morphological variation could be due to phenotypic plasticity rather than genetic background.

How much of the invader's genetic variability can slip between our fingers? A case study of secondary dispersal of Poa annua on King George Island (Antarctica)

Abstract We studied an invasion of Poa annua on King George Island (Maritime Antarctic). The remoteness of this location, its geographic isolation, and its limited human traffic provided an opportunity to trace the history of an invasion of the species. Poa annua was recorded for the first time at H. Arctowski Polish Antarctic Station in the austral summer of 1985/6. In 2008/9, the species was observed in a new locality at the Ecology Glacier Forefield (1.5 km from “Arctowski”). We used AFLP to analyze the genetic differences among three populations of P. annua: the two mentioned above (Station and Forefield) and the putative origin of the introduction, Warsaw (Poland). There was 38% genetic variance among the populations. Pairwise ФPT was 0.498 between the Forefield and Warsaw populations and 0.283 between Warsaw and Station. There were 15 unique bands in the Warsaw population (frequency from 6% to 100%) and one in the Station/Forefield populations (which appears in all analyzed individuals from both populations). The Δ(K) parameter indicated two groups of samples: Warsaw/Station and Forefield. As indicated by Fus Fs statistics and an analysis of mismatch distribution, the Forefield population underwent a bottleneck and/or founder effect. The Forefield population was likely introduced by secondary dispersal from the Station population.