Cytogenetic Variability, Pollen Morphology and RAPD Analysis in the Amphiploid Avena barbata x Avena nuda in State of Methylation and Demethylation Genome

The genus Avena belongs to the family Poaceae. Avena barbata (genome AABB)  is a wild, tetraploid species (2n=4x=28), which originally came from two diploid species: A. hirtula and A. wiestii. Avena nuda is a cultivated diploid (2n=2x=14), a genome AA. Avena barbata x Avena nuda is octoploid (2n=8x=56). The knowledge of interaction original genome in hybrid is significantly for studying  a young hybrid population.

The aim of the research was to establish all relationships between parental species and amphiploid in Avena. Many examinations were performed in this work:  GISH (the probe A. nuda) and FISH (the probes are: 25S rDNA Arabidopsis thaliana, 5S rDNA Triticum aestivum, telomeric Ht100.3 Arabidopsis thaliana), silver staining, RAPD analysis and pollen morphology. Moreover DNA methylation patterns of Avena chromosomes and their alteration by 5-azacytidine treatment was researched. The organization of the chromosomes in the mitotic cells and the relationships of the genomes was examined. It was confirmed that karyotype of the hybrid is on a level of the octoploidy. There were frequent chromosomal aberrations–including telocentrics, transposons, allocyclic chromosomes, rings, bridges, cycle of BFB. Extensive studies of the nuclear architecture and the gene expression (genomic imprinting) in this hybrid was documented. A similarity matrix for all species was calculated from their PCR-generated banding patterns. The dendrogram and genetic distance indicate the hybrid is closely related to maternal species.  Pollen grains with two, three and four pores were photographed as a result of the apomictic system of reproduction. It is characteristic for plants obtained by polyploidisation.