Do pentaploid hybrids mediate gene flow between tetraploid Senecio disjunctus and hexaploid S. carniolicus s. str. (S. carniolicus aggregate, Asteraceae)?

Abstract Polyploids with odd-ploidy levels may play an important evolutionary role as they enable backcrosses their parental cytotypes. We chose the ploidy-variable Senecio carniolicus species group to address overarching question if pentaploid individuals, which occur at high frequencies in immediate contact zones of tetraploids and hexaploids, mediate effective interploidy gene flow. employed a set approaches including relative genome size (RGS) determination viability tests pollen, RGS embryo, germination experiments seeds, survival seedlings tackle following specific questions. Is pollen individuals viable suggesting regular meiosis spite level? Are five sets chromosomes split into 2.5 compliments, or rather two three compliments? Do crossings between produce seeds seedlings, that pentaploids are independent unit? found stainability is not strongly reduced chromosome complements most often complements. Seeds originating from homoploid show very low whereas hexaploids were more successful. No significant difference seedling was observed among different but emerging 5 x crosses significantly smaller than both, crosses. Altogether, our results indicate mediators flow do form unit.